I was walking home and noticed some big wasps licking flowers. Fascinated, I drew closer and observed them feeding. I noticed that the wasps’ abdomen (lower segment) was pulsating; the segments were extending and retracting continuously. I though it looked a lot like breathing, but I know that insects breath through small openings in their body, not trough lungs like vertebrates do.
I’ve never heard of this phenomenon before and I’m intrigued. I would theorize that it has something to do with digestion, similarly to our stomach churning food.
My questions are: Why do they do that? Do they do it continuously? Do many other insects do it too?
Just because arthropods get air through tiny holes in their bodies (called “spiracles”, and arranged so that most body segments have a pair, one on each side) does not mean they can’t act to move air in and out of these holes as fast as possible. Many insects have large air sacs in the abdomen, and as such, compression and expansion of the abdomen results in a large and rapid exchange of gases, which is much better than waiting for diffusion to do the trick. Bees and wasps simply engage in more pronounced abdominal pumping than most other insects, because they have a MUCH higher metabolic rate than most. A honeybee drone, for instance, has a body temperature of around 115 F (45 C), so he’d darn well better breathe as fast as he can - and so much for the misconception of what it means to be “cold-blooded”.
Only three hours! That was fast. Doug Yanega, thank you very much for the detailed answer. I find insects fascinating.
About your answer, doesn’t it mean that some insects have the potential to develop some sort of lung-like organ without major anatomical changes? Isn’t the absence of lungs in insects the limiting factor for their size?
White Wolf, your sentence is grammatically incorrect.
