Saliva For Lunch?
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I am fascinated by paper wasps, as should be evident to anyone who follows this blog. To me, they are among the most beautiful of all living creatures. I love their sleek forms and their brilliant colors. They also have exceedingly complex societies, among the most advanced of all insects, and their lifestyles and behavior yield seemingly endless surprises that just continue to amaze me.
Yesterday, I was hiking a trail in Sabino Canyon when I saw a paper wasp hovering over a small mesquite tree. Paper wasps are normally very difficult to photograph. They are actually quite shy around humans. They have excellent senses and they know we’re there. Normally, one will fly away as it is approached. But, this one seemed really focused on something in the vegetation. It hovered for a few seconds and then, descended rapidly. I moved in for a photograph and made a series of images before the wasp flew away.
Later, when I looked at my images I discovered that this wasp had captured a small caterpillar. I was pleased to have caught the action, but I wasn’t surprised. Paper wasps are known to prey on caterpillars. I assumed that the wasp would devour its prey, either at the site of the capture or, perhaps in some safe area.
I did a little on-line research to verify my assumption and I was astonished to discover that paper wasps don’t eat caterpillars. They are limited strictly to a liquid diet because the tube connecting their necks are so narrow as to preclude anything solid from going down. Paper wasps bring their prey back to their nests where they dismember it and feed it to their young.
In this second photo you can plainly see how narrow the wasp’s neck is and why eating solid food is impossible.
So, what do adult paper wasps eat? Well, here’s the weird and amazing part. They can drink plant nectar, but that’s insufficient to sustain them. Wasps need protein. And, for that, they rely on their offspring. Back at the nest and after the youngsters have been fed, adult paper wasps do a little dance that consists of rhythmically wagging their bodies along the nest’s surface, producing vibrations. The wasps’ larvae evidently respond to those vibrations by producing saliva! The saliva is rich in protein from digested food — caterpillars, for example. The adults eagerly drink the saliva and so, they get nourished by their own offspring.
I’ve learned not to be surprised by anything in nature. The more one looks and studies, the more wonderful it gets.
Photos made with a Canon 5Diii, 180 f3.5L Macro Lens assisted by Canon 600EX-RT Speedlite, ISO 125, M setting, f 14 @ 1/160.