Inbred bumblebees less successful

Jul 02, 2009

Declining bumblebee populations are at greater risk of inbreeding, which can trigger a downward spiral of further decline. Researchers writing in the open access journal BMC Evolutionary Biology have provided the first proof that inbreeding reduces colony fitness under natural conditions by increasing the production of reproductively inefficient 'diploid' males.

The sex of bumblebees is normally determined by the number of chromosome sets an individual receives. Males, born from unfertilised eggs, are haploid (just one chromosome set), while females receive genetic material from a father and a mother and so are diploid (two sets of ). In situations of , however, the likelihood of generating a 'freak' diploid male is increased.

Penelope Whitehorn, from the University of Stirling, UK, led a team of researchers who sought to investigate the effects of a generation of these diploid males on the fitness of bumblebee colonies. She said, "The study of 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".

The researchers mated fertile female bees in the laboratory with either their brothers or with unrelated males. Those queens that established colonies in the laboratory could be divided into three groups - inbred queens producing diploid males, inbred queens producing normal colonies without diploid males and a control, non-inbred group. After monitoring the initial founding of the colonies in the laboratory, the researchers then compared the development and survival of these three colony groups under natural field conditions. According to Whitehorn, "A number of fitness parameters were severely negatively affected by diploid male production, including colony growth rate, total offspring production and colony survival. However, no significant effects of inbreeding in the absence of diploid male production were detected".

This study demonstrates that diploid males are extremely detrimental for wild bumblebee colonies. Diploid males are produced at the expense of industrious females, but unlike these female workers, they do not contribute to colony growth and productivity. In fact, they do not function very well as males either, as they are much less fertile than normal males and any offspring they do produce are always unviable or infertile. The researchers conclude that diploid males may act as indicators of the genetic health of populations, and that their detection could be used as an informative tool in bee conservation.

More information: Impacts of inbreeding on bumblebee colony fitness under field conditions, Penelope R Whitehorn, Matthew C Tinsley, Mark JF Brown, Ben Darvill and Dave Goulson, (in press), http://www.biomedcentral.com/bmcevolbiol/

Source: BioMed Central (news : web)

Explore further: Research helps steer mites from bees

add to favorites email to friend print save as pdf

Related Stories

Inbreeding insects cast light on longer female lifespans

Feb 06, 2009

Inbreeding can unexpectedly extend male lifespan. Insect experiments described in the open access journal BMC Evolutionary Biology have shown that, in seed beetles, inbreeding causes males to live longer, while shortening ...

Inbred males' scent gives them away

Apr 17, 2008

Female mice can steer clear of inbred males on the basis of their scent alone, according to evidence presented online on April 17th in Current Biology.

Females avoid incest by causing male relatives to leave home

Aug 15, 2007

Researchers at the University of Sheffield in the UK and Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin, Germany, have found that female hyenas avoid inbreeding with their male relatives by giving them little ...

Royal corruption is rife in the ant world

Mar 11, 2008

Far from being a model of social co-operation, the ant world is riddled with cheating and corruption – and it goes all the way to the top, according to scientists from the Universities of Leeds and Copenhagen.

Recommended for you

Research helps steer mites from bees

Sep 19, 2014

A Simon Fraser University chemistry professor has found a way to sway mites from their damaging effects on bees that care and feed the all-important queen bee.

Bird brains more precise than humans'

Sep 19, 2014

(Phys.org) —Birds have been found to display superior judgement of their body width compared to humans, in research to help design autonomous aircraft navigation systems.

User comments : 0