Cannibal Spiders May Have Poor Impulse Control
Spiders or "Arachnids" are a type of insect commonly hated among the general populace, but it's mate may hate that spider even more than you do.
A group of researchers questioned something that is commonly heard when learning about these creepy crawlies. "Why do spiders eat their mates when they would be better off matting with them?" In the case of many spiders the females will eat the males sometimes before mating sometimes after. These researchers were puzzled as to what causes this to occur.
They preformed an experiment on a type of Wolf Spider as seen above. They captured 80 young females and gave them as much prey as they would eat. after the females had molted the researchers put a male in. In cases where the female had eaten more food before mating the males were killed more often. After noticing this they compared it to a few of the female spiders that always killed their mates, and a some females that were more choosy. They found that the aggressiveness shown towards prey correlates to the aggressiveness shown towards their mates as well. While some females always killed their mates they would never reproduce, others were choosy and picked only big and strong males to mate with, and even others didn't kill their mates at all.
Next time you go to ask your girlfriend on a date think twice. Yikes!
Article:
http://www.scientificamerican.com/article/cannibal-spiders-may-have-poor-impulse-control/
Themes:
- Science is based on evidence
- Role of motivation and curiosity
- Role of chance
Questions:
Why hasn't natural selection ruled out this trait entirely?
Is this trait or cannibalism shown in any other organisms?
This was very cool because I have known for a while that certain animals, mostly insects and arachnids, have the trait to eat their mate after mating. It also puzzled me to why they would possibly do this. This provided a decent explanation and I thought that the idea for the experiment was also very creative. I still don't like spiders, though. Even so, it is really cool that the scientific community is able to learn more about this.
ReplyDeleteIn this article, the scientists were testing the aggressive spillover hypothesis, which means they are testing to see if the female will be more agressive towards the mate based on their behavior towards prey. These traits are most commonly found in arachnids, such as the spiders mentioned in this article. This article is very interesting, and scientists debate whether this topic is just the female trying to find a better mate, or if it is actually the aggressive spillover hypothesis. Super cool!
ReplyDeleteWhile it could be spillover aggression, this article (http://www.livescience.com/17616-spider-sexual-cannibalism-offspring.html) suggests that the eating of the male actually produces healthier offspring. In orb web spiders, males are only able to have sex twice in a lifetime, so dying after reproducing is actually an evolutionary advantage if it causes the offspring to be healthier.
ReplyDelete