Research Summary
Citation: Gramacho, K. P., and Spivak, M. (2003). Differences in olfactory sensitivity and behavioral responses among honey bees bred for hygienic behavior . Behavioral Ecology and Sociobiology 54: 472-479.
Web Link:University of Minnesota Bee Lab Publications
Brief Description: Honey bees bred for hygienic behavior exhibit disease and Varroa infestation resistance. Hygienic behavior involves a two step process where worker bees uncap the wax-covered cells with diseased brood and then remove the damaged larvae or pupae. This study involved identifying and collecting bees that were either uncapping cells or removing the infected brood. These bees were organized in their respective groups and tested for their ability to discriminate between the odors of diseased and healthy brood. Bees identified as uncappers discriminated between the odors better then bees identified as removers.
Uncappers in the above situation where collected from brood killed by freezing. In an additional experiment, worker bees where collected while uncapping brood killed by a pin. These uncappers of pin killed brood where compared to uncappers of freeze killed brood. It was found that uncappers of pin killed brood had significantly less olfactory sensitivity then the uncappers of freeze killed brood. This may be due to pin killed brood having a greater stimulus intensity.
Implications: Initiation of hygienic behavior with the uncapping of diseased or infested cells depends on the olfactory sensitivity of the worker bees and the intensity of the odors from the infected brood. Bees with the greatest olfactory sensitivity probably initiate hygienic behavior first due to the ability to detect low stimulus odors. It is important in a selection program for hygienic behavior to breed from colonies which have the highest olfactory sensitivity. Using freeze killed brood instead of pin killed brood would therefore be a better selection test to determine which colonies have the highest olfactory sensitivity.
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