Tenebrionid Headstands

Doug Von Gausig has very kindly provided two pictures of tenebrionid beetles doing headstands. Both are species of Eleodes. One species has grooves along the elytra (the fused front wings of the beetle -- remember, these are flightless beetles that walk around on the ground), and the other one has smooth elytra. Each species has defensive secretions. The grooves probably help the defensive secretions spread out across the elytra, coating them with quinones and hydrocarbons that repel predators. Interestingly, some tenebrionids have receptors that are sensitive to the breath of mammals. When these receptors register the heat, moisture, and odors of mammalian breath, the glands evert, spilling out their noxious substances.  Here's a challenge for some of you beetle fans: Can you identify these two species of Eleodes?

   

Comments

[Chris Wemmer]

I'm guessing from its shiny form that number 2 is E. gigantea. (I'm using Evan's and Hogue's new Calif beetle field guide.) Don't think Dillon and Dillon will be much help for number 1!