Teuchestes fossor (Linnaeus, 1758)

A widespread and generally common species native to the Palaearctic and Asian regions east to South Korea, it is adventive and now widespread in the U.S.A. In the U.K. it is common throughout England and Wales, becoming more local and scattered in the north and with only a few records from Scotland. The adults appear in middle or late May and are soon abundant, remaining so until numbers fall in July and only occasional specimens are seen in August. They are crepuscular and nocturnal and easily observed in flight over dung pasture in the evening, they come to light and may thus be recorded far from apparently suitable habitat. The typical habitat is dung pasture where they develop in cattle dung but they also occur in horse dung in a variety of habitats. They are late successional species, arriving at dung pats after a crust has formed. The flight period is May and June when several, or even many, males may be found in a single pat but there is evidence that females release a chemical that deters other females from alighting. Oviposition occurs during June and July or earlier depending upon the season; single eggs are laid through the dry crust and only one or two will be laid each day by a single female. Larvae develop within the dung and are mature by late summer when they enter the soil, often to some depth, to pupate. The adults eclose in the autumn but, generally, remain in the soil to overwinter. In most years the peak of activity occurs in middle or late May when hundreds or even thousands of adults may be seen around dung pasture on warm evenings, they continue to be abundant for about the months and then vanish; large numbers often reduce to just a few within a week or so. This is the only Aphodius species to have been found in Mammoth dung!

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An unmistakable species; the largest of our U.K. Aphodius at 9-13 mm. and entirely black although specimens with reddish elytra are not uncommon. The size combined with the form of the scutellum, which is between a fifth and a quarter of the elytral length, will identify the species. The male has three strong tubercles between the eyes whereas in the female these are either missing or rudimentary. The clypeus is obtusely angled in front of the eyes and strongly emarginate anteriorly. The pronotum is strongly convex; the surface with sparse and strong punctures but otherwise smooth and unadorned in both sexes. The elytral striae are narrow between convex interstices. The tibiae, and especially the front tibiae which are adapted for digging rather than pushing, have large external teeth which quickly become worn in life so giving some idea of how long the specimen has been active.