A couple of years ago, my husband and I set out to see how many species of wasps and bees we could document with photos in our small urban yard. We’re up to nearly 90, which covers all the conspicuous and easy-to-ID stuff. One of the challenges has been to differentiate among all the black and yellow wasps. The yellowjackets and other hornets aren’t too bad, but there are many species of potter and mason wasps in the family Eumeninae that are very similar except for the number or arrangement of yellow spots or stripes on a black body.
A series of good photos from multiple angles often cinches the ID. Occasionally we have to resort to netting an individual, chilling it, and looking at some features under a microscope while consulting detailed keys.
That is how I discovered a remarkable structure found on some bees and wasps, especially the Eumeninae: the acarinarium.
Acarinaria are special structures on the body of bees and wasps that function exclusively to harbor mites. They may be a hollow chamber, a hairless area that is easy for mites to cling to, or a series of pits along the edge of an abdominal segment. In my photo of the potter wasp above, the mites are carried on the thorax.
The mites on the wasp are benign – they are in a non-feeding phase while on board. If the mites are on a male wasp, they transfer to the female when the wasps mate. Potter and mason wasps are not social wasps; each female constructs a separate nest made of mud, in the ground, in wood, or some other cavity. As the female provisions her nest, the mites disembark. There they continue to develop, and once the immature wasp pupates, the adult mites feed on the young wasp. Amazingly, this apparently does not harm the wasp. A new generation of mites hitches a ride out of the nest on the wasp when it emerges.
Evolving modified body parts to accommodate mites makes sense so long as the mites are beneficial. It’s presumed that the mites perform a service in the nest prior to them feeding on the wasp, such as combating fungi, predators, or parasites that might damage wasp eggs or young. Each genus of wasp is associated with a particular genus of mite, so this relationship is very specialized. Yet the precise mechanism of this mutualism is still poorly understood.
Now, do we start a mite list for the yard?
Tags: bees, Insects-and-Spiders, Michigan, mites, postaday 2011, wasps
Fascinating….I too content myself in my yard discovering all sorts of macro/micro lives. So few do….sorry to say.
Mites are also found on hummingbirds and I once saw some footage taken at the Explorer’s Inn Peru showing mites rushing down the beak of a hovering feeding hummingbird to scoop up some nectar for themselves and then rush back on the beak back to the hummingbird proper, all in mite of a second….
This post is too interesting (and surprising) to pass up. I’m encouraged to take a closer look at these critters – except I’m allergic if stung. Took have a degree in Zoology, took entomology but that was in the 60′s and we didn’t get into such “mitey” fine details. Had no idea that such a relationship existed. Thanks for sharing. What camera equipment are you using to get so up close and personal? Great photo!
Very interesting, indeed. I haven’t had the pleasure of finding any insects with phoretic mites, but there are a number of nice photos on Buguide.net. Most of them on Eumeninae wasps and carrion beetles, but there is even one on a damselfly.
http://bugguide.net/node/view/194182
http://bugguide.net/node/view/84363
http://bugguide.net/node/view/84930
This one should go in the Guiness book of records. I can’t imagine how that carrion beetle manages to walk.
http://bugguide.net/node/view/489470
That’s really interesting. Just goes to show that you don’t need to travel to exotic locales to find cool stuff, there’s a ton of it right under our noses.
Thanks to everyone for the comments. I originally considered doing a broader topic that included both hummingbird mites (which actually hitch rides in hummingbird nasal cavities to disperse to other flowers to find other mites to mate with) as well as dragonfly mites. Posts for another time! Bill, I use a Canon Digital Rebel XS with a 100 mm macro lens, hand-held. You still have to get fairly close, but I have never been stung. Remember, only female hymenopterans can sting, in many species males are more common than females, and even large species, so long as they are not social nesters, are not aggressive and have mild stings (not helpful if you are allergic, of course, but at least you are unlikely to get stung).
My husband and I often post on our insect work and adventures at Urban Dragon Hunters — http://urbanodes.blogspot.com