Thursday, August 9, 2007 - 9:00 AMCOS 115-4: Patterns of local adaptation in an insect-plant interaction
Rodrigo Cogni, Stony Brook University
The evolution of interactions among species often happens in a geographical mosaic, in which selection, drift and gene flow affect geographically structured populations. If natural selection is a strong factor, local adaptation is expected, meaning that local resident genotypes are expected to have higher fitness than genotypes from other populations. I investigated local adaptation at different geographical scales in the interaction between the alkaloid-bearing legume Crotalaria pallida and its seed predator, the arctiid moth, Utetheisa ornatrix. I studied three populations in southeast Brazil (about 150 Km apart) and compared a Brazilian population to a population from Florida . Larvae from each population were fed fruit from plants from each population in a common garden. At a local scale, there was no significant interaction of plant population and moth population on any of the moth fitness components measured. At a continental scale, moths from Florida and Brazil both had significantly heavier pupa eating their local plant population than when fed on plants from Brazil and Florida , respectively. Local adaptation was observed at a continental geographical scale, but not at a local scale.