What I'm writing about today is a bit different. I managed to snap a picture of a bumble bee-imitating robber fly last week in my local ravine park. Although it's possible that the bumble bee-imitation confers some anti-predation advantages to the robber fly through Batesian mimicry, something else is probably also going on here: Wicklerian-Eisnarian mimicry. The idea with this kind of mimicry is that an organism imitates a less harmful one in order to avoid detection by its prey. Robber flies prey on other insects, including bees; looking a lot like a bumble bee is probably a pretty good way to get close enough to their prey to kill them, since bees are nectar and pollen eaters rather than insect eaters. From the perspective of many insects, a bumble bee is no particular threat, while a robber fly is definitely worth avoiding.
There are many other types of mimicry besides these two, as well. I was rather pleased to get a picture of a bee mimic that isn't a pollinator but rather a predator. Pretty neat! They also sound a lot like bumble bees, interestingly, so the mimicry goes beyond visual cues in the case of this robber fly, which I think is in the genus Laphria, and which has caught an emerald ash borer (Agrilus planipennis). Robber flies consume their prey by piercing their bodies with a hardened tube that serves as their mouth, through which they inject their prey with some digestive enzymes and then suck out the delicious bug juice that results.
|Laphria sp. consuming Agrilus planipennis (sorry for the crummy cell phone camera photo)|