Exploring plant volatile-mediated interactions between native and introduced plants and insects.

Area of Science:

• Ecology
• Chemical Ecology
• Invasive Species Biology

Background:

• Plant-plant and plant-insect interactions are often mediated by volatile organic compounds (VOCs).
• The role of VOCs in ecological interactions within invasion scenarios remains understudied.
• Understanding these interactions is crucial for managing invasive species and their ecological impacts.

Purpose of the Study:

• To investigate how introduced plants affect the volatile organic compound (VOC) profiles of a native plant.
• To assess the influence of plant VOCs on the host-searching behavior of native and introduced insects.
• To evaluate the potential for invasive plants to disrupt native plant-insect communication.

Main Methods:

• A semi-field trial exposed native Leptospermum scoparium (mānuka) to introduced Calluna vulgaris (heather) and Cytisus scoparius (Scotch broom).
• Volatile organic compound (VOC) emissions from mānuka were analyzed using gas chromatography-mass spectrometry.
• Y-tube olfactometry and Petri dish preference tests were conducted with native Pyronota festiva (mānuka beetle) and introduced Lochmaea suturalis (heather beetle).

Main Results:

• Mānuka plants adjacent to heather showed reduced emissions of green leaf volatiles, sesquiterpenes, and total VOCs.
• The native beetle P. festiva exhibited poor discrimination based on VOCs alone but performed better with additional cues.
• The introduced beetle L. suturalis demonstrated high host-specificity in both olfactometry and preference tests.

Conclusions:

• Invasive plants can significantly alter native plant volatile profiles, potentially disrupting native plant-insect interactions.
• Volatile organic compounds (VOCs) play a key role in mediating interactions between native and introduced species.
• Thorough host testing of biocontrol agents is essential to prevent unintended host shifts and ecological disruption.