Homalodisca coagulata (Hemiptera : Cicadellidae) feeding posture
The sharpshooter Homalodisca coagulata Say (Hemiptera: Cicadellidae) is a polyphagous insect that feeds primarily from the xylem vessels of host plants. This insect is an efficient vector of the xylem-limited, plant-pathogenic bacterium Xylella fastidiosa Wells, which is the causal agent of several important diseases in ornamental and agricultural crops. In wild populations, H. coagulata have been observed to almost exclusively orient with their anterior facing toward the roots (AFR), regardless of branch position. The orientation of H. coagulata seemed to be chosen before stylet insertion. Neither masking plant chemical and morphological surface cues nor placing test plants in the absence of light affected body posture. The introduction of 1.5-V direct current electricity to the plants resulted in altered body positioning. Removal of both front tarsi influenced body position; however, removal of only the right or left front tarsi had no effect on H. coagulata body position. Removal or masking of right, left, or both antennae resulted in altered body position.