Featured Research

from universities, journals, and other organizations

In The Absence Of Sexual Prospects, Parasitic Male Worms Go Spermless

Date:
November 11, 2008
Source:
Cell Press
Summary:
When females aren't around, one species of parasitic nematode worm doesn't even bother to make any sperm, reveals a new report.

When females aren't around, one species of parasitic nematode worm doesn't even bother to make any sperm, reveals a new report in the November 11th issue of Current Biology, a Cell Press publication.

"This is very unusual for a male to need a female to be present before he produces sperm," said Christine Griffin of the National University of Ireland, Maynooth. "We searched the literature but could find no report of this in any other animal. Animals have evolved all sorts of strategies, some quite bizarre, to increase their lifetime reproductive success, but this particular one does not appear to be common." Lifetime reproductive success refers to the number of offspring produced over the course of a lifetime.

Scientists have generally considered sperm production to be cheap relative to the production of eggs in females, she said. But that notion has been challenged of late in animals that must produce a lot of sperm or particularly large sperm. The males of some other species of rodents, fish, and insects, for example, cut back on sperm according to their social circumstances. But they generally don't go without.

The researchers haven't yet shown how this behavior in the parasitic nematodes known as Steinernema longicaudum benefits the males of the species. But, they say, this newly discovered behavior makes some sense in light of the worms' unusual life history.

"Most animals can move around in search of a mate, and so should be ready to make the most of any opportunities that present themselves," Griffin explained. "Like many parasites, Steinernema enter their host insect when they are still juvenile and develop inside. A male that finds himself alone cannot leave the insect to search for a mate." Since only juvenile worms invade insects, those solitary males just have to wait until a young mating prospect joins him and grows up. Under these circumstances, she said, a mating partner can't appear suddenly, leaving the male no reason to be sexually mature.

Griffin's team, which included Lemma Ebssa, now at Rutgers University, made the discovery while studying the reproductive behavior of the nematode. They were surprised to find that it took some time before successful mating occurred between a pair of worms placed together.

"Initially, we thought that perhaps the female was unreceptive and/or immature, as this would be the more normal situation in animals," Griffin said. "However, further experiments showed that it was the male that was unready. We then took a closer look and discovered to our great surprise that the reproductive tract of naive males was smaller than that of males that had been with a female for some time, and it contained no sperm."

The researchers think that the signal from females to mature may be chemical in nature, since lone males matured even when females were placed on the other side of a permeable barrier. (The nematodes don't have eyes with which to see.) The researchers don't yet know whether the pheromones that stimulate male maturity are the same as those that sexually attract him to females.

The researchers include Lemma Ebssa, Ilona Dix, and Christine T. Griffin, of the Department of Biology, National University of Ireland Maynooth, Kildare, Ireland.


Story Source:

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


Cite This Page:

Cell Press. "In The Absence Of Sexual Prospects, Parasitic Male Worms Go Spermless." ScienceDaily. ScienceDaily, 11 November 2008. <www.sciencedaily.com/releases/2008/11/081110153615.htm>.
Cell Press. (2008, November 11). In The Absence Of Sexual Prospects, Parasitic Male Worms Go Spermless. ScienceDaily. Retrieved September 15, 2014 from www.sciencedaily.com/releases/2008/11/081110153615.htm
Cell Press. "In The Absence Of Sexual Prospects, Parasitic Male Worms Go Spermless." ScienceDaily. www.sciencedaily.com/releases/2008/11/081110153615.htm (accessed September 15, 2014).

Share This



More Plants & Animals News

Monday, September 15, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Conservationists Face Uphill PR Battle With New Shark Rules

Conservationists Face Uphill PR Battle With New Shark Rules

Newsy (Sep. 14, 2014) — New conservation measures for shark fishing face an uphill PR battle in the fight to slow shark extinction. Video provided by Newsy
Powered by NewsLook.com
Shocker: Journalists Are Utterly Addicted To Coffee

Shocker: Journalists Are Utterly Addicted To Coffee

Newsy (Sep. 13, 2014) — A U.K. survey found that journalists consumed the most amount of coffee, but that's only the tip of the coffee-related statistics iceberg. Video provided by Newsy
Powered by NewsLook.com
'Magic Mushrooms' Could Help Smokers Quit

'Magic Mushrooms' Could Help Smokers Quit

Newsy (Sep. 11, 2014) — In a small study, researchers found that the majority of long-time smokers quit after taking psilocybin pills and undergoing therapy sessions. Video provided by Newsy
Powered by NewsLook.com
Spinosaurus Could Be First Semi-Aquatic Dinosaur

Spinosaurus Could Be First Semi-Aquatic Dinosaur

Newsy (Sep. 11, 2014) — New research has shown that the Spinosaurus, the largest carnivorous dinosaur, might have been just as well suited for life in the water as on land. Video provided by Newsy
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