Location: Chemistry Research Unit
Title: Fallen fruit as a putative alternative food source of the Small Hive Beetle Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 10, 2008
Publication Date: N/A
Technical Abstract: The small hive beetle (Aethina tumida) (SHB) is reputed to occasionally use fallen fruit as an alternative food source in the absence of honey bee hives. However, attraction to fruit has not been adequately documented, nor has the effect of fruit age or microbial infection on attraction been considered. We first investigated the ability of fruits to support growth of the yeast Kodamaea ohmeri, a SHB symbiont that produces volatile cues that strongly attract SHB adults to beetle-infested honey bee comb. The yeast spread as a creamy white growth within 72 hours across the surface of inoculated oranges and blackberries, but not apples. We also evaluated the orientation responses of individual SHB adults to volatiles from exposed oranges 1) in various stages of senescence and 2) variably inoculated with K. ohmeri in an four-arm olfactometer bioassay. SHB adults were attracted more often to odors from oranges in advanced stages of senescence (15 days of ripening) over less senescent fruits. By contrast, SHB adults did not significantly differentiate between odors from yeast-inoculated and sham-inoculated oranges. Headspace volatile analysis revealed that apples, oranges and blackberries infected by K. ohmeri emit far lower amounts of isopentyl acetate (IPA) and 2-heptanone (two bee alarm pheromone mimics that are known to strongly attract SHB) than yeast-infested hive materials. Host preferences of SHB adults for honey bee hive materials over fruits may be driven by the low production of these important volatiles by its yeast symbiont. Use of fruit by SHB may be limited to older, more senescent fruit.