Today on a tree in my backyard I spotted an incredible gathering of cicada killers. These large solitary wasps are yellow-striped and an inch-and-a-half long. They dig burrows, paralyze cicadas, and then entomb their prey in a nursery where the young wasp larvae eat them alive. I’ve got a special interest in this species, so I know them well. But I’ve never seen what I witnessed today.
The small ash tree was alive with activity. These wasps pack a potent sting but won’t attack a human like smaller wasps defending a nest, so I eased close with a camera and tried not to fuzz them up. It was soon clear that the wasps were feeding on sap in the super hot weather. Tree sap is sweet and provides food for all kinds of insects. But like blood, it isn’t supposed to leak outside the vascular system. Ash borers were the culprits. These beetles complete development in ash wood and then burrow out through the bark. Exit wounds allow sap to bleed, and apparently the wasps could smell the sweet ooze. So they were feeding heavily before the arduous weeks of provisioning their own nests.
I guessed that at least a thousand of the giant wasps were on the tree. They were buzzing and fighting over the best locations, and other insects were seen as well: green june bugs, black spider-hunting wasps, and a few butterfly species. But the cicada killers, usually seen by themselves as their “solitary wasp” category implies, were urgently sucking the sweet juice. Both males and females were present in abundance, but I saw no sign of mating activity at this key time of summer. They were just stocking up on the sweet goo.
I wanted a tree bark perspective, but didn’t want to approach the wasps that closely. So I taped a small video camera onto a garden hoe, turned on the camera with LCD viewer so that I could see it from a handle’s distance away, and then eased the camera to the tree’s surface. That provided a “snail’s eye” view of the activity up the tree trunk.
Cool. Except it was danged hot. Take a look at the footage for an unusual summer view of outdoor Kansas. Something is always there if you look.