Onthophagus joannae Goljan, 1953

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POLYPHAGA Emery, 1886

SCARABAEOIDEA Latreille, 1802

SCARABAEIDAE Latreille, 1802

SCARABAEINAE Latreille, 1802

ONTHOPHAGINI Burmeister, 1846

ONTHOPHAGUS Latreille, 1802

This locally common species occurs throughout Europe from Portugal east to Russia and Ukraine and from the Mediterranean north to central Fennoscandia and the UK; here it is local and not uncommon across Wales and southern England north to Lincoln although generally absent from the West Country. On the continent it occurs from lowland to mountain altitudes of 1500m and is often abundant on open, sunny foothills and mountain pastures exposed to the sun, in the UK it is generally associated with sandy and calcareous grassland, especially on hillsides with patches of shrubby vegetation. Adults occur from April or May and may suddenly appear in numbers; on the continent they sometimes emerge in massive numbers along with other Onthophagus species, often O. ovatus (Linnaeus, 1767) (which is very difficult to distinguish from the present species on external morphology), and here they have often been found with O. similis (Scriba, 1790), they are generally abundant during May and June and persist into August. They are most frequently found in sheep, goat and horse dung but we have found them in deer droppings in the Chiltern hills and on several occasions, when they have been absent from other dung, we have found them in great abundance in rabbit droppings, sometimes 2 or 3 beetles tightly squeezed into a single pellet, and each pellet on countless middens packed tight with beetles. They fly readily and may occasionally be seen on fence-posts etc. on dung-pasture margins or in flight low above the grass. They may also be found on carrion and among decaying fungi; we once unearthed a well-decayed and absolutely appallingly aromatic subterranean fruiting body on a chalk hillside in South Bucks and within minutes it was attracting large numbers of adults along with abundant rove beetles and other scarabs.  Mating occurs in the spring and mated females dig vertical burrows close to or beneath host material, burrow depth depends upon soil type underlying strata and burrows are usually branched, each branch accommodating a brood-chamber which is provisioned with food into which a single egg is laid. Larvae develop rapidly and pupation occurs in the brood-chamber in the summer, this stage takes a week or two and adults eclose in the summer but remain in place to overwinter and appear the following spring.

Onthophagus joannae 1

Onthophagus joannae 1

Onthophagus joannae 2

Onthophagus joannae 2

Onthophagus joannae 3

Onthophagus joannae 3

Onthophagus joannae 4

Onthophagus joannae 4

4-6mm. This species is readily distinguished from our other species by the combination of entirely dull-black colouration, smoothly-rounded pronotal margins i.e. not sinuate behind the anterior angles, and uniform pale pubescence to the head, pronotum and elytra. Head with a transverse ridge on the vertex in the male; almost smooth in the female. Pronotum transverse and evenly rounded, the posterior angles hardly traceable, anterior angles strongly produced forward, surface smoothly convex and moderately strongly and densely punctured. Elytra transverse and evenly rounded from acute humeral angles to the apex; striae weakly-impressed and without larger punctures, interstices convex and finely punctured. Legs long and robust; pro-tibiae with 4 teeth externally which tend to become quickly worn in life, meso- and meta-tibiae strongly broadened to a truncate apex, each with 2 strong terminal spurs, the inner one at least as long as the first tarsomere.

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