Heritability of tibia fluctuating asymmetry and developmental instability in the winter moth (Operophtera brumata L.) (Lepidoptera, Geometridae)

Broad-sense heritability of fluctuating asymmetry and developmental instabi lity in the winter moth were analysed in a full-sib breeding experiment. Ef fects of both genetic background and common environment on both tibia FA (m easured for the three pairs of legs) and body size were studied. As body si ze has previously been shown to be a reliable indicator of larval feeding s uccess and expected fitness, the relationship between FA and body size was investigated as well. This relationship is of interest because it has been argued that the low heritability of FA results from a strong relationship b etween FA and fitness. Broad-sense h(2) of body size equalled zero whereas the effect of common environment was strong. The heritability of FA was low and not statistically significant for separate tibias. For FA based on the average of the three tibias h(2) equalled 0.07 and differed significantly from zero. The heritability of developmental instability equalled 0.09. Thu s the use of the hypothetical repeatability to translate the h(2) of FA to h(2) of developmental instability did not result in a strong increase in th is species. Individual asymmetry was not correlated with fitness (as estima ted by body size), indicating that the low heritabilities of FA are not a c onsequence of a strong correlation with fitness. Between-trait correlations in the unsigned FA were significant. However, these correlations are not n ecessarily indicative of an individual asymmetry parameter as the signed FA values were positively correlated as well, suggesting interdependent devel opment of the three pairs of legs. Further research is necessary to investi gate what the effects of interdependent development are on patterns in FA.