GENE FLOW AND INEFFECTIVE ANTIPREDATOR BEHAVIOR IN A STREAM-BREEDING SALAMANDER

Area of Science:

• Evolutionary Biology
• Ecology
• Animal Behavior

Background:

• Antipredator behavior is crucial for prey survival.
• Gene flow can impede local adaptation by homogenizing populations.
• Streamside salamander larvae face conflicting selection pressures in ephemeral vs. permanent streams.

Purpose of the Study:

• To investigate how gene flow affects antipredator behavior evolution in Ambystoma barbouri larvae.
• To determine if isolation influences the development of anti-fish behaviors.
• To assess the relationship between measured behaviors and larval survival in the presence of predators.

Main Methods:

• Assayed feeding rates and predator escape behavior in laboratory-reared larvae from 15 populations.
• Compared larval survival in artificial streams with natural fish predators.
• Examined populations along a gradient of genetic and geographic isolation from fishless streams.

Main Results:

• Larvae from populations with fish exhibited stronger antipredator responses than those from fishless populations.
• Increased isolation from fishless populations correlated with stronger antipredator responses.
• Larvae from more isolated populations demonstrated enhanced survival in predation experiments.

Conclusions:

• Gene flow between populations with conflicting selection pressures limits local adaptation in streamside salamanders.
• The study highlights the role of gene flow in swamping local adaptation across multiple populations.
• Behavioral plasticity in response to predation is influenced by population isolation and gene flow.