Male mate recognition and female phenotypes: testing for reproductive character displacement in demoiselle damselflies (Calopteryx spp.)

Wasteful reproductive interactions between species, known as reproductive interference, impact numerous ecological and evolutionary processes (e.g., determining whether species can coexist). Theoretical models of reproductive interference largely focus on male signal traits and their impacts on female mating decisions. Nevertheless, male mating decisions are often the primary drivers of reproductive interference. Demoiselle damselflies (Calopteryx spp.) are a model system for studying the evolutionary consequences of social interactions between species. Yet, despite the fact that male damselflies initiate mating interactions, there has been little research into the mechanisms by which variation in female demoiselle phenotypes impact male sexual responses. Consequently, there remains much unexplained spatial and temporal variation in reproductive interference, even in this model system. To address this critical gap in our understanding of how male behaviour and female phenotypes impact the dynamics of reproductive interference, this PhD will employ a unique combination of behavioural experiments on damselflies in the field, public engagement through citizen science, and cutting-edge AI methods.
Specific Aims: To date, data from behavioural experiments suggest that there are low levels of reproductive interference between the two species of demoiselle damselflies in in the United Kingdom (C. virgo & C. splendens; Figure 1) where they coexist. To test the hypothesis that low levels of reproductive interference have resulted from selection driving divergence in traits that mediate interspecific reproductive interactions (i.e., reproductive character displacement), the student will:
(1) build on an ongoing citizen scientist scheme to quantify geographic variation in the wing coloration of female Calopteryx damselflies in the UK to test the prediction that females of the two species are more dissimilar in zones of sympatry than in allopatry; and (2) conduct behavioural experiments to map male mate recognition functions (i.e., the decision rules males use to determine if an individual is a potential mate) to test the prediction that males are more discerning in sympatry than in allopatry.