Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: HEMIPARASITIC PLANTS INCREASE ALPINE PLANT RICHNESS AND EVENNESS BUT REDUCE ARBUSCULAR MYCORRHIZAL FUNGAL COLONIZATION IN DOMINANT PLANT SPECIES
Review round: 2
Reviewer: 2

Output:
Basic reporting: no comment
Experimental design: no comment
Validity of the findings: no comment
Additional comments: Review on on a revised manuscript 28743
Hemiparasitic plants increase alpine plant richness and eveness but reduce arbuscular mycorrhizal fungal colonization in dominant plant species
Submitted to PeerJ

The manuscript was substantially improved and all major comments were taken into account by the authors. The data analysis was improved to match the structure of the data and to provide statistical tests for the research questions. Also the results are interpreted carefully, taking into account the observational type of sampling. The manuscript can be accepted for publication, I just noted two very minor points which should be solved before final publication (I do not need to see the revised version).

L. 123 - 128: The grammar of this part is wrong and “the presence of Castilleja” is repetitive. Either just move “1)” after “how” (“we measured how 1) the presence of Castilleja…”), or preferably rephrase to: “Here, we measured how the presence of Castilleja 1) was related to plant richness and evenness of the surrounding plant community, 2) would alter community composition, and 3) would reduce dominant plant associations…”

L. 272: presence should not be italic

Petr Blažek

České Budějovice, 28 August 2018


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: MAPPING THE DISTRIBUTION OF SCALE-RAYED WRASSE ACANTHOLABRUS PALLONI IN SWEDISH SKAGERRAK USING ANGLING RECORDS
Review round: 1
Reviewer: 1

Output:
Basic reporting: I have reviewed the manuscript “Mapping the distribution of scale-rayed wrasse Acantholabrus palloni in Swedish Skagerrak using angling records “.
The manuscript maps the spatiotemporal occurrence of scale-rayed wrasse in the Skagerrak area. The authors use underutilized angling records for this matter, which could act as method in coastal monitoring, e.g. for inclusion in MSFD monitoring programs, mapping presence/absence of endangered species. However, I question the utility of the study as there is no clear research objective, structure and discussion of the manuscript.
Experimental design: In general, the manuscript provides little new knowledge on the occurrence of scale-rayed wrasse and/or the use of angling records as a monitoring methodology. Furthermore, the manuscript does not fall within the scope and aims of PeerJ concerning the objective determination of scientific and methodological soundness (see comment above). I would recommend to reject the submitted manuscript.
Validity of the findings: The authors state that the species has been noted as not being native to Swedish waters. However, fishbase.org attests a probability of occurrence of this species in the Skagerrak of 0.6-0.79 and lists the scale-rayed wrasse as native species in SE since 1999. The same source also attests a northern distribution range further up the Norwegian coast unlike the authors conclusion that the occurrence in the Skagerrak areas maps the edge of the species northern distribution.
In the case of historical records, the data sources used could not be verified, e.g. GBIFs data provides no picture. The authors recognize that the mass limit for recording (250-300g) and the small gap size of this species compared to the regular hook and bait sizes used skew the list of records towards larger specimen. Unfortunately, the manuscript fails to address this major limitation in the discussion as these factors not only skew the distribution to larger individuals but may also lead to complete non-reporting of the occurrence of this species as standard angling gear used in these depths is not suitable to capture this relatively small species (25cm ~ 183g according to size and LWR data from fishbase).
Why was no comparison done with commercial sampling data (coastal monitoring programs)? Without comparison it is difficult to be certain about the utility of using angling records for monitoring purposes.
Additional comments: No additional comments


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: MAPPING THE DISTRIBUTION OF SCALE-RAYED WRASSE ACANTHOLABRUS PALLONI IN SWEDISH SKAGERRAK USING ANGLING RECORDS
Review round: 1
Reviewer: 2

Output:
Basic reporting: Please see my comments to authors, but in summary

English is ok
More references especially on angler citizen science could be usefull
Article structure is not super, but can easily be improved.
Experimental design: Please see my comments to authors

There are some issues with the methods and replicability,i.e. in terms of using personal communications as a significant part the data material. But I think the authors can improve this
Validity of the findings: Please see my comments to the authors
IN short I find the conclusion supported by the data
Additional comments: This study use a citizen science approach, i.e. catch records form anglers, to demonstrate that A. palloni is present in areas near the Swedish coast where it has not previously been found. The study therefore give a noce example of how angler citizen science can be a useful contribution for ichthyological investigations, i.e. spatial patterns, of non-commercial fish species.

I find the study relevant and innovative, but I have also some concerns as well as suggestions for improvements that I hope the authors would consider.

In my opinion, the study is based on angler citizen science. Hence in the introduction, I miss a brief general introduction to angler citizen science as such, e.g. how common it is, some examples and its potential, e.g. to describe presence of rare species. I would put this at the very beginning of the introduction as this would lead to the specific aim of the study, i.e. to demonstrate presence of rare species.

Further the introduction lacks study objectives, i.e. “this study aim to demonstrate how angler driven citizen science e.g. through web-based log books where anglers report catches and internet scraping, can further our knowledge about presence of rare species”….or something along those lines.

IN terms of replicability, I see it as a fundamental problem, when “personal communications” and “own observations” constitute a major part of the results. Depending on how you view it, such input can be hard to replicate. In this case it was 12 out of 37 observations i.e. close to 33% of the observations. Still I judge that the personal communication results seems consistent with the rest of the data, so I tend to say it is ok. But this potential problem should be acknowledged in the discussion and supplemented by statements about how you verified these “personal communication” reports.

You discuss temporality over years, i.e. if your results suggest that A. Palloni arrived recently to the areas, or if it has been present the whole time, but anglers have not fished for them. I think that you can not conclude anything about temporal patterns, so a conservative approach would be to conclude that the study simply demonstrate that A palloni is now present in the area (and probably well established), but the study can not be used to illucidate any temporal patterns.

On the other hand you do not dicuss temporality within a year, which I suggest you consider to do. In table 1 clearly more reports are from the summer period, which probably reflects that this is the time of year where the anglers fish for A. palloni. But maybe there is reports of anglers fishing outside summer without luck that could allow discussions/speculations about whether A. palloni migrate in and out of the area on a seasonal basis? Just a suggestion.

At several places in the introduction, the methods and results the authors tend to engage in discussions. This should be moved to the discussion section. See specific examples below.

Having said all this I think that the wording of the conclusion presented in the ms is very precise and could be used as a guideline for the authors during their revision. The wording in the conclusion contains pretty exact what can be concluded from the study, i.e. that angler citizen science in terms of angler reports and records (whats the difference btw?) can be a useful contribution for ichthyological investigations of non-commercial fish species. I agree with the conclusion and think iits supported by the data presented. Therefore, if the paper is properly revised, it can stand as a nice illustration of the usefulness of angler citizen science.

To sum up
The Introduction needs more work and should include study objectives. A lot of the present text in intro, rmethods and results should be moved to the discussion. Finally the discussion should be expanded (to include a discussions of;

-Temporal stability (between years and within years)

-Reliability of the data and shortcommings, including the role of personal communication data in the overall study and how they were verified, the likelihood that even more fish were present but not sampled/presented (which is now placed in methods and results e.g. lines 64-67 & 98-100), did anglers misidentify and there is probably more.

-Some of the present discussion can be integrated and reused, but I would suggest a rearrangement of the discussion into a more clear structure.
The conclusion is nice and clear 

Specific comments
Line 41-45. Move this to the discussion, where you can use it to argue that chances of misidentification was low. Having said that you argue on line 118-120 that misidentification is indeed possible. So please be clear about this in the discussion.
Lne 64-67. This should be moved to the discussion section, where it can be included in a section discussion shortcomings of the study, e.g. that anglers reporting is skewed towards larger specimen as they probably do no capture the smaller ones due to gear choice.
Line 72-73 you state that all records was verified by the authors. Please explain how you did this in case were data was provided as “personal communications”?
Line 90-92. This should be moved to the discussion as a part of where you discuss temporality, i.e. if your results suggest that A. Palloni arrived recently to the areas, or if it has been there the whole time but anglers have not fished for them. I think that you can not conclude about this, so a conservative approach would be to conclude that the study simply demonstrate that A palloni is now present in the area, but the study can not be used to illucidate any temporal patterns. IN other words it is likely that the sudden emergence of A.palloni in the angler reports is a result of behavioral changes of anglers towards being specimen fishers and that the word of A. palloni as a potential species have been spread. Hence angling pressure have increased and more A. palloni have been reported
Line 98-100. This should also be moved to the discussion and used to support that the presented results are likely to be conservative, i.e. that you have received personal communication reports about even more A. Palloni, but not included these as they did not contain sufficient information.
Line 118-120. In the introduction you state that misidentification is unlikely…but here you state the opposite. Please expand this discussion and be precise. Is misidentification likely or not and how could if have affected your data.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: MAPPING THE DISTRIBUTION OF SCALE-RAYED WRASSE ACANTHOLABRUS PALLONI IN SWEDISH SKAGERRAK USING ANGLING RECORDS
Review round: 2
Reviewer: 1

Output:
Basic reporting: The authors have done a very good job to improve the quality of the manuscript, e.g. adding a clear study objective, adding context to the issues related to data collection of data-limited species, specifying the genesis and records of the first occurrence of A. palloni in Swedish waters, widening the discussion to include seasonal occurrence, issues on species identification, and the use of citizen science data.

