• May 18, 2018
To the left are the large cages which kept the males and to the right are the small enclosures to keep each female individually. Photo: Supplied
Research done at University of Auckland shows a direct correlation between lifespan and the number of mates a female has.
PhD student Morgane Merien, conducted a yearlong study looking at the costs and benefits sex had on female stick insects (Clitarchus hookeri).
“It’s great to have some clear evidence on the link between sexual reproduction and lifespan,” says Ms Merien.
The female insect has the ability to either mate with males or reproduce asexually (facultative parthenogenetic).
The study’s results showed multiple-partner females had the shortest lives.
Ms Merien says, “when a female had more sex, they died earlier, way earlier. The more you have sex, the earlier you die.”
"The same thing has been found in quite a few animals, lizards, sharks, birds."
The females were kept in a little box and would give them one male at a time.
Ms Merien says the difference is humans “have the ability to resist if we want to,” unlike insects.
Sexual health specialist, Dr Nicky Perkins, says this research does not apply to humans.
“No, I don’t think it’s relevant for me to comment. I only deal with humans.”
Merein’s supervisor, Associate Professor in Biological Sciences, Gregory Holwell says conclusions cannot be taken and applied to humans.
“Because humans don't have the option of reproducing parthenogenetically, we can't really relate most of these results to humans.”
“However, the fact that sexual females who mated multiply had higher offspring viability than monogamous females, suggests that genetic compatibility might be involved, and that females are bet-hedging.
Genetic incompatibility underlies many types of infertility across the animal kingdom, including in humans, so this is an interesting result in that respect.”
Holwell says Merein’s enthusiasm for the natural world carried her through and is essential to becoming a great scientist.
Merein has already enrolled in a PhD to continue studying colour variation and camouflage in stick insects.