NATURAL INSECT ENEMIES OF PLANTS ARE OFTEN USED TO MANAGE THE SPREAD OF DAMAGING INVASIVE PLANTS.SUCCESSFUL INSECT ENEMIES, OR BIOCONTROL AGENTS, EXPAND FROM ORIGINAL RELEASE SITES AND OCCUPY THE ENTIRE RANGE OF THE INVASIVE PLANT. HOWEVER, DURING A RANGE EXPANSION, HARMFUL VERSIONS OF GENES CAN BECOME MORE FREQUENT AT THE LEADING EDGE OF THE EXPANSION (TERMED GENETIC LOAD).ADDITIONALLY, TRADE-OFFS BETWEEN IMPORTANT TRAITS CAN EVOLVE DURING RANGE EXPANSION.FOR EXAMPLE, AN INDIVIDUAL'S ABILITY TO MOVE ACROSS A LANDSCAPE MAY INCREASE WHILE REPRODUCTION DECREASES. WE DO NOT CURRENTLY KNOW HOW THESE PROCESSES IMPACT RANGE EXPANSIONS OF BIOCONTROL AGENTS. THEREFORE, OUR GOAL IS TO DETERMINE HOW GENETIC LOAD AND TRADE-OFFS INTERACT AND INFLUENCE THE SPEED AND EXTENT OF RANGE EXPANSION.WE FOCUS ON ONE BIOLOGICAL CONTROL AGENT, THE NORTHERN TAMARISK BEETLE, WHICH HELPS CONTROL THE INVASIVE TREE TAMARISK IN THE WESTERN UNITED STATES.TO ACHIEVE THIS GOAL, WE WILL FIRST MEASURE GENETIC LOAD BY LOOKING AT REPRODUCTIVE OUTPUT AND LIFESPAN OF INDIVIDUALS WITH PARENTS THAT ARE EITHER RELATED OR UNRELATED. THIS WILL SHOW WHETHER HARMFUL VERSIONS OF GENES ARE MORE FREQUENT IN SOME AREAS OF THE RANGE AND HOW MUCH THEY IMPACT FITNESS. SECOND, WE WILL EVALUATE TRADE-OFFS BY MEASURING BOTH FLIGHT ABILITY AND NUMBER OF OFFSPRING TO SEE IF INDIVIDUALS HAVE INVESTED IN ONE TRAIT AT THE EXPENSE OF THE OTHER. RESULTS FROM THIS WORK WILL BE PRESENTED AT SCIENTIFIC MEETINGS AND IN PEER-REVIEWED PUBLICATIONS TO INFORM LAND MANAGERS AND THE SCIENTIFIC COMMUNITY OF OUR RESULTS. ULTIMATELY, THESE EXPERIMENTS WILL REVEAL HOW FAST THE RANGE EXPANSION OF THE TAMARISK BEETLE CAN PROCEED. FOR EXAMPLE, IF WE FIND THAT BEETLES CARRY FEW HARMFUL VERSIONS OF GENES AND DO NOT SHOW TRADE-OFFS, WE CAN EXPECT A FASTER RANGE EXPANSION. WITH THIS INFORMATION, WE CAN IMPROVE MANAGEMENT OF OTHER BIOCONTROL SYSTEMS, INVASIVE PLANTS, AND RESTORATION OF HABITAT.