Floral scent contributes to interaction specificity in coevolving plants and their insect pollinators

Area of Science:

• Ecology
• Evolutionary Biology
• Chemical Ecology

Background:

• Species interactions are shaped by chemical signals, including attractants and repellents.
• Coevolving plant-insect relationships can diverge if pollinators show specialized responses to local plant cues.
• Floral scent and color are key attractants influencing pollinator behavior.

Purpose of the Study:

• To investigate daily floral scent production patterns in three geographically isolated Lithophragma species.
• To test how scent divergence affects the attraction of their primary pollinator, the floral parasitic moth Greya politella.
• To determine the role of floral scent in mediating plant-pollinator specificity.

Main Methods:

• Experimental investigation of daily floral scent emission patterns.
• Olfactometer bioassays to assess moth responses to different floral scents.
• No-choice oviposition trials to evaluate pollinator preference and pollination success.

Main Results:

• Complex, species-specific floral scent profiles were emitted in higher amounts during daylight hours, coinciding with moth activity.
• Minimal divergence was observed in petal color among the studied Lithophragma species.
• Female Greya politella moths exhibited a stronger response to the scent of their local host plant species.
• Moths were more likely to oviposit in and pollinate their local host species.

Conclusions:

• Floral scent is a crucial attractant in the Lithophragma-Greya politella interaction.
• Specialized pollinator responses to specific plant chemistry can drive interaction specificity.
• This local specialization contributes significantly to the coevolutionary patterns between plants and highly specialized pollinators.