Wasp-powered Spider-raft

In a mood to excavate a wasp nest, I decided to revisit the sandy river bank where I'd seen several square-headed wasps nesting just last week. The main trail at the Cowling Arboretum follows the Cannon River for a good distance. I stopped at one point and looked out over the river, hoping to see dragonflies. There were none. But I did notice something about the size of a fallen leaf moving on the surface of the water below me. I climbed down the bank for a closer look and suddenly realized what I was seeing---a large spider wasp ferrying a large fishing spider. I hurried to get a few photos before it made landfall. What a spectacle to witness a wasp-propelled spider creating a wake like a barge.

As soon as the wasp came ashore, it abandoned the spider (probably I'd made it nervous tromping along the river bank to keep up). The wasp landed a few feet away and groomed herself, but eventually made her way back to reclaim the spider. After dragging the spider a few inches, the wasp flew off, a fair distance this time, disappearing beyond a downed tree and rocks. But the wasp soon returned again. Perhaps she had gone ahead to inspect and ready the burrow or crevice in which it would place the spider.

Looking at the photos I took, comparing them to the single set of photos I could find online, I noticed that in both instances the wasp extended it flat front feet and used them like water skis. as it towed the spider across the water.

Posted on September 12, 2017 03:41 AM by scottking