The issue on species occurrence and the different standards used by the different data sources (e.g. fishbase vs SAA) were addressed by the authors in the response to the reviewers and partly in the revised manuscript. In the response to the reviewers the authors give a more thorough description on the limitation of fishbase as distribution mapping database. This should be included in the discussion as this is useful information to judge the validity and quality of such data. I leave this decision however with the editor.

In the text I have identified a few typos, and made a comment where the wording is vague or sentences are too long. After these small changes I suggest the article is ready to be published.
Experimental design: no comment see above
Validity of the findings: no comment see above
Additional comments: No additional comments


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: MAPPING THE DISTRIBUTION OF SCALE-RAYED WRASSE ACANTHOLABRUS PALLONI IN SWEDISH SKAGERRAK USING ANGLING RECORDS
Review round: 2
Reviewer: 2

Output:
Basic reporting:
Experimental design:
Validity of the findings:
Additional comments: Review of “Mapping the distribution of scale-rayed wrasse Acantholabrus palloni in Swedish Skagerrak using angling records”.

I got this manuscript after revision by other reviewers. I have read the comments given by them and agree with much of the critizism.
The manuscript gives an overview of the knowledge of a fish species that is poorly known and difficult to study. It shows that it is not an occasional guest but a species that really belongs to the Swedish fish fauna. The manuscript is relevant and interesting and I recommend it to be published with revisions. However, I had problems with the DISCUSSION. It must be structured in a better way. I have made an analysis of the current structure (contents of each paragraph) and give suggestions for improvements. Remember, one paragraph should in principle contain only one aspect or topic. Some of the paragraphs contain more than one topic and these topics come in a somewhat illogical order.

ABSTRACT
Line 15: Delete: “In this paper, “ and “tentatively”.

DISCUSSION, contents of paragraphs:
§1, line 152: General conclusion/introduction to the Discussion.
§2, line 155: This paragraph is a mixture of different aspects: lines 155-162 and 171-173 contain comment on the results in this study. Lines 162 (Speculatively …) to 171 (… 2016) is a speculation about climate effects but is not based on any references. These aspects should be sorted into different paragraphs.
§3, line 174: Also this paragraph is a mixture of various aspects. Lines 174-176 covers seasonality related to bias within the method; Lines 176… is about an additional record in November and how it is related to the hydrography; Lines 179… is a general discussion about the species’ abilities for dispersal; Lines 189… is about the value and limitations of angling data, as well as potential future studies.
§4, line 197: habitat and recent changes in fishing methodology.
§5, line 211: the value of Acantholabrus palloni for anglers, commercial fisheries and aquaculture.
§6, line 223: the value of citizen generated data and comparison with ornithology.
§7, line 239: existence of additional observations.
My suggestion is that the contents of the discussion is reorganized in the following order:

General conclusion/introduction to the Discussion.
Relate to the results in this study.
Bias in the methodology
Changes in fishing methodology during the last 150 years.
Distribution in the Skagerak area related to the hydrography.
Biogeography of the species (It has an enormous distribution, from Gabon to Norway, and exists also around mid-Atlantic islands (Acores, but also Madeira and Canary Islands, Source: FishBase). This indicates ability for dispersal. The first sample in Sweden (Cedhagen & Hansson 1995) was a juvenile. It must have been born in the vicinity of the sampling station.
“Climate change” is a kind of mantra expressed in various situations, typically without any deep thoughts about it. The warmest decade of the last century, on a global scale as well as in Skagerak, was the 1930’s, but this is seldom reported. (It was ice-free up to the North Pole). A summary of the old oceanographic data in the Gullmar fjord where was published by Svansson (1984). The climate anomaly data during the 1930’s for the Gullmar fjord is available there. • The species was sampled near Flekkefjord, southernmost Norway, already in 1869 (Öberg 1870). This find was referred by Liljeborg (1891) and Stuxberg (1894). It was during the last part of the so called “Little Ice Age”. Andersson (1964, 3. Ed.) wrote that the species was found a few times from Kristiansand to Stavanger (The species was already mentioned in the first edition of this book from 1942). A recent invasion of the species in the region because of climate change during recent time (say the last 40-50 years) can therefore be ruled out.
The authors refer to Kullander & al. (2012). This is a very good book but it does not include all knowledge, or all details, up to that year. The oldest reference in the manuscript is Svanssons oceanography paper from 1975. This is fine, but the oldest reference about fish was published in 1990 and most of the sources are probably accessible on Internet. This is a very limited source of information, particularly when writing about faunal changes in a historical perspective. Young scientists must understand that it is important to consult also older, analogous references in printed form, such as books. The university library in Stockholm, where the first author works, has one of the absolutely most complete scientific libraries on this planet, particularly natural sciences within the period 1880-1960. It can match corresponding libraries in, e.g., London, Paris and St. Petersburg. The authors have no excuse not to use it.
I guess that the lack of previous reports of Acantholabrus palloni could be a parallel to that of the overlooked fish species Thorogobius ephippiatus (Holm & Mattson 1980) from the same area.
References
Andersson, K.A. (Ed.). 1964. Fiskar och fiske i Norden, vol 1. 3. Ed. Natur och Kultur, Stockholm.
Holm, T. & Mattson, S. 1980. Thorogobius ephippiatus (Pisces) found on the west coast of Sweden. Sarsia 66: 87-88.
Liljeborg, W. 1891. Sveriges och Norges Fauna. Fiskarne. Upsala, W. Schultz.
Stuxberg, A. 1894. Sveriges och Norges Fiskar jämte inledning till fiskarnes naturalhistoria, (3): 354. Albert Bonniers Förlag, Stockholm.
Svansson, A. 1984. Hydrography of the Gullmar Fjord : Gullmarsfjordens hydrografi. Meddelande från Havsfiskelaboratoriet, Lysekil, (And references to primary data from the Gullmar fjord since the year 1900 in its references).
Öberg, P.E.W. 1870. Acantholabrus Couchi Cuv. Et Val., en för Skandinaviens Fauna ny fiskart. Öfversigt af Kongl. Vetenskaps-Akademiens Förhandlingar 1870, No 4: 391-395.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: TRAIT-BASED PREDATION SUITABILITY OFFERS INSIGHT INTO EFFECTS OF CHANGING PREY COMMUNITIES
Review round: 1
Reviewer: 1

Output:
Basic reporting: The manuscript deals with an interesting subject of using knowledge existing knowledge on the prey spectrum of demersal fish from the literature that is generalized through a trait-based approach to investigate changes in invertebrate prey communities through time and its potential effects on the availably of suitable prey for the investigated fish species.

The paper is in parts well written but other parts are very difficult to understand as the authors fail to explain concepts in detail often using language that without additional clarifying sentences cannot be followed. The overall structure of the ms is also difficult to follow. The paper is in essence writtten as a method paper which describes the use of existing knowledge on prey-predator relationships to analyse the potential impact of changes in prey communities in a time series. The reader has however to wait until the method section before she or he can conceptually understand what the papers new method is about. The authors should provide a conceptual description of the method they are introducing already in the introduction.  While detail about calculations can go into the method sections there is a need to provide a brief yet complete overview of the methodology they are introducing. This can be followed with the description on what data this method was applied to and what indicators were calculated to describe the specific aims of the study with respect to the long-term data series analysis.

Similarly, the abstract equally lacks a clear language and structure (indicated in general comments). Here the authors explain what can be done with their approach without fully explaining conceptually what their approach entails i.e. taking prey spectrums from published literature, translating them into traits categories to generalize them i.e. eliminating taxonomical concept to describe the suitability of prey communities through time.

The authors should take care to introduce new concepts and to explain those with simple, yet concise language. As an example, the authors talk about “binary predation links” extracted from the literature. Here what they mean is that they used studies reporting on prey spectrums and that they used these to determine the presence or absence of a species/taxa as pey for the fish species forming part of the study. Similar jargon is used throughout the paper and should be avoided. I have tried to highlight as many of these sections as possible in the general comment part of the review.

Overall the literature used is correct although there are important recent papers missing which report on anthropogenic modification of benthic prey communiteis and its effect on fish feeding (Hinz et al. 2017; Scientific reports 7 (1), 6334; Hiddink et al. 2016, Journal of applied ecology 53 (5), 1500-1510; Johnson et al 2014 Proceedings of the Royal Society) as well as older literature (Hinz et al. 2005, Journal of Fish Biology 67, 125-145). With respect to the background this could be enlarged with the mentioned references and others that report about the human induced or natural changes in prey communities and its potential consequences for predatory communities. This aspect is touched upon but within the introduction but could benefit from being supported by examples (one or two sentences would be sufficient here). Also, the abstract should contain the general rational and justification of the study which in general well described in the introduction.

The aim and hypothesis of the paper is not clear. The paper introduces a new method and applies it to a long-term data set. The analysis is then used to interpret the ecological data. Thus, the paper is not an evaluation of the method and it does not aim to show the superiority of the newly introduced methods over traditional species-based prey analyses (at least there is no such section attempting a formal evaluation of the method). I therefore would recommend that the paper clearly states the ecological aims of the paper with respect to the long-term data more specifically. The new method gets introduced to solve ecological questions with the ecological question being the focal point rather than the method. This confusion about what the paper aims to achieve also might have lead to the difficulty in structuring the ms in a way it can be easily read and interpreted.
Experimental design: The paper presents primary research in its scope; however the research questions is not well defined, and the paper appears to be unable to decide if it wants to be a method paper or present an ecological analysis. I appreciate that the authors aimed to do a bit of both, but my recommendation would be to lower the emphasize in both introduction and discussion with respect to the methods capabilities and focus more on the ecological results. The only way the methods can be appreciated is if the results show clear and interpretable results that make sense in an ecological context. Only through presenting a thorough interpretation of the results the reader can evaluate if the method introduce can help interpret trends and provide new insights. In the current form the authors try too hard to sell their idea instead of letting the results speak for themselves. e.g. the abstract, the introduction and other parts of the paper read a lot of:  we demonstrate; we evaluate, we show…. novel framework etc.

