The Fascinating and Deadly Eastern Cicada Killer
“All life, under the burning sun of mid-morning, seemed lying low, keeping silent, all except the cicadas.” Edwin Way Teale from Journey into Summer
“Cats may scrape leaves and grass over dead pretty to conceal it, and some wasps drag drugged but living insects into previously constructed homes so the wasp larvae can safely feed on fresh meat.” Bernd Heinrich from Live Everlasting: The Animal Way of Death.
Over the years I have encountered my share of bees, hornets and wasps. We enjoy our small pollinator garden planted specifically for busy honeybees, “humble” bumblebees, beautiful butterflies and other pollinating insects. When it comes to hornets and wasps, however, I am much more wary, especially of ground nesting yellow jackets, paper wasps and fearsome bald-faced hornets. Recently I stumbled upon a wasp unknown to me and I will admit to being shocked by its large size and the nature of its activity that day. Let me explain.
Last Sunday I took a leisurely stroll into our back field where we pasture our horses during summer months. My objective was to look things over before bringing our tractor and “brush hog” into the field to knock down weedy stubble left over from the grazing horses. From about 10 feet away I noticed movement on a patch of grass that the horses had cropped to just 2 inches. I cautiously approached what I though was a single large insect and discovered it was two in the deadly clutch of predator versus prey.
The top insect was a wasp of some kind, but it was about 2 inches long and much larger than any wasp I had seen before. The wasp had in its grasp a cicada at least an inch long. Cicadas are those somewhat rotund, noisy bugs that are mostly heard and not seen as they make their buzzing whines in treetops on hot summer days. Readers may recall recent news stories about a type of wasp from Asia discovered on the west coast called “Murder Hornets.” As I carefully approached the scene unfolding before me, I whispered to myself, be careful Ranger Bill, be very careful.
I watched as the poor cicada was dragged through the grass until the wasp lifted off and flew across the field with its prey clutched in its legs. I walked back to the house and immediately began an internet and field guide search to discover more about this amazing insect –the eastern cicada killer.
I found the most succinct description of the wasp from a paper, “The Biology of Cicada Killer Wasps,” by Professor Chuck Holliday of Lafayette College.
“Eastern cicada killers (Sphecius speciosus) are the large wasps which dig burrows each summer in well-drained lawns, playing fields, plant nurseries and sloping terrain with varying amounts of grass east of the Rocky Mountains in the US and south into Mexico, Guatemala and Honduras. They begin their excavations a few weeks after our annual cicadas start singing.”
A few facts from Professor Holliday include:
- It is the female cicada killer that stings and paralyzes the cicada and carries it back to its burrow.
- The female will then lay an egg on the cicada and seal the cell.
- A grub will hatch from the egg in a few days, eat the cicada and overwinter underground in a hard cocoon which it weaves. It will pupate in the spring, hatch in July or August, and dig its way to the surface.
- The adult cicada killer will live above ground 2-6 weeks and all adults die annually.
Here is another interesting quote from Professor Holliday:
“The cicada killer has adapted its life cycle to be in synchrony with that of its hosts: Like the several species of ‘annual’ cicadas with which it feeds its young, a cicada killer spends over 90% of its life underground as a larva. Like most hunting and parasitic wasps, the cicada killer is a beneficial insect; it exerts a measure of biological control on cicadas, some species of which damage deciduous trees by laying eggs under the soft bark of the new growth on the trees’ terminal branches. Because they emerge each year in mid-July, cicada killers are not significant predators of periodical (13- and 17-year) cicadas, which emerge in May and June and die off by mid-July.”
I also found interesting information in a paper by Lee Townsend, Extension Entomologist from the Kentucky State College of Agriculture and Environment. Here are some additional facts.
- The female cicada killer is mild mannered and is directly focused on its task for the weeks it is above ground.
- They are solitary wasps and choose nest sites that are well drained, light-textured soils in full sunlight near trees that harbor cicadas.
- Up to 100 cubic inches of soil can be excavated by the tunnels of the cicada killer wasp and sometimes skunks have been known to dig up the tunnels and feed on the cicadas and wasp larvae.
- The tunnels have a U-shaped collar of loose soil around the opening and can range from 30 to 70 inches long and be 12 to 15 inches below the surface. There can be an average of 15 egg-shaped side chambers per tunnel, each containing 1 to 3 paralyzed cicadas with the egg hatching in 2-3 days.
- The female has a large stinger that is plunged into the cicada to inject paralyzing venom. Their stings are painful to humans, though they are not aggressive and do not have the same nest guarding instincts of other bees and hornets.
- The males do not have stingers but are territorial and may hover and challenge people pushing mowers or riding on tractors.
You can imagine my surprise when I recounted my discovery of the cicada killer wasp to my colleague Nick Velles. With a grin he showed me a picture on his phone of a cicada killer clutching its prey. The lawn of his in-law’s house has several tunnels. Apparently, this fascinating wasp is alive and well in our region.
Like Nick, I too have a special admiration for the insect species that live among us. There can be no doubt they outnumber our mammal, bird, amphibian and reptile species. During these dry hot days of summer there are a multitude of intriguing insects for us to discover and marvel at. I hope you’ll join me as we explore and come to appreciate all living things that reside with us here in The Last Green Valley – even the one with the auspicious name of cicada killer.
Information for this column was gleaned from the Kaufman Field Guide to Nature of New England, The Biology of Cicada Killers, by Professor Chuck Holliday of Lafayette College, and Lee Thompson, Extension Entomologist from Kentucky State College of Agriculture and Environment. Note that Professor Holliday is now retired, but his paper on cicada killers has been archived by Lafayette College.
Bill Reid is the Chief Ranger of The Last Green Valley National Heritage Corridor and has lived in the region for more than 35 years. He can be reached at firstname.lastname@example.org
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