Chemical ecology of the Florida rosemary grasshopper, Schistocerca ceratiola

Monday, November 17, 2014: 10:00 AM
E147-148 (Oregon Convention Center)
Cody Gale , Biology, University of Central Florida, Orlando, FL
Hojun Song , Department of Biology/ Song Lab, University of Central Florida, Orlando, FL
The Florida Rosemary Grasshopper, Schistocerca ceratiola, is a reclusive relative of the locust endemic to Florida. S. ceratiola is one of two completely monophagous species of grasshoppers in North America and is host-associated with Ceratiola ericoides, an allelopathic shrub known colloquially as rosemary. S. ceratiola is historically observed to be nocturnal and is physically adapted to a nocturnal life history with cryptic coloration for daytime camouflage and enlarged eyes, presumably for enhanced night vision. C. ericoides produces a novel dihydrochalcone, ceratiolin, which decomposes in sunlight to produce hydrocinnamic acid, a strong inhibitor of growth for other plants in the Florida scrub.  This study begins to decipher the relationship between the nocturnal life history of the grasshopper and the photosensitive metabolites in the host plant. Qualitative analysis using high-performance liquid chromatography and mass spectroscopy verified the presence of ceratiolin not only in the regurgitant of the insects but also in the hemolymph. Levels of ceratiolin in the hemolymph will be measured before and after a period of exposing the grasshopper to longwave ultraviolet light. This experiment demonstrates the potential for ceratiolin to decompose within the body of the insect when exposed to sunlight, a process that implies physiological efffects. The results provide a foundation for understanding the plausibility that S. ceratiola evolved nocturnal behavior to avoid the photolytic decomposition of ceratiolin in the hemocoel.