user4108: I realized a few days ago that I was about to reach the 20k of reputation. Of course, I followed my reputation in the past few days. Two or three days ago, I had ~19,950 of reputation. I now have 19,808 of reputation and little notice about where the ~142 points lost.
I lost ten points yesterday for one "unupvote" and 40 points today for 4 "unupvotes" (all lost at the same time). While these unupvotes appear quite unusual, they only explain the loss of 50 points of reputation. There was no notice of users having cancelled his/her account.
Here is what my reputation summary of the past few days look like


Is it "normal" to loose reputation points without notice? How does it work?
Any guess why I may have lost all those points?
Is there any way to know if such points loss have been frequent since I started on to be active on the SE sites or is it quite exceptional?


user8160: Though it's answered already, for the future reference: it's well possible for you to see what has caused this. Just go to your reputation tab, and check "show removed posts".

You can do it only in your tab, regardless of your rep. Moderators can also do it with another accounts, but not 20k users, as incorrectly mentioned @Chris.
(the confusion was probably due to the ability of 10k+ users to see the deleted posts directly, but not from the reputation tab of other users)

user5144: You don't see this, because it was caused by two deleted threads which are only seen by mods and trusted users (over 20k), so once you go over it, you will see it. Here is what your reputation statistics looks to me:

This question was deleted by yourself, causing the loss of 10 reputation points (2 upvotes for your question). 
This question got auto-deleted by the system after it was closed and the answer had no positive upvote score (in fact it had one downvote and one upvote, showing it at zero). This caused you 108 in reputation loss.
Together with the other losses (40 today for reversed upvotes, 118 yesterday for the deleted questions) and 10 the day before for another unupvote) this accounts for 168 reputation points lost.
Other sources for the removal of reputation points can be the deletion of users which voted. Upvotes are binding unless the question or answer is edited, in which case the upvoter can take back their vote, as it was given for an older version of the question/answer.

4108: <p>I realized a few days ago that I was about to reach the 20k of reputation. Of course, I followed my reputation in the past few days. Two or three days ago, I had ~19,950 of reputation. I now have 19,808 of reputation and little notice about where the ~142 points lost.</p>

<p>I lost ten points yesterday for one "unupvote" and 40 points today for 4 "unupvotes" (all lost at the same time). While these unupvotes appear quite unusual, they only explain the loss of 50 points of reputation. There was no notice of users having cancelled his/her account.</p>

<p>Here is what my reputation summary of the past few days look like</p>

<p><a href="https://i.stack.imgur.com/frUA1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/frUA1.png" alt="enter image description here"></a></p>

<ul>
<li>Is it "normal" to loose reputation points without notice? How does it work?</li>
<li>Any guess why I may have lost all those points?</li>
<li>Is there any way to know if such points loss have been frequent since I started on to be active on the SE sites or is it quite exceptional?</li>
</ul>
 8160: <p>Though it's answered already, for the future reference: it's well possible for you to see what has caused this. Just go to <a href="https://biology.stackexchange.com/users/current?tab=reputation">your reputation tab</a>, and check "show removed posts".</p>

<p><a href="https://i.stack.imgur.com/URZwa.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/URZwa.gif" alt="&quot;show removed posts&quot;"></a></p>

<p>You can do it only in your tab, regardless of your rep. Moderators can also do it with another accounts, but not 20k users, as incorrectly mentioned @Chris.</p>

<p>(the confusion was probably due to the ability of 10k+ users to see the deleted posts directly, but not from the reputation tab of other users)</p>
 5144: <p>You don't see this, because it was caused by two deleted threads which are only seen by mods and trusted users (over 20k), so once you go over it, you will see it. Here is what your reputation statistics looks to me:</p>

<p><a href="https://i.stack.imgur.com/cihtP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cihtP.png" alt="enter image description here"></a></p>

<p><a href="https://biology.stackexchange.com/questions/35739/efficient-algorithm-to-calculate-various-population-divergence-statistics">This</a> question was deleted by yourself, causing the loss of 10 reputation points (2 upvotes for your question). </p>

<p><a href="https://biology.stackexchange.com/questions/40614/does-genetic-homeostasis-slow-down-evolution/40661">This</a> question got auto-deleted by the system after it was closed and the answer had no positive upvote score (in fact it had one downvote and one upvote, showing it at zero). This caused you 108 in reputation loss.</p>

<p>Together with the other losses (40 today for reversed upvotes, 118 yesterday for the deleted questions) and 10 the day before for another unupvote) this accounts for 168 reputation points lost.</p>

<p>Other sources for the removal of reputation points can be the deletion of users which voted. Upvotes are binding unless the question or answer is edited, in which case the upvoter can take back their vote, as it was given for an older version of the question/answer.</p>
