CICADA KILLER WASPS ARE A THREAT ONLY TO CICADAS
By Chris Williams on July 24, 2017.
Cicadas have burrowed out of the ground and are singing in the trees. That means that cicada killer wasps are also out and are probably leaving impressive holes in yards. Maybe it’s because they have the word “killer” in their name, that these large wasps get a bad rap that they don’t deserve.
Since we only see them for a short time each year in late summer, we forget how impressive cicada killers can be. These wasps range from an inch to more than an inch and a half in length. They have to be big so they can manage chunky cicadas, their only prey. Their abdomen is black with yellowish markings similar to a yellowjacket’s but their head, thorax, legs, and wings are rust-brown.
THESE LARGE WASPS WOULDN’T HURT A FLY!
Cicada killers are solitary wasps and are not part of a wasp colony. Instead, a mated pair constructs the ground burrows that house their larvae. They are extremely docile wasps since they don’t have a colony to defend. Only the female of the pair can sting but she almost never does, you would have to handle a cicada killer wasp roughly to receive a defensive sting. The stinger-less male guards while she digs the nest burrow (see Cicada Killer Wasps Are Really Just “PussyCats!”).
When completed, each ground burrow ends up being about ½ inch in diameter and several inches deep. With that job done, the female locates and stings a cicada to paralyze it and flies with it back to her burrow. She deposits one or two paralyzed cicadas in each burrow and lays an egg on each one. The larvae that hatch out feed on the still living, but motionless, cicadas that were provided by “mom.”
CAN’T GROW GRASS? THEY LIKE THAT
Areas of bare ground with sandy soil make nest digging that much easier. Since these are big wasps, the round burrow opening (1/2 inch) is quite noticeable, especially since the female deposits a good amount of excavated soil next to the opening. Each female digs and provisions several burrows, each with a cicada and her egg. In a good location, several females may dig burrows in the same general area so you can imagine that a good cicada hatch can mean lots of cicada killer wasps digging burrows.
Cicada killers prey on both the annual cicada, some of which are out each year, and the periodical cicadas which emerge only every 13-17 years. Once the female wasp has dug, provisioned, and sealed her burrows, she moves on. The larvae spend the winter in their burrows and emerge as wasps the following summer.
Both cicadas and cicada killer wasps are interesting insects that usually don’t cause any lasting damage to plants or yards. The wasps rarely damage healthy lawns since they avoid grassy areas. One way you can discourage their digging in your yard is to work at eliminating areas of bare soil either by cultivating grass or by adding mulch or other cover. In cases where too many wasps are digging too many holes, there are control measures that will kill digging wasps and also reduce next year’s population. Give us a call.