Quantifying diet breadth through ordination of host association.

Area of Science:

• Ecology and Evolutionary Biology
• Insect-Plant Interactions
• Quantitative Ecology

Background:

• Quantifying dietary niche width is crucial in ecology and evolutionary biology.
• Traditional measures of herbivore diet breadth often rely on simple counts of host plant taxa.
• Existing methods may not fully capture the complexity of herbivore host associations.

Purpose of the Study:

• To propose a novel index,
• "ordinated diet breadth" (ODB), for quantifying herbivore dietary niche width.
• To develop a method that accounts for plant traits and multivariate distances in host association.
• To differentiate between herbivores with clustered versus unusual host combinations.

Main Methods:

• Calculating multivariate distances among plants in ordination space based on host associations.
• Utilizing plant properties such as phytochemistry, phenology, and other traits.
• Applying the ODB index to a dataset of nymphalid butterfly host records.

Main Results:

• Host use among nymphalid butterflies is often clustered in multivariate space.
• The ODB index provides a more refined measure of host range compared to traditional taxonomic approaches.
• Demonstrated the ability to distinguish herbivores with specialized versus generalized host associations.

Conclusions:

• The ODB index offers a robust and nuanced approach to measuring dietary niche width in herbivores.
• This method enhances our understanding of insect-plant interactions and evolutionary patterns.
• Potential applications include testing hypotheses of nonrandom host association and predicting diet breadth shifts.