Herbivorous insects: model systems for the comparative study of speciation ecology

Area of Science:

• Evolutionary Biology
• Ecology
• Speciation Research

Background:

• The role of ecological divergence in driving species-level evolutionary diversification has been a long-standing question since the evolutionary synthesis.
• Ecological speciation has recently emerged as a significant area for empirical investigation.

Purpose of the Study:

• To advocate for the use of ecologically specialized, phylogenetically diverse, and experimentally tractable herbivorous insects as model systems for studying speciation.
• To propose a general comparative framework for rigorously testing hypotheses about the mechanisms and macroevolutionary generality of ecological speciation.

Main Methods:

• Reviewing the suitability of various herbivorous insect taxa for experimental study.
• Developing and applying a comparative framework to test speciation hypotheses.
• Illustrating the framework's utility with a case study on *Neochlamisus bebbianae* leaf beetles.

Main Results:

• Ecologically specialized herbivorous insects offer unique advantages for studying the mechanisms of reproductive isolation and speciation.
• A comparative framework can effectively test hypotheses regarding the contributions of different ecological speciation mechanisms.
• Specialized host associations in *Neochlamisus bebbianae* demonstrate clear ecological divergence and premating isolation.

Conclusions:

• Herbivorous insects are valuable models for understanding the ecology of speciation.
• The proposed framework facilitates rigorous testing of speciation mechanisms.
• Experimental analysis of host-associated divergence is crucial for understanding speciation ecology.