Phoretic Mites!

What's that schmutz on my wasp?!?!

As a science teacher for the past several years, I've taught about symbiosis and definitely thought I knew about this topic.  Symbiosis is defined as "a close relationship between two organisms where one lives on, in, or very near the other and where at least one of the organisms benefit from the relationship."

I've always taught about the three types of symbiosis:
Mutualism:  A symbiotic relationship where both organisms benefit (i.e. bees & flowers)
Commensalism: A symbiotic relationship where one organism benefits and the other is not really affected (i.e. barnacles on whales)
Parasitism: A symbiotic relationship where one organism benefits and the other is harmed (i.e. tapeworms)

And now I feel like a lousy science teacher!!  I recently learned about another type of symbiosis that I knew nothing about: phoresy.  And this type of symbiosis is pretty fascinating.  It's a transportation symbiosis!  One organism (the "phoront") is transported from one place to another by the host.  Neither organism depends on the other in a physiological way.

I learned about this while looking at bees and wasps under the microscope.  I saw that the Eumenid wasp pictured above had some brownish "stuff" on it.  "What is that?  Weird pollen?  Some sort of fungus?"  Nope.  The answer is phoretic mites!

So here's the story of the mites:
Mites that are on a male wasp can be transferred to a female wasp during mating.  The female wasp carries the mites back to her nest and they disembark.  While she lays her eggs and the larvae develop, the mites live in the nest.  It is thought that they are "housekeepers" in a way, feeding on debris in the nest and even "cleaning" the developing wasps.  The mites time their reproduction to coincide with the time that the new generation of wasps leaves the nest.  The "baby" mites hop onto the newly grown wasps and get carried to new nests where the cycle continues.

What's amazing is that some wasps actually have little body cavities (usually on the thorax) where the mites can safely congregate.

I was fascinated by this phenomenon and started seeking out more information, especially related to wasps.  So currently there are three scientific papers and a section of a book on solitary wasps on my table waiting to be read...  I'm excited to learn more!

I looked up other pictures online when I was geeking out on phoresy.  Apparently it's pretty common in beetles as well:

from bugguide.net

from wildabouttheworld.com