''Teuchestes fossor'' is a species of

dung beetle Dung beetles are beetles that feed on feces. Some species of dung beetles can bury dung 250 times their own mass in one night. Many dung beetles, known as ''rollers'', roll dung into round balls, which are used as a food source or breeding cha ...

native to the

Palaearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

, but is also widespread in North America following accidental introduction and naturalisation during European settlement. Both adults and larvae are coprophagous, differentiating resource use by respectively feeding on the liquid and fibrous fractions of herbivore dung. It can be readily collected from the dung of livestock, and other large mammals This species is known to support a number of key

ecosystem services Ecosystem services are the many and varied benefits to humans provided by the natural environment and healthy ecosystems. Such ecosystems include, for example, agroecosystems, forest ecosystem, grassland ecosystems, and aquatic ecosystems. Th ...

in cattle pastures. ''Teuchestes fossor'' was formerly a member of the genus ''

Aphodius ''Aphodius'' is a genus of beetles in the family Scarabaeidae. In most species both the adults and larvae are coprophagous (dung feeding) although some species have herbivorous or saprophagous larvae. ''Aphodius'' species typically dominate dun ...

''.

Appearance

''Adult''

''Teuchestes fossor'' is a highly convex beetle measuring between in length, and in breadth. The scutellum is long, and reaches more than 20% sutural length. The elytral striae are relatively narrow. The

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on ea ...

is densely punctured towards side and front angles. Its typical colour is a uniform glossy black, although it can also rarely occurs in a dark red form where it may superficially resemble '' Acrossus rufipes''. Males are differentiated from females by a small but prominent horn on the head.

Larvae

Larvae are typical C-shaped scarabaeid larvae, and undergo three larval

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

s before pupation.

Ecology

Like other species within the genus, this dung

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

is classified as an 'dwelling' or 'endocoprid' species, where in place of rolling dung balls—beetles feed and reproduces within the confines of

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

ian dung. Adult beetles preferentially colonise older cattle dung, moving between several dung pats as adults. Eggs are laid singly beneath the dung crust and in the underlying soil. Adult beetles typically occur at low densities in mated pairs, and mate-finding and anti-aggregation are thought to be mediated by

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

s. Despite being found in open environments like

pasture Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or swine ...

s, ''Acrossus fossor'' is sensitive to desiccation and larvae experience significant mortality when highly exposed environments.

Sensitivity to veterinary anthelmintics

A number of studies have shown that

coprophagous Coprophagia () or coprophagy () is the consumption of feces. The word is derived from the grc, κόπρος , "feces" and , "to eat". Coprophagy refers to many kinds of feces-eating, including eating feces of other species (heterospecifics), of ...

insects suffer a suite of lethal and

sublethal Non-lethal weapons, also called nonlethal weapons, less-lethal weapons, less-than-lethal weapons, non-deadly weapons, compliance weapons, or pain-inducing weapons are weapons intended to be less likely to kill a living target than conventional ...

effects in response to veterinary anthelmintic residues. Adult beetles show negligible sensitivity to the anthelmintic

ivermectin Ivermectin (, '' EYE-vər-MEK-tin'') is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat inf ...

, but in contrast larvae are highly sensitive.

Role as a beneficial insect

The feeding of larvae and adults enhances the rate at which dung disappears from the pasture surface. This action allows for the growth of new forage, while also acting to release nutrients back into the soil, and helps relieve surface soil compaction. As adults and larvae often feed at the soil-dung interface, soil particles may be inadvertently introduced into the dung and the contributions of ''Acrossus fossor'' to dung removal may be underestimated.

References

{{Taxonbar, from=Q14895372 Scarabaeidae Beetles of North Africa Beetles of Asia Beetles of Europe Beetles described in 1758 Taxa named by Carl Linnaeus