REPRODUCTIVE AND DEVELOPMENTAL BIOLOGY OF GONATOCERUS ASHMEADI

• Author(s): Hoddle, Mark; Pilkington, Leigh;
• Abstract: The reproductive and developmental biology of Gonatocerus ashmeadi Girault, a parasitoid of the glassy-winged sharpshooter Homalodisca coagulata (Say), was determined at five constant temperatures in the laboratory; 15; 20; 25; 30; and 33C. At 30C, G. ashmeadi maintained the highest successful parasitism rates with 46.1% of parasitoid larvae surviving to adulthood. Lifetime fecundity was greatest at 25C. Temperature had no effect on sex ratio of parasitoid offspring. Mean adult longevity was inversely related to temperature with a maximum of 20 days at 15C to a minimum of eight days at 33C. Developmental rates increased nonlinearly with increasing temperatures. Developmental rate data was fitted with the modified Logan model for oviposition to adult development times to determine lower developmental threshold (1.1C, and 7.16C estimated by linear regression), optimal developmental temperature (30.5C), and upper lethal temperature threshold (37.6C). Linear regression of developmental rate for temperatures 15-30C indicated that 222 degree-days were required above a minimum threshold of 7.16C to complete development. Demographic parameters were (calculated and pseudoreplicates for intrinsic rate of increase (r)m(), net reproductive rates (R)o(), generation time (T)c(), population) (doubling time (T)d(), and finite rate of increase ()) were generated using the bootstrap method. Mean bootstrap estimates of demographic parameters were compared across temperatures using ANOVA and nonlinear regression.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium