| Abstract: | Whether an individual strives to breed or restrains from reproducing directly but increases the fitness of another individual through its help, may be viewed as a result of a trade-off between fitness costs and benefits arising from this decision. A population of the large carpenter bee Xylocopa sulcatipes Maa was studied in southeast Israel over a two year period. Female reproductive success, in terms of genetic representation in the gene pool (genetic gain), was calculated using coefficients of relatedness and the number of offspring produced by solitary, reproductively dominant and helper bees of social nests. In one year helper females, that shared a nest with a related female accrued a higher genetic gain than did solitary females. In the subsequent year solitary females did better than the helper bees. In nests founded by unrelated females a helper bee accrued only little genetic gain. However, evidence is presented to show that subordinate behaviour can have an adaptive value and can ultimately be beneficial through nest inheritance by the subordinate bee. |
