Abstract
Many animal species rely on changes in body coloration to signal social dominance, mating readiness and health status to conspecifics, which can in turn influence reproductive success, social dynamics and pathogen avoidance in natural populations. Such colour changes are thought to be controlled by genetic and environmental conditions, but their relative importance is difficult to measure in natural populations, where individual genetic variability complicates data interpretation. Here, we studied shifts in melanin-related body coloration in response to social context and parasitic infection in two naturally inbred lines of a self-fertilizing fish to disentangle the relative roles of genetic background and individual variation. We found that social context and parasitic infection had a significant effect on body coloration that varied between genetic lines, suggesting the existence of genotype by environment interactions. In addition, individual variation was also important for some of the colour attributes. We suggest that the genetic background drives colour plasticity and that this can maintain phenotypic variation in inbred lines, an adaptive mechanism that may be particularly important when genetic diversity is low.
Highlights
Animal coloration can indicate social status or the health condition of animals [1]
Changes in chroma differed significantly between lines (t54.49 1⁄4 3.128, p 1⁄4 0.003) being higher in R than DAN individuals; this attribute was influenced by individual identity when models were compared (x2 1⁄4 197.41, d.f. 1⁄4 2, p, 0.001; electronic supplementary material, table S3c). Environmental fluctuations, such as the presence of conspecifics or parasitic infection, have the potential to influence the phenotypic traits exhibited by individuals, including colour
Our results suggest that both infection and social context influence lightness, observable colour and brightness in an inbred fish species which, to some extent, displayed individual variation
Summary
Animal coloration can indicate social status or the health condition of animals [1]. Colour signalling allows individuals to assess the social dominance, mating capability and/or health& 2019 The Authors. Animal coloration can indicate social status or the health condition of animals [1]. Changes in the distribution of melanin and carotenoids cause colour variation that has been related to behaviour, social dominance and infection status. Carotenoid pigments, responsible for bright orange coloration, have been widely studied for their role in the immune response of vertebrates and in the production of related signalling for sexual selection [5,6,7]. Melanin-based coloration might play a role in sexual selection through its link to body condition, as the genes involved in melanin production regulate different phenotypic traits, which can be affected by frequency-dependent selection and/or local adaptation [9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
