Friday, March 17, 2006
"It's said that Elvis Presley's love of fried peanut butter sandwiches started during his impoverished childhood, and the fat-soaked snack remained a favourite dish for the rest of his life. Locusts and Elvis could have something in common. In a study published in Science, Oxford researchers showed that the value given by locusts to a particular food depended on their condition at the time of eating it first.
The researchers set up trials to look at how organisms learn and on what basis they choose. They manipulated the preferences of the locusts: the insects met peppermint-flavoured grass when they were hungry and lemon-flavoured grass when they were not so hungry, and later behaved as if peppermint-flavoured grass was preferable. When they reversed the treatments, the locusts reversed their preference.
...This latest research into locusts suggests the point at which this mechanism may have been acquired could go even further back in evolutionary terms. It also casts light on why organisms sometimes don't seem to behave in an optimal or adaptive way."