Behavioral Ecology and Sociobiology

, Volume 59, Issue 5, pp 589–596 | Cite as

Impacts of flight distance on sex ratio and resource allocation to offspring in the leafcutter bee, Megachile rotundata

  • Jason H. PetersonEmail author
  • Bernard D. Roitberg
  • J. H. Peterson
Original Article


Fisher's theoretical prediction of equal investment in each sex for a panmictic population (The genetical theory of natural selection. Clarendon, Oxford, 1930) can be altered by a number of factors. For example, the sex ratio theory predicts variation in equal investment in each sex when the maternal fitness gains from increased investment differ between sexes. Changing sex allocation because of changing payoffs may result from different ecological situations, such as foraging conditions. We investigated the impact of foraging travel cost on relative investment in sons vs daughters. Field studies were carried out with the central-place-foraging leafcutter bee Megachile rotundata (Fabricius), which has smaller males than females. Therefore, less investment is required to produce a viable son compared with a daughter. We found that with increased flight distance to resources, females produced a greater proportion of sons. Females also invested fewer resources in individual sons and daughters and produced fewer offspring with increased flight distance.


Sex ratio Flight distance Central-place-forager Megachile rotundata Leafcutter bee 



We thank NSERC, Canada, for a scholarship to Jason Peterson and an operating grant to Bernard Roitberg. Thank you to our field assistant Gordon Peterson and our laboratory assistants Angela Mah and Mary Peterson. Larry Dill, Bob Lalonde, Brian Ma, Jen Perry, Mark Winston and two anonymous reviews made useful suggestions on earlier versions of this paper. When we carried out our experiments, we adhered to the legal requirements of Canada.


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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Jason H. Peterson
    • 1
    Email author
  • Bernard D. Roitberg
    • 1
  • J. H. Peterson
    • 2
  1. 1.Behavioral Ecology Research Group, Department of BiologySimon Fraser UniversityBurnabyCanada
  2. 2.Department of BiologyThe King's University CollegeEdmontonCanada

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