Annual Dog-Day Cicadas (Neotibicen canicularis; family Cicadidae) are singing in Ohio. Curtis Young (OSU Extension, Van Wirt County) heard his first cicada on July 3. Dave Shetlar (Professor Emeritus, OSU Entomology) reported hearing his first cicada in central Ohio last Friday and I heard my first cicada song late last week in the southwest part of the state.
These so-called annual cicadas have undergone some taxonomic tweaking in recent years. I placed them in the genus, Tibicen, in my past BYGL Alerts. However, that genus now includes only a few European species. Annual cicadas found in the eastern U.S. including Ohio are now placed in the genus, Neotibicen. Those in the western U.S. and Mexico are now grouped in the genus, Hadoa.
Our annual cicadas share several behavioral traits with periodical cicadas (Magicicada spp.; family Cicadidae). 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.
Periodical cicadas are so-named because it takes 17 or 13 years for new adults to emerge en masse in spring. Brood X (10) will emerge in Ohio next spring; however, we saw and heard a few "early-birds" from this brood back in May and early June. Periodical cicadas are spring insects; annual cicadas are summer insects.
I posted a BYGL Alert about the early appearance of this brood and you can read the Alert by clicking on this hotlink:
Dog-day cicadas develop more quickly compared to periodical cicadas. It takes 2-3 years for the nymphs to complete their development; however, some adults emerge every year due to overlapping generations. 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.
Like their periodical familial cousins, dog-day cicada males also "sing" to attract females. However, they 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!
As with periodical cicadas, dog-day cicada females use their long, spade-like ovipositors to insert eggs through the bark of twigs and into the white wood. The resulting damage splits the bark and white wood leaving deep longitudinal furrows of ruptured tissue. The injury often causes the twig to die, the leaves to turn brown ("flag"), and the twig to detach and drop. However, owing to the smaller numbers of dog-day cicadas, their egg-laying damage usually goes unnoticed.
Dog-Day Cicada Nemesis
The appearance of our annual dog-day cicadas means their nemesis, the cicada killer wasp (Sphecius speciosus), should soon be seen cruising woodlands and landscapes in search of their exclusive prey. Cicada killers feed exclusively on annual dog-day cicadas; they do not prey upon periodical cicadas. The synchrony with annual cicadas makes sense if you consider that the wasps would starve to death waiting 13 or 17 years for a periodical cicada meal.
The wasps measure 1 1/8 to 1 5/8" in length and are one of the largest wasps found in Ohio. 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 defensive 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 is not recommended.
Cicada killers are considered beneficial insects and the females are not aggressive; stinging encounters are very rare. If the killers take-up residence in a public location, one option is to educate the public. This approach was very successful a few years in a park in Hamilton County. Complaints dropped to zero after the 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.
A Word About Big Wasps
The appearance of cicada killer wasps commonly triggers e-mails and phone calls to Extensioneers in Ohio and elsewhere in the eastern U.S. about Asian giant hornets (AGH) (Vespa mandarinia). European hornets (V. crabro) which are now found in Ohio and much of the eastern U.S. may also be mistaken for AGH.
AGH has not been found in Ohio. However, it was found late last season in the northwest corner of Washington State and just across the U.S. - Canadian border on Vancouver Island, B.C. It's the first time this non-native honey bee killer had been confirmed in North America.
Given that AGH somehow found its way to western North America, we must remain vigilant. There could be other inadvertent introductions elsewhere in North America including Ohio. If you have any doubts regarding the identity of a big wasp, report it!
The Ohio Department of Agriculture (ODA) has created an AGH Reporting Tool so Ohioans can provide photographs and locations of suspicious insects. Although photographs can't serve as official confirmation, they are helpful in making an initial identification before opening an investigation.
Here is the hotlink to the ODA's Asian Giant Hornet Online Reporting Portal: