Mutural Recognition by Pheromones
In another experiment, Boch and Morse (1979) divided a colony by a double screen partition and gave each half a queen. Although the top pheromone odours could freely pass though the screen each half w...
In another experiment, Boch and Morse (1979) divided a colony by a double screen partition and gave each half a queen. Although the top pheromone odours could freely pass though the screen each half was able to recognize its own - queen when tested several days later, indicating that the queens had not acquired a similar pheromone odour. Therefore, adsorption of odour onto the body surfaces of queens is not alone sufcient to explain their individual pheromone characteristics.
There is evidence that the individual pheromones are partly genetically determined and so is partly based on pheromones produced by the queens themselves. In laboratory tests Breed (1981) found that small groups of workers accepted queens that were sisters to their own queens more readily than they accepted non-sister queens; furthermore inbred sister queens were more readily accepted than outbred sister queens. Lern about the pheromones influence on bees.
Even when queens are kept in the same environment so that they adsorb the same odours onto their cuticular surfaces, workers can still differentiate between them (Free et al., 1987d). Queens were caged separately, each with a group of 50 workers, in the same incubator and given the same food for ten days. When the workers were then allowed to choose between a chamber containing their own queen and one containing another previously caged queen, most moved into the chamber with their own queen.
In the eld (Boch and Morse, 1982) swarms recently dequeened chose to cluster round queens that were sisters to their own queens (produced from a breeder queen that had received semen from a single drone of her own line) in preference to unrelated queens. However, they still preferred their own queen to her sisters, suggesting that the pheromone queens adsