By Lillian Burbulis

Faculty Mentor: Lauren Cirino

Abstract

Animals must partition resources into life history traits resulting in tradeoffs because resources are finite. A tradeoff is the allocation of resources to one trait over another. Life history theory states that energy is allocated in a hierarchical fashion. For example, somatic maintenance should be a higher priority than reproduction, resulting in more resources being allocated to somatic maintenance compared to reproductive traits. One example of a somatic maintenance trait is an immune response which supports all upkeep of the body. The metabolic investment hypothesis states that energy must follow a hierarchical order, prioritizing somatic maintenance over reproduction. Another hypothesis for energy being allocated is the terminal investment hypothesis. This hypothesis states that energy will bypass a hierarchical order to increase overall fitness, resulting in resources being bypassed to reproduction. Our goal is to examine how resources are partitioned throughout the body using leaf-footed cactus bugs that can trade off resources between reproductive traits. We placed late-stage juveniles into four treatments: wounding only, autotomy and wounding, wounding only, and control. We used testes size as a metric to determine reproductive fitness and wounding to determine if the immune system had been upregulated. Under the terminal investment hypothesis, we expect males which have been both autotomized and punctured to have the largest testes mass as they are investing in current reproduction rather than overall survival. Under the metabolic investment hypothesis, we expect males which have only been autotomized to have the largest testes, as an immune response was not inflicted meaning the extra resources do not need to follow a hierarchy when being distributed.