The method section unfortunately lacks a lot of detail and it is therefore often difficult to follow what precisely has been done. This is often not helped by using jargon or not explaining concepts fully using plain language, one example among others being “binary feeding links” (see above comments). I would recommend that the authors expand on their Figure 1 to also include all other previous steps i.e. dataset using literature data to compile prey spectrums for predators an also include the time series analysis. A schematic flow chart could replace Figure 1 that include all steps of the analysis making it easier for a reader to follow the steps of the data treatment. Also, I would consider labelling the indices in a way within the text that reflects what the abbreviation summarises.  species-specific trait-based Diet Spectrum = DS and I would rename S to RS = food Resource Suitability furthermore I would distinguish between RScommunity/species.

The GLMM formulation contains two variables I found difficult to picture in the analysis performed. While I can appreciate that the location is being introduced as a random effect I can not understand why both fish species and traits were introducing as random effects in the model. The identity of species in my mind is irrelevant for this type of analysis and equally the traits. Both were used in the traits approach presented to calculate S for each station and year, why would they subsequently need to be introduce them into the model? The authors need to remove these or explain the need to include these variables as random factors. This applies to both the GLMM performed on the community S and well as on the species S.

Within the functional diversity section, I would recommend that the authors are using the term prey traits diversity, as in my opinion the assumptions about functionality are difficult to justify.

The description on the predation link structure using interaction network analysis is lacking sufficient detail to be understood. I still feel unable to follow what has been done here despite reading the section several times. Equally the results puzzle me; how can the authors conclude anything about prey selectivity with respect to specialization or general feeding and plasticity if they have not analysed the stomach content of fish. All that is being monitored is prey availability changes through time based on literature extracted diet spectrums. Therefore, I cannot follow conclusions such as those put forward e.g. in the abstract “that changing functional compositions of prey can alter the predator-prey linkage-structure by modifying predator specialisation toward available food resources”. What I suspect has been done, is that the authors looked at the number of prey species available within each site and year i.e. potential prey diversity, however, I am not sure due to the language used within this section and the lack of detail to explain concepts. I would recommend rewriting this section using simple plainer language.

The reporting of results is also in parts lacking in detail. Some of the results are loosely summarised without going into the necessary detail representing a lack of technical standard (see general comments). For example, the authors fail to report on the grouping of fish with similar feeding traits in detail. When resporting on the increases in food suitability it is at the beginning not clear what the results refer to the the whole community or individual species. Furthermore there is a lack of bridging sentences or analyses that could have connected the indivdual results reported logically. For example there are several speceis that did not show increasing food suitabilty. It would be interesting to know why these did not respond and what traits were responsible for the lack of response or the reverse. e.g. T. quadriconis appears to have an affinity to soft shell. Such details and depth of anlysis are missing from the ms but would have been useful in providing an in depth understanding of the sytem. This lack of detailed reporting is later also reflected in the discussion which remains at large superficial with respect to the interpretation of the ecological findings of this study (see also general comments).
Validity of the findings: The data presented appears of good quality and the approach used certainly is interesting and has merit. The statistical analysis due to the above mentioned methodological questions could not be fully evaluated. In principle the methods chosen appear sound, but the authors need to address the above mentioned questions. The interpretation of results and conclusions presented could be greatly improved. The interpretation of the ecological results as already mentioned is in my opinion too superficial. As a reader I really wanted to understand the reasons why suitability for some species increased for some species but not for others and which prey traits or trait combinations were responsible. Furthermore, it left me with the question if fish communities in real life responded to these changes, after all the authors present a potential model. Did the fish species for which an increase in prey suitability was detected increase in population size for example or did condition of these improve. I believe only by providing detailed contextual ecological interpretation of the results can the new method introduced be to some extend evaluated and appreciated. In its current form the authors present a new method of data treatment in which the case study is presented as a side story. I would recommend to the authors to rewrite the paper with the focus on the specific ecological question of their case study and to present the method as a tool to get new insights.

I think the paper would also benefit from a section in which the limitation of the introduced approach is discussed. The whole analysis is based on the prey spectrums extracted from the literature for each fish species based one or two existing studies. Studies analysing prey composition from stomach samples can be highly variable and the things ingested at the time when the study was conducted may not reflect necessarily typical prey. Also, often stomach content studies focus on a particular life phase of fish as ontogenetic changes in prey preference can occur. Prey also is found in different proportions in the stomachs indicating prey preferences this has not been considered by this analysis, as no weighting was provided towards preferred prey and only presence and absences were considered. Thus, rare prey items that may be ingested by accident or circumstantially while consuming other prey will have had the same weighting as a dominant frequently ingested prey type. As a minimum requirement I would think that the authors need to discuss these limitations or provide evidence why these  are unlikely to influence the results.
Additional comments: The abstract should be restructured as in its current form it’s difficult to follow. I would recommend starting the abstract with the justification of why this study was conducted following the structure of the introduction i.e. why is it important to understand the effect of prey changes to predators considering all the anthropogenic changes occurring today. This should be followed by pointing out the problem of absence of data. After that the method can be introduced in two sentences. Here simply describe the steps you used i.e. prey spectrum from literature, translating prey spectra into trait spectra per species, application of this data to long term changes in benthic communities to establish prey suitability through time and space. Now the application of the method to the specific dataset can be explained. Followed by demonstrating the ecological results. The conclusions should be based on the ecological data with an end sentence justifying through the results the introduced method.

Line 34-35 Not sure how this is possible …..how can predator specialisation be modified if you are using existing literature data and are only exploring the avaialbity of suitable prey??
The introduction is overall ok but from line 87 it become difficult to follow hereafter.

Line 87-94 this section is a bit out of place the information given should form part of the discussion or alternatively you need to work better on an ecological question resulting from your previous results. Thereafter I would recommend starting to introduce your new analytical approach. Less detailed compared to the method section but describing the principle pillars of your approach. Here you have to make sure that you use simple language instead of using jargon. I would follow this up with a clear definition of ecological questions you want to answer. Currently there is a lot of general talk about the method you will introduce and I don’t think this is very useful here.line

Line 151 -160 this section needs more clarity a lot or jargon is used and detail is missing to be understood by an unsuspecting reader. Terms like binary feeding links should be avoided. That these are extracted from past literature needs to be made clear here its not enough just to refer to the supplementary material. I would recommend modifying figure 1 to include all the different data types used and connect those within  flow diagram to help the read understand how you treated the data.

Line 163-164 gets in essence repeated in line 172-173. This whole first paragraph I would recommend rewriting as it is difficult to follow

Line 165-167 explain better that CWM is in essence the “potential prey resource avaialbity”.

Line 175 mention the name of the index before you introduce the formula.

Line 186-187 explain what your response variable is I assume its S. I would recommend writing the model you are using if full for both the community and the species level.

Line 188 Why were fish species and traits introduced as random effects?? These were necessary to calculate S so why introduce them here?

Line 198 Why traits as random factor?

Line 200 while the term functional diversity has been around for a while I think unless some functional properties can easily be assumed I would recommend the authors to use the term prey trait diversity. I think it’s more appropriate for the data presented here.

Line 216-227 this section I am afraid I do not understand also after reading and looking at the results I am not sure what is being presented here. What is meant by an interaction network? This section is full of jargon an lacks simple language and detail to be understood.

Line 229-237 This very general summary of the results is not very useful. Please describe results in detail which species did have similar traits and describe groupings. Detail which prey traits where specific to which group of fish.

Line 244 if exposure was not significant it could be removed from the model to give a simpler more robust model.

Line 267-285 I am not able to comment on this section as I could not follow from the method what has been done here. But in general, there appear various parts e.g. line 275 which would belong into the method section. I would recommend rewriting this section in conjunction with the method section so it can be understood by the reader without any prior knowledge or reading required.

Line 290-299 This first paragraph does not add much to the paper and can be removed. Generalized summaries of results are not very useful. The discussion should start with line 301

Line 334 Describe temporal change in the availability of suitable prey which species did benefited and through the increased in which prey traits. I think it would be useful aiming to explain what these changes are based on. There are some explanations in the discussions, but I feel they are currently not concisely presented. Furthermore, as a reader I would like to know have had any effect on fish populations in particular for those species that where you found to have a very significant increase in the avaialbity of suitability prey. Currently there is some very general speculation about an general increase in fish biomass but I think a more complete presentation of results and a more detailed ecological discussion are needed here that include the fish species presented by this study.

Line 340 benthic biomass may decrease due to an increase in fish biomass (i.e. feeding pressure please read Hinz et al 2017 or Hiddink et al. 2016 etc.). As fish populations can limit benthic communities there is an inherent problem with the newly introduced method i.e. prey and potential prey spectrums as analysed here can be modified by through the fish themselves (top down control). This would need to be discussed along with other limitations of this approach.

Line 387-404 unable to comment on this section as I was unable to understand what analysis was performed here.

