Repeated parallel differentiation of social learning differences in benthic and limnetic threespine stickleback fish

Area of Science:

• Behavioral Ecology
• Evolutionary Biology
• Animal Behavior

Background:

• Social information use reduces costs and increases foraging efficiency.
• Delayed local enhancement, or increased interest in a location due to past conspecific presence, is a simple form of social information use.
• Stickleback fish ecomorphs provide a model for studying parallel evolution and the effects of hybridization.

Purpose of the Study:

• To investigate delayed local enhancement in benthic and limnetic stickleback ecomorphs from independently evolved populations.
• To determine if social learning differences parallel evolutionary divergence in these ecomorphs.
• To assess the impact of hybridization on social information use patterns.

Main Methods:

• Comparative study of delayed local enhancement in two stickleback ecomorphs (benthic and limnetic).
• Sampling conducted across three lakes with varying evolutionary histories, including intact species-pairs and a hybrid swarm.
• Behavioral observations focused on responses to the past presence of conspecifics.

Main Results:

• Benthic sticklebacks in intact species-pair lakes showed higher delayed local enhancement, despite being more solitary.
• No evidence suggests perceived predation risk or past predation pressure explains these differences.
• In a hybrid swarm lake, limnetic-looking fish exhibited delayed local enhancement, a reversal of the pattern in intact lakes.

Conclusions:

• Results support the parallel differentiation of social learning abilities in recently evolved fish species.
• Hybridization can erode and potentially reverse established patterns of social information use.
• Social learning differences appear to evolve in concert with ecological divergence in stickleback species pairs.