You might notice a few unwanted guests at your end-of-summer picnic.
These stripey visitors hover around your burgers, your brownies; even your drinks.
These are wasps, and although they are an important part of the ecosystem — controlling pests, pollinating plants — they can be very annoying to us humans.
So why are wasps drawn to our outdoor feasts? And why do they only get especially intrusive in the late summer?
In a word, sugar.
All summer long, worker wasps have to feed the new generation of larva. To get important protein, they hunt for other bugs, like aphids and caterpillars (thus keeping the pests away from our crops).
The worker wasps feed those chewed up bugs to the growing larva, and in return, larva secretes a sugary substance that feeds the workers.
As summer stretches on, some of the larvae get ready to pupate into adult wasps. So they retreat into their own homespun pupal caps, no longer needing nourishment from the workers.
As the ratio of available workers to pupating larvae increases, as does the adult wasps’ need for sugar that they’re no longer getting from their baby siblings.
So the wasps start looking elsewhere for sugar — that’s when they start pollinating plants.
And invading our picnics.
So the next time a wasp comes to visit your half-eaten hot dog, remember how hard she’s worked all summer and give her a break.
Read more animal stories here.