During this week’s Tuesday morning BYGL Zoom Inservice, Curtis Young (OSU Extension, Van Wirt County) reported that he heard the first Annual Cicadas (family Cicadidae) this season singing in northwest Ohio over the 4th of July Weekend. Likewise, I heard my first cicadas in the southwest part of the state this past Friday.
Annual cicadas share several behavioral traits with their periodical cicada (Magicicada spp.) cousins. The nymphs of both types of cicadas develop underground sustained by juices sucked from tree roots and it takes multiple years for them to complete their development from eggs to new adults.
Once the periodical and annual cicada nymphs complete their development, they leave the soil and climb stems to molt. This event is commonly described as the last instar nymphs exiting the soil. However, it’s actually new adults wrapped in the last instar’s exoskeleton that are climbing the stems. The result is that the cicadas leave behind their shed “skins” (plural exuviae, singular exuvium) stuck to the stems of trees and other vegetation.
As with periodical cicadas, annual cicada females use their long, spade-like ovipositors to insert eggs through the bark of twigs and into the white wood. They can produce twig dieback (“flagging”); however, owing to the smaller numbers, their egg-laying damage usually goes unnoticed.
Of course, a big difference between the two types of cicadas found in Ohio is represented by the names periodical and annual. Periodical cicadas take 13 or 17 years to complete their development from eggs to adults and they emerge in the spring.
Annual cicadas emerge in the summer, and they develop more quickly compared to periodical cicadas. It takes 2-3 years for the nymphs to complete their development. However, we see and hear adults every year because of overlapping generations within a species and because there are more than one species in Ohio.
Our most common annual cicada in Ohio is the Dog-Day Cicada (Neotibicen canicularis) so named because the adults appear sporadically throughout the “dog days” of summer usually beginning in July. Indeed, the specific epithet, canicularis, is derived from the Latin word, canicula, which references the Dog Star, Sirius.
Ohio is also home to 11 other species of annual cicadas including the Northern Dusk Singing Cicada (Megatibicen auletes) which is the largest-sized annual or periodical cicada in North America. You can view pictures of the different species by visiting the Cicada Mania website. The hotlink is listed under “Additional Resources” below.
Indeed, for years, my pictures of the Swamp Cicada or Morning Cicada (N. tibicen tibicen) were mislabeled as “Dog-Day Cicada.” Of course, had I paid greater attention to the male’s songs, I would have been aware of my error. Along with pictures, the Cicada Mania website also includes high-quality audio files for each species.
Like the periodical cicadas, annual cicada males "sing" to attract females and each species has its own tune. This prevents females from wasting time and energy responding to males of another species (oops!). Indeed, as the audio files on Cicada Mania demonstrate, you can identify the species based on hearing the males sing.
However, unlike periodical cicadas, annual cicadas do not "chorus" with large numbers synchronizing their song. An occasional dog-day cicada buzzing to entice a female doesn't compare to the cacophony created by a multitude of periodical cicadas. It's like comparing a barbershop quartet to a million-man chorus!
Cicada Killers: Will the Nemesis of Annual Cicadas Show Up?
Normally, the arrival of annual cicadas also marks the appearance of Cicada Killer Wasps (Sphecius speciosus). Cicada killers feed exclusively on annual cicadas; they do not prey upon periodical cicadas or any other insect. Their synchrony with annual cicadas makes sense if you consider that the wasps would starve to death waiting 13 or 17 years for a periodical meal.
However, the numbers of cicada killer wasps have been down over much of Ohio for the past few years with populations being highly localized at best. Indeed, while my observations are anecdotal, the last years that I observed widespread distribution of cicada killers in southwest Ohio were in 2012 and 2016. Interestingly, both years had below-normal precipitation with 37.27 inches and 37.78 inches, respectively.
Cicada killers are the largest native wasp found in Ohio measuring 1 1/8 to 1 5/8” in length. As with all Hymenoptera (wasps, bees, etc.), only the females possess stingers (ovipositors); however, they are not aggressive. The males are aggressive, but they lack stingers.
The females spend their time digging and provisioning burrows with paralyzed cicada-prey. They prefer to dig their brood burrows in bare, well-drained soil that is exposed to full sunlight. Although the wasps are considered solitary, all of the females have the same nesting requirements. So it is not unusual for there to be numerous burrows, and wasps, in relatively small areas.
The males spend their time establishing and defending territories that encompass multiple females. They are notoriously pugnacious and will aggressively buzz any transgressor who dares to enter their territory including other males as well as picnickers, golfers, volleyball enthusiasts, and gardeners. Fortunately, it's all a rouse since they lack the necessary equipment to deliver a sting.
Although the males can't sting, their large size coupled with low-level flights over sand volleyball courts, sparse lawns, and bare areas in landscapes can be disconcerting generating demands for control options. However, insecticide applications to kill the killers are not recommended.
Cicada killers are considered beneficial insects and the females are not aggressive; stinging encounters are extremely rare. If the killers take up residence in a public location, one option is to educate the public. This approach was very successful a several years ago in parks in southwest Ohio. Complaints dropped to zero after a sign was posted.
The best way to manage cicada killers if they appear where they're not wanted is to modify their habitat. Renovating lawns late this summer to thicken the turfgrass will keep the killers out of lawns. Applying mulch to cover bare soil or raking mulch to disturb and redistribute possible burrowing sites will convince females to nest elsewhere. The same is true for golf course sand traps and sand volleyball courts. Periodical raking will prevent the wasps from becoming established.