Novel methods of monitoring the feeding behavior of Homalodisca coagulata (Say) (Hemiptera; Cicadellidae)
The glassy-winged sharpshooter, Honialodisca coagulata (Say), is an important agricultural pest because it is an effective vector of Xylella fastidiosa, the pathogen that causes Pierce's disease in grapevines. Knowledge of the feeding behavior of H. coagulata is important in understanding pathogen transmission, and this knowledge is important in developing innovative pathogen control strategies. Ingestion of fluid by sharpshooters was monitored as movement of fluid from reservoirs connected to short stems of plant tissue. We quantified the amount of fluid processed while the insects were freely moving on the plants stems offered for feeding. Females fed longer than males, and both ingested large amounts of plant fluid and both excreted large amounts of fluid. Excreta droplets were often actively flung from the body by flicking the abdomen. While actively ingesting, the abdomen made exaggerated movements that stopped during excretion. These movements only appeared after mouthparts penetrated the plant tissues. The abdominal movements were correlated with ingestion of plant fluids as monitored by fluid uptake from the reservoir.