Female 'Burying Beetles' Prefer Smaller Males. Why?
Size matters, at least for female burying beetles that are more attracted to smaller males because they are less likely to get into fights, according to a new study from the University of Exeter. Despite attracting more females, however, smaller males do not make better parents than their larger counterparts.
Burying beetles are about an inch and a half long and characterized by a striking, distinctive coloring: Their body is shiny black with orange-red markings. Researchers believe small male beetles were more successful at attracting female mates to the breeding ground of an animal carcass because they stir less competition than larger individuals, according to a news release.
"These results show that by being choosy about their males, female burying beetles might avoid complicated relationships involving male fights and extra female competitors," lead researcher Dr. Paul Hopwood, from the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus, Cornwall, explained in the release.
Still, while they seem to be more attractive to female beetles, smaller males are no better parenting than larger individuals -- and burying beetles are known to be exceptionally good parents in the insect world.
Researchers chose to explore the insects' mating behavior and parenting style by placing male beetles in the wild with a dead mouse -- an ideal place for them to mate and rear a family. The beetles were originally raised in laboratory groups with different ratios of males and females, so that males could size up their competition before being released to mate.
Ultimately, researchers found smaller beetles attracted female partners to the mouse faster than the bigger beetles. The findings did not, however, find any link between a beetle's size and ability to become a good parent.
"We found no evidence that males of any size, or from any social background, were more committed parents," Hopwood added in the university's release.
Alternatively, larger males in many species are often more successful at mating -- either because females find them more attractive or because they can use their brawn to intimidate small rivals -- but end up having more sexual partners and are less committed to their offspring.
Their study was recently published in the Journal of Evolutionary Biology.
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