When is dispersal for dispersal? Unifying marine and terrestrial perspectives

Area of Science:

• Ecology
• Evolutionary Biology
• Organismal Biology

Background:

• Current research on dispersal evolution often assumes it's a direct adaptation.
• Many traits influencing dispersal have functions unrelated to dispersal itself.
• The question of when dispersal is the primary target of selection remains open.

Purpose of the Study:

• To critically evaluate the ecological causes of selection on traits that influence dispersal.
• To compare dispersal mechanisms and selection pressures in marine and terrestrial organisms.
• To identify limitations in current theories of dispersal evolution.

Main Methods:

• Review and synthesis of existing literature on dispersal evolution.
• Comparative analysis of marine and terrestrial dispersal systems.
• Evaluation of ecological selection pressures on dispersal-related traits.

Main Results:

• Marine dispersal is often passive, with rare specific adaptations; selection may favor limiting dispersal.
• Terrestrial dispersal is more difficult, often requiring specific adaptations, which are common.
• Traits influencing dispersal can be under selection for functions other than dispersal itself.

Conclusions:

• Dispersal evolution is not always a direct adaptation; it can be a byproduct of selection on other traits.
• Existing theories may be incomplete by oversimplifying the dispersal-fitness relationship.
• Marine taxa and indirect selection effects on traits are often overlooked in dispersal research.