Living organisms continuously produce chemical, thermal, respiratory, and microbial cues that change when a tissue becomes wounded, infected, ischemic, or dies. This information is particularly important for parasites that use other living animals as resources to determine whether a potential host is suitable. Yet, we know surprisingly little about how the nervous system extracts this information and transforms it into neural representations of host tissue state. To address this gap, our laboratory will use one of nature's most remarkable examples of host tissue state sensing, the New World screwworm (also known as the primary screwworm), Cochliomyia hominivorax, which has intrigued entomologists and evolutionary biologists for over a century, as a model to decipher how this parasite locates hosts, distinguishes suitable from unsuitable resources, and makes decisions that directly determine its survival and reproduction.