As mating season approaches, male animals are faced with a question that can make or break their chances at reproducing: does it pay to be a lover or a fighter? Or both?
Researchers from The University of Manchester and Syracuse University in New York working with the University of Western Australia, found that where animals fall on the lover/fighter scale depends on how much they are able to ensure continued mating rights with females.
In species where fighting for the right to mate means greater control of females, such as in the elephant seal, males invest more in weapons and less in testes size.
But males produce large weapons and testes in species where fighting for females occurs both before mating with weapons and after mating with sperm.
Some males found fighting the most successful method. Others found fighting was only the first step in sexual relations and also had to rely on large testes ensure their fertility.
The study, published in Nature Communications today (23 January) looked at over 300 species and found that males' ability to monopolise a female for continued mating drove the way they evolved.
The study looked at sexual behaviours in male mammals, birds, fish, insects and flatworms and has found that males only traded-off investment in weapons and testes when they were sure that females wouldn't fool around with another male when their back was turned.
John Fitzpatrick, a Lecturer in Animal Evolution at The University of Manchester who was senior author of the research, said these finding help to explain why some animals appear to invest maximally in expensive sexual traits but others are more frugal.
Dr Fitzpatrick said: "We set out to see why some species show trade-offs in sexual traits and others do not the answer lies in how successfully males are able to keep females from mating with rivals.
"We know animals try to get females in a cou
|Contact: Alison Barbuti|
University of Manchester