Our glorious bank of Sedum outside the visitor centre has been attracting a host of different bumblebees, honeybees, wasps and butterflies. I always get a headache when trying to sort out bees so have despatched some images to be sorted out for me... more to follow.
Anyway, as you may be aware the decline of the honeybee has been blamed on a virus carried by the Varroa mite. On this picture of a Buff-tailed Bumblebee you can clearly see that Bumblebees also carry their own parasitic hitchhikers! However, I had always assumed that they were feeding off of the bees but a quick google search resulted in the following on the Bumblebee Conservation website:
'These mites do not actually harm bees directly. In sufficient numbers they can make flight or even movement difficult. We suggest that people try coaxing the mites off the bees using a childs paint brush.
At least 15 genera of mites are associated with bumblebees. The most familiar of these are mites of the genus Parasitellus which are very often to be seen attached to the bodies of adult bumblebees, particularly queens. These mites are only ever found in close association with bumblebees. However, they do not feed directly upon bumblebees, but are phoretic, using the adult bees for transport between nests. This is a common phenomenon; mites have poor locomotory abilities, but with their small size they can easily attach themselves to larger organisms and so gain a free ride. Parasitellus species are thought to feed upon wax, pollen, and other small arthropods that are found in bumblebee nests. Only the deutonymph stage is phoretic, colonising new nests by transferring from workers to flowers, and then awaiting the arrival of another worker. The prevalence of Parasitellus spp. is generally high - up to 80% of queens are affected. With this level of prevalence at the beginning of the season, it is not surprising that the vast majority of bumblebee nests become infested by the end of their growth.
Because these mites do not feed upon the bees themselves, it is debatable whether they have a negative impact. However, infestation levels can be high. Up to 165 mite have been found on a single. It seems inevitable that loads of this magnitude must hamper a queen's ability to fly, and so her ability to find food, a mate and a hibernation site. Try to help these queens by brushing off the mites.''