Fig. 2

Schematic representation of possible shape of genotype-by-environment interactions expected if temperature modifies fitness of genotypes determining male morphs. We predicted that for at least some fitness components measured (male reproductive success, development time, longevity), fighter genotypes will have higher fitness at decreased temperature (18 °C), compared to standard laboratory temperature (24 °C), whereas for scramblers the difference should be less pronounced or even reversed. A cross-over relationship shown in the figure is just one possible shape of such interaction. Crossing of fitness functions, coupled with seasonal temperature fluctuations, could contribute to maintenance of genetic polymorphism for male morphs