Meeting Abstract
P3.4 Monday, Jan. 6 15:30 Nutritional effects on male traits and female mate choice in hybrid populations of northern swordtails Xiphophorus malinche x birchmanni. DELCLOS, PJ*; ROSENTHAL, GG; Texas A&M University; Texas A&M University pdelclos@bio.tamu.edu
A major goal in evolutionary ecology is to determine how a given environmental factor may affect a suite of ecologically relevant traits within a species, which can have consequences on both how fitness is distributed within a population and on overall population dynamics. For example, differences in nutrient availability among populations have been shown to indirectly affect population size and mean fitness by altering the reproductive allotment of females. Sexual selection via mate choice can further affect population mean fitness. However, our knowledge of how nutrition directly affects female mate choice and sexual selection is very limited. We examined how different environmental factors may affect hybrid Xiphophorus populations by measuring male phenotypic traits in the field and correlating these to various aspects of habitat and community. We found a significant positive correlation between the amount of benthic algae within a given site and the coefficient of variation of standard length and dorsal fin length, a secondary sexual trait in males, suggesting an effect of resource quantity on the male phenotypic pool. This result is in accord with previous studies suggesting that well-fed female X. birchmanni show weaker preferences than starved ones. We reexamined this study by varying the diets of females from hybrid populations varying in algal abundance. We found that females from the low-algae site that were fed a low-protein diet showed significant preferences for well-fed male chemical cues. All other combinations of site of origin and diet resulted in no significant net preference. This study provides a foundation for future experiments that will examine nutrition as a potential link between our behavioral trials and field data.
