The Horned Passalus, or bess beetle, is a large, shiny black beetle that lives in highly organized family groups inside rotting logs, with parents caring for their larvae — an unusual level of social behavior for beetles. Both adults and larvae communicate with squeaking sounds produced by rubbing body parts together. Adults partially pre-digest wood for their larvae to consume.
Best time to see a Horned Passalus
The best time to see a Horned Passalus is March–July, when about 66% of U.S. sightings happen, based on 29,245 research-grade iNaturalist observations.
Not certain it is a Horned Passalus? What bug is this? walks through what to check first and the lookalikes that catch people out.
Recent Horned Passalus sightings near you
Live, research-grade observations from iNaturalist. Allow location to center the map on you.
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