Most studies of phenotypic plasticity investigate the effects of an individual environmental factor on organism phenotypes. However, organisms exist in an ecologically complex world where multiple environmental factors can interact to affect growth, development and life histories. Here, using a multifactorial experimental design, we examine the separate and interactive effects of two environmental factors, rearing host species (Vigna radiata, Vigna angularis and Vigna unguiculata) and temperature (20, 25, 30 and 35°C), on growth and life history traits in two populations [Burkina Faso (BF) and South India (SI)] of the seed beetle, Callosobruchus maculatus. The two study populations of beetles responded differently to both rearing host and temperature. We also found a significant interaction between rearing host and temperature for body size, growth rate and female lifetime fecundity but not larval development time or larval survivorship. The interaction was most apparent for growth rate; the variance in growth rate among hosts increased with increasing temperature. However, the details of host differences differed between our two study populations; the degree to which V. unguiculata was a better host than V. angularis or V. radiata increased at higher temperatures for BF beetles, whereas the degree to which V. unguiculata was the worst host increased at higher temperatures for SI beetles. We also found that the heritabilities of body mass, growth rate and fecundity were similar among rearing hosts and temperatures, and that the cross-temperature genetic correlation was not affected by rearing host, suggesting that genetic architecture is generally stable across rearing conditions. The most important finding of our study is that multiple environmental factors can interact to affect organism growth, but the degree of interaction, and thus the degree of complexity of phenotypic plasticity, varies among traits and between populations.
|Number of pages||13|
|State||Published - Aug 2007|
Bibliographical noteFunding Information:
Acknowledgements We thank D. Johnson and O. Njoku for help weighing and mating beetles during the experiment. We also thank K. Haynes for statistical advice, and thank Jay Rosenheim and two anonymous reviewers for providing helpful comments on earlier drafts of the manuscript. Financial support was provided in part by a National Science Foundation grant (NSF DEB-01-10754) to C. W. F. Institutional guidelines were followed for animal care.
- Callosobruchus maculatus
- Genetic architecture
- Reaction norm
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics