Evolutionary dynamics in breeding systems under sexual conflict

Roger Härdling,  Lund University

I am interested in how selection pressures arising from evolutionary conflicts between the sexes affect animal evolution. My main focus is on issues related to breeding behaviour, such as evolution of mating system and parental care, and on consequences for genetic differentiation within and between populations. One part of my research interest is to develop and analyse theoretical models that combine behavioural ecology with population genetics, life-history theory and population dynamics. I also study different model organisms empirically to test and verify critical model predictions and assumptions.

I study sexual conflict in the diving beetle Dytiscus marginalis, where females occur in two distinct and conspicuous morphs without intermediary variants. One female morph has deep grooves on the wing covering elytra, but the other has completely smooth cover wings, just like the males. Males have modified front legs, with large discs full of tiny suction cups which are used in mating attemps to grab the female, so it has been proposed that the grooves on the back have evolved to make escape from harassment easier. The aim is to test whether sexual conflict is the selective reason for the maintenance of polymorphism, as my theory and models suggests. We use different methods to do this, from studying behaviour in the laboratory to breeding experiments to study genetic consequences of conflict.

I am also interested in the variation of solutions to the social game between the sexes. Usually, sexual interactions are the female’s “market”, since females produce the offspring and males compete for females. Sometimes, though, males have something to offer as well and then the situation may be different. I investigate this general situation both by game-theoretical modelling and by empirical studies of a curious bug species (Phyllomorpha laciniata) where females lay most eggs on the back of males of the same species, to protect the eggs from predators.

Together with international collaborators I investigate the sensory biology of the species, such as neurophysiological adaptations and pheromone ecology, as well as the behavioural variation in relation to my theoretical predictions about e.g. density and predation risk effects. The aim is to understand what factors determine the fitness costs and benefits of different male and female behavioural strategies, and why the game is solved in the way that it is.

I investigate the evolution of cooperative breeding and develop game-theoretical models that consider how cooperative breeder behaviour interacts with life-history traits and environmental factors. Generally, I am interested in how social behaviour gives rise to selection pressures acting on life-history traits. Such selection pressures may lead to the evolution of specific life-history adaptations for sociality in cooperative organisms.