There are currently six Onthophagus extant species that can still be found in the UK and two that are now thought to be extinct. Most Onthophagus males have a noticeably pointed horn on the posterior margin of the head. There are two exceptions. Onthophagus joannae males do not have horns and Onthophagus taurus where the males have rather impressive bull like horns, hence the name. Onthophagus can be sexed by looking at the abdomen – in females the pygidium is uniform in width, in males it is narrower in the middle (see image below).
In the British Isles, Onthophagus range in size from 4 – 11mm. The smallest is Onthophagus joannae and the largest Onthophagus medius. All the species are tunnellers. They dig directly below the dung source and bury a small section of dung in which eggs are laid.
A downloadable guide is available in the Resources section.