Wednesday, October 6, 2010
THE ADVANTAGE OF STARVING: SUCCESS IN CANNIBALISTIC ENCOUNTERS AMONG WOLF SPIDERS
As we all know, cannibalism is often observed among various species in the animal kingdom. Although I don't have too much knowledge about insects, I do know that in some species of insects, cannibalism is normal and can be used as a reproductive strategy or can be used in situations in which the insect is extremely hungry and can't find other means of nutrition. However, I did not know that there is actually an advantage to being one of these cannibalistic species and being extremely hungry.
Peterson et al. (2010) found that hunger and body size differences in wolf spiders increase the likelihood that a cannibalistic event will take place. They performed various experiments that tested whether a cannibalistic event took place for three different groups of spiders: 1) spiders of the same size, 2) spiders of different levels of hunger, and 3) a control group of spiders that were just fed. Spiders from each of these groups were placed in different orders in separate petri dishes and observed over a period of time. After performing these experiments, they found that during an encounter of a hungry spider and a satiated spider of the same mass, the hungry spider was more likely the cannibalistic predator. They also found that a hungry spider is more likely to attack a smaller spider of equal hunger than a smaller spider that was satiated. They even found that in some cases, a smaller, hugry spider launched an attack on a bigger spider. This research supports the fact that when a spider is hungry, it will have increased aggression and will take greater risks than a spider that is not hungry.
Although data suggests starvation to be an advantage to hungry spiders, after being starved for a certain number of days, it was found that spiders actually fall prey to cannibalistic spiders because they are too weak to fight. I found it extremely interesting that spiders have evolved to be very adapted to starvation, however the level at which starvation turns from advantage to disadvantage is unknown. If you would like to read more about this study click here!
posted by Abbie Lamarre-DeJesus (2)
Subscribe to:
Post Comments (Atom)
The evolution of cannibalism in these spiders is very interesting! The true advantage would be the ability to establish that balance between starvation and nourishment. It would keep them on their toes, but they would not be too emaciated to fight. Do you know if cannibalism is more frequent among insects than any other animals? For example, mice will sometimes eat their pups.
ReplyDeleteKatie Kalutkiewicz
Yes, cannibalism is also frequent in some animals, for example infanticide occurs among many species of mammals where a new male comes and eats all the offspring so the females will reproduce with him. However, cannibalism definitely occurs more frequently among insects.
ReplyDeleteAbbie Lamarre-DeJesus
That's pretty cool. Do you know if there are any other studies going on to see what that starvation threshold is? and would a smaller starving spider ever go after a larger starving spider?
ReplyDeleteLeah Salloway
I do not understand why the wolf spiders would more likely eat a smaller spider of equal hunger than a smaller spider that was satiated. Is this behavior mutualistic?
ReplyDeleteAhmed sandakli