We studied the embryonic development of Homalodisca coagulata (Say) and H. lacerta (Fowler) at a range of temperatures. Development rate of both species was linearly related to temperature up to ca. 30o C . There were small but significant differences between H. coagulata and H. lacerta in their embryonic development periods for temperatures in the range of 16.7-32.9o C, with H. lacerta eggs, for the most part, taking longer to completely develop than eggs of H. coagulata . H. coagulata required 113.8 degree-days from oviposition to egg hatch, with a minimal development threshold of 11.9o C. Embryonic development of H. lacerta required 104.8 degree-days and the minimal development threshold was 12.6oC. At higher temperatures the hatch rate for H. coagulata was significantly reduced, especially at 35oC (from 72-89% to 45%). Embryonic development was broken down into 5 stages. For H. coagulata, the pre-eye spot stage (1st stage) lasted for almost two thirds of the total development period. On average 13% of the eggs had developmental problems with 11% of eggs showing no development and 2% exhibiting abnormal development seen as eye spots developing either centrally or on the opposite side of where nymphs eventually exit the eggs.
Species 1: Homoptera Cicadellidae Homalodisca coagulata (Glassy-winged sharpshooter)
Species 2: Homoptera Cicadellidae Homalodisca lacerta (Smoke tree sharpshooter)
Keywords: degree-day, hatch rate
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