Meeting Abstract
When populations occupy different environments, divergent selection pressures can result in phenotypic differentiation in traits that provide a local fitness advantage. Trinidadian guppy (Poecilia reticulata) populations are separated by physical barriers which result in repeated shifts in selective pressures from predator avoidance in high predation environments towards resource competition in low predation environments. Previous studies have shown that these changes result in a range of locally adapted morphological and behavioral traits, including color, length of gestation, and shoaling behavior. Regarding prey capture, although consumption rates and head morphology may differ, suction-feeding behaviors do not, and the role of local adaptation on feeding is unclear. We analyzed morphological differences such as body size, eye area, jaw positioning and body depth to validate known differences between populations. Since biting is a more relevant behavior for guppies, we then filmed adult females from replicate high/low predation pairs while they used biting behaviors to feed on an agar substrate. We did not find divergence in either morphological or kinematic traits, suggesting a general lack of local adaptation, contrary to previous findings. A lack of divergence could be due to less pronounced morphological divergence in females, perhaps as a constraint of bearing young, and the absence of divergent selection on prey capture performance. In female guppies, morphology and performance are not locally adapted, and divergence may exist primarily in behavioral traits (consumption rates) as a result of competition in low predation environments.
