Looking for Social Behavior?

Lift the log.

Posted Jul 17, 2017

Robert Mather
Bess Beetle parents caring for their larva in Oklahoma, USA.
Source: Robert Mather

Each summer I try to write a fun article that isn’t as serious as the usual political and social issues that form the content of most of my articles. In this article, I will describe my encounter with Bess Beetles, better known as Odontotaenius disjunctus.

This spring, I hiked in the woods of Southeastern Oklahoma with a small group that included two biologists. This combination provided us a wonderful experience of learning about every aspect of the habitat. When we moved one decomposing log from the road, we found what the two biologists identified as Odontotaenius disjunctus (Wicknick & Miskelly, 2009).

As we quickly learned, these are no ordinary beetles. These beetles are pair-bonding social creatures. As a social psychologist with a background in evolutionary psychology, this immediately caught my attention. We observed a pair-bonded male and female caring for a larva. The larvae of this species can digest the decomposing wood of the tree, but grow faster when digesting the pre-processed wood that has been digested by the parents first (Tallamy & Wood, 1986). Both larvae and adults can produce sounds, and use these sounds to communicate. Parents locate their lost offspring via sound detection. The cost of being a lost larva can be great. In addition to slower development without the pre-digested food provided by the parents, the larva is at higher risk of infanticide by adults who have not reproduced but take over the burrow for their own future offspring (King, 2007).

We cleared the log from the road and carefully placed the parents and larva near each other in what was left of the log on the side of the road. The family was relocated within the same habitat, but was still united.  

Behavior is not the exclusive domain of humans, though many psychologists often ignore comparative literature that describes other species. Psychologists of all varieties should note the wonders of nature every chance they can. We live in what is truly an amazing natural world.


King, A. (2007). Infanticidal behavior in the subsocial beetle Odontotaenius disjunctus (Illiger) (Coleoptra: Passalidae). Journal of Insect Behavior, 20, 527-536.

Tallamy, D. W., & Wood, T. K. (1986). Convergence patterns in subsocial insects. Annual Review of Entomology, 31, 369-390.

Wicknick, J. A., & Miskelly, S. A. (2009). Behavioral interactions between non-cohabiting Bess Beetles, Odontotaenius disjunctus (Illiger) (Coleoptra: Passalidae). The Coleopterists Bulletin, 63, 108-116.