Moisture, a vital but neglected factor in the seasonal ecology of insects: Hypotheses and tests of mechanisms

Of the major physical factors that influence insect seasonal ecology, moisture is least understood and least appreciated. It is our premise that experimental probing of insets from diverse zones and various habitats would reveal general patterns of insect responses to moisture that are as striking as those for photoperiod and temperature. using the paradigms of photoperiod and temperature as ec ophysiological determinants of insect seasonality, we hypothesize that moisture influences insect life cycles via one or more of three mechanisms - as a token stimulus for diapause, modulator of developmental or reproductive rates, or behavioral cue for vital seasonal events. For heuristic purposes, we offer each of these hypotheses in close association with approaches for testing their validity in insects that undergo dry-season dormancy. The approaches appear appropriate for examining the role of moisture in the life histories of terrestrial invertebrates other than insects, as well ads plants and microbes that have a seasonal resting sate. Elucidating moisture's role in insect seasonal cycles is critical to the development of comprehensive phenological models, improved insect management systems, and identification of novel evolutionary mechanisms for adaptation to wet-dry seasons, especially in tropical, subtropical,and Mediterranean regions.