I personally question the conclusion that heptanone is "used" by the bees for defensive purposes. Merely because it has certain properties does not therefore prove that it is employed thus. For example, vanilla extract contains pure alcohol but we used it to give vanilla flavor to cakes. It is not used as a recreational beverage, as would be other alcohol containing substances such as Guinness. Heptanone has been identified as an odorant, with signaling properties. It is also used as a flavorant in human food products. It is not used as an anesthetic. Even alcohol has anesthetic properties but isn't generally used for that, except in cowboy movies. So one must be clear in differentiating between properties of a substance and the actual purpose for which it is produced. 

PLB

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