Horned Passalid Beetle

“Chirping” Beetle
Hi Bugman!
My son and I live in Salisbury, Maryland. We found the attached bug (picture) under a log in our front yard. He (or she) is very strong, and makes a chirping kind of noise when you touch it. If you please, what’s that bug?

Hi Marie,
This is a Horned Passalid Beetle, Odontotaenius disjunctus. According to BugGuide: “Lifestyle of this family is unique for beetles: live in small colonies where larvae are cared for by adults of both sexes. Long life cycle, apparently more than one year. Larvae eat a rotting wood prechewed by adults. (Some references state larvae eat feces of adults as well.) Larvae and adults also cannibalize injured larvae. Adults reported to fly very seldom. Adults are found at lights on occasion, despite statements in several sources. They may disperse by walking, but have been seen in Durham, North Carolina, to open elytra and fly briefly under lights (pers. observation, P Coin). A nuptial flight has also been observed (MacGown and MacGown, 1996). Both adults and larvae make noises by stridulation, and this is said to serve as communication between them. Adults also stridulate when picked up, and especially, blown on. Stridulation mechanism of adults by rubbing abdomen against the wings. Larvae stridulate with reduced third pair of legs–these scratch against other legs.”

Leave a Comment