by Tammy Thorne
One of U of T Scarborough’s own is set to become Canada’s pre-eminent researcher on the reproductive strategies of ring-tailed lemurs.
Professor Joyce Parga of the social sciences department at UTSC recently received funding from the Canada Foundation for Innovation (CFI) to start a lab that will be the first in Canada to use genetics to study social behaviour in non-human primates. The anthropologist launched the Molecular Anthropology and Primatology Laboratory for the Study of Evolution (MAPLE) this year.
The lab space in SW-311 of the Science Wing is currently being renovated through funds from the CFI. The lab will serve as a unique facility for DNA and genetic work related to the species, although no lemurs will be housed on site.
“There is no lab presently in Canada that analyzes non-human primate DNA for the purposes of informing us about social behaviour. There are a few in the United States, and this is the first here in Canada that will be combining behavioural primatology and genetics,” Parga said.
One of the goals for the MAPLE lab is to quantify lifetime male reproductive success and compare this to male reproductive strategies. The ring-tailed lemur is facing a high risk of extinction in the wild and one of Parga’s goals is to analyze samples from ring-tailed lemurs in Canada to help the Species Survival Plan (SSP), a group that makes breeding recommendations for ring-tailed lemurs in captivity in North America.
“This research will have implications for captive breeding programs and we should be able to make some concrete suggestions for the ring-tailed lemur SSP.”
Ring-tailed lemurs have unusual social behaviour relative to most mammals since females dominate the males in the group. Parga started out looking at female mate choice but noticed many other factors at play that determined which males got the chance to mate, so she became interested in looking at male reproductive success.
“I can record data on male mating success all day long, but to know who is actually producing offspring, we need genetic data,” she said.
The reproductive rituals of ring-tailed lemurs are also unusual as they are seasonal breeders who only mate in the fall months in the northern hemisphere. Breeding is controlled by light cues and female lemurs are only in estrous for one day – sometimes for as little as four hours.
“Males do not have a lot of time,” she said. “Every female in the group will go into estrous within a two-week period, but never at the same time. So think about it from a male’s perspective.”
Parga said that male-on-male competition can get very bloody and can even result in death. She said “sneak copulation” is a technique that some of the younger, lower-ranked males use. “A good way to avoid being ripped to shreds is to sneak behind a tree to mate with a female,” she said. “One smaller, younger male I observed definitely mated to ejaculation using the sneak copulation technique, but was he successful? Was he the ones getting the females pregnant?”
Parga noted that reproductive success could also lie in sperm precedence. “We don’t really know yet if there is any relationship between mating order, for example, and fertilization success in this species,” she said.
For Parga the question remains: Who is the baby’s daddy? “We need to find out who is actually siring these infants.”
To find out and obtain samples, Parga travels every fall to St. Catherines, an island off the coast of Georgia in the southern United States. The island is the only place in the world where researchers can follow free ranging ring-tailed lemurs outside of their native Madagascar. The privately-owned island is the location of a lemur colony started in 1985 by the Wildlife Conservation Society.
She said the new MAPLE laboratory provides an excellent opportunity to expand students’ horizons. “There are a number of students, and particularly anthropology students, who aren’t exposed to laboratory genetics at all,” said Parga. “Anthropology students may discover that they have a nascent interest in molecular genetics, and for undergraduates to get this research experience is really valuable. This lab will be a wonderful resource for our students.”