Featured Research

from universities, journals, and other organizations

Opportunity leads to promiscuity among squirrels, study finds

Date:
December 16, 2010
Source:
University of Guelph
Summary:
Scientists have discovered why female squirrels are so promiscuous. Turns out it has nothing to do with genes and everything to do with how many males are knocking at their door. The fact that female squirrels will mate with as many males as available even if the costs far outweigh the benefits has baffled scientists. The research team discovered that female squirrel behavior results from opportunity alone and not from genetics, limiting its ability to evolve.

A male red squirrel approaches a female during her mating chase.
Credit: Ryan W. Taylor

University of Guelph researchers have finally figured out why female squirrels are so darn promiscuous. Turns out it has nothing to do with genes and everything to do with how many males are knocking at their door.

"Their behaviour is overwhelmingly influenced by opportunity," said graduate student Eryn McFarlane, who, along with integrative biology professor Andrew McAdam and a team of researchers from across Canada, solved a mystery that has baffled biologists for years.

Their findings appear in the Royal Society Journal Biology Letters.

Female squirrels are less than picky when it comes to mating, often entertaining as many suitors as possible. Such risky female behaviour is puzzling in the mammal world.

Although it makes sense for male squirrels to have as many mates as possible to ensure the most offspring, promiscuity doesn't always make sense for females, said McFarlane.

"Having multiple partners means more energy expended on mating, increased exposure to predators as well as increased potential for the spread of sexually transmitted diseases," she said. "Promiscuity also encourages harassment from male squirrels trying to coerce them into having sex."

Trying to solve this puzzle has prompted a lot of research into the possible benefits of mating with many males, said McAdam. However, optimal mating strategies can evolve only if there is a genetic basis to the behaviour.

The Guelph team discovered that female squirrel behaviour results from opportunity alone and not from genetics, limiting its ability to evolve.

"We found the more males in the area interested in participating in the mating chase, the more squirrels she will mate with," McFarlane said. "There are no strong ties between mating behaviour and genetics in red squirrels. So even if the costs of mating with many males outweighs the benefits there doesn't seem to be much capacity for them to evolve lower levels of promiscuity."

The researchers analyzed data collected from 108 mating chases involving 85 female squirrels. Researchers Jeff Lane and Ryan Taylor collected the data as part of the Kluane Red Squirrel Project, a long-term field experiment in the Yukon investigating the importance of food abundance to the ecology and evolution of red squirrels. Established in 1987, the project has seen scientists from several collaborating universities, including the University of Guelph, monitoring behaviour and reproduction of about 7,000 squirrels.

After analyzing the data, McFarlane and McAdam found that female squirrels mated with anywhere from one to 14 partners and that female promiscuity was not reliably inherited by offspring.

"A female squirrel that only chose to mate with one male could have a daughter that mates with many males," McAdam said. "It seems the tendency to mate with fewer males isn't something that is being passed down to offspring."

A female red squirrel usually goes into heat for only a single day each year, typically releasing three or four eggs to be fertilized. During the preceding few days, she leaves scent nearby to let males know she's getting ready. On the day itself, she runs around to encourage interested males to give chase.

Whether several males, or perhaps only one or two, wait by the nest, females often mate with as many as are available.

"The reality is that organisms cannot always be well adapted to their environment," said McAdam. "Sometimes organisms do things that detract from their survival because they aren't able to evolve a better alternative."


Story Source:

The above story is based on materials provided by University of Guelph. Note: Materials may be edited for content and length.


Journal Reference:

  1. S. Eryn McFarlane, Jeffrey E. Lane, Ryan W. Taylor, Jamieson C. Gorrell, David W. Coltman, Murray M. Humphries, Stan Boutin and Andrew G. McAdam. The heritability of multiple male mating in a promiscuous mammal. Biology Letters, 2010; DOI: 10.1098/rsbl.2010.1003

Cite This Page:

University of Guelph. "Opportunity leads to promiscuity among squirrels, study finds." ScienceDaily. ScienceDaily, 16 December 2010. <www.sciencedaily.com/releases/2010/12/101215102321.htm>.
University of Guelph. (2010, December 16). Opportunity leads to promiscuity among squirrels, study finds. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2010/12/101215102321.htm
University of Guelph. "Opportunity leads to promiscuity among squirrels, study finds." ScienceDaily. www.sciencedaily.com/releases/2010/12/101215102321.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins