Calculation and Thematic Mapping of Demographic Parameters for Homalodisca vitripennis (Hemiptera: Cicadellidae) in California

The reproductive and developmental biology, including life tables, for Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), the glassy- winged sharpshooter, were quantified at four constant temperatures in the laboratory: 20, 25, 30, and 33 degrees C. Mean time from egg oviposition to adult death and mean female adult longevity was greatest at 25 degrees C. Mean total progeny production was greatest at 25 degrees C at 214 eggs per individual. The percentage of females ovipositing at each experimental temperature was relatively low at 22, 46, and 56% at 20, 25, and 30 degrees C, respectively. No oviposition occurred at 33 degrees C. Upper, lower, and optimal developmental thresholds were calculated for all life stages, and for egg to adult emergence these were 35.95, 13.99, and 29.45 degrees C, respectively. Key demographic parameters were calculated and intrinsic rate of increase and net reproductive rate were highest at 30 and 25 degrees C at 0.04 and 40.21 d, respectively. Meangeneration times and population doubling times were lowest at 25 (97.66 d) and 30 degrees C (15.51 d). Modeling of demographic parameters indicated that approximately three generations of H. vitripennis per year are needed for the existence of permanent populations. Historical weather data were used to map the number of generations and estimate net reproductive rates for H. vitripennis throughout California. Data presented here will be useful for modeling and estimating the possible invasion success of H. vitripennis in areas other than California.