Acrobat Ants

In a gap between later afternoon storms, towering walls of dark clouds blocked out sky canyons, and the sunlight raced through them like flash floods for a few minutes.

I went out to the big pond at the St Olaf Natural Lands, thinking I'd find bluet damselflies, but no such luck. I did happen across several Common Whitetail dragonflies, the first encounter with this large, showy species this year. This male will become even showier in a week or two as its abdomen turns bright white.

The sun disappeared behind a blue-black thunderhead. Distant thunder rolled in from the west. Even the flowers dimmed. So I went no further, turned and headed back to the car. On the way, I stopped for a quick inspection of one of the University of Minnesota bee survey blocks. It was immediately obvious that this nest block had been compromised by ants as they swarmed in and out of several of the nest entrances. A mason wasp had been captured. I took a photo of the wasp and the ants. Looking at the photo a little while later, I noticed the ant's peculiar, heart-shaped abdomens and the prong of spines. These are Acrobat Ants, of the genus Crematogaster, which actually hunt wasps. They secure their prey by the legs, pulling the legs out in all directions so that the wasp is incapacitated, stretched spread-eagle by a mob of ants. A neat trick to catch a wasp.

Posted on 17 de maio de 2017, 04:36 AM by scottking