Western Tarnished Plant Bug Egg Development and Hatch Under Constant and Variable Temperatures

The western tarnished plant bug is presently the most important pest of Arizona cotton.  Cotton culture in the West is highly dependent on the availability of irrigation water.  As water supplies become more limited, water conservation techniques such as deficit irrigation will likely result in at least periodically increased cotton canopy temperatures.  The Pest Management and Biocontrol Research Unit at Maricopa, AZ is studying the molecular basis of thermal stress reactions in Lygus in order to design molecular-based management tactics to capitalize on these microclimatic changes.  We examined the development time and diel pattern of hatch of Lygus eggs at combinations of moderate and high temperatures, either held constant or exhibiting a thermoperiod.  Development time was similar between constant and variable temperature regimes at moderate temperatures, but development was faster at high constant temperatures compared with high variable temperatures.  Also, egg hatch displayed a distinct diel pattern under the high variable temperature regime.  Ecological implications of these distinctions between constant and variable temperature regimes are discussed.