2008-09-06

It's evolution, baby

Image revised from http://photography-on-the.net/forum/showthread.php?t=500821

Top news from Nature.com here! For me, this is exciting since it is a very good example of how the evolutionary forces can work. It concerns the tiger moths, which are rejected of a number of predatory species even though they'd probably make a good addition in terms of nutients. Some time ago, it was discovered that some tiger moths produces ultrasonic sounds. Now, this sound is also used by bats, which otherwise likes to eat other individuals of the Lepidoptera. But this sound it is not used to locate the moths. Instead, its used to ward them off, since the bats precive the sounds as toxicity signals (and the tiger moths don't really taste good so if the bat would take a chunk, he'd probably leave it directly which in turn leaves no gain for either the moth or the bat). Tiger moths that are around during summer, when bats are a major threat, uses this as a good way of avoiding becoming dinner. However, some other types emerges when it's springtime and the bats aren't as active. Then, there are other greedy eyes in the environment, such as birds. To cope with this other type of predator, these tiger moths rely on bright coloring to send of some statements to the birds that there's no use in eating them since they would taste unpleasant. Visual signals is also used during the summer, but mainly in day active moths since the daylight makes colors more efficiant. SO, what's cool about this is that two different predators and different light-settings have led to the divergence different antipredator defences within the same species. Like X-men, but for real.

Sources:
http://www.nature.com/nature/journal/v455/n7209/edsumm/e080904-11.html
http://www.nature.com/nature/journal/v455/n7209/full/nature07087.html

2 kommentarer:

Unknown sa...

men åsa, skriv på svenska. jag är sjukt intresserad men 12 år och orkar inte läsa på engelska.

Septikemi sa...

Mjä, jag tycker att det är lättare att uttrycka mig om sådanthär med engelska :P Du får använda googles "translate"-funktion! Det är lite roligt också.