“Effects of prior contest experience and contest outcome on female reproductive decisions and offspring fitness”

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Natalie Pilakouta, Cerian Halford, Rita Rácz, and Per T. Smiseth

Winners and losers spend more time caring for their offspring than parents with no fighting contest experience

Beetles that win or lose a fight become better parents than beetles with no fighting experience

A female burying beetle (Nicrophorus vespilloides) feeding predigested carrion to a begging larva.
(Credit: Per T. Smiseth)

Animals commonly fight over mates, territories, food, and other resources. During these fights, animals gain information about their size and condition relative to other individuals in the population. For example, losers might perceive themselves as being in worse condition than their competitors. Their worse condition might mean that their chances of breeding in the future are limited, in which case the best strategy for these losers might be to invest in current reproduction.

Researchers from University of Edinburgh (Natalie Pilakouta, Cerian Halford, and Per Smiseth) and University of Debrecen (Rita Rácz) tested this hypothesis in burying beetles. This species breeds on carcasses of small vertebrates, which are a very rare and valuable resource, so there is fierce competition for them. The authors set up fights between pairs of female beetles and then compared the reproductive decisions of winners, losers, and controls that had no fighting experience. They found no difference in the reproductive strategies of winners and losers. Instead, they found that both winners and losers spent more time providing care to their offspring than females with no fighting experience. This increase in parental care resulted in higher reproductive success for winners and losers, who had more surviving offspring than females with no fighting experience.

This work provides a previously unexplored link between fighting experience and reproductive strategies. In species where parents adjust their reproductive strategies based on their contest experience and where these adjustments affect the number and/or size of their offspring, contests could influence and be influenced by population dynamics. This could in turn lead to a feedback loop between local-scale social interactions, individual-level behavioral changes, and population-level processes. Read the Article