Tuesday, January 12, 2016

Adaptations - Aggressive Mimicry

Back in 2013, I wrote a post titled  "Mom! The Viceroy won't stop copying me!" about how animals use mimicry to deter predators.

In that post, I wrote about two forms of mimicry known as Batesian mimicry and Mullerian mimicry.  Batesian mimicry is a form of mimicry in which a harmless species copies the warning signs of a harmful species to scare away predators.  Mullerian mimicry is a type of mimicry in which two distasteful, poisonous, or otherwise harmful species have evolved to resemble each other - sharing the warning signs that keep predators away.

Recently, while searching through old photos I found an example of a third type of mimicry.

Bee Hunter - a type of robber fly

This is not a bee.  It's a type of fly known as a robber fly.  At first glance, this seems to be a clear cut case of Batesian mimicry.  By evolving with the colors of a bee, this fly is afforded protection from any potential predators without needing to have a stinger of its own.  This is a very common (and sensible) survival strategy

Bee Hunters exhibit aggressive mimicry - they look like their prey to fool them

However, this species in not exhibiting pure Batesian mimicry.  It does get some protection benefits from its yellow-and-black coloring, but in this species those colors serve a more sinister purpose.  This is one of several species of robber flies known as a Bee Hunter.  The Bee Hunter uses a form of mimicry known as aggressive mimicry.

Bee Hunter (closeup) - note the spines on the legs used for grasping prey and the proboscis used to such fluids from prey

Aggressive mimicry is a type of mimicry used by predators to appear harmless to their prey.  In this case, the Bee Hunter is a predator that preys on pollinators such as bees and wasps.  By resembling a bumblebee, the Bee Hunter appears to these insects as another harmless pollinator and is able to ambush them with less effort.  It grasps them with its long front legs - spine on the legs help immobilize their prey.  The Bee Hunter is covered with long stiff hairs that further help protect it from struggling prey.  One a prey is captured, the Bee Hunter uses is stiff proboscis to impale the unfortunate victim and suck out its insides.

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