** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE CIRCADIAN CLOCK IS AN INTERNAL MECHANISM THAT ALLOWS ORGANISMS TO PREDICT AND RESPOND TO RHYTHMIC CHANGES IN THEIR ENVIRONMENT. STUDIES SPANNING VARIOUS TAXA HAVE DEMONSTRATED THAT HOST BIOLOGICAL CLOCKS INFLUENCE DAILY PATTERNS IN IMMUNE RESPONSES, DISEASE SEVERITY, AND DISEASE TRANSMISSION. ALTHOUGH MUCH IS KNOWN ABOUT RHYTHMS IN HOST-PARASITE INTERACTIONS IN MAMMALS, EQUIVALENT UNDERSTANDING WITHIN PLANT-PEST INTERACTIONS IS LACKING. COMPARABLE TO HUMAN PARASITES, SOME PLANT PESTS EXHIBIT CLOCK-REGULATED RHYTHMS IN TRAITS THAT ALLOW THEM TO SUCCESSFULLY PARASITIZE THEIR HOSTS. OUR RESEARCH AIMS TO CHARACTERIZE THE INFLUENCE OF CIRCADIAN CLOCK REGULATED RHYTHMS IN GENE EXPRESSION, BEHAVIOR, AND PERFORMANCE IN THE BIRD CHERRY-OAT APHID (RHOPALOSIPHUM PADI), A NOTORIOUS PEST OF WHEAT AND OTHER GRAINS WORLDWIDE. WE AIM TO CONDUCT A TIME-COURSE TRANSCRIPTOME EXPERIMENT IN RHYTHMIC AND CONSTANT LIGHT REGIMES TO DETERMINE THE GENES IN R. PADI WHICH ARE REGULATED BY THE CIRCADIAN CLOCK. NEXT, WE AIM TO USE VIDEO TRACKING AND TRADITIONAL INSECT ASSAYS IN RHYTHMIC AND CONSTANT LIGHT REGIMES TO DETERMINE CLOCK REGULATED RHYTHMS IN LOCOMOTORY BEHAVIOR, HONEYDEW EXCRETION, AND REPRODUCTION. FINALLY, WE AIM TO CHARACTERIZE THE DIRECT INFLUENCE OF THE CIRCADIAN CLOCK ON APHID BEHAVIOR AND PERFORMANCE BY SILENCING CIRCADIAN CLOCK COMPONENTS USING A NANOPARTICLE-FACILITATED TOPICAL RNAI APPROACH. THE PROPOSED PROJECT WILL ALLOW FOR THE DEVELOPMENT OF SKILLS IN APHID BEHAVIORAL ASSAYS, BIOINFORMATICS, APPLIED INSECT MOLECULAR BIOLOGY, AS WELL AS DATA ANALYSIS AND SCIENCE COMMUNICATION AND WILL PROVIDE KNOWLEDGE TO AID IN THE DEVELOPMENT OF INNOVATIVE PEST MANAGEMENT STRATEGIES.