Thymol Affects Congruency Between Olfactory and Gustatory Stimuli in Bees

Area of Science:

• Behavioral Ecology
• Insect Neurobiology
• Pesticide Toxicology

Background:

• Honey bees learn odor-sugar associations crucial for foraging.
• Pesticides, including acaricides like thymol, can impair bee memory.
• Varroa mite control introduces thymol into colonies, raising concerns about its effects on bees.

Purpose of the Study:

• To investigate if honey bees equally memorize different odorant/sugar pairs.
• To determine if thymol exposure affects this learning and memory.
• To assess the impact of thymol on odor-sugar congruency.

Main Methods:

• Differential appetitive olfactory conditioning experiment with honey bees.
• Exposure to varying concentrations of thymol.
• Retrieval tests to assess memory and odor/sugar congruency.
• Electroantennography to measure odorant detection.

Main Results:

• Honey bee responses to odorants varied based on the paired sugar (congruency).
• Thymol exposure altered odor-sugar congruency during retrieval tests.
• Odorant detection remained intact despite thymol exposure, as shown by electroantennography.

Conclusions:

• Subtle effects like odor-sugar congruency are important in pesticide impact studies.
• Thymol can subtly affect learned associations in honey bees, beyond direct memory impairment.
• Understanding these nuanced effects is vital for assessing pesticide risks to non-target insects.