The field scabious is a multipetaled blue–sometimes purple–ball of a flower. It provides sustenance to a host of pollinators, but one bee–the scabious bee, or Andrena hattorfiana–relies exclusively on the plant’s bounty to feed her young.
Such specialized matches are common for bees, whose size, shape, range and even breeding schedule can be influenced by the lifestyle of the paired plant. Now a new study shows that such bees and the plants that sustain them are declining in tandem–for reasons unknown.
The researchers also looked at another pollinating species, hoverflies, and found conflicting overall results. But both bees and hoverflies that depended on particular plants or habitats suffered while their more migratory or generalist brethren prospered. "In Britain, pollinator species that were relatively rare in the past have tended to become rarer still, while the commoner species have become more plentiful," explains team member Stuart Roberts of the University of Reading in England. "Even in insects, the rich get richer and the poor get poorer."
By David Biello