Wonderful Blue Winged Wasps

I have a new, favorite insect: blue-winged wasps. Some of you may recall that last year I had enormous numbers of June bugs and Japanese beetles hovering over the pasture next to my orchard. (If you want a refresher, click HERE.) At the time, I was determined to purchase and apply a product to kill the grubs that hatch into these eating machines. Life got in the way, and I never did the research to determine which grub killer was the best choice – you know, the right product to address these specific insects, toxic enough to be effective but not so toxic that it would kill beneficial insects. So, the year went by without any insecticide application. And Mother Nature did the work for me, free of charge.

Scolia dubia, commonly known as two-spotted scoliid wasps, blue-winged scoliid wasps or digger wasps, have pretty blue wings, black head and thorax with a rusty-colored abdomen, with a couple of yellow blobs on their rear segments. Females are not aggressive, and won’t sting you unless you really, really mess with them. Males do not have the capacity to sting. They will let you get up close and personal with a cell phone. Despite groups of them congregating in the late afternoon on the wires of my protective cages around blueberry plants, they are known as solitary wasps. This means that they nest alone and feed their babies alone, unlike hornets or paper wasps that live in communes.

When I see large number of these wasps zooming around the pasture just a few inches above the ground, they are shopping for a family dinner. Guess what is on the menu? It is the white grubs that develop into June bugs and Japanese beetles! When the wasp detects a grub, she dives into the soil (see common names above – “digger” wasps) and paralyzes the grub with a sting, then lays her egg on the grub’s body. When the egg hatches, the hatchling’s first meal – a dinner that lasts about two weeks -- is the paralyzed grub. The wasp larva spins a cocoon and becomes a prepupa in the Fall and rests during winter. As warm temperatures return, the prepupa becomes a pupa, which then molts into an adult that emerges in the Spring.

While any insect that hunts and destroys Japanese beetle grubs is a hero in my estimation, blue-winged wasps are also good pollinators. They visit goldenrod often, so check yours out to see if you are hosting these very good bugs.

Blue-winged wasps congregate on fence wire just before dusk.

This blue winged wasp has a dusting of pollen on her head after visiting the nearby pollinator garden.

Not a great photo, but this wasp has detected a white grub under the turf. She drove into the ground and emerged after depositing her egg on the grub.

Writing Spiders

Writing spiders (Argiope aurantia) have made their annual appearance in the Snoddy garden. These black and yellow spiders are large and easy to spot. Other common names are zigzag spider, corn spider, gold orb weaver, scribblers and a host of others. The name is pronounced Argiope (ar-JY-oh-pee) aurantia (aw-RAN-tee-a), although I found alternate pronunciations on websites. These spiders are found in all 48 contiguous states.

Argiope spiders build large, elaborate webs that often contain heavier threads that look like X’s or Z’s. This gave rise to the common name ‘writing spider’ and also the folklore that ‘if a writing spider spells your name, you are going to die that night.’ My mother passed that tall tale along to me, so as a child I consulted the webs daily to see if my time was up. (Thanks, Mom!) There are various theories as to the purpose of these heavier threads, known as stabilimentum (attract prey, keep birds from flying into webs, add web stability) but none of them are proven. Parents should teach their children to admire from a distance, since Argiopes will bite if handled. The bite is not toxic but hurts like a bee-sting.

Trivia: In the children’s book Charlotte’s Web, Charlotte was such a talented spider that she wrote entire phrases (“Some Pig”) instead of simple X’s and Z’s.

Last week my husband spotted the remains of what appeared to be another Argiope (just a pair of legs) wrapped in silk in one of our regular webbers. He asked me if they were cannibals. A little research revealed that males have an irreversible seizure after mating and they die in less than an hour. The female wraps him up in silk and stores him on the edge of her web for an afternoon snack.  She selects a location for her web where the likelihood of a meal is high and the chance for disturbance seems low. Once this site is chosen, she will remain there every day. Webs are spun from self-produced silk that is stronger than steel of the same diameter. She tears her web down and reconstructs it every night. Webs can be two feet across. Females are approximately three times the size of males. 

The typical life span of an Argiope is one year.  The female leaves a sack of eggs for posterity and dies with the first hard frost. The eggs hatch within the sack during late fall or winter. The babies (300 or more) emerge in the warmer weather of spring. Any that are not consumed by birds or other predators start the cycle again.  

When I began photographing our resident Argiopes for this blog article, I noticed that they always hang head-down on their webs. When insect prey is snared in the sticky web threads, they move lightning-fast to wrap them up into a “eat it later” package. Occasionally they hold pairs of their legs together so tightly that it appears that they have four legs instead of eight. 

Many people have a fear of spiders (“arachnophobia”) but they are beneficial to the environment and should not be killed. If an Argiope builds her web in an inconvenient location, across your doorway for instance, destroying the web several days in a row will encourage her to relocate to a more hospitable site.

Argiope heads are covered with silvery hairs.

Is she writing YOUR name?