They are also susceptible to ectoparasites like lice, fleas, mites, and chiggers. Chiggers, fleas, sand flies, leeches, and mosquitoes found every inch of exposed skin. Known parasites include a number of ticks, mites, chiggers, fleas, worms, and single-celled organisms. Benzyl benzoate is used as a repellent for chiggers, ticks, and mosquitoes. Chiggers are the parasitic larval stages of these free-living mites. Although commonly referred to as chiggers, true chiggers are mites, which are minute arachnids. The mite larvae, called chiggers, are natural ectoparasites of rodents. Trombiculid mites (chiggers) also feed on blood, but only in the larval stage. Species are called also chiggers, scrub itch-mite. During grooming, gray bats also ingest ectoparasites such as chiggers that live in their fur. Humans get infected upon accidental contact with infected chiggers. Infection starts when chiggers bite on the skin during their feeding. Chiggers seem to affect warm covered areas of the body more than drier areas. Wild rats of the genus "Rattus" are the principal natural hosts of the chiggers. During the wet season, chiggers are usually found in tall grass and other vegetation.