Featured Research

from universities, journals, and other organizations

Primate Sperm Competition: Speed Matters

Date:
September 27, 2007
Source:
University of California, San Diego
Summary:
Sperm cells from the more promiscuous chimpanzee and rhesus macaque species swim much faster and with much greater force than those of humans and gorillas, species where individual females mate primarily with only one male during a reproductive cycle.

Researchers at UC San Diego and UC Irvine have found evidence that supports the theory that reproductive competition during the evolution of primate species has occurred at the level of sperm cell motility.

In a paper published online by the Journal of the Royal Society Interface, a team led by Michael Berns, an adjunct professor of bioengineering at UCSD and a professor ofbiomedical engineering at the Beckman Laser Institute at UC Irvine, and UCSD Ph.D. candidate Jaclyn Nascimento reported that sperm cells from the more promiscuous chimpanzee and rhesus macaque species swim much faster and with much greater force than those of humans and gorillas, species where individual females mate primarily with only one male during a reproductive cycle.

Female chimps and macaques typically mate with several males in a social group, so that a male with faster and stronger swimming sperm cells would in theory bemore likely to successfully fertilize an egg.

“Rapidly swimming sperm cells would be evolutionarily favored when the mating pattern is polygamous and that is consistent with our measurements of chimp and rhesus macaque sperm,” said Nascimento.

The researchersfound significantly lower swimming forces and slower swimming speeds with human sperm, and the slowest of all belonged to gorillas. “Dominant silverbacks are known to effectively discourage other males from mating with the females in their harems, so faster sperm wouldn’t seem to be an advantage to them,” Nascimento said.

However the scientists were surprised that the speed and force of human sperm fell in between the gorillas and the chimps. “Maybe humans haven’t always been as monogamous as we had thought,”Berns said.

Beginning more than 35 years ago, scientists began using laser beams to trap individual atoms, microscopic particles, DNA molecules, and various cells. Berns has been a pioneer in the design of “laser tweezers,” which rely on the momentum inherent in laser light: when the path of laser light bends as it passes through a small transparent object such as a cell, some of the light’s momentum is transferred to the cell, effectively holding, or trapping it. The brighter the laser, the more firmly the cell is held.

After attending a talk at the Center for Reproduction of Endangered Species (CRES) at the San Diego Zoo about the theory that faster sperm could have an advantage in the reproductive success of polygamous primates, Berns modified his laser tweezers so that after a cell was trapped, the light intensity could be reduced in a precise manner.

Such a timed decay in laser brightness allows a trapped sperm cell to escape at the point at which its swimming force exceeds the trapping force. The adjustable laser tweezers and sperm-tracking software allowed the team led by Berns and Nascimento to precisely and accurately measure swimming force and speed of hundreds of individual sperm cells from males of the four primate species.

“While biologists have been interested in this sperm competition question for years, it required the collaboration of biologists, physicists and engineers to design the right equipment to test the theory,” said Berns.


Story Source:

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


Cite This Page:

University of California, San Diego. "Primate Sperm Competition: Speed Matters." ScienceDaily. ScienceDaily, 27 September 2007. <www.sciencedaily.com/releases/2007/09/070925090250.htm>.
University of California, San Diego. (2007, September 27). Primate Sperm Competition: Speed Matters. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2007/09/070925090250.htm
University of California, San Diego. "Primate Sperm Competition: Speed Matters." ScienceDaily. www.sciencedaily.com/releases/2007/09/070925090250.htm (accessed April 17, 2014).

Share This



More Plants & Animals News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Change of Diet Helps Crocodile Business

Change of Diet Helps Crocodile Business

Reuters - Business Video Online (Apr. 16, 2014) Crocodile farming has been a challenge in Zimbabwe in recent years do the economic collapse and the financial crisis. But as Ciara Sutton reports one of Europe's biggest suppliers of skins to the luxury market has come up with an unusual survival strategy - vegetarian food. Video provided by Reuters
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Thousands Of Vials Of SARS Virus Go Missing

Thousands Of Vials Of SARS Virus Go Missing

Newsy (Apr. 16, 2014) A research institute in Paris somehow misplaced more than 2,000 vials of the deadly SARS virus. Video provided by Newsy
Powered by NewsLook.com
Raw: Three Rare White Tiger Cubs Debut at Zoo

Raw: Three Rare White Tiger Cubs Debut at Zoo

AP (Apr. 16, 2014) The Buenos Aires Zoo debuted a trio of rare white Bengal tiger cubs on Wednesday. (April 16) 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