Post-mating clutch piracy in an amphibian

Area of Science:

• * Reproductive Biology
• * Ethology
• * Evolutionary Ecology

Background:

• * Female multiple mating and alternative mating systems can reduce sexual selection opportunities.
• * Sperm competition and alternative reproductive systems are common in external fertilizers.
• * Multiple paternity occurs in amphibians and fishes without complex mating behaviors.

Purpose of the Study:

• * To report and describe clutch piracy in a montane population of the common frog (Rana temporaria).
• * To investigate the prevalence and fitness consequences of this novel reproductive behavior in vertebrates with external fertilization.
• * To explore how alternative mating strategies, like clutch piracy, influence sexual selection intensity.

Main Methods:

• * Observation of reproductive behavior in a montane population of Rana temporaria.
• * Identification and description of 'clutch piracy' where males fertilize eggs from freshly laid clutches.
• * Assessment of the proportion of clutches affected by piracy and the impact on fertilization success.

Main Results:

• * Clutch piracy was observed in 84% of clutches, a previously unknown behavior in vertebrates with external fertilization.
• * Pirate males fertilized eggs in clutches, increasing fertilization success for some pairs.
• * The behavior was not size-dependent, and some males engaged in both mating and piracy in the same season.

Conclusions:

• * Clutch piracy in Rana temporaria provides direct fitness benefits to both pirate males and females.
• * This alternative mating strategy may mitigate the effects of strong sexual selection, potentially driven by a male-biased sex ratio.
• * The common frog serves as a model system for studying the interplay between alternative mating strategies and sexual selection.