Egg Stage of Homalodisca vitripennis and Homalodisca liturata (Hemiptera: Cicadellidae): Ovometrics, Embryonic Development, and Nonparasitic Mortality

ABSTRACT Morphometric and developmental aspects of the egg stage of glassy-winged sharpshooter, Homalodisca vitripennis (Germar), and Homalodisca liturata Ball were investigated. Considerable overlap exists between the two species with respect to egg length, width, and clutch size, making these variables unreliable in identifying their eggs to species. Embryonic development of the two species was observed at constant temperatures ranging from 8.7 to 40.4°C. No signs of development were observed at 8.7°C, development was aborted early in development at 11.5°C, and egg masses were desiccated at 40.4°C. For both species, rates of embryonic development increased linearly with increasing temperatures from 16.7 to 25.6°C, peaked at 31.2°C, and decreased between 32.9 and 35.0°C. Based on linear regression, the minimum thresholds for embryonic development were 12.0 and 12.6°C, and heat unit requirements were 111.4 and 104.5 degree-days for H. vitripennis and H. liturata, respectively. We quantified four physiolog...