Leaf Induction Impacts Behavior and Performance of a Pollinating Herbivore.

Area of Science:

• Plant Science
• Chemical Ecology
• Insect Behavior

Background:

• Flowering plants utilize volatile compounds to attract pollinators and deter herbivores.
• Interactions between vegetative and floral traits can influence insect behavior.
• Leaf traits are particularly important when larval and adult insect stages interact differently with plants (e.g., larvae as herbivores, adults as pollinators).

Purpose of the Study:

• To investigate how leaf induction and associated volatile differences in plants affect adult moth behavior.
• To determine if moth preferences align with larval performance on induced versus control plants.
• To link changes in plant chemistry to observed moth behaviors.

Main Methods:

• Vegetative induction was manipulated in four *Nicotiana* species.
• Adult moth (*Manduca sexta*) foraging and oviposition choices were measured using paired induced and control plants with artificial flowers.
• Larval growth rates were assessed on leaves from control and induced plants.
• Plant headspace volatile compounds were collected and analyzed using gas chromatography.

Main Results:

• Adult moth foraging preference was influenced by vegetative defensive status in one species (*N. excelsior*), with females nectaring more from induced plants.
• Moths consistently oviposited more on control plants than induced plants across all four species.
• Larval growth rates were higher on control leaves compared to induced leaves, aligning with oviposition preferences.
• Induced plants showed higher emission levels of volatile compounds compared to control plants, though volatile profiles were similar.

Conclusions:

• Vegetative plant defensive volatiles play a significant role in host plant selection by insects.
• Insects differentiate between leaf information when making choices for nectaring versus oviposition.
• These findings highlight the intricate relationships between plants, pollinators, and herbivores.