INCREASING AVERAGE TEMPERATURES IMPACT AGRICULTURE, INCLUDING THE SPREAD AND PERSISTENCE OF INSECT PESTS. SEVERAL STINK BUG (HEMIPTERA: PENTATOMIDAE) SPECIES ARE SIGNIFICANT SOYBEAN PESTS THROUGHOUT THE ENTIRE GROWING REGION, AND TEMPERATURE CHANGE MAY BE PLAYING A ROLE IN THE OBSERVED RANGE EXPANSION OF KEY SPECIES. IN THIS PROJECT WE WILL EXAMINE FOUR SOYBEAN STINK BUG SPECIES REGARDING THEIR HOT AND COLD THERMAL TOLERANCES, THEIR REPRODUCTIVE POTENTIAL WITHIN THESE THERMAL TOLERANCES, AND THEIR ENDOSYMBIONT FLORA (WHICH MAY BE INFLUENCING THESE TOLERANCES). ONE OF THESE SPECIES (BROWN MARMORATED STINK BUG) OCCURS PREDOMINANTLY IN THE NORTHERN U.S.; ONE (REDBANDED STINK BUG) IN THE SOUTHERN U.S.; AND TWO SPECIES (GREEN AND BROWN STINK BUGS) OCCUR ACROSS THE ENTIRE GRADIENT IN BETWEEN. BY EXAMINING BUGS COLLECTED AT THESE GEOGRAPHIC EXTREMES OR FROM A TRANSECT ACROSS THIS GEOGRAPHIC GRADIENT WE WILL BE ABLE TO COMPARE THERMAL RESPONSES AND ENDOSYMBIONT DIVERSITY OF INDIVIDUALS FROM DIFFERENT TEMPERATURE REGIMES. THIS WILL PROVIDE DATA FOR INFERENCES ABOUT THE CURRENT AND FUTURE PEST POTENTIAL OF THESE SPECIES IN SOYBEAN PRODUCTION. OUR OBJECTIVES ARE 1. DETERMINE STINK BUG DEVELOPMENTAL THRESHOLDS UNDER CONSTANT AND FLUCTUATING TEMPERATURES; 2. DETERMINE THERMAL TOLERANCES (HOT AND COLD) IN FOUR STINK BUG SPECIES AT DIFFERENT LATITUDES; 3. IDENTIFY AND COMPARE GUT ENDOSYMBIONT SPECIES IN FOUR STINK BUG SPECIES AT DIFFERENT LATITUDES. THESE OBJECTIVES WILL PROVIDE DATA ON HOW STINK BUGS REACT TO INCREASING TEMPERATURE AVERAGES AND EXTREMES AND HOW THEIR THERMAL CAPABILITIES CORRELATE WITH ENDOSYMBIONT LOAD.