Oecologia

, Volume 158, Issue 4, pp 757–764

Testing competing measures of profitability for mobile resources

  • Maryse Barrette
  • Gi-Mick Wu
  • Jacques Brodeur
  • Luc-Alain Giraldeau
  • Guy Boivin
Behavioral Ecology - Original Paper

DOI: 10.1007/s00442-008-1175-y

Cite this article as:
Barrette, M., Wu, GM., Brodeur, J. et al. Oecologia (2009) 158: 757. doi:10.1007/s00442-008-1175-y

Abstract

Optimal diet theory often fails to predict a forager’s diet choice when prey are mobile. Because they escape or defend themselves, mobile prey are likely to increase the forager’s handling time, thereby decreasing its fitness gain rate. Many animals have been shown to select their prey so as to maximize either their fitness gain or their fitness gain rate. However, no study has yet compared directly these two measures of profitability by generating testable predictions about the choice of the forager. Under laboratory conditions, we compared these two measures of profitability, using the aphid parasitoid Aphidius colemani and its host, Myzus persicae. Fitness gain was calculated for parasitoids developing in each host instar by measuring life-history traits such as developmental time, sex ratio and fecundity. Fitness gain rate was estimated by dividing fitness gain by handling time, the time required to subdue the host. Fourth instar aphids provided the best fitness gain to parasitoids, whereas second instar aphids were the most profitable in terms of fitness gain rate. Host choice tests showed that A. colemani females preferred second instar hosts, suggesting that their decision maximizes fitness gain rate over fitness gain. Our results indicate that fitness gain rate is a reliable predictor of animal’s choice for foragers exploiting resources that impose additional time cost due to their mobility.

Keywords

Fitness Handling time Parasitoids Optimal diet 

Supplementary material

442_2008_1175_MOESM1_ESM.doc (78 kb)
Appendix Table 1 (DOC 78 kb)

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Maryse Barrette
    • 1
    • 2
  • Gi-Mick Wu
    • 1
    • 2
  • Jacques Brodeur
    • 3
  • Luc-Alain Giraldeau
    • 4
  • Guy Boivin
    • 1
    • 2
  1. 1.Agriculture and Agri-Food CanadaSt-Jean-sur-RichelieuCanada
  2. 2.Department of Natural Resource SciencesMacdonald Campus of McGill UniversitySte-Anne-de-BellevueCanada
  3. 3.Département des Sciences Biologiques, Institut de Recherche en Biologie VégétaleUniversité de MontréalMontrealCanada
  4. 4.Université du Québec à MontréalMontrealCanada

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