Abstracts (first author)
Plastic mating strategies: transcriptomics of male responses to mating rivals in Drosophila melanogaster
Behavioural plasticity is an important strategy that enables animals to respond to short term fluctuations in the environment. The socio-sexual environment can vary rapidly, dictating the level of mating opportunities and competition an individual encounters. Males of many species show plasticity in response to this variation. For example, in Drosophila melanogaster, males show a sophisticated and consistent response to the threat of mating competition as signalled by the presence of rivals. Following exposure to a rival male, focal males mate for significantly longer than their counterparts held alone. This results in a significant increase in male fitness in both competitive and non-competitive matings. Males use a complex set of cues to assess the presence of rivals. However, there are also costs, and individuals that maintain responses to rivals throughout life show reduced lifespan and mating success in older life. Plastic responses to rivals are highly flexible and associated with variation in the transfer of ejaculate proteins into females during mating. In this study, we investigated the underlying transcriptomic changes that characterise responses to rivals, using a global mRNAseq approach. We analysed gene expression changes according to the length of exposure to rivals and within different tissue types (the head and thorax versus abdomen). This enabled us to identify highly differentially expressed candidate genes associated with sensing rivals, with temporal changes in behaviour and with manipulating ejaculate content in response to exposure to rivals. These data allow us to investigate the phenotypic role of these transcriptional changes and explore how such a response is regulated. The work is important for understanding how sophisticated and flexible behavioural plasticity can evolve.