Host-plant finding, acceptance and feeding of Anasa tristis (Degeer) (Heteroptera: Coreidae)

Colwell Ann Cook, Purdue University

Abstract

The purpose of this investigation was to determine how closely a phytophagous heteropteran, Anasa tristis, fits a host plant utilization model by determining the stimuli necessary for finding, accepting, and feeding on its host plant, pumpkin, Cucurbita pepo. The insect was found to follow the model presented. It was found that vision and olfaction are important components of host plant finding, for without these sensory systems the insects were unable to find their host plants efficiently. But, neither sensory system is solely capable of directing A. tristis to its host plant. Investigations into specific colors, sizes, shapes, or pumpkin, Cucurbita pepo, odors were not conclusive. The insects proceeded to accept their host plants by displaying a sequence of behaviors--walking to examining to probing to feeding. Olfactory cues appear to govern the acceptance of host plants since removal of antennae removed an inhibition to feeding. The cues processed by tarsi of A. tristis also play a key role in acceptance of host plants. Insects with blocked tarsal receptors were more likely to feed. Regardless of treatment once insects begin to examine the plant, they proceeded on to exhibit feeding behavior. Second instar larvae of A. tristis survive through the second stadium on cucumber, Cucumis sativa, but die on the day that their cohorts on pumpkin molt to third instar. Second instars were wired to an electronic feeding monitor. Second instars do feed on cucumber but only about half as often as insects on pumpkin. Once feeding began, the length of time spent per feeding event was the same regardless of plant. However, total feeding time on cucumber was nearly half that of pumpkin.

Degree

Ph.D.

Advisors

Neal, Purdue University.

Subject Area

Entomology|Ecology

COinS