Missouri Master Naturalists- Springfield Plateau Chapter

Tuesday, December 11, 2018

Hattie's Scarab


Hattie's Scarab
I received this photograph from our friend Courtney who found the insect with her 3 year old assistant Hattie. They sent it in to INaturalist and got a tentative ID of Bolbocerosoma bruneri. That would put it in the Geotrupidae family, the Earth-Boring Scarab Beetles, EBSB, (also called dung beetles). 

B. bruneri - Marci Hess cc
I would agree with the genus Bolbocerosoma but have reservations on the species. All the photographs of B. bruneri on Bugguide show a thin curved black line on the thorax immediately behind the head which is missing in the picture above, so I am going to stick to Bolbocerosoma sp which gives us 12 species to choose from in the USThey all have in common the orange pronotum, black markings and five deep punctuate grooves on their elytra.


EBSB with its mound - Ag.Purdue.edu
EBSB have a very interesting life cycle. They burrow tunnels into the ground, some up to 9 feet deep. They may have multiple chambers at the bottom and the opening on top frequently has a pile up of dirt like a miniature prairie dog mound.  They deposit an egg at the bottom and then food above it forming a plug. This can include collected feces, decaying plant material, and fungus. The adults do not care for their young.  When grown, the grub will pupate, the adult emerges and climbs to the surface to fly off, probably relieved to be out in the fresh air.

They soon however return to the same old diet, eating decaying material and fungus and  and are often found on dung piles or compost heaps. Adults come to light which probably explains the one on Courtney's porch. Once you get past the "yuck" factor, remember that they are an earth-friendly species, similar to a vulture in recycling carbon and nitrogen from dead and decaying material into the soil. You didn't have any other plans for that dung, did you?