This morning in the flower garden I found a Siricid, a horntail wasp, a large male, crawling slowly up and down the raceme of a flowering mint. Soon I discovered, beneath him, a second male of the same species, and they seemed to be in some sort of competitive ritual. But, whoa! The surprise is that the smaller male hasn’t moved much because…
Did you see it? After watching them for about three hours, during which time the larger one continued wandering up and down the stalk, I noticed that the smaller one was moving only very slightly. I didn’t realize it until I enlarged a photo afterwards. Then I went back for a better look. Yikes! A crab spider!
Crab spiders are generalist predators that roughly match their substrate, so they qualify as “aggressive mimics.” The phenomenon is also known as “mimesis” when the model is inanimate, or at least not another similar species. Background mimics or cryptic species are mimetics.