BugBowl at Purdue is approaching and we are preparing our petting zoo. A popular petting zoo insect is the Passalid or Bess Beetle, Odontotaenius disjunctus. I described some of the Bess Beetle behaviors and diet in a previous post.
The Bess Beetles have one of the highest levels of social behavior among all beetles. Colonies share tunnels in rotting logs, food, microorganisms and defense. They communicate by sound and odor. Vision is not as important because it is dark in the tunnels of rotting logs.
O. disjunctus does not can fly even though its forewings (elytra) are fused and do not open. The 1946 report by Gray states that they do not fly but there are a few reported observations of them in flight and they occasionally are attracted to light traps. The hind wings are not used for flight as in other beetles. In the Bess Beetle, the hind wings produce sounds by rubbing across the abdomen.
According to Jack Schuster (Florida Entomologist 66:486-496, 1983) Bess Beetles make 7 distinct types of sounds under a variety of circumstances. This translates into at least 14 signals, a large number for an arthropod. Sounds are produced for defensive purposes to startle predators, and warnings to nest mates. Males produce sound when fighting other males and the beetles produce courtship sounds. Bess beetles are quite common, but often overlooked because they are typically safely tucked away out of sight in rotten logs. You can see them and pet them at BugBowl Saturday April 14 and Sunday April 15, 2012.
Passalid Beetle
Passalid beetles are also interesting because of their extraordinary acarofauna: more than two dozen families of mites are associated with passalids and many of these families are known from no other associations. Most don’t seem to be parasitic, but the exact nature of the relationships are mostly obscure. You can see a few of the mites in the post below (scroll down a bit):
http://macromite.wordpress.com/2010/02/14/mite-farm-or-some-animals-are-more-equal-than-others/
Very cool link. Nice pics.
Biology is indeed messy. But I’m ok with that.
Are you sure they don’t fly? I get them in Lindgren funnel + blacklight traps every so often.
Good catch. They can fly when they disperse. The original studies suggested that they don’t fly but upon further investigation, I found some reports on their flight behavior. I have never seen them fly and am not sure what conditions would motivate them to fly.
I talked to my advisor, and he suggested that they might have some alternating generations that can and can’t fly – possibly dealing with nutrition availability or something like that. Maybe they fly when they’ve used up a log? Sounds like a good research project