Ecological divergence promotes the evolution of cryptic reproductive isolation

Area of Science:

• Evolutionary Biology
• Speciation Research
• Behavioral Ecology

Background:

• Cryptic reproductive isolation evolves post-copulation, hindering gene flow.
• Previous studies linked cryptic isolation to sexual conflict and selection.
• Ecological factors' role in cryptic isolation remained under-explored.

Purpose of the Study:

• Investigate the role of ecological divergence in cryptic reproductive isolation.
• Examine post-mating, pre-zygotic isolation mechanisms in walking stick populations.
• Determine if ecological divergence influences female fitness after inter-population mating.

Main Methods:

• Comparative study of walking stick populations with differing host-plant associations.
• Assessed female reproductive output (oviposition rate, lifetime fecundity) after within- and between-population matings.
• Controlled for mating events occurring on different versus same host-plant species.

Main Results:

• Reduced female oviposition and lifetime fecundity observed in between-population matings.
• This reduction in female fitness was contingent on populations utilizing different host-plant species.
• Ecological divergence, specifically host-plant use, directly impacts post-mating reproductive isolation.

Conclusions:

• Ecological divergence is integral to the evolution of cryptic reproductive isolation.
• Post-mating sexual interactions can evolve as a byproduct of ecological divergence.
• Reproductive isolation mechanisms are not necessarily independent of the ecological environment.