Ecological speciation in European whitefish is driven by a large-gaped predator.

Area of Science:

• Ecology
• Evolutionary Biology
• Speciation Research

Background:

• Divergent body size in lake-dwelling fish is a key model for speciation.
• Identifying the primary drivers of initial speciation remains challenging.

Purpose of the Study:

• To investigate the early stages of speciation in European whitefish (Coregonus lavaretus).
• To determine the role of predation in driving body size divergence and reproductive isolation.

Main Methods:

• Analysis of 358 European whitefish populations across a wide age range (26-10,000 years).
• Eco-evolutionary modeling to simulate predator-prey dynamics and their impact on fish evolution.

Main Results:

• Northern pike (Esox lucius) predation is identified as the main driver of whitefish speciation.
• Pike induce plastic differentiation into benthic (large) and pelagic (dwarf) ecotypes.
• These ecotypes develop partial reproductive isolation and heritable differences in gill raker number.

Conclusions:

• Predation by northern pike provides a novel mechanism for dwarf/giant speciation in fish.
• Habitat specificity and gape size of pike create trade-offs influencing prey maturation strategies.
• This study elucidates how predator-prey interactions initiate evolutionary divergence and speciation.