Line 407-412 I would recommend using the conclusion to summarize your ecological results and to demonstrate that the new method was able to highlight new insights you otherwise would not have attained. Here it is important to clearly name these advantages of your method. In this way readers can evaluate for themselves the usefulness of your approach.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: TRAIT-BASED PREDATION SUITABILITY OFFERS INSIGHT INTO EFFECTS OF CHANGING PREY COMMUNITIES
Review round: 1
Reviewer: 2

Output:
Basic reporting: The sentence structure and use of words/grammar needs to be addressed throughout the article. For example I suggest:

Line 18 – should ‘predatory’ be replaced with ‘predator’?
Line 36: ‘on community levels’ be replaced with ‘at the community level’
Line 42: ‘reorganizations of communities’ be replaced with ‘community reorganizations’
Line 57-62: The first sentence is specifically relating to prey suitability and does not lead well to the second one which is more general. Rewrite either one or both sentences and particularly consider what ‘this perception’ is relating to
Line 63: ‘straightforward’ to be one word rather than two.
Line 64: ‘it’ be replaced with ‘this approach’
Line 71: it does not make sense to put ‘especially’ at the beginning of this sentence
Line 82: the ‘while it is applicable to all predatory-prey systems’ does not make sense here. this needs to be reworded
Line 82-86: this sentence needs to be reworded in order to make sense. I also suggest breaking it down into two separate sentences
Line 95: ‘mean’ be replaced with ‘means’
Line 97: ‘especially’ be replaced with ‘particularly’
Line 103: ‘we set out’ be replaced with ‘we aimed’, ‘if’ be replaced by ‘whether’
Line 107-110: reword this sentence as it does not currently make sense.
Line 120: reword the end of the sentence as it does not make sense. Reword the beginning of the sentence to make it clear where the fish were included for example ‘In our analyses we included’
Line 124: ‘of’ be replaced with ‘to’
Line 132-133: ‘of’ be replaced with ‘from’, reword the sentence
Line 134-137: redo the grammar in this sentence
Line 137: ‘have been’ be replaced by ‘were’
Line 153: ‘pray’ be replaced by ‘prey’
Line 186-190: ‘if’ be replaced by ‘whether’, remove ‘has’, put a comma after ‘sites)’, break this sentence into two sentences
Line 195: add ‘varied’ or ‘changed’ after ‘species’
Line 209: ‘sample site’ be replaced with ‘site sampled’
Line 210:’if’ be replaced with ‘whether’
Line 217: ‘build’ be replaced with ‘built’
Line 219: ‘may’ with ‘can’
Line 248: reword sentence as doesn’t make sense
Line 250: ‘instance’ be replaced with ‘example’, ‘shows’ be replaced with ‘showed’
Line 270: spelling for ‘absolute’
Lie 274: remove gap between ‘/ generality’
Line 279-280: add a comma after ‘values’ and after ‘flesus’
Line 283-285: reword this sentence as it doesn’t make sense
Line 289: remove ‘-term’
Line 306-308: reword sentence as doesn’t make sense
Line 318-320: there is repetition between ‘this is in line’ and ‘supporting our claim’, I suggest removing one of these phrases
Line 321: remove the first ‘the’ and consider rewording the sentence
Line 329: ‘compared to its’ be replaced by ‘in relation to prey’
Line 361: reword the sentence as it doesn’t make sense
Line 364: remove ‘the’ and reword the sentence – ‘for predators’ does not make sense in regards to how this sentence is written
Line 374-376: reword the sentence as doesn’t make sense
Line 377-381: reword the sentence – consider breaking it into two separate sentences
Line 393-395: reword the sentence as doesn’t make sense
Figure 2 caption: ‘after’ be replaced with ‘by’
Experimental design: Line 98: please explain what is meant by ‘binary’ when this term is first mentioned
Validity of the findings: Line 290-291: this sentence is repeating the introduction, reword as for discussion
Line 304-306: this sentence is repeating the introduction, reword as for discussion
Line 416: a conclusion should not include something not include any new concepts. In this case neither ‘conservation management’ nor ‘ecosystem assessment tool’ are mentioned previously in the article. If you want to include these here they need to be mentioned in the introduction. They could also possibly be mentioned in the abstract.
Additional comments: I found this research interesting and thorough and believe that it makes a good contribution to its field. However the sentence structure, grammar and use of wording needs to be addressed throughout the article before it is suitable for publication.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: TRAIT-BASED PREDATION SUITABILITY OFFERS INSIGHT INTO EFFECTS OF CHANGING PREY COMMUNITIES
Review round: 2
Reviewer: 1

Output:
Basic reporting: Line 91-95: Sentence is too long and therefore difficult to follow.
Line 95: Should ‘however’ be replaced by a different word here?
Line 142-145: This sentence needs rewording e.g. should there be an ‘a’ between ‘as’ and ‘model’?
Lines 346-354: This sentence needs rewording overall, it doesn’t make sense in english.
Line 394 replace ‘non’ with ‘none’.
Line 487: Should ‘changes’ be reworded to ‘changed’.
Experimental design: I am happy with the authors response to reviewers.
Validity of the findings: I am happy with the authors response to reviewers.
Additional comments: Overall I am generally happy with the response to reviewer comments.
However, I still have a few comments, relating to sentence structure/word choice, that I believe need addressing before the manuscript is ready for publishing.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: EXPERIMENTAL FOOD SUPPLEMENTATION INCREASES REPRODUCTIVE EFFORT IN THE VARIABLE ANTSHRIKE IN SUBTROPICAL BRAZIL
Review round: 1
Reviewer: 1

Output:
Basic reporting: This is a nice experimental paper that will advance our understanding on tropical bird nesting strategies and fragmentation effects. In general I think this is a great paper is well written and experimentally test all hypothesis supporting some and providing new and interesting effect that fragmentation have on tropical bird nesting success.
Experimental design: Well done, however it was not clear if they also place the same containers where the mealworms where place, but empty, in the control territories.
Validity of the findings: The results and analysis are robust and appropriate for the experimental design and data.
Additional comments: In general I suggest expanding in some ideas in the discussion:

1) It is clear that food availability have an effect but is also clear that effect is stronger on smaller fragments less variation (at least in renesting intervals). I suggest that the authors should expand on this.

2) If you have data on female body mass it will be nice to know if female body mass differ between fragments, this may be also an important factor when considering reproductive effort.

3) It will be worth mentioning if the females that were successful and re-nested did it because the juveniles died or because the male took care of the nestlings.

4) Bi-parental incubation is common among antbirds (I suppose this species have bi-parental incubation), thus it will be relevant mentioning if male and female nesting effort change among fragments (if you have the data). I am just think that it could be possible that males help more in larger fragments than in small fragments due to higher natural food availability thus investment per nesting attempts will be lower, allowing individuals to expand breeding season, increase re-nesting attempts, etc. This could be also an alternative hypothesis that may explain your results. Males help more when there is more food.

5) I think is also important to discuss the possible causes of the variation observed in Figure 3 (Daily survival Rate in small fragments) and Figure 4 Renesting interval large fragment).

Specific comments

Page 11, Line 197: Do you have data on juvenile survival of the nest that were successful and females re-nested? If you don’t have detail data, I think it will be worth mentioned if you think if the juveniles died or the male took care of them by them self.

Page 13, line 245-247: This is a strong statement that I don’t think can be generalize for tropical species. The increment of clutch size with food abundance may be true for species were clutch size vary naturally (as you showed in this study), but there are studies with food supplementations that haven’t observed an increase in clutch size. Furthermore, I am not aware of a good example of clutch size increment with food supplementation in species that have fix clutch size (like most tropical bird species). If you do please cite those studies here and clarify, but if you don't I suggest avoiding making general statement here. Because your results cannot be generalize for most tropical birds that have a fix clutch size.

Page 13, Line 266-267: There are many paper that have conducted food experiments with interesting result that should be cited here, I suggest to expand on references search. I suggest to read and consider including Conway and Martin 2002, Sanz, J. J. 1996, Londoño et al. 2008 and Cucco & Malacarne (1997) as these references can add and expand to the current discussion on nest activity and food availability. Also all but (Conway and Martin 2002) conducted food manipulation and Skutch's papers cited here did not. Furthermore, some of the references that I suggest here showed that nesting bird with supplemented food do not always change the amount of trips to the nest. Thus, I think that studies that have not conduct food manipulation experiments will be helpful to make your point in this section.

Page 14, Lines 268-269: I suggest to site more recent papers See also Cox et al. 2012 The Auk, 129(1):147-155. 2012. Cox et al. 2012 Landscape Ecol 27:659–669.

