Wasps are beautiful but deadly in the bug world
As summer winds down, the kids are back in school and our summer reading lists are exhausted. How about a story of beauty, intrigue, and deceit to spice things up?
You might find a good thriller at the library, or maybe on Netflix.
Better yet, you can step out into your own garden.
There you'll find murder mysteries with complex plots, gorgeous females, and unwitting victims.
The major players are not Marion Cotillard and Brad Pitt (sorry), but wasps.
There are lots of them of different sizes, colors, shapes. Their lifestyles include secret tunnels, trap doors, and covert operations, as exciting as any spy thriller.
Wasps are insects in a group called the Hymenopterans.
Although most people think of yellowjackets when they hear the word “wasp,” the nonnative yellowjackets are an exception to the rule.
The wasps we're looking at today are solitary, native creatures.
The solitary wasps are strikingly beautiful. Take, for example, the svelte female blue mud dauber.
Mud daubers have a long, sleek build, with a super narrow waist. When the sun hits the wings just right, they're a deep, shimmery blue.
With that intense color and slender profile, a female blue mud dauber is a drop-dead beautiful creature.
Her victims don't exactly drop dead, though. They die slowly, bit by bit.
The basic plot line is this: Blue mud daubers hunt spiders, either by snatching them from their webs or luring them out of their safety zones.
Once the spider is in her grasp, the wasp injects venom. Thus paralyzing the eight-legged victim, the mud dauber shanghaiers it to her nest.
Procuring the nest itself is part of the blue mud dauber's drama.
They take over abandoned nests made by other species of mud daubers. Sometimes, the blues usurp nests that are still occupied.
They may even take the other species' hard-earned spider stash, toss it out, and then put their own spiders in the nest.
Of what use are the paralyzed spiders? You might think that a spider would be a good meal for a large mud dauber.
But the adult mud dauber doesn't eat the spider; she lays eggs in it.
Laden with wasp eggs, the alive-but-motionless spider is stuffed in wasp's nest.
As wasp eggs grow and develop, the young have a convenient and plentiful supply of juicy spider guts.
In other words, the young wasps eat the spider alive, from the inside out.
Yes, it's a tragedy for the spider, but if you don't care for spiders, you'll probably root for the wasps in this drama. You'll be especially glad to know that blue mud daubers have a hankering for black widow spiders.
Who's the good guy and who's the bad guy? It's up to you.
There's an entire group of wasps that have skinny waists like the blue mud dauber.
This group is known as the thread-waisted wasps — or, ichneumons.
Each year, someone calls me in a panic over seeing a big wasp with a thin waist and a really, really long “stinger.”
They're usually referring to an ichneumon.
The so-called “stinger” is not a weapon and it does not sting. It's called an ovipositor, a tool for laying eggs.
The giant ichneumon is out for a specific kind of insect to serve as host for her eggs.
The insect hosts are well hidden, however.
The ichneumon has to do a fair amount of reconnaissance to find them.
Traveling along tree trunks and fallen logs, she taps the bark with her antennae.
Following the clues she receives, she locates a hole in the bark — and there they are.
The insect larvae she's seeking, called pigeon horntails, are burrowed in hidden tunnels in the wood.
The ichneumon slides her long ovipositor into the hole and lays eggs inside the horntail larvae. The giant ichneumon offspring are thus well-provisioned with nutrition from the hapless horntail.
Another outstanding beauty in the wasp world is a sand wasp named bicyrtes quadrifasciatus. (There's no official common name, so let's say “BQ” for short.)
I watched a lovely BQ out in the prairie at LeRoy Oakes Forest Preserve recently, busily drinking nectar from flowers.
Adult sand wasps, like other solitary wasps, are nectar-feeders in their adult stage.
And, like other solitary wasps, they parasitize other insects to provision their young.
The victims of sand wasps are stink bugs — specifically, the brown marmorated kind.
You know, those nasty brown bugs that come into your house by the droves and stink to high heaven? Before this pest arrived, the BQ sand wasp parasitized various kinds of native stink bugs.
Recently, the BQ has narrowed down its preferences and now selects only the invasive, nonnative brown marmorated stink bugs. More power to the sand wasps!
There are many more species of solitary wasps in our area, each with its own twist on the story of finding victims to parasitize.
The drama is cool to watch, but viewer discretion is advised.
If you don't want the gory details, you can always skip to the last chapter.
The ship sinks — er, the victim succumbs — but the next generation of beautiful wasps carries on in the dramatic ecology of life.
• Valerie Blaine is the environmental education manager for the Forest Preserve District of Kane County. You may reach her at blainevalerie@kaneforest.com.