Incest leaves bumblebees facing threat of extinction

Rare Bumblebee species face being wiped out by inbreeding, as declining populations force them to mate with relatives, Scots scientists have warned.

The insects are now mainly confined to small isolated sites, after being isolated by intensively farmed land.

The researchers say incest is rife, producing sterile males that cannot reproduce.

Bumblebees are crucial to the environment and food production, because they pollinate plants and crops.

Biologist Penelope Whitehorn said: "The study of genetic diversity and inbreeding in bumblebees is currently of particular importance, as many species have been suffering from significant population declines. The intensification of agriculture and the associated loss of flower-rich meadows and other habitats on which bumblebees depend has led to isolation of groups of bees and a consequent loss of their genetic diversity, increasing their susceptibility to possible deleterious effects of inbreeding."

She went on: "Inbreeding and the loss of genetic diversity are known to be significant threats to small, isolated populations. The genetic health of populations is increasingly viewed as one of the most important factors in maintaining fitness in an uncertain and changing environment.

Her team at Stirling University mated fertile female bees in the laboratory with either their brothers or unrelated males. The results of the study are published in BMC Evolutionary Biology.