Influence of Constant Temperature on Development, Survival and Fecundity of Sugarcane Mealybug, Saccharicoccus-Sacchari (Cockerell) (Hemiptera, Pseudococcidae)

Abstract

Generation time of S. sacchari females reared on potted cane ranged from 107 days at 20-degrees-C to 25 days at 30-degrees-C. Three models were fitted to developmental data. The linear model indicated a minimum threshold temperature of 17-degrees-C and the inverse polynomial model a maximum development rate at 30.4-degrees-C. Developmental response to temperature varied from that previously reported in Egypt and the Philippines. The largest and most fecund females were produced at 30-degrees-C. Net reproductive rate varied from 82.0 and 79.7 at 20 and 33-degrees-C respectively to 205.5 at 30-degrees-C. The intrinsic rate of natural increase (r(m) increased from 0.038 at 20-degrees-C to 0.186 at 30-degrees-C. The value of the common shape parameter of the Weibull distribution used to describe adult survivorship curves was 3.5, indicating type I survivorship curves. The ovipositional threshold (V0) was estimated as 16.5-degrees-C. The rate of development of individuals had a major influence on fecundity, both directly and indirectly, through adult female size and the duration of the oviposition period. The ability of S. sacchari to produce large individuals with high fecundities when corresponding rates of development were highest give this tropical species a capacity for rapid population growth at high temperature.