Behavioral Ecology Advance Access originally published online on August 25, 2008
Behavioral Ecology 2008 19(6):1075-1079; doi:10.1093/beheco/arn108
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Male elimination in the honeybee
a Department of Zoology, 203 Natural Sciences Building, Michigan State University, East Lansing, MI 48824, USA b Kellogg Biological Station, Michigan State University, Hickory Corners, MI 49060, USA
Address correspondence to K.E. Wharton. E-mail: wharton2{at}msu.edu.
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Abstract |
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In a striking example of sex allocation modification, female social insect (hymenopteran) workers sometimes cannibalize a fraction of their colony's immature males. The commonly cited explanation for this male elimination is that workers are in genetic conflict with the queen and are biasing the colony's sex allocation in their favor. However, this behavior might allow workers to tailor their colony's investment in reproduction to environmental conditions and therefore might play an important role even in the absence of queen–worker conflict. So far, male elimination has been demonstrated only in species where the potential for queen–worker conflict is high. Here we present experimental evidence for facultative male elimination in the honeybee, a species where queen–worker conflict is expected to be minimal or absent because of multiple mating by the queen. We manipulated the abundance of older male brood in colonies and found that survival of younger male larvae was lower when we increased the abundance than when we decreased it. Survival of worker larvae was high across colony conditions. These results suggest that genetic conflict is not a necessary precondition for male elimination in social insect societies. Instead, male elimination might sometimes reflect adaptive adjustment of male reproductive function, potentially increasing colony efficiency in the interests of all colony members.
Key words: cooperation, kin selection, male elimination, male reproductive function, queen–worker conflict, sex allocation.
Received 25 February 2008; revised 18 July 2008; accepted 27 July 2008.