Evolution of Extreme Reproductive strategies

Clare Holleley - Evolution of Extreme Reproductive Strategies


The Brown Antechinus has a very unusual mating strategy. Every year after a synchronised mating period, all of the males will die. I am very interested in teasing apart how such a seemingly costly strategy could be evolutionarily advantageous.

By conducting paternity analysis in a free-living population of Antechinuses I showed that larger males with larger scrotal size (a surrogate for sperm quantity) generally had more offspring. We hypothesise that this indirectly selected for increased hormone production (corticosteriod) which increases reproductive success but ultimately results in the death of the individual.


Clockwise From Top Left: Antechinus stuartii a small shrew-like marsupial with a very unusual reproductive behaviour.|  The main attraction “Hollywood Style” in the small town of Dungog where the research took place. Clare Holleley is standing between N & G.|  Immature Antechinus offspring still occupying their mother’s pouch.|  Relics from Gondwana. The  Antarctic Beech forest occurring in high altitude regions near Dungog.|  Inset: Thin-plate spline of multivariate selection operating on male Antechinuses.

Collaborators: Chris Dickman and Mathew Crowther.

Full list of all collaborators available here.

The evolution of Terminal Male investment in Reproduction: when is Sex Worth Dying for?

Publications from this Investigation

Holleley CE, Dickman CR, Crowther MS, Oldroyd BP. 2006. Size breeds success: multiple paternity, multivariate selection and male semelparity in a small marsupial, Antechinus stuartii. Molecular Ecology 15: 3439-3448.