Study: Inbred bumblebees less successful

STIRLING, Scotland, July 1 (UPI) -- Scottish-led scientists say they've discovered the first proof that inbreeding reduces bumblebee colony fitness by hiking production of inefficient males.

The scientists led by Penelope Whitehorn from the University of Stirling said the sex of bumblebees is normally determined by the number of chromosome sets an individual receives. Males, born from unfertilized eggs, are haploid -- having just one chromosome set. Females receive genetic material from a father and a mother and so are diploid -- having two sets of chromosomes.

In situations of inbreeding, however, the likelihood of generating a "freak" diploid male is increased.

"The study of genetic diversity and inbreeding in bumblebees is currently of particular importance as many species have been suffering from significant population declines," Whitehorn said.

The researchers said their study demonstrates diploid males are extremely detrimental for wild bumblebee colonies since they do not contribute to colony growth and productivity. The diploid males are much less fertile than normal males and any offspring they do produce are either not viable or infertile.

The researchers conclude diploid males may act as indicators of the genetic health of populations, and their detection could be used as an informative tool in bee conservation.

The study appears in the journal BMC Evolutionary Biology.