BIOLOGICAL CONTROL IS INHERENTLY RISKY, YET IS ONE OF THE ONLY LONG-TERM SOLUTIONS TO CONTROLLING INVASIVE WEEDS. INTRODUCED BIOCONTROL AGENTS ARE EVOLVING, AND AS THEIR POPULATIONS EXPAND, SPATIAL DYNAMICS ARISE THAT CAN LEAD TO RAPID DIVERGENCE BETWEEN POPULATIONS AT THE EDGE OF THE EXPANSION AND POPULATIONS AT THE CORE. BIOCONTROL POPULATIONS AT THE EXPANSION FRONT MAY EVOLVE INCREASED DISPERSAL ABILITY, WHICH COULD INCREASE EFFICACY, BUT MAY ALSO EXPOSE THEM TO NOVEL HOSTS AND INCREASE THE RISK OF NON-TARGET ATTACK.OUR OVERARCHING GOAL IS TO IMPROVE UNDERSTANDING OF WHETHER AND HOW ECO-EVOLUTIONARY DYNAMICS AFFECT THE SUCCESS AND SAFETY OF BIOCONTROL VIA EVOLUTION OF DISPERSAL CAPACITY AND HOST SPECIFICITY. WE FOCUS ON THE ASIAN SALTCEDAR BEETLE, A BIOCONTROL AGENT RELEASED AGAINST TAMARIX, A CRUCIALLY IMPORTANT RANGELAND WEED. WE WILL QUANTIFY EVOLVED DIFFERENCES IN DISPERSAL CAPACITY AND HOST SPECIFICITY BETWEEN DIFFERENT POPULATIONS ALONG REPLICATE TRANSECTS OF THE EXPANSION FRONT. WE TAKE A MULTIDISCIPLINARY APPROACH INVOLVING FIELD AND LAB EXPERIMENTS AS WELL AS 'NEXT GENERATION' SEQUENCING TO IDENTIFY SPECIFIC GENETIC LOCI THAT EXPLAIN VARIANCE IN THESE TRAITS. OUR SPECIFIC OBJECTIVES ARE:1. TO EVALUATE ECOLOGICAL GENETIC VARIATION IN DISPERSAL CAPACITY AND IN HOST SPECIFICITY ACROSS THE EXPANDING FRONT OF A BIOCONTROL AGENT TRACKING ITS TARGET HOST2. TO IDENTIFY SPECIFIC GENETIC LOCI THAT EXPLAIN VARIANCE IN DISPERSAL AND HOST SPECIFICITY, AND USE THIS PANEL OF LOCI TO TRACK ECOLOGICALLY RELEVANT GENETIC VARIATION ACROSS THE EXPANDING RANGE OF A BIOCONTROL AGENT.OUR RESULTS WILL HAVE A MAJOR IMPACT ON CONTROL OF AGRICULTURAL PESTS BY IMPROVING THE SAFETY AND EFFICACY OF BIOLOGICAL CONTROL, THROUGH ELUCIDATING THE ROLE OF ECO-EVOLUTIONARY DYNAMICS IN DISPERSAL AND HOST USE. FURTHER, THE RESEARCH IS BROADLY RELEVANT TO ENHANCING OUR ABILITY TO PREDICT THE ESTABLISHMENT AND SPREAD OF INVASIVE SPECIES AND BENEFICIAL INSECTS ALIKE.