Many Carpenter Bees carry Mites in special pouches, and this relationship is not yet fully understood.
The European Carpenter Bee (Xylocopa violacea) is a very large insect, often confused with some of the larger Bumblebees. It is a solitary species that bores a hole in wood to lay its eggs. The tunnel is usually deep enough for about a dozen eggs, each supplied with a mixture of pollen and nectar. Although these bees chew holes in wood, and use the sawdust between successive eggs, they do not eat it.
Carpenter Bees
There are about 500 species of Carpenter Bee worldwide, all with very similar habits. There are five species in America, and although they make holes in wood (and the females are capable of stinging) they are not a serious nuisance. Indeed they can be very ‘tame’ (Tame Carpenter Bee Images). They prefer to tunnel into untreated and unpainted wood, and the more aggressive males cannot sting. It is possible to protect important timber by simply painting it, so there is no need to resort to the use of insecticides.
Pollination
Although Carpenter Bees will sometimes chew holes in tubular flowers to ‘rob’ nectar they are very good pollinators of many ‘open-faced’ flowers. Very little is known about their preferences and, until shown to be otherwise, it is probably best to consider their role ‘important’.
Mites
The European Carpenter Bee has a special ‘Mite Pouch’ where it carries mites. Exactly why they do this is not known, but it is likely that the mites help keep the brood clean. The mites probably eat fungi that would otherwise grow in the burrows and damage the developing young. The fact that the bees have evolved a special ‘acarinarium’ (mite pouch) shows how important this bee-mite relationship is, even if we do not fully understand it!
Animal Relationships
The bee-mite relationship is just one of many that are not at present well understood. As more and more becomes known about the importance of particular relationships between animals (and often specific animals with specific plants) it becomes clear how important they can be. Fig Wasps are a case in point – the figs cannot survive without the wasps, and the wasps cannot survive without the figs. Before this was understood it might have been tempting to kill off the nasty little insects that got into the fruit!
Caution
The Carpenter Bees represent just a few species among millions that we do not fully understand. While we are probably quite right to try to eradicate insects which carry diseases, it is not a good idea to ‘declare war’ on insects which can be a marginal ‘nuisance’ – at least not until we fully understand their role in the natural world.
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