In haplodiploid insects, males develop from unfertilized eggs; consequently, unmated females can reproduce. In a patchy, highly structured population, where brothers compete for mates and the reproductive return through sons is lower, females should minimize the number of male offspring. Consequently, unmated females are likely to have a reduced fitness compared to mated females. Here, we tested the oviposition behaviour of the haplodiploid beetle Coccotrypes dactyliperda. In this species, the unmated female can mate with her son to produce daughters. We predicted that unmated females could increase their fitness by (1) producing only few and small sons sufficient for mother-son mating and (2) dispersing to a patch occupied by conspecific females in order to increase their or their sons' chance of mating. We demonstrate that (1) unmated females are common (23 % of all females), (2) they oviposit more frequently than mated females in occupied patches, (3) unmated females oviposit more eggs than mated females-this is in spite of the trade-offs, evident in this study, between the number of sons and the number of the mother's future offspring after mating, (4) unmated females have a higher proportion of dispersing sons, and (5) sons of unmated females are smaller than sons of mated females. We conclude that the incidence of unmated females in the structured populations of C. dactyliperda is explained by plasticity in their oviposition behaviour. We discuss conditions where a high incidence of unmated females can persist as a successful strategy in structured populations.
Bibliographical noteFunding Information:
Acknowledgments The authors gratefully acknowledge Tamar Keasar and her lab members for stimulating discussions and Peter H. Biedermann for his friendship and constructive comments on this manuscript. We thank Ofer Ovadia for assistance with image capture software and Dvorah Gordon for lab assistance. We thank four anonymous referees for very useful comments. We are grateful to Ian Hardy for suggesting areas of major improvement. This research was partially supported by the Israel Science Foundation grant 184/06 to A. Bouskila, T. Keasar, and A. R. Harari.
- Coccotrypes dactyliperda
- Local mate competition
- Male dispersal
- Unmated females
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology