Featured Research

from universities, journals, and other organizations

Tarantulas' personality determines whether they copulate with males or cannibalize them

Date:
April 22, 2014
Source:
Plataforma SINC
Summary:
Sexual cannibalism in spiders – the attack and consumption of males by females before or after copulation – is very widespread. A new investigation analyses the reason behind such extreme behavior, at times even before the females have ensured the sperm’s fertilization of their eggs.

An image of a Mediterranean tarantula, Lycosa hispanica.
Credit: Eva de Mas

Sexual cannibalism in spiders -- the attack and consumption of males by females before or after copulation -- is very widespread. A new investigation analyses the reason behind such extreme behaviour, at times even before the females have ensured the sperm's fertilisation of their eggs.

After copulating with a male, female spiders tend to practice sexual cannibalism, that is to say, they attack the males and eat them. Researchers from the Experimental Station of Arid Zones (EEZA-CSIC) have studied why, at times, this behaviour arises before copulation, often without having ensured the sperm's fertilisation of their eggs.

"This tendency towards cannibalism could depend on the aggressive genetics of the females which make them attack males in the same way as they attack prey," Rubén Rabaneda-Bueno, first author of the study on tarantulas published in Ethology, explained.

In order to evaluate the female personality for sexual cannibalism, the authors offered randomly selected males to a group of female virgin tarantulas and documented whether they attacked the males or copulated with them.

In addition, prior to these meetings, they studied the voracious personality of the females when feeding on beetles and other natural prey, among which there were more ravenous or more docile females that differed in their fattening rate.

Finally they searched for a connection between the cannibal personality and the nourishing personality of the females, and whether it was related to the females being more demanding at the time of choosing a mate.

"More cannibalistic females were also more voracious towards their prey, and thus the better nourished. This is surprising since they have more nutritive resources to invest in their offspring before finding the first males," Rabaneda added. "Their priority should be ensuring the sperm's fertilisation of their eggs instead of eliminating their potential donors."

Cannibalism in choosing a mate

Furthermore, the males of this species assume an important contribution of nutrients for which reason it would be expected that the more docile and worse nourished females would exploit this source of food before copulation, cannibalizing the males.

"We reached the conclusion that there are aggressive genetics which vary among females and make them act aggressively both when they feed off prey and when they approach a male in courting," added Jordi Moya Laraño, director of the study. "Others are docile in both contexts, highlighting the existence of different personalities."

Thus, there are females with aggressive personality that are voracious, fatten up a lot and tend to cannibalize males when they are still virgins. On the other hand, there are docile females that eat less prey and prefer to copulate first before attacking their possible mates.

"While docile females attack inferior males and prefer to mate with superior males, aggressive females kill males regardless of their condition, which demonstrates their inability to distinguish males as sources of sperm or food, indiscriminately cannibalizing them," Rabaneda pointed out.

This study affirms that different levels of aggressiveness or feminine personalities contribute in generating variability in masculine reproductive success. "As such, sexual cannibalism could function as a way of choosing a mate which would also occur in various ways according to the female's personality," he concluded.

Further information

Cannibalism does not depend on the size of the tarantulas.

The size of the female was not decisive in the cannibal tendency of tarantulas, as has been seen in other spider species. "This could seem contradictory given that we would expect more voracious females to be bigger, noting an association not only between voraciousness and cannibalism, but also with size," the researcher insisted.

However, the females store their resources in the abdomen -- the soft part of the spider, directly linked to an increase in weight -- when they feed, beyond body size which represents the upper rigid part and which could remain unchanged in adulthood despite variations in weight.


Story Source:

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


Journal Reference:

  1. Rubén Rabaneda-Bueno, Sara Aguado, Carmen Fernández-Montraveta, Jordi Moya-Laraño. Does Female Personality Determine Mate Choice Through Sexual Cannibalism? Ethology, 2014; 120 (3): 238 DOI: 10.1111/eth.12197

Cite This Page:

Plataforma SINC. "Tarantulas' personality determines whether they copulate with males or cannibalize them." ScienceDaily. ScienceDaily, 22 April 2014. <www.sciencedaily.com/releases/2014/04/140422084730.htm>.
Plataforma SINC. (2014, April 22). Tarantulas' personality determines whether they copulate with males or cannibalize them. ScienceDaily. Retrieved September 14, 2014 from www.sciencedaily.com/releases/2014/04/140422084730.htm
Plataforma SINC. "Tarantulas' personality determines whether they copulate with males or cannibalize them." ScienceDaily. www.sciencedaily.com/releases/2014/04/140422084730.htm (accessed September 14, 2014).

Share This



More Plants & Animals News

Sunday, September 14, 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