Phenotypic plasticity in response to habitat risk.

摘要

Phenotypic plasticity is an ideal mechanism for response to potential habitat risk. Phenotypic plasticity allows an organism to respond with a phenotype that may increase the probability of survival under potentially risky conditions. An increased ability to detect and predict catastrophic habitat change would result in a greater likelihood of an organism being able to respond to and ultimately survive the catastrophe.;I initially examined hatch rate plasticity and development time plasticity of a single population of Ae. albopictus. Hatch rate was shown to vary in response to altered frequency of hatch stimulation, a potential indicator of drought and a possible cue predicting future habitat desiccation. Eggs exposed to potential drought conditions were shown to have an increase in their hatch rate relative to eggs exposed to non-drought conditions. This was shown to be not an age related effect. Development time also showed a plastic response. Larvae that were hatched from eggs exposed to the potential drought conditions for long times developed much more quickly than eggs exposed to non-drought conditions. These responses indicate that Ae. albopictus may hatch faster, and develop faster in response to a drought.;A second set of experiments examined that hatch plasticity and development time plasticity of multiple populations of Oc. triseriatus. Populations were selected based on regional frequency of rainfall. The regional frequency of rainfall did influence the hatch plasticity and development time plasticity of the species. Populations from habitats that were more prone to extended period of infrequent rain, indicating a greater probability of drought, had the opposite plasticity response as the previous experiment. In these populations, eggs hatched more rapidly and larvae developed more quickly under plentiful rainfall conditions. Populations that experienced more frequent rainfall had the same plasticity response as Ae. albopictus .;From these data, it appears that organisms are capable of responding to cues that may predict random catastrophic habitat change even if the cue itself is not harmful to the organism. It also appears that the actual plasticity response varies in different populations relative to the probability of the catastrophic habitat change in each population.