Clue
to why females live longer than males
A study from the University of Exeter has found that male flies
die earlier than their female counterparts when forced to evolve with the
pressures of mate competition and juvenile survival. The results could help
researchers understand the mechanisms involved in aging.
The research, published in the journal Functional
Ecology, used populations of the fly Drosophila simulans that
had evolved under different selection regimes. The study shows that mate
competition (sexual selection), along with survival (natural selection), is
tougher on male aging than it is on females reducing their lifespan by about a
third.
Some species, like the flies in this study, age quickly over a
number of days while others -- including some trees and whales -- age slowly
across centuries.
Professor David Hosken from Biosciences at the University of
Exeter said: "We found dramatic differences in the effects of sexual and
natural selection on male and female flies. These results could help explain
the sex differences in lifespan seen in many species, including humans, and the
diverse patterns of aging we observe in nature."
The flies were subjected to elevated or relaxed sexual and natural selection and left to evolve in these conditions. To elevate sexual selection groups of males were housed with single females. A stressful temperature was used to elevate natural selection.
Males court females by singing, dancing and smelling good but
their efforts come at considerable cost and this cost is amplified when they
also have to cope with stressful temperatures.
The results of the study showed that under relaxed sexual and
natural selection, male and female flies had very similar lifespans -- around
35 days. However males that evolved under elevated sexual selection and
elevated natural selection had a much shorter lifespan -- just 24 days -- and
died seven days earlier than females under the same conditions.
Both sexual selection and natural selection were found to affect
lifespan but their effects were greatest on males. The findings show that the
sexes can respond differently to the same selection regimes.
Story Source:
The above story is based on materials provided by University of Exeter. Note:
Materials may be edited for content and length.
Journal Reference:
C. Ruth Archer, Eoin Duffy, David J. Hosken, Mikael Mokkonen,
Kensuke Okada, Keiko Oku, Manmohan D. Sharma, John Hunt. Sex-specific
effects of natural and sexual selection on the evolution of life span and
ageing inDrosophila simulans. Functional Ecology, 2014; DOI: 10.1111/1365-2435.12369
Cite This Page:
University of Exeter. "Clue to why females live longer than
males." Science Daily,
1 December 2014.
<www.sciencedaily.com/releases/2014/12/141201125154.htm>.