Perth researchers have discovered that the strongest males lose their breeding edge over weaker males when there is more competition.
“Males of the Australian quacking frog, found only in south west WA, use their strong forearms for mating with females,” explains Dr Bruno Buzatto, an ARC Early Career Research Fellow at The University of Western Australia. “As you would expect, mating success favoured frogs with strong forearms when there are only a few males to compete with.”
Current thinking assumes being stronger will increase mating success, but Bruno has found that mating success changes in high density populations.
“I discovered that when there is lots of competition for mates, weak males mated more than strong males,” reveals Bruno. “Surprisingly, there is less advantage in being strong and fighting when there is more competition.”
Sperm competition is also involved, as high male-male competition means that the sperm of different males compete to fertilize the female’s eggs.
Mate competition and having multiple partners is common in many animals, and so understanding the evolution of animal weapons and sperm competition, according to Bruno may even shed light on the evolution of livestock, and ultimately, even ourselves.
Bruno presented his research at Fresh Science WA 2015. Fresh Science is a national program that helps early-career researchers find and share their stories of discovery. Over 20 early-career researchers nominated for Fresh Science WA, which was held at the Western Australian Museum (training) and the Brisbane Hotel (public challenge event) and was supported by the Western Australian Museum, Curtin University, Edith Cowan University, Murdoch University, the University of Western Australia and the University of Notre Dame, Australia.
Contact: Bruno Buzatto, The University of Western Australia, bruno.buzatto@uwa.edu.au
Two large males of the Australian quacking frog (Crinia georgiana) wrestling for a territory
Three males of the Australian quacking frog (Crinia georgiana) mating with a single female (white) at the same time
Two large males of the Australian quacking frog (Crinia georgiana) wrestling for a territory
Fresh Science is on hold for 2022. We will be back in 2023.