Comparative morphology of antennal sensillae of three disjunct populations of Wyeomyia smithii (Diptera: Culicidae)

The purple pitcher plant mosquito, Wyeomia smithii, is a commensal of the purple pitcher plant, Sarracenia purpurea.  While northern populations of the species are autogenous, populations found in Florida exhibit anautogeny after an autogenous egg batch.  During the past 16 years, an isolated relict population in Georgia has exhibited increasing blood feeding behavior, becoming more similar to Florida populations.  We hypothesize that for W. smithii from Georgia to become successful at feeding there would need to be phenotypic shifts in their olfactory receptors to facilitate more accurate detection and location of potential hosts. To this end, our study compares the sensillar morphology of populations from Georgia, Florida and North Carolina (where populations remain autogenous) to determine whether there has been a shift in antennal morphology commensurate with the observed shift in feeding behavior.  We examined fine antennal structure using scanning electron microscopy to count olfactory receptors linked to carbon dioxide detection, and to assess any shift in antennal morphology that may have occurred during the past 16 years.