1. ¹Department of Animal Ecology I, Bayreuth University, Bayreuth, Germany
2. ²Institute of Biology, Leiden University, Leiden, The Netherlands

Correspondence: Dr K Fischer, Department of Animal Ecology I, Bayreuth University, PO Box 101 251, D-95440 Bayreuth, Germany. E-mail: klaus.fischer@uni-bayreuth.de

Received 1 August 2006; Revised 12 September 2006; Accepted 28 September 2006; Published online 15 November 2006.

Abstract

We use artificial selection experiments targeted on egg size, development time or pupal mass within a single butterfly population followed by a common-garden experiment to explore the interactions among these life-history traits. Relationships were predicted to be negative between egg size and development time, but to be positive between development time and body size and between egg size and body size. Correlated responses to selection were in part inconsistent with these predictions. Although there was evidence for a positive genetic correlation between egg and body size, there was no support for genetic correlations between larval development time and either egg size or pupal mass. Phenotypic correlations among the three target traits of selection gave comparable results for the relationships between egg mass and development time (no association) as well as between egg mass and pupal mass (positive association), but not for the relation between development time and pupal mass (negative phenotypic correlation). In summary, correlated responses to selection as well as phenotypic correlations were rather unpredictable. The impact of variation in acquisition and allocation of energy as well as of the benign conditions used deserve further investigation.