Reproductive Biology and Survival of Diabrotica barberi (Coleoptera: Chrysomelidae): Effect of Temperature, Food, and Seasonal Time of Emergence

Abstract

The reproductive biology of Diabrotica barberi Smith & Lawrence was studied in the laboratory at seven constant temperatures, six dietary regimes at 25°C, and at two time periods during adult emergence in the field. Preoviposition periods ranged from a mean of 24.8 d at 15°C to 11.8 d at 25°C, and the mean period of oviposition ranged from 65.7 d at 15°C to 33.7 d at 30°C. Mean female and male longevity were similar, ranging from ca. 90 d at 17.5°C to 42 d at 30°C. Eggs were laid in clutches with a mean of 25 to 31 eggs. Clutch size was independent of temperature but the interval between clutches, the number of clutches, and overall fecundity were all affected by temperature. At 22.5°C females laid an average of 8.7 clutches, one every 6.4 d with a mean fecundity of 274 eggs. In contrast, at 30°C females laid a mean of 4.3 clutches at a frequency of 7.3 d with a mean fecundity of 118 eggs. Beetles failed to mature and survived poorly when provided only with food sources from immature corn plants. Reduction in the quality of food associated with corn plant maturity significantly reduced the period of oviposition, fecundity, and longevity. Feeding for various periods after emergence allowed maturation and some oviposition but continual feeding was necessary for continued oviposition and normal survival. Adult size was not correlated with any aspect of reproduction, and adults emerging relatively early and late in the field differed in size but not significantly in reproductive potential.