Animals must make economical decisions about how to distribute limiting resources in order to maintain health and survival. The investigators focus on carotenoid pigments, a particularly important and limiting resource in the diets of human and non-human animals. Vertebrate animals cannot synthesize carotenoids and must obtain them from dietary sources which may be available in only limited quantities. Carotinoids they play three important - and sometimes competing - roles in animal physiology. First, carotenoids are directly responsible for many examples of red, orange and yellow coloration in animals, and this coloration is often necessary for attracting mates. Second, carotenoids in the bloodstream or stored in tissue support the immune system. Third, carotenoids are important antioxidants, which protect the body's cells by removing potentially damaging molecules called free radicals. The carotenoid trade-off hypothesis predicts that when dietary carotenoids are limiting, animals will allocate existing carotenoids to whichever tissue type is most beneficial to them at that time. The investigators take a unique approach to exploring this hypothesis by studying carotenoid trade-offs in female, convict cichlids, Amatitlania nigrofasciata, Central American fish in which females - not males - are brightly colored. Females have the added constraint of allocating carotenoids to their eggs to facilitate offspring survival. The investigators will combine laboratory and field research to examine how environmental stressors such as predators and parasites influence carotenoid allocation strategies, and how these strategies impact health, attractiveness, and offspring survival. Because all vertebrate animals rely in some way on carotenoids, this research will provide fundamental insights into how ingesting and properly allocating essential nutrients affects both physiology and reproduction. This proposal includes a significant training component, as both principal investigators will train and mentor undergraduate and graduate students at their institutions. They will also work with Nicaraguan collaborators to increase research infrastructure at a Nicaraguan biological field station and train Nicaraguan students.