Page 26: I suggest removing Figure 1.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: EXPERIMENTAL FOOD SUPPLEMENTATION INCREASES REPRODUCTIVE EFFORT IN THE VARIABLE ANTSHRIKE IN SUBTROPICAL BRAZIL
Review round: 1
Reviewer: 2

Output:
Basic reporting: No Comments
Experimental design: I found the research questions and predictions poorly described, especially with respect to the interactive effect of predation risk, fragment size and food availability on bird reproduction.
In addition, the sample sizes used in each treatment (control and fed-nests) are not clearly stated, so that I have troubles to evaluate the accuracy of the statistical analyses (i.e. with respect to fragment sizes).
Validity of the findings: Due to apparent very small sample sizes (i.e. number of nests) in the smallest forest fragment, and lack of spatial replication in fragment size categories (i.e. 3 study fragments: one of 24ha, one of 112ha and one of 214ha), I am sceptical about the actual possibility of testing the effect of fragment size and its interaction with the food treatment on bird reproductive parameters.
Additional comments: COMMENTS TO ROPER ET AL.
The present manuscript describes the effect of experimental food supplementation on some breeding components of a tropical passerine, the variable antshrike. The study has been conducted in three forest fragments of varying sizes, and the reproductive response of birds is compared among fragment sizes. I found the study interesting, especially because there are very few food supplementation experiments of that type at low latitudes and food allocation strategies in tropical birds still remain poorly understood. However, I found very surprising that this thread was not used at all in the manuscript (nothing about food allocation and reproductive strategies in tropical birds is discussed in the Introduction and Discussion (what are the predictions, how such strategies are predicted to differ compared to birds living in temperate areas?). In addition, the manuscript suffers from some serious drawbacks, including overall lack of structure (especially in the Introduction), wordiness, poor English syntax, unclear working hypotheses and statistical methods. This unfortunately renders the manuscript hard to follow. I list my comments below, in more details.
The Introduction suffers from a serious lack of cohesion, which creates some confusion about the main objectives of the study. Even the last part of this section, where the authors attempt to define their working hypotheses, is weak. The Introduction does not really match the expectations of the reader and the hypotheses that can be tested with the available dataset (but this feeling may be caused by the difficulty I had to follow the ideas and the logic of the statements). For example, throughout the whole Introduction, the authors attempt to explore varying scenarios involving interacting effects of food availability, predation risk and fragment size on varying components of bird reproduction, but the aim section only talks about testing the “importance of food abundance”: “we predict that food supplementation will result in increased reproductive effort, which may be manifest as increased number of nesting attempts, reduced intervals between nesting attempts, greater nesting success and combinations thereof”. No prediction is given for the effect of the two other factors and their interactions. I agree that these interactions are complex, but you need to make an effort to clarify the logic in your statements throughout the whole section. What are your expectations based on the literature, and most importantly, what can you actually test with your study design and the data in hand? This should be clearly summarised in the Aim section. I also recommend repeating concisely each question or hypothesis when you describe the statistical analyses, since you present several analyses, one for each of the four breeding responses recorded (number of nesting attempts, length of renesting interval, breeding season length, nesting success).
It is not clear what hypotheses you intend to test with respect to predation risk. Because you stress (legitimately) in the Introduction the interactive effect of forest fragment size and predation risk and present nest survival data in three fragments of varying sizes, my first impression was that you used fragment size as a surrogate of predation risk. Is that correct? If yes, do you assume that birds dwelling in small forest fragments face higher predation rates compared to larger fragments due to larger perimeter/area ratio (i.e. the boundary effect, which is by the way not mentioned at all), fewer nesting sites, less heterogeneity in the landscape structure and lower food availability? Nest survival data from control sites (presented in Figure 3) suggest it might be the case. Nothing is said on predator density or even predator identity in the different fragment sizes; is this data available?
To my opinion, the authors have missed some very important concepts around life-history and reproductive strategies in tropical birds. Resource allocation trade-offs of tropical birds are still poorly known. While it has been suggested that tropical resident birds should invest extra energy into self-maintenance rather than immediate reproduction (e.g. Ricklefs & Wileski 2002 Trends Ecol. Evol.), other studies have suggested that birds living at low latitudes are more plastic in advancing their timing of breeding, and therefore increasing their breeding success, than birds living at high latitudes, where factors other than food constrain life-history parameters (see e.g. Scheuerlein A, Gwinner 2002 J. Biol. Rhythms, and Ruffino et al. 2014 Front. Zool.). There are very few experimental studies testing the effect of food supplementation/limitation on the reproductive strategies of birds living in tropical areas, and to me this study has the potential to dig into this poorly known research area. The authors should devote a significant part of the Introduction/Discussion to these concepts.
Moreover, more should be said about the originality of the species. It is apparently a poorly known species and this should be stressed already in the Introduction. Why would you study this particular species? Is it of conservation concern?
As a consequence of the major points listed above, I strongly suggest rewriting most of the Introduction.
I found very hard to track sample sizes and there is nothing more frustrating to search for this information throughout the whole text. At the first mention, on line 97, it is only indicated that “about half of the pairs” were supplemented (how many exactly?). Then, on line 153-155, it is written that a total of 103 nests were found and monitored, but only three pairs were monitored in the smallest fragment, and eight pairs in the two others (which equals to 19 pairs in total, and not 103). Does the figure 103 nests include nests surveyed during 2001 and 2002)? Later, on lines 176-177, it is mentioned that “none of the seven nests were successful in the small fragment”, compared to five out of 63 in the medium-sized one, and 17 out of 29 in the largest one (which equals to 99 nests in total, and not 103).
It seems that the number of nests monitored in both the control and treated samples of the small fragment is very small (probably <10, maybe <5? Given the figures in Table 1, I tend to conclude that N = 1 for control nests and N = 2 for fed nests). If this is the case, I seriously doubt that these data would be useful in any of the analyses including Fragment Size as an explanatory variable. We can actually see from Figure 3 that the confidence intervals of mean nest survival rates in the small fragment are huge! In addition to very few forest fragments used in the analyses (N = 3) and a lack of spatial replication of each size category, I am very sceptical about the actual possibility of testing the interactive effect of fragment size and food availability on bird reproduction. If the sample size of the small fragment is too small, an alternative option is to drop those nests, merge the data from the two largest fragments and drop the fragment size hypothesis (since, anyway, you only have little power with the data in hand).
The statistical analyses are poorly described. I had a hard time understanding the structure of the models used. The information is patchy and it should be made clearer what variables are used in what models to answer what question.
On lines 211-212, it is written that the effect of fragment size on clutch size could not be tested due to low sample size. However, on lines 128-129, it is mentioned that clutch sizes were compared among fragment sizes with log-likelihood ratio tests. Did I miss something here?

Minor comments
Some examples where the structure of the text should be improved (i.e. lack of cohesion between sentences): Line 26-28: what is the link with predation risk mentioned in the previous sentence? Line 44-49: I don’t follow the logic between the two parts of the sentence. Lines 50-53: “When predation rates are high, renesting is even more important for annual reproductive success”: this sentence suggests that birds tend to renest more often to overcome high predation rates. However, the following sentence claims the opposite. Line 130-132: I really don’t understand this sentence.
Line 25: Ruffino et al. (2014-Front. Zool.) have recently published an updated meta-analysis on the effect of food supplementation on bird reproduction
Line 29-31: I don’t understand the rationale here (“because of its influence on both the number of nesting attempts and individual nest success”). “When breeding seasons are long”: are you referring here to multi-brooded species being more likely to respond to increase in food abundance, as was suggested by e.g. Svensson (1995-Anim. Behav.)?
Line 30: should correct to “…food limitation may affect annual…”
Line 50: should be corrected to “…between fragment size and both predation risk and food abundance…”
Line 74: Should the Latin species authority appear at the first mention of the Latin species name (i.e. in the Introduction)?
Line 85: should correct to “… size, are all very poorly known,…
Line 99: do you mean “domestic (animal?) cages”?
Line 100: what is the density of feeders provided by fragment (i.e. how many per active nest?). This information is lacking to evaluate whether or not the abundance of food was enough to trigger a reproductive response.
Line 104: Did you make any observations of intruders (from control areas or non-target species) feeding on the mealworms? This is important information in order to evaluate the efficiency of the food treatment.
Line 111-112: what do you mean by their interactions?
Line 112: should read “covariate”
Lines 114-119: unnecessary statements. If needed, the predictions can be rephrased in one short sentence.
Line 123: what do you mean by “The other variables are continuous”? Which ones? The ones that you cite are count variables (renesting intervals: number of days, number of renesting attempts).
Line 126-127: why not analysing also the effect of food on the renesting intervals of successful nests and comparing the results to those of failed nests?
Line 136: do you mean “covariates” by “correlated variables”? Were renesting intervals and breeding season length included in the annual productivity models?
Line 146-152: This part should be reduced and moved to the Methods (although I am not entirely convinced that it should be kept at all). This cannot be part of the results since there were no breeding birds and therefore no treatment. Same remark for the 2000 data that were not included in the analyses (lines169-173).
Line 180: 112ha instead of 105ha
Line 246-247: “all but two of the 25 3-egg clutches followed food supplementation”. Do you mean that only two of the 3-egg clutches observed were from non-supplemented areas?
Line 247: should read “two largest fragments”
Line 245-263: These two paragraphs are confusing and would need to be restructured with more logic between ideas and arguments. From the clutch size analyses, your results suggest that birds dwelling in the largest forest fragments are more food-limited (they increase their clutch size) than those from the small fragment (they don’t). However, you conclude the opposite on lines 249-251 or do you mean that food quantity was not enough in the small fragment to overcome a greater food stress or predation risk compared to the larger fragments?
Figures: please add sample sizes above each bar
Figure 6: the unit of the y-axis label should be “number of pairs.year-1”


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: SOCIALITY GENES ARE ASSOCIATED WITH HUMAN-DIRECTED SOCIAL BEHAVIOUR IN GOLDEN AND LABRADOR RETRIEVER DOGS
Review round: 1
Reviewer: 1

Output:
Basic reporting: See below
Experimental design: See below
Validity of the findings: See below
Additional comments: This paper is a follow up to the same group’s interesting demonstration from a genome-wide association study that two SNPs from chromosome 26 are associated with human-directed social behavior in laboratory beagles (Persson et al., 2015).

The present paper extends those earlier findings by examining gene-behavior associations for the previously identified SNPs in two breeds of retrievers (Golden- and Labrador-retrievers). Genetic data is also presented for wolves; and mention is briefly made that border collies and Shetland sheepdogs were tested but results are not presented because “no significant results were found” (lines 352-353).

