Among the diversity of substances used by amphibians for chemical defense, lipophilic alkaloids are not produced by them. These compounds are obtained from their diet, specially mites and ants, and are stored in skin granular glands. One of the characteristics of this chemical defense system is the huge variation in abundance, richness and composition of alkaloids between species, population and among individuals of the same population. A possible explanation for this individual variation in alkaloids diversity observed in coespecifics is that older individuals could have been exposed to a bigger diversity of arthropods that posses alkaloids than younger individuals. In such case, a positive relation between diversity of alkaloids present in an individual and its age would be expected. The species of genus Melanophryniscus (Bufonidae), that are distributed in the central east area of South America, are among the species that are capable of sequestrate alkaloids. The main goal of this study is to test a relation between the age and the diversity of alkaloids in the skin of individuals of M. simplex. Also, we want to test if there is a difference of obtained data through osteochronology among different long bones of the amphibian. The age is going to be related to the individual alkaloid diversity using data already obtained from previous project of the same research group.
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