Genetics. Published Articles Ahead of Print: June 18, 2008, Copyright © 2008
doi:10.1534/genetics.108.087270


A more recent version of this article appeared on July 1, 2008.

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Four QTLs that Influence Worker Sterility in the Honey Bee (Apis Mellifera)

Peter R Oxley 1*, Graham J Thompson 2 and Benjamin P Oldroyd 1

1 University of Sydney
2 The University of Western Ontario

* To whom correspondence should be addressed. E-mail: peter.oxley{at}usyd.edu.au.

Submitted on January 17, 2008
Revised on March 10, 2008
Accepted on 28 April 2008


Abstract

The all-female worker caste of the honey bee (Apis mellifera) is effectively barren in that workers refrain from laying eggs in the presence of a fecund queen. The mechanism by which workers switch off their ovaries in queenright colonies is pheromonally cued, but there is genetically-based variation among individuals: some workers have high thresholds for ovary activation, while for others the response threshold is lower. Genetic variation for threshold response by workers to ovary-suppressing cues is most evident in "anarchist" colonies in which mutant patrilines have a proportion of workers that activate their ovaries and lay eggs, despite the presence of a queen. In this study we use a selected anarchist line to create a backcross queenright colony that segregated for high and low levels of ovary activation. We used 191 informative microsatellite loci, covering all 16 linkage groups to identify QTLs for ovary activation and test the hypothesis that anarchy is recessively inherited. We reject this hypothesis, but identify four QTLs that together explain approximately 25% of the phenotypic variance for ovary activation in our mapping population. They provide the first molecular evidence for the existence of quantitative loci that influence selfish cheating behavior in a social animal.

Key Words: altruism, eusocial, interval mapping, microsatellite DNA, worker sterility