Temporal niche differentiation often leads to priority effects rather than coexistence: Lessons from a marine midge

Area of Science:

• Ecology
• Evolutionary Biology
• Population Dynamics

Background:

• Temporal niche partitioning is a proposed mechanism for species coexistence.
• Recent work questions the ease of coexistence based on temporal niche differences.
• Allee effects, where population growth rate decreases at low densities, can impact coexistence.

Purpose of the Study:

• To investigate the complex role of temporal niches in species coexistence.
• To examine how Allee effects and hybridization influence coexistence in the marine midge Clunio marinus.
• To complement and strengthen previous findings on temporal niche differentiation and coexistence.

Main Methods:

• Case study of the marine midge Clunio marinus.
• Modeling of Clunio biology, incorporating hybridization effects.
• Analysis of temporal emergence patterns and mating behaviors.

Main Results:

• Coexistence in Clunio marinus is associated with distinct timing traits but complicated by Allee effects.
• Allee effects create strain-specific advantages, potentially increasing hybridization risk for rare strains.
• Most factors analyzed (temporal niches, Allee effects, hybridization) promote positive frequency dependence and priority effects, rather than stable coexistence.

Conclusions:

• Temporal niche differentiation alone is insufficient to explain species coexistence.
• Allee effects and hybridization significantly complicate coexistence, often leading to priority effects.
• Ontogenetic niche shifts can promote coexistence if timed appropriately, offering a deviation from general findings.