Overall I feel the paper has many interesting parts but they do not add up in the present draft to a satisfying whole. Sometimes what is presented comes across as off-cuts found on the lab’s cutting-room floor rather than a sustained piece of science.

In total five groups of canids receive some kind of consideration in this paper:
1.	Wolves (from Swedish wildlife parks, no indication of the location of the original wild populations from which these animals were derived, not even the continent.) 19 individuals; genotyping; no behavioral work.
2.	Golden retriever dogs (Swedish registered purebreds) 61 individuals; genotyping and behavioral testing on unsolvable problem and temperament test (not reported here). Half of the golden retrievers received an intranasal dosing with oxytocin prior to the behavior tests.
3.	Labrador retrievers (Swedish registered purebreds) 100 individuals distinguished as 52 common-type and 48 field-type (i.e. bred for field work or not); genotyped and behavioral testing on unsolvable problem and pointing test.
4.	Shetland sheepdogs; 28 individuals “tested and genotyped in same manner as the Labrador and golden retrievers” Data not presented.
5.	Border collies 23 individuals “tested and genotyped in same manner as the Labrador and golden retrievers” Data not presented.

It is a great shame that no two types of canids are tested exactly equivalently (at least of the three types for whom results are presented – wolves, goldens and Labrador retrievers; the Shetlands and Border collies may have been tested identically to one of the breeds of retrievers, but their results are not presented beyond the comment: “the results do not contradict the findings in Labrador and golden retrievers” l. 351.) This makes it difficult to draw over-arching conclusions, and, indeed, the paper is rather thin on conclusions beyond generalities that the SNPs are associated with social behavior in the golden and Labrador retrievers – and alleles differ in frequency between the dog breeds and the wolves. They conclude that “This suggests that selection of favourable alleles in the genomic region of the SNPs has been an important part of dog domestication.” But I can’t see how they can conclude this. The genotype-behavior associations presented here appear to be different in the 2 breeds of dog for which fairly full results are reported – and even between the field and common Labrador retrievers. Consequently, the selection observed here could just as likely be due to selection in the creation of these breeds (likely less than 200 years ago) than in the original process of domestication (likely over 15,000 years ago).

The Figures only show significant findings which means that different behavior-genotype associations are presented for the golden and the Labrador retrievers. For the Goldens, associations of SNP1 with frequency of contact with the experimenter and frequency and duration of contact with the owner are presented. For Labrador retrievers and the same SNP1, associations of duration of owner gaze and mean pointing are presented. This means that a reader cannot affirm that the same trends of gene-behavior relationship are present in both dog breeds.

For a paper of this kind I would prefer to see all the gene-behavior relationships even those that are not significant. This would make it easier to conclude whether the patterns of relationship generalize across breeds or are different for the different breeds.

One other major point. In the Abstract and Introduction, the authors set up the argument that “During domestication, dogs have evolved human-directed social skills allowing humans and dogs to communicate and cooperate.” (Abstract) – and - “since during 15 000 years of parallel evolution, they have developed unique human analogue social skills (Hare & Tomasello 2005; Topal et al. 2009; Wang et al. 2016).” Lines 59-60.

I don’t think this line is defensible any more. Hare & Tomasello and Topal et al are now getting out of date as citations. Wang et al. 2016 does not present behavioral data.

The human-directed social skills cited have been demonstrated in numerous non-domesticated species and subspecies (e.g., Gacsi et al 2009; Giret et al., 2009; Hall et al., 2011; Pack & Herman, 2004; Range & Viranyi, 2011; Smet & Byrne, 2013; Schloegl et al., 2008; Scheumann & Call, 2004. Tomasello & Call, 2004;  Udell et al. 2008;  von Bayern & Emery, 2009). Thus they are not coupled to domestication.  Insofar as there may exist human-direct social skills uniquely in dogs these may be the consequence of the unique environment in which pet dogs are reared, not anything about their genetics. Furthermore, insofar as there may exist genetically-influenced human-directed social skills uniquely in dogs, these may be due to recent selection in the formation of dog breeds within the last 200 years and not selection leading to domestication of wolves >15,000 years ago.

Overall I would like to see a revision of this paper that presents all the results from all the breeds, whether significant or not and which allows assessment of whether the observed genotype-behavior relations are possible evidence of a signal from domestication, or from the creation of these modern breeds of dogs. A paper like that could be very interesting to many readers.

Finally under major points – there is at least one other group addressing this issue in a related way: vonHoldt et al 2017 ought to be discussed here.

1.	Minor points

Table 1. Gaze is not operationalized (it is defined as “gaze”). Needs more concrete operationalization of this behavior.

A sketch of unsolvable task needed

L 231-232. No choices need to be recorded somewhere; we cannot have trials that are lost from the analysis. And was the trial repeated until a choice was made? If so, the total number of trials needs to be included in the analysis.

Figure 3B. I don’t think the y axis scale is %.

References:
Giret, N., Miklósi, Á., Kreutzer, M., & Bovet, D. (2009). Use of experimenter-given cues by African gray parrots (Psittacus erithacus). Animal Cognition, 12(1), 1–10. https://doi.org/10.1007/s10071-008-0163-2
Gacsi, M., McGreevy, P., Kara, E., & Miklosi, A. (2009). Effects of selection for cooperation and attention in dogs. Behavioral and Brain Functions, 5(1), 31. https://doi.org/10.1186/1744-9081-5-31
Hall, N. J., Udell, M. A. R., Dorey, N. R., Walsh, A. L., & Wynne, C. D. L. (2011). Megachiropteran bats (Pteropus) utilize human referential stimuli to locate hidden food. Journal of Comparative Psychology, 125(3), 341–346.
Pack, A. A., & Herman, L. M. (2004). Bottlenosed dolphins (Tursiops truncatus) comprehend the referent of both static and dynamic human gazing and pointing in an object-choice task. Journal of Comparative Psychology, 118(2), 160.
Range, F., & Virányi, Z. (2011). Development of gaze following abilities in wolves (Canis lupus). PloS One, 6(2), e16888.
Scheumann, M., & Call, J. (2004). The use of experimenter-given cues by South African fur seals (Arctocephalus pusillus). Animal Cognition, 7(4), 224–230.
Schloegl, C., Kotrschal, K., & Bugnyar, T. (2008). Modifying the object-choice task: Is the way you look important for ravens? Behavioural Processes, 77(1), 61–65. https://doi.org/10.1016/j.beproc.2007.06.002
Smet, A. F., & Byrne, R. W. (2013). African Elephants Can Use Human Pointing Cues to Find Hidden Food. Current Biology, 23(20), 2033–2037. https://doi.org/10.1016/j.cub.2013.08.037
Tomasello, M., & Call, J. (2004). The role of humans in the cognitive development of apes revisited. Animal Cognition, 7(4), 213–215.
Udell, M. A. R., Dorey, N. R., & Wynne, C. D. L. (2008). Wolves outperform dogs in following human social cues. Animal Behaviour, 76, 1767–1773.
von Bayern, A. M., & Emery, N. J. (2009). Jackdaws respond to human attentional states and communicative cues in different contexts. Current Biology, 19(7), 602–606.
vonHoldt, B. M., Shuldiner, E., Koch, I. J., Kartzinel, R. Y., Hogan, A., Brubaker, L., … Udell, M. A. R. (2017). Structural variants in genes associated with human Williams-Beuren syndrome underlie stereotypical hypersociability in domestic dogs. Science Advances, 3(7), e1700398. https://doi.org/10.1126/sciadv.1700398


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: SOCIALITY GENES ARE ASSOCIATED WITH HUMAN-DIRECTED SOCIAL BEHAVIOUR IN GOLDEN AND LABRADOR RETRIEVER DOGS
Review round: 1
Reviewer: 2

Output:
Basic reporting: The authors did an excellent job securing a relatively large sample of golden retrievers and Labrador retrievers to examine whether there are associations between genotype and human-directed social behaviors in these breeds. Based on information provided in the Introduction and elsewhere, I am unclear on why the authors separated dog behaviors directed at the owner vs. experimenter and question whether it was necessary to analyze behaviors directed at owner and experimenter separately.

Overall, the study is well written.

The tables and graphs were well-done. However, since only behaviors associated with significant findings were presented in the graphs and the table associated with the models was only included as supplementary material, it was difficult to identify commonalities and differences between the two breeds studied.
Experimental design: The authors used solid experimental methods in their work with the two primary breeds that participated in the study; however, given that the golden retrievers and Labrador retrievers were recruited to participate in different studies, the presentation of findings is not as seamless as it could be (e.g. one breed of dogs received intranasal oxytocin and the others did not). I have provided suggestions below regarding ways to improve the presentation of findings regarding each breed. For example, I suggest including Table S1 in the actual paper rather than as a supplement. Also, more details are needed regarding how reliability of the behavioral coder(s) was assessed.

Lines 113-116: Perhaps the authors could add something in this section regarding how the wolf samples were ethically sourced? Did the procurement of the wolf DNA fall under the same permit as the one for the dog study (51-13)? Did anyone at the wildlife parks provide consent for the samples to be used?

Lines 131-132: What is meant by “wild captives or had been praised at the wildlife parks”? Were “wild captives” wild-caught? For the wolves that had been raised at the wildlife parks, for how many generations had their relatives been in captivity (and, presumably, engaging more with and relying more on humans than wild wolves)? Is it reasonable to assume that the captive wolves are representative of the wild wolf gene pool, or is there evidence of in-breeding or a severely limited gene pool in the captive population?

