Professor, PhD (Vice Dean for Education)
Sigrunn Eliassen

Evolution of Mating Systems

My current research focuses on the evolution of mating systems and cooperative behaviours. I am particularly interested in how mating strategies change the incentives of males and females to invest in parental care and cooperation within a group. Cooperation often produces benefits that are greater than solitary action, but from an evolutionary perspective it is hard to explain why individuals accept a cost to themselves to benefit others.

Using evolutionary modelling, we study how mating strategies, in particular extra-pair paternity, alter the costs and benefits of cooperative investment. Females in most species mate with more than a single male during a breeding cycle. Even in species that pair monogamously offspring commonly have different fathers. For males there is a clear benefit of mating with several females as they can sire offspring without having to pay the costs of care, but the benefit to females is more of a puzzle.

In an ongoing project I collaborate with Christian Jørgensen and Marc Mangel to develop theoretical models of common ecological mechanisms that illustrate how extra-pair mating may trigger male-male cooperation in predator defence and sharing of resources.

Foraging ecology and learning

I am also interested in how animals may allocate their foraging effort in response to experiences of local resource conditions, as environments vary in time and space. The need to acquire information affects foraging decisions and influences distribution patterns and resource consumption. Foragers need to make apparently complex decisions on which prey to select, where to forage, and for how long.

Animals gain information by exploring their surroundings, for instance by sampling different prey types or resource patches. Foragers that are able to learn from experience may track changes in environmental conditions. Individuals however, pay for information by spending energy and time, forgoing opportunities to gain resources elsewhere. The value of learning therefore depends on the benefits an animal obtains from using information and the costs of collecting it.