Featured Research

from universities, journals, and other organizations

Discerning males remain faithful ... if you are a spider

Date:
April 24, 2012
Source:
BioMed Central Limited
Summary:
Discerning males remain faithful...if you are a spider. Sex for male orb web spiders is a two shot affair since the act of mating destroys their genitalia. If they survive being eaten during their first encounter with a female, they have two choices – to mate again with the same female (monogynous) or try to find a new partner (bigynous). New research shows that choice of mating behavior for A. bruennichi depends on the size and age of the first female they mate with.

This shows a cannibalized male orb web spider (Argiope bruennichi) inside the female's web.
Credit: S.M.Zimmer

Discerning males remain faithful...if you are a spider. Sex for male orb web spiders (Argiope bruennichi) is a two shot affair since the act of mating destroys their genitalia. If they survive being eaten during their first encounter with a female, they have two choices -- to mate again with the same female (monogynous) or try to find a new partner (bigynous). New research published in BioMed Central's open access journal Frontiers in Zoology shows that choice of mating behavior for A. bruennichi depends on the size and age of the first female they mate with.

Monogamous behavior, such as mating for life, is thought to evolve when paternal protection of the female increases fertilization success. For cannibalistic spiders, monogamy means that the life of the male can be very short indeed. However this can improve chances of fatherhood: males of the black widow spider can increase the duration of mating, and hence the likelihood of successful fertilization, by allowing themselves to be eaten.

Monogamous spiders like A. bruennichi have evolved specialized pedipalps, which are used to transfer sperm into a female's reproductive organs. These specialized genitalia are usually damaged during mating, breaking off inside the female, and forming a plug to prevent subsequent fertilization by a different male. Each male can consequently only mate twice in their entire lives, but, if they survive the first encounter (a female will usually eat the male if mating continues to long) they can then chose to either mate with her again or to find a different female to mate with.

Researchers from the Zoological Institute, University of Hamburg, discovered that the mating strategy of A. bruennichi was not random. Males made mating decisions based on females mating status (virgin or already mated) age, weight, availability of other females, and the time of day.

Klaas Welke explained, "Amongst spiders, regardless of age, heavier females are the most fertile. Males were more likely to mate twice with the same female if it was early in the day, she was heavy, and if the nearest other females were sub-adult. Males kept on searching for a second female if it was late in the day and the first female was light. We found that bigynous males preferred to 'trade up' to heavier females as second mates, but ran the risk of attempting to copulate with already mated females."

Two thirds of the monogamous males were eaten after their first mating. These males, which only managed to mate once, tended to mate with the oldest and heaviest females. Klaas Welke explained, "These females are the ones which have the highest fecundity and which are most ready to lay their eggs. While these males do not have a second chance at mating their probability of reproductive success is high."

Based on paternity of lifetime reproductive success bigyny appeared to be the more successful strategy. Despite this about half of the males were monogamous and half bigynous demonstrating that males alter their behavior to make the best of the situation they find themselves in.


Story Source:

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


Journal Reference:

  1. Klaas W Welke, Stefanie M Zimmer, Jutta M Schneider. Conditional monogyny: female quality predicts male faithfulness. Frontiers in Zoology, 2012; 9 (1): 7 DOI: 10.1186/1742-9994-9-7

Cite This Page:

BioMed Central Limited. "Discerning males remain faithful ... if you are a spider." ScienceDaily. ScienceDaily, 24 April 2012. <www.sciencedaily.com/releases/2012/04/120424222729.htm>.
BioMed Central Limited. (2012, April 24). Discerning males remain faithful ... if you are a spider. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2012/04/120424222729.htm
BioMed Central Limited. "Discerning males remain faithful ... if you are a spider." ScienceDaily. www.sciencedaily.com/releases/2012/04/120424222729.htm (accessed April 16, 2014).

Share This



More Plants & Animals News

Wednesday, April 16, 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
Couples Who Sleep Less Than An Inch Apart Might Be Happiest

Couples Who Sleep Less Than An Inch Apart Might Be Happiest

Newsy (Apr. 16, 2014) A new study by British researchers suggests couples' sleeping positions might reflect their happiness. Video provided by Newsy
Powered by NewsLook.com
Passengers Abuzz After Plane Hits Swarm of Bees

Passengers Abuzz After Plane Hits Swarm of Bees

AP (Apr. 16, 2014) An Allegiant Airlines plane from Las Vegas to Duluth, Minnesota turned around shortly after take-off, after a swarm of bees clouded the windshield and got sucked into the engines. (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