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← Insects are scared to death of fish

Greyman's Avatar Jump to comment 16 by Greyman

Comment 3 by JuJu :

If larvae are stressed to the point of death prior to metamorphism doesn't that mean they aren't surviving long enough to pass on their genes? So wouldn't that characteristic eventually fade out based on the principles of natural selection? And wouldn't the ones that don't stress out to the point of death, or lack of development, be the ones that survive to breeding age and spread the genes that don't exhibit theses behaviors. Rather wouldn't they spread the genes that allowed them to avoid that fate in order for the species to survive. Wouldn't the genes that code for stressful dying eventually become less prevalent within the population?

Not entirely.  Remember that larvae not stressed by predators are more likely to be eaten.

Mutation rates are also increased by stress.  Organisms in hazardous environments are thus more likely to produce offspring with an adaptive mutation if they are stressed by the situation.  It also increases the chance of deleterious mutation, but in situation where offspring survival is threatened anyway it becomes a viable desperation gamble.  Where as the survival of offspring in safe environments is more likely if they maintain the genetic status quo.

Thus there's a selection pressure towards a certain level of stress response.

Sat, 29 Oct 2011 15:32:39 UTC | #885218