Behavioral Responses of the Bumblebee Bombus terrestris to Volatile Compounds from Blueberries

TL;DR

This study identifies specific floral scents that attract bumblebees to blueberries, which could help improve pollination and crop yields using natural methods.

Contribution

The study identifies key volatile compounds that attract or repel bumblebees, offering a novel approach to enhance blueberry pollination.

Findings

Alcohols like geraniol, linalool, and α-terpineol at low concentrations attract bumblebees.

High concentrations of benzaldehyde, benzenepropanal, and citral repel bumblebees.

Linalool and styrene are the most abundant volatile compounds in blueberry blossoms.

Abstract

Blueberries rely on insects to carry pollen between flowers, but natural pollination is often too low to ensure high fruit yields. This study explored which floral scents attract buff-tailed bumblebees, the most effective pollinators of this crop. We collected air samples from around blueberry blossoms and found 32 different fragrance compounds, with two scents, linalool and styrene, being the most common. We then tested how the bees reacted to these scents by measuring their antennal signals and observing their choices in a simple maze. The bees were drawn to low levels of certain sweet, plant-based alcohols, while high amounts of some sharp-smelling chemicals turned them away. These results identify the key scents that guide bees to flowers and open the door to creating natural sprays that can safely draw more pollinators to blueberry fields. Such sprays could help farmers produce larger harvests and higher-quality fruit without relying on harmful chemicals, supporting both agriculture and the environment.

Bumblebees are important pollinating insects in crop pollination. Chemical attractants can effectively improve the flower-visiting efficiency of bumblebees, thereby increasing blueberry yields. To identify volatile compounds that attract bumblebees, we collected volatile compounds from blueberry flowers using headspace extraction. Gas chromatography– mass spectrometry (GC–MS) identified 32 volatile compounds, with Linalool and Styrene being the primary substances that accounted for 25.93% and 14.28%, respectively. The olfactory threshold of bumblebee antennae was assessed using electroantennography (EAG), and the behavioral responses from bumblebees were investigated using a Y-tube olfactometer. Results indicate that among the six classes of volatiles—alcohols, aldehydes, esters, ketones, aromatic compounds, and olefins—alcohols constituted the predominant proportion. Among these, six compounds—benzaldehyde, phenylpropylaldehyde, citral, linalool, α-terpineol, and geraniol—induced significant antennal responses in bumblebees. Our assays showed that geraniol, linalool, and α-terpineol at concentrations of 0.1 μg/μL, 1 μg/μL, and 10 μg/μL elicited attraction, whereas higher concentrations of benzaldehyde, benzenepropanal, and citral had repellent effects.

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