INSECT HERBIVORY CAUSES BILLIONS OF DOLLARS IN CROP LOSSES WORLDWIDE. ONE STRATEGY FOR MANAGING PESTS AND MINIMIZING CROP LOSS IS TO SELECT OR DEVELOP CULTIVARS WITH TRAITS THAT PROVIDE RESISTANCE TO INSECT HERBIVORY. CULTIVAR TRAITS THAT PROVIDE RESISTANCE TO HERBIVORY INCLUDE INDUCED DEFENSES, OR PHYSICAL OR CHEMICAL DEFENSES THAT ARE ONLY EXPRESSED IN RESPONSE TO INSECT FEEDING. INDUCED DEFENSES CAN REDUCE CROP DAMAGE DUE TO INSECT HERBIVORY, BUT OFTEN COME AT A COST TO PLANT REPRODUCTION, WHICH COULD IN TURN AFFECT CROP YIELD (PARTICULARLY FOR CROPS IN WHICH THE REPRODUCTIVE PARTS OF THE PLANT, E.G., FRUITS AND SEEDS, ARE HARVESTED). HOWEVER, LITTLE IS KNOWN ABOUT HOW THESE COSTS AFFECT PLANT AND INSECT POPULATIONS IN THE LONG TERM, OR WHETHER THESE EFFECTS DIFFER BASED ON PLANT LIFE HISTORY (E.G., ANNUAL/PERENNIAL, SEASONALITY OF REPRODUCTION). THE GOAL OF THIS PROJECT IS TO UNDERSTAND THE LONG-TERM CONSEQUENCES OF INDUCED DEFENSES FOR PLANT AND INSECT POPULATIONS. THIS WILL BE ACCOMPLISHED THROUGH TWO OBJECTIVES: (1) MEASURING EFFECTS OF HERBIVORE DENSITY ON THE EXPRESSION OF INDUCED DEFENSES IN PLANT POPULATIONS THROUGH TIME AND (2) DETERMINING HOW THE STRENGTH OF REPRODUCTION-DEFENSE TRADEOFFS, THE RATES AT WHICH DEFENSES ARE INDUCED AND DECAY, AND THE EFFECT OF INDUCED DEFENSES ON HERBIVORES INFLUENCE PLANT REPRODUCTIVE OUTPUT AND HERBIVORE DENSITIES. IN OBJECTIVE 1, WE WILL USE A FIELD EXPERIMENT TO MEASURE INDUCED DEFENSES THROUGH TIME IN WILD UPLAND COTTON, GOSSYPIUM HIRSUTUM, IN RESPONSE TO FEEDING BY DIFFERENT NUMBERS OF INSECT HERBIVORES. IN OBJECTIVE 2, WE WILL ANALYZE TWO VERSIONS OF A MATHEMATICAL MODEL, REPRESENTING WILD, CONTINUOUSLY REPRODUCING PERENNIAL POPULATIONS AND ANNUALLY CROPPED POPULATIONS, RESPECTIVELY. RESULTS FROM THIS PROJECT WILL BE DIRECTLY RELEVANT TO AGRICULTURAL PEST MANAGEMENT (E.G., IDENTIFYING CULTIVARS WITH HIGH, STABLE ANNUAL YIELDS ACROSS MANY POTENTIAL HERBIVORY LEVELS) AND TO THE CONSERVATION OF CROP WILD RELATIVES AS GENETIC RESERVOIRS. MORE BROADLY, THIS WORK WILL ADVANCE OUR UNDERSTANDING OF THE IMPLICATIONS OF GROWING NATURALLY PERENNIAL SPECIES ON AN ANNUAL CYCLE.