Sexual conflict over mating affects females more than males, impacting the parental care behaviour, research shows.
In experiments on beetles, British researchers at University of Exeter used artificial selection and mating crosses among selection lines to determine if and how mating behaviours co-evolve with parental care behaviours.
“The research shows costs of mating in females appear to determine how patterns of parental care evolve in response to changes in mating behaviour,” explained Nick Royle from the centre for ecology and conservation at University of Exeter.
In species with biparental care such as beetles and humans, the results indicate that males are followers not leaders in the evolution of family life. It is how selection acts on females, not males, that really counts here, he added.
Both males and females provide parental care, but females are the primary care givers, as in humans.
So anything that affects the ability of females to provide parental care, such as costly mating, is likely to reduce overall reproductive productivity, the study noted.
The study found that male parental care behaviour did not change in response to selection on mating rate, but females responded to selection for high mating rates with a reduction in parental care.
“Productivity of pairs with females from lines selected for high mating rate was lower than that for pairs where females were from lines selected for low mating rate due to costs of mating for females and because males did not compensate for changes in female behaviour, the researchers maintained.
The results are contrary to classical parental care theory and instead support the idea that sexual conflict is more important than parentage in determining patterns of parental care.
The research was published in the journal Ecology Letters.