Afrotropical Carpenter Bee (female)

This bee has developed a special cavity, called an acarinarium, on the abdomen. The cavity has evolved specifically to transport mites. The relationship is an example of a mutualism that is of benefit to both the bee and the mite. The mites hitch a ride from the nest the bee developed in to any new nests that she constructs for her off-spring. The mites feed on fungi in the nest keeping it away from the pollen provisions and her larva. More to read and a picture here: http://www.waspweb.org/Apoidea/Apidae/Xylocopinae/Xylocopini/Xylocopa/X…
Xylocopa bees do have quite a painful sting but they are not aggressive and will only sting for defence. Individuals live independently of the others (i.e. they are solitary) or in small groups. Xylocopa bees are larger than honey bees, hairy, often colourful and their wings make a loud buzzing sound while flying. Xylocopa bees nest in tree trunks, in dead wood, bamboo, or structural timbers. They construct their nests by boring tunnels in wood materials, which is why they are known as carpenter bees.