Submitted to: Sweetpotato Whitefly Progress Review Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2000
Publication Date: N/A
Technical Abstract: Developed a system to measure homopteran respiration during feeding. Insects were placed in a flow-through respiration chamber specifically designed to provide access to an artificial diet. The respiration chamber was connected to a commercial infra-red gas analyzing system that continually monitored and recorded respiratory CO(2) evolution during feeding. Using this system, respiration rates of 240 and 251 umol CO(2) h(-1) g(-1) were determined for whiteflies and cotton aphids, respectively, at 30 d C on diets containing 15% sucrose. Whitefly respiration increased with temperature over the range of 25-46 d C with a Q(10) of about 2.12 on diets containing 15% sucrose. Respiration rates were similar throughout this temperature range on diets containing 10, 15 & 20% sucrose, but were considerably lower at all temperatures on diets containing 2.5% sucrose and at temperatures gt 35 d C on diets containing 5% sucrose. Respiration rates decreased following the addition of sodium azide to the diet or upon extended exposure to 47 d C. The rate at which respiration decreased at 47 d C was inversely related to the concentration of sucrose in the diet over the range of sucrose concentrations from 2.5-15% sucrose. The results indicate that whiteflies require a sucrose concentration between 5 & 10% for maximum basal metabolism. Higher concentrations of sucrose in the diet delayed high temperature mortality, possibly a reflection of the high sucrose requirement for sorbitol synthesis in these insects.