Sisterson Mark S, Wallis Christopher M, Stenger Drake C
USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Ave., Parlier CA 93648-9757 (
Environ Entomol. 2017 Apr 1;46(2):299-310. doi: 10.1093/ee/nvx042.
Glassy-winged sharpshooters must feed as adults to produce mature eggs. Cowpea and sunflower are both readily accepted by the glassy-winged sharpshooter for feeding, but egg production on sunflower was reported to be lower than egg production on cowpea. To better understand the role of adult diet in egg production, effects of xylem-sap chemistry on glassy-winged sharpshooter egg maturation was compared for females confined to cowpea and sunflower. Females confined to cowpea consumed more xylem-sap than females held on sunflower. In response, females held on cowpea produced more eggs, had heavier bodies, and greater lipid content than females held on sunflower. Analysis of cowpea and sunflower xylem-sap found that 17 of 19 amino acids were more concentrated in cowpea xylem-sap than in sunflower xylem-sap. Thus, decreased consumption of sunflower xylem-sap was likely owing to perceived lower quality, with decreased egg production owing to a combination of decreased feeding and lower return per unit volume of xylem-sap consumed. Examination of pairwise correlation coefficients among amino acids indicated that concentrations of several amino acids within a plant species were correlated. Principal component analyses identified latent variables describing amino acid composition of xylem-sap. For females held on cowpea, egg maturation was affected by test date, volume of excreta produced, and principal components describing amino acid composition of xylem-sap. Principal component analyses aided in identifying amino acids that were positively or negatively associated with egg production, although determining causality with respect to key nutritional requirements for glassy-winged sharpshooter egg production will require additional testing.
玻璃翅叶蝉成虫必须取食才能产出成熟的卵。豇豆和向日葵都是玻璃翅叶蝉乐意取食的植物，但据报道，在向日葵上的产卵量低于在豇豆上的产卵量。为了更好地了解成虫食物在产卵中的作用，比较了以豇豆和向日葵为食的雌性玻璃翅叶蝉，木质部汁液化学成分对其卵成熟的影响。以豇豆为食的雌性比以向日葵为食的雌性消耗更多的木质部汁液。相应地，以豇豆为食的雌性比以向日葵为食的雌性产卵更多、身体更重、脂质含量更高。对豇豆和向日葵木质部汁液的分析发现，19种氨基酸中有17种在豇豆木质部汁液中的浓度高于在向日葵木质部汁液中的浓度。因此，向日葵木质部汁液消耗量的减少可能是由于其质量被认为较低，而产卵量的减少是由于取食量减少和每单位体积消耗的木质部汁液回报降低共同作用的结果。对氨基酸之间的成对相关系数进行检查表明，同一植物物种内几种氨基酸的浓度是相关的。主成分分析确定了描述木质部汁液氨基酸组成的潜在变量。对于以豇豆为食的雌性，卵的成熟受测试日期、排泄物产生量以及描述木质部汁液氨基酸组成的主成分影响。主成分分析有助于识别与产卵呈正相关或负相关的氨基酸，尽管要确定玻璃翅叶蝉产卵关键营养需求的因果关系还需要进一步测试。
