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Advisor(s)
Abstract(s)
The occurrence of intra-sexual variation in reproduction is a widespread phenomenon in teleosts. One such form of variation consists in
the occurrence of alternative male types: males that invest resources in mate attraction and males that exploit the investment of the former
males, by trying to sneak fertilizations during spawning. These alternative reproductive tactics can be classified according to their plasticity
during the life span of the individuals (i.e., fixed vs. sequential vs. reversible). Furthermore, the differences between morphs within a given
species may involve a set of different traits, including reproductive behavior, the differentiation of male morphological traits, and the patterns
of gonad tissue allocation and the differentiation of gonadal accessory glands. In this paper, we review the available data on four species
exhibiting different types of intra-sexual plasticity in reproduction that have been studied in our lab. The data on the proximate mechanisms,
androgens and forebrain arginine-vasotocin (AVT), underlying these alternative tactics suggest that between-morph differences in androgen
levels, especially in 11-ketotestosterone, are especially present in species where the alternative male types have evolved morphological traits
that are tactic-specific (i.e., sexual polymorphisms) and that differences in AVT appear to be related to between-morph differences in the
expression of courtship behavior. Therefore, this comparative approach leads us to propose that the different endocrine systems are involved
in the differentiation of different sets of traits that make up alternative phenotypes, and that the differentiation of alternative tactics is not
controlled by a single endocrine system (e.g., androgens).
Description
Keywords
Sexual plasticity Alternative reproductive tactics Fish Androgens Testosterone 11-ketotestosterone Arginine vasotocin Reproductive behavior
Citation
Hormones and Behavior, 48, 430-439