Lines 145-148: Based on the information provided in this paragraph, it seems it may not be worth further discussion of the Shetland sheepdogs or border collies in the Results or Discussion. I agree that it makes sense to share those findings as supplemental material, but if the authors felt the samples were too small to draw conclusions, I don’t think it is appropriate to make inferences about those breeds (e.g. “possible association in two additional breeds”—lines 383-384).

Lines 155-162: Given the authors’ previous findings of an association between OT and human-direct social behavior, and given the focus of the current study on human-directed social behavior, it seems the main effects of OT treatment and any interactions between OT treatment and genotype should be reported within the manuscript rather than as supplemental information.

Lines 208-210: Who coded the videos? Was inter-rater reliability established? I agree that the ethogram (Table 1) is necessary, but I think it would be good to mention within the body of the paper that the behaviors scored focused on proximity, physical contact, and gaze in relation to the experimenter and owner.

Lines 305-341: It appears that each of the six behaviors was tested as the dependent variable for SNP1 and SNP2, which means 12 models were examined—although only the statistically significant findings are reported in the text. Was any statistical correction made for running so many models?

Also, due to the number of models run and differences in significant findings for golden retrievers and Labrador retrievers, I find it challenging to identify ways in which findings from the two breeds complement each other and ways in which they diverge. It would be helpful if the authors could address the similarities and differences more explicitly in the Discussion.

Additionally, what are we to make of owner-oriented behaviors vs. experimenter-oriented behaviors? Did the authors hypothesize genotype would impact engagement with owners and experimenters differently? I don’t see any mention of this in the Introduction. If there were no hypotheses about whether dogs of particular genotypes would engage differently with owners vs. experimenters, might it make sense to combine engagement with owner and experimenter? This would reduce the number of models run, as there were be three dependent variables (gaze, proximity, and physical contact) rather than six.

Line 343: So that the reader can readily view all findings, significant and non-significant, I suggest including Table S1 within the actual paper rather than as a supplement.
Validity of the findings: I am unsure what to make of the findings. The authors ran six models for SNP1 and six for SNP2 for golden retrievers and for Labrador retrievers. The way the data are presented, it is difficult to identify similarities between breeds regarding the relationship between genotype and behavior, and I’d like to see the authors provide more of a synthesis in the Discussion regarding commonalities and differences between the findings for golden retrievers vs. Labrador retrievers.

Lines 348-354: In the Methods section, the authors mention data for border collies and Shetland sheepdogs was limited and that “they were only included as supplementary data” (line 148). Thus, I think this paragraph is unnecessary.

Lines 427-429: Why do the authors believe this behavioral difference is due to selection rather than differences in the types of experiences had by field vs. common type Labrador retrievers? In other words, might owners of field Labradors be more likely to encourage contact seeking than owners of common Labradors?

Lines 435-443: This does not read as a cohesive paragraph and is not a strong way to wrap up the Discussion. It would be better wrap up the Discussion by describing the study’s main strengths and limitations and clearly connect the value this research holds for understanding dog evolution as well as human social behavior and disorders.
Additional comments: Line 27: Change “associated to” to “associated with.”

Lines 45-47: Consider beginning the Results section of the abstract with these sentences about genetic variation (or lack of genetic variation) in the dog breeds and wolves tested.

Line 91: Consider rephrasing “social disorders in humans such as…” as “human social disorders such as…”

Lines 92-94: This sentence is vague and lacks clarity.

Line 176: I am unsure what is meant by “one and the same for each of the breeds.”

Line 177: Change “experimenter that” to “experimenter who.”

Line 231: Just double-checking that the dog only had 3 seconds to make a choice? This seems like a rather short time period, but then again, dogs can be quite fast.

Line 241: I am familiar with the term “whole blood” but not “full blood.” Are the authors referring to “whole blood”?

Table 1: Were “zone” and “physical contact” mutually exclusive behaviors? The way the zone behavior is defined, a dog could be in physical contact (within one body length) and simultaneously in physical contact.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: SOCIALITY GENES ARE ASSOCIATED WITH HUMAN-DIRECTED SOCIAL BEHAVIOUR IN GOLDEN AND LABRADOR RETRIEVER DOGS
Review round: 2
Reviewer: 1

Output:
Basic reporting: The concerns I had with the initial submission have been addressed, and I have no additional concerns.
Experimental design: The concerns I had with the initial submission have been addressed, and I have no additional concerns.
Validity of the findings: The concerns I had with the initial submission have been addressed, and I have no additional concerns.
Additional comments: The concerns I had with the initial submission have been addressed, and I have no additional concerns.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: STRUCTURAL AND FUNCTIONAL ANALYSIS OF THE ROLES OF THE HCV 5′ NCR MIR122-DEPENDENT LONG-RANGE ASSOCIATION AND SLVI IN GENOME TRANSLATION AND REPLICATION
Review round: 1
Reviewer: 1

Output:
Basic reporting: This manuscript analyses the “open and closed conformation” of the 5´UTR of HCV viral RNA extended up to nt 174 of core, hence including domain VI. First, by using SHAPE methodology, the authors confirm the existence of reactive/unreactive nt within domain VI (suggesting unpaired/paired nt, respectively). Then, the wt RNA, and several mutations disrupting and restoring the hairpin of domain VI, as well as the target sequences of miR122 at the 5´end, are used to explore the role of the closed and open conformation of the 5´UTR in translation and replication of HCV RNA in HuH7 cells (miR122 positive) or HeLa cells (miR122 negative). The authors conclude that domain VI is involved in the formation of the open and closed form of the HCV IRES, as previously reported. However, no effect was observed on translation or replication in the presence or absence of miR122. They conclude that the involvement of domain VI in translation control should be related to a still unknown event, different than formation of closed and open conformation. The manuscript is well written, despite the results are not increasing our understanding of the involvement of the “open and closed conformation” of the HCV IRES region in the biology of HCV RNA.
Experimental design: The authors present a simple scenario concerning two mutually exclusive HCV RNA structures predicted to adopt open and closed conformations (l. 104-108), which involve two miR122 binding sites at the 5´end, and at the 3´end, the base of stem-loop VI. However, it has been previously shown that the HCV 5´UTR encompassing the IRES element adopts flexible, dynamic conformations in solution (i. e., Perard et al). Comments to a flexible nature of this region regarding the interpretation of the results obtained by SHAPE are lacking.
According to the results stated in l. 307-311, the authors could not map the accessibility to S1 miR122 binding site (nt 1-20). Therefore, the conclusions regarding the open and close conformation are not valid, as only the accessibility to SLVI is accurately determined. This comment also applies to the sentence in l. 348-349 (… despite the inability to measure the reactivity of nt within the S1 site). Moreover, figures 3 to 5 show the changes in reactivity pertaining nt 427-507. The authors refer to same NMIA reactivity and structural predictions as data not shown for a variety of unmodified templates. As it stands, this sentence is not informative. The authors should show the SHAPE reactivity of the entire 5´UTR.
Validity of the findings: see above
Additional comments: see above


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: STRUCTURAL AND FUNCTIONAL ANALYSIS OF THE ROLES OF THE HCV 5′ NCR MIR122-DEPENDENT LONG-RANGE ASSOCIATION AND SLVI IN GENOME TRANSLATION AND REPLICATION
Review round: 1
Reviewer: 2

Output:
Basic reporting: The work presented by Bentley and co-workers, represents an interesting structural and functional study of the long range association between domain SLVI and the S1 miR122 binding site within the 5’ end of the hepatitis C RNA genome. They confirm the existence of such interaction but they question its functionality. However they point out a functional role of domain SLVI as regulator of the viral translation by a still undefined mechanism. This is a very interesting observation which is worthy to pursue.
The manuscript is well written, clear and concise. The references provided are appropriate in general. However this reviewer suggests adding in line 76 (introduction) more recent reviews covering the cited topic, if any, and in particular would be interesting for readers to see references of recent reviews focusing in the functional role of RNA structural domains in the HCV genome.
1. A formatting correction, a space should be added in between the number and the units all throughout the text (e.g., 4 h; 5 nM; and so on)
2. The word “conformation” is misspelled several times, instead “confirmation” is written. Authors might want to carefully revise all the manuscript.
Experimental design: The work is well-defined and executed, and the structural analysis is clear and convincing. The experimental work is described is sufficient detail.
It would be helpful for the readers that the authors add in figure 1B a schematic representation of the pJFH1-luc-trans:ΔNS5B, which has been previously described by the authors (Tuplin et al., 2015). Although they provide the reference it would help to see it in comparison with the other constructs used in this work.
Validity of the findings: The conclusions are well sustained by the provided results; however there are a couple of issues that are worthy to be addressed.
1. Results shown in figure 3, clearly suggest that in the absence of miR122 the LRA between S1 site and the 5’ end of the SLVI domain takes place leading to the formation of the closed conformation as it is interpreted by the authors (lines 343-348). However these results are not in good agreement with the data shown in the following section as it is stated in its heading (line 359) saying that the LRA is favored ONLY when … SLVI structure is disrupted.
Authors should provide an explanation of this apparent discrepancy.
2. The results are based on the use of sequence mutants that induce the desired structural changes in the base of the SLIV stem and/or the lack of binding at the S1 site. The phenotypic analysis of these mutants (effect on viral translation and replication) allow the authors to draw the conclusion of the lack of functionality of the switch between the “open” and “closed” conformation and further to propose a non-described translation regulation role for the SLVI domain. However, the authors have not considered the potential pleiotropic effect of structural rearrangement induced by mutants that may hide the functional role of LRA.
In addition they have not discussed the potential phenotypic role of the S2 miR122 binding site in the context of a mutant S1 site.
Additional comments: No additional comments


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: STRUCTURAL AND FUNCTIONAL ANALYSIS OF THE ROLES OF THE HCV 5′ NCR MIR122-DEPENDENT LONG-RANGE ASSOCIATION AND SLVI IN GENOME TRANSLATION AND REPLICATION
Review round: 1
Reviewer: 3

Output:
Basic reporting: I recomned the authors to improve significativelly the correspondence of their findings to already published work and their claims to be limited to their results. They have to introduce the limitations of the methodology employed in their work, I provide some lines. And absolutely not, they can not, contradict previous work with a -data not shown-.
For the rest it is OK.
Experimental design: The authors bases their experimentation in a quite new technique, which has the nice name of SHAPE. This is being widely used. But is it has some shortcomings, and specially for the problem the authors are trying to solve.

