|Gold-necked Carrion Beetle|
|Tomentose hairs on thorax, mites clinging to the neck - Click to enlarge|
Phoresy in the title refers not to the lead singer of a hard rock band but the act of hitching a ride on a larger animal of a different species as transport from place to place. This relationship excludes parasitism where the transporting animal is harmed. In general there are three factors in common in phoresy. (1) The mite actively seeks the host. (2) It doesn't feed or develop while on the host. (3) It departs at a food source to mature and reproduce. Obviously carrying around a load of mites is expensive in energy so why has the relationship evolved? Jim McClarin explained their mutualistic relationship this way in Bugguide.
"The mites benefit the beetle. They eat the eggs and freshly-hatched maggots of carrion flies that would both compete for food and poison the food with their high-ammonia waste products. The mites help the beetle's larvae to survive, giving their own young a new generation of beetles to ride to the next carcass. It's a beautiful relationship that stinks to high heaven :-)"Mites lack the wings to seek out dead animals which are their source of food. Fortunately they have become good neighbors with carrion beetles, in this case Nicrophorus tomentosus. Different species of mites tend to ride on beetles in the same genus and some species seem to prefer either N. tomentosus or the closely related N. orbicollis.* Nicophorus sp. support at least 14 species of mites in 4 different families. One of the most studied and largest at 1mm is Poecilochirus carabi.*
|Poecilochirus nymphs - Steve Nanz|
|Mites on the elytra - Tom Murray CC|
|"All aboard!" - REK|
* Mites: Ecological and Evolutionary Analyses of Life-history Patterns
More on mite phoresy at Scienceblogs.com.