Aarhus University Seal / Aarhus Universitets segl

TRINE BILDE - Evolutionary biology of mating systems and cooperation

We study population genetics, adaptation, and group-living using social spiders as model system. The social spiders are unique among group living animals, as the transition to permanent sociality is associated with strong inbreeding, cooperative breeding, and highly female-biased sex ratios. Our research aims to understand the ecology and evolution of sociality, reproductive division of labour, and population genomic consequences of inbreeding. 

Social spiders show extremely low genetic variation but occupy wide habitat ranges with strong temperature and humidity clines. We are interested in understanding how plastic and environmentally determined factors (epigenetics, microbiome) influence adaptation. Our research is mainly performed on the African genus Stegodyphus that contains both social and subsocial (pre-social) spiders, which allows comparative studies.

We also study sexual selection and alternative male mating strategies in Pisauara mirabilis spiders. Males provide females with a nuptial gift to obtain a mating, in the form of an insect prey wrapped in white silk. Sometimes males wrap worthless objects such as exoskeletons or plant parts that are worthless for females. Males also play dead – thanatosis – as a male mating effort. We aim to understand the evolution and maintenance of male alternative mating strategies across natural populations.