Hibiscus harlequin bug developmental, weight, and iridescence data

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Despite the fact their colouration functions as an aposematic signal, and is thus expected to be under purifying selection, Hibiscus harlequin bugs (Tectocoris diophthalmus) show an impressive level of variation in their iridescent colouration both within and between populations. Previous work has shown that part of this variation may be due to plasticity in response to temperature. However, populations vary both in the extent of plasticity, and in the distribution of different colour patterns, suggesting a heritable component. To date no studies have examined the heritability of colouration in this species. Here we focus on a single population in the southern part of range, as these populations contain the greatest colour variation. We reared full-sib families of know pedigree in the laboratory and analysed the extent of iridescent colouration once they eclosed to adulthood. We then looked for evidence of heritability, condition dependence, and antagonistic sexual selection acting on colour in this species. We found surprisingly low levels of heritability for colouration, particularly in males. In addition there was no evidence that condition dependence played a role in the determination of adult colouration. There was, however, a sex by genotype interaction for iridescent cover, in the form of a negative intersexual genetic correlation: in families where sons had high iridescent cover the daughters had low, and vice-versa. Thus antagonistic sexual selection is unlikely to be maintaining diversity in colouration in this species.