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Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/15/2010 Publication Date: 12/1/2010 Citation: Krugner, R. 2010. Differential reproductive maturity between allopatric populations of Homalodisca vitripennis (Hemiptera: Cicadellidae) in California. Crop Protection. 29:1521-1528. Interpretive Summary: Various aspects of behavior and population ecology of glassy-winged sharpshooter (GWSS), Homalodisca vitripennis, in the southeastern U.S. have been studied extensively but little is known how these critical parameters vary among populations, including those established in California. Thus, additional work was required to identify biotypic variation and to better understand the genetic basis and ecological significance of differential traits. Laboratory studies identified differences in reproductive behavior between two separate GWSS populations in California (Riverside and Bakersfield). More specifically, insects from Riverside reached reproductive maturity earlier than insects from Bakersfield and also produced numerically more eggs. Results of this study are an important step towards more extensive investigations on interaction of biotypes with natural enemies and evolution of insecticide resistance. Identification of differences in biological and behavioral parameters among GWSS populations may serve as a key component to tailor effective pest management strategies to specific agricultural environments and may have important ramifications for understanding entry pathways of this invasive species. Technical Abstract: Homalodisca vitripennis (Germar) is native to southeastern U.S. and northeastern Mexico. It was detected in southern California in the late 1980s and in the San Joaquin Valley in 1999, where it transmits the bacterium Xylella fastidiosa Wells et al. to grapevines and other crops. The reproductive behavior of H. vitripennis from two allopatric populations in California (Riverside (RIV) and Bakersfield (BAK)) was evaluated under identical conditions. The RIV and BAK populations had different preoviposition periods that persisted through the second generation of each lineage. From adult molt, the preoviposition period in both female generations and was significantly shorter for RIV (F0 = 28.2 d and F1 = 62.3 d) than BAK females (F0 = 46.1 d and F1 = 170.4 d). On average, F0 and F1 females deposited 390.6 (range, 21-967) and 196.3 (range, 0-755) eggs, respectively, without significant differences in fecundity among the F0 and F1 treatments. The F0 mating pairs: 'RIV × 'RIV, 'RIV × 'BAK, 'BAK × 'RIV, and 'BAK × 'BAK produced on average 185, 94, 79, and 0 fertilized eggs, respectively, which indicated a delayed reproductive maturity of BAK males and females. The proportion of fertilized eggs deposited decreased gradually until females completely exhausted sperm reserves. |
