Honey Bee AgressionBiology 342 Fall 2012Tess Myers |
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What makes bees all uppity?The causes of variation in bee colony aggression levelsAs we know, bees can go swiftly from the fuzzy and cute "bumble" bees that we see buzzing around flowers, to an angry stinging foe. It's easy to understand how one bee gets aggressive, but how does the whole colony know to attack? It turns out that there is a chemical pheromone signal called isopentyl acetate that bees use as an alarm signal- when a bee is disturbed, it releases a little puff of this pheromone, which alerts the surrounding bees to the alarm, and causes them to likewise release more alarm signal. This quickly cascades into a full-on colony wide alert, sometimes even extending to neighboring bees from other colonies.
A team of researchers in 2009 looked at the regulation of genes that are affected by exposure to alarm pheremon. among other experiments, thay looked at gene expression in the brains of old and young bees who had been exposed to alarm pheromone, thereby providing valuable insight into the lifetime effects of alarm pheremone on EHB's. It turns out that the alarm pheromone causes not only an instantaneous aggressive response, but also may cause long-term sensitization in bees. The researchers looked at the expression of an immediate early gene and the transcription factor c-Jun in the antennal lobes, and saw that it was significantly unregulated 1 hour after exposure to alarm pheromone. The researchers suspect that this is related to long-term sensitization, which would help explain why older bees are faster and more aggressive to respond. (Alaux et al, 2009)
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