Environmental and genetic influences on mating strategies along a replicated food availability gradient in guppies (Poecilia reticulata)

Abstract

Food availability is expected to influence the relative cost of different mating tactics, but little attention has been paid to this potential source of adaptive geographic variation in behavior. Associations between the frequency of different mating tactics and resource availability could arise because tactic use responds directly to food intake (phenotypic plasticity), because populations exposed to different average levels of food availability have diverged genetically in tactic use, or both. Different populations of guppies (Poecilia reticulata) in Trinidad experience different average levels of food availability. We combined field observations with laboratory "common garden" and diet experiments to examine how this environmental gradient has influenced the evolution of male mating tactics. Three independent components of variation in male behavior were found in the field: courtship versus foraging, dominance interactions, and interference competition versus searching for mates. Com pared with low-food-availability sites, males at high-food availability sites devoted more effort to interference competition. This difference disappeared in the common garden experiment, which suggests that it was caused by phenotypic plasticity and not genetic divergence. In the diet experiment, interference competition was more frequent and intense among males raised on the greater of two food levels, but this was only true for fish descended from sites with low food availability. Thus, the association between interference competition and food availability in the field can be attributed to a genetically variable norm of reaction.Genetically variable norms of reaction with respect to food intake were found for the other two behavioral components as well and are discussed in relation to the p atterns observed in the field. Our results indicate that food availability gradients are an important, albeit complex, source of geographic variation in male mating strategies.

Physiological adaptation along environmental gradients and replicated hybrid zone structure in swordtails (Teleostei:Xiphophorus)

“…As with many environmental gradients, stream gradients are multivariate, consisting of superimposed and correlated abiotic and biotic variables, such as temperature, precipitation, food availability, vegetation and predation (Endler, 1995; Grether et al. , 1999; Kolluru et al. , 2007; Walsh & Reznick, 2009).…”

“…Here, ENM enabled us to disentangle the complexity of environmental differences along the elevational gradient. As with many environmental gradients, stream gradients are multivariate, consisting of superimposed and correlated abiotic and biotic variables, such as temperature, precipitation, food availability, vegetation and predation (Endler, 1995;Grether et al, 1999;Kolluru et al, 2007;Walsh & Reznick, 2009). Using ENM followed by DFA allowed us to identify abiotic factors important in predicting the distribution of parentals and their hybrids, and helped us to focus on fitness-relevant variables that were the strongest drivers of the observed patterns.…”

Are fancy guppies (<em>Poeciliareticulata</em> Peters, 1859) invasive?

“…Therefore, a result similar to yellow guppies would have also been obtained for black guppies, of there was a prolonged experimental period. Kolluru et al (2006Kolluru et al ( , 2007 also showed that the fin regeneration in guppies is possible even in the presence of natural stressors such as predators and infectious agents, and they regrew more fin tissues when the food level was raised. Hockley et al (2014) have shown that the swimming speed of guppies is affected by the hydrodynamic drag imposed by their fins.…”

Behavioral and hormonal flexibility across light environments in guppies (Poecilia reticulata)

“…Archard et al (2009) found that guppy mating behavior, especially the courtship display, is correlated with both the quantity and quality of light. Males displayed more at lower light levels and at light levels simulating dawn and dusk than at higher light levels and those simulating levels at high noon (Endler 1987;Kolluru et al 2007;Archard et. al 2009).…”

“…Males also engage in aggressive interactions with other males. These interactions include both competitive interactions in which multiple males competitively court the same females, and dominance interactions in which males interact aggressively with each other without females nearby, potentially to establish relationships with respect to future mating rights to receptive females (Kolluru and Grether 2005;Kolluru et al 2007).…”