Unreal Nature

March 30, 2009

The Same Only Different

Filed under: Uncategorized — unrealnature @ 6:59 am

This is old news (it was reported twenty years ago) but it’s still interesting to consider:

The researcher, Erick Greene of the University of California at Davis, disclosed his findings on the caterpillar Nemoria arizonaria in the journal Science last week.

In effect, he said, the caterpillars hatched in spring eat their way into bright yellow and green outfits resembling a flower. Fall caterpillars munch on leaves to assume the subdued gray- green appearance of a plain twig. The survival strategy, Mr. Greene said, probably developed as a way for caterpillars to conceal themselves from hungry birds. ”Both fall and spring caterpillars have identical genetic material,” Mr. Greene said. ”The spring brood and the fall brood look exactly the same when they hatch. ”Their later change depends entirely on what the caterpillar eats,” he continued. ”Diet cues turn on or off the right set of genes so that they turn into the right shape at the right time of year.”

— from Diet Determines Color and Shape of a Caterpillar (AP) (Feb 7, 1989) in the NY Times

nemoria_arizonaria_b

(above) Catkin eating caterpillar on the left; oak leaf eating caterpillar on the right. These two pictures are of siblings from the same brood.

-Julie

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1 Comment

  1. Nice: a lovely example of “Genotype + Environment = Phenotype”.

    Comment by Ray Girvan — March 31, 2009 @ 4:52 am


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