Diversity of Arthropod Responses to Host-plant Water Stress in a Desert Ecosystem in Southern New Mexico

Abstract

Abstract Previous studies of insect-plant interactions have produced the contradictory Plant Stress Hypothesis (that stressed plants are more suitable hosts for phytophages) and Plant Vigor Hypothesis (that vigorous plants are more suitable hosts for phytophages). However, experimental studies of phytophage responses to host stress have involved only one, or a few, related phytophagous species, not whole communities of organisms associated with a particular plant species. We evaluated responses of various arthropods associated with creosotebush Larrea tridentata to manipulated water availability and plant stress in southern New Mexico during 1990–1991. Of 44 arthropod groups (taxa or functional groups) evaluated in our study only two taxa (including a lepidopteran folivore) showed significant negative response to water availability, thereby supporting the Plant Stress Hypothesis. Ten taxa (including eight phytophages) responded positively to water availability, supporting the Plant Vigor Hypothesis. One p...