- In difference for the original description fo the strucutre of stem-loop VI, whcih was performed accordign well stablished standarts, using RNAse V1 and ssRNAses, here the authors have swicht to a methodolgy of much  lower euristic value:
- it is an indirect technique: what is read is the blocking of a primer extension of  a cDNA reaction, and not the RNA itself.
- it suffers of polarity problem, the strucuture can only be mapped from 3' end.
- it has no way of falsability, in contrast to RNAses A, T1 their reactivities should not coincide with RNase V1 and viceversa, and if this happens, then there is an interesting situation to analyse.
- If two or more structures are present at the same moment these will be promediated at each base, so there is no way to ascertain if this is the case.
Validity of the findings: The results are fine, the mutational analysis greatly support previous biochemical analysis by Diaz-Toledano. it is a high complementary analysis. The authors should not try to ignore the work of Diaz-Toledano. The authors should distinghuish what is a computer prediction, from what has been already probed by several bicohemical methodologies, and also distinguish the history of findings. The first long range annealing propossed in HCV is that of 5' and stem loop VI. This was deduced by two groups in parallel, Honda&Lemon and Kim et al, but no one of this groups did structural analisis , they deudced the structure from functional or phylogentic analysis, so their findings are the first but indirect respect to the structure. The first structure determination of the LRA is that of Begurisitain et al, by direct detection of the LRA duplex, who also showed at least 80% of the form closed in respect to the opened.
Then the first in demosntrate opening by miR122 is Diaz-Toledno et al. Some of the prhases of authors that say that this structure has been proposed, they should say probed. Please review all the paper.
I do not understand why the results in vivo may not reflect the in vitro LRA formation.
Additional comments: -There is a substantial contradiction between the expectations from the title and the end of the abstract. -Despite the authors do not find correlation between Open/Closed forms, with translation or replication, this can not be extended to the global viral phenotype.  Leibniz the German matematician said: when we negate something we are wrong. I wil try to rethink the results and avoid the negative proposal.
- The second big parapraph of the introduction, is too large and it is not quite relevant for the paper, this are other Long range interactions, mostly out of the focus.


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: STRUCTURAL AND FUNCTIONAL ANALYSIS OF THE ROLES OF THE HCV 5′ NCR MIR122-DEPENDENT LONG-RANGE ASSOCIATION AND SLVI IN GENOME TRANSLATION AND REPLICATION
Review round: 2
Reviewer: 1

Output:
Basic reporting: OK
Experimental design: OK
Validity of the findings: OK
Additional comments: OK


Instruction: You are one of the reviewers, your task is to write a review for the article. You will be given the title of the article, the number of the round in which the article is located, and your order among the reviewers.

Input:
Title: UNIMODAL HEAD-WIDTH DISTRIBUTION OF THE EUROPEAN EEL (ANGUILLA ANGUILLA L.) FROM THE ZEESCHELDE DOES NOT SUPPORT DISRUPTIVE SELECTION
Review round: 1
Reviewer: 1

Output:
Basic reporting: • The article is generally clear and well written and has only one unexpected word choice; “plumpier” may perhaps better be written as “more plump”. That may well be a matter of choice as some others would prefer “plumper”. Here, however, I would suggest “less slender” as eels with their “anguilliform shape” [here in the locomotory sense as coined by Breder 1926] aren’t “plumpy“.

    • The scientific background literature of the Introduction is reasonably complete. I could only find one important omission of relevance to the MS:

Muschick et al. 2011. Adaptive phenotypic plasticity in the Midas cichlid fish pharyngeal jaw and its relevance in adaptive radiation. BMC Evolutionary Biology, (2011) 11:116. (https://doi.org/10.1186/1471-2148-11-116)
(https://bmcevolbiol.biomedcentral.com/articles/10.1186/1471-2148-11-116).

The article by Muschick et al. (2011) is far more relevant than the cited general articles on bats (Saunders & Barclay 1992) or the ecomorphology of crocodylians (Iijima et al 2017). The other articles cited refer to interpretations of ecomorphology (Hahn & Cunha 2005, Narayani et al 2015, Norton & Brainerd 1993) are both relevant and interesting, but remain interpretative and not really conclusive.

The Muschick et al. (2011) article demonstrate using a controlled experimental design how different food items change head morphology. Much of the current manuscript’s text appears to assume the reverse, that different head morphologies lead to different feed strategies. I am not convinced that is the case here. A shift in perspective would permeate how the wordings of the entire manuscript are chosen and written as well as how previous research may and can be interpreted.

This is a very important difference in causality and must be addressed far more clearly by the authors in the current manuscript.

    • The structure of the article conforms to an acceptable format as per the journal’s standards.

    • Figures are relevant to the article, even if Figure 6 has diminutive fonts and is hard to read.

    • There are no raw data, but the abundance of graphs should make them superfluous.

    • The manuscripts is self-contained with results relevant to the four (sub-)hypotheses tested.

    • There are four research questions in this manuscript which are reciprocally relevant to each other.

.
Experimental design: • It is my impression that this is original primary research within the Aims and Scope of the journal.

    • The four stated research questions are well defined, relevant and meaningful on their own. Later, the paper states that the results challenge the results and conclusions of several other recent papers. However, the Introduction may perhaps be better divided into paragraphs better reflecting the backgrounds of the four distinct research questions; the Discussion already is divided as per those research questions. Still, as explained below, they may also be seen as four sub-hypotheses of another more encompassing question about “disruptive selection”. That question would also be of more general interest.

    • One should note that the ecological and evolutionary interpretations suggested in other articles and duly referred to in the Introduction also are discussed by the authors. Still, they are apparently not considered “research question” even if they make up much of the discussion. Here I think of

        ◦ resource polymorphism
        ◦ resource selectivity
        ◦ phenotypic plasticity
        ◦ disruptive selection

In fact, it may be the most important conclusion of this paper that they have no evidence for disruptive selection as has been suggested in other papers. One of the main arguments here is then that they have examined only one river system and that there is no bimodality. Other articles have compared allopatric eels, from two different river systems where a pooled bimodality then rather reflects the differences between rivers (biotic/abiotic) than any “disruptive selection”. That, I find, is an important aspect of this manuscript and should perhaps even be reflected in the title:

“Unimodal head width distribution of the European eel (Anguilla anguilla L.) from a single river drainage does not support disruptive selection”.

    • It is my impression that the reliability of the presented results is high. The number of observations is 272 which the authors themselves suggested (at line 250) might be on the low side. Yet, given the simplicity of the research questions it is my conviction that the reliability remains high. Had this been a multivariate analysis it would likely have been too few observations, and, an initial power analysis should then have been performed as well. Here that shouldn’t have been needed.

    • The research has been conducted in conformity with the prevailing ethical standards in the field, explicitly referring to that at lines 175-176.

    • The material and methods used have been described with sufficient details to be reproducible by other investigators.

.
Validity of the findings: • The authors of the current manuscript challenges previous research, by finding that bimodality is not a general phenomenon to eels. That is a key finding.

The results may at first be seen as trivial as the authors have only investigated one river system leading to unimodality and dismissed other authors’ results because being from two different river systems. The authors interpret this lack of bimodal as a better way to analyze “disruptive selection” in eels. I fully agree with that approach. I think that “disruptive selection” can be seen as a full research question on its own, with the current four research questions as “sub-hypotheses”.

The authors write (at lines 273-274): ”The equal support for both unimodality and bimodality is likely caused by the strong overlap between the two normal distributions in the bimodal model”. That wording suggests the authors believe(d) statements like “this narrow-headed eel is really a broad-headed, contrary to factual observation”. It suggests the authors may have had an initial difficulty in accepting their own observations. I find that strange and perhaps it should be reworded as it may appear sarcastic. Still, the conclusions that follow suggest that narrow-headed eels are narrow-headed eels. That is good.

    • I have not seen the raw data and have no reason to believe they are wrong. I don’t think they are necessary here. The statistical methods used are well chosen and good enough for the purpose. The number of observations most likely are too few for several forms of multivariate analyses.

    • My overall suggestions are that the authors make a clearer distinction between the perspectives:

- Head morphology leading to food items
- Food items leading to head morphology

Here, the term “food items” can be replaced with “swimming performance”, “habitat choice” etc. The causality perhaps remains obscure either way as the manuscript did not include stomach analysis, but … you can’t have it all.

    • The article does challenge the conclusions of other articles and I think the authors have demonstrated that many statements in literature lack substance. Yet I think the wordings and the Discussion needs to be rewritten and expanded with more perspectives regarding correlation and causality.

.
Additional comments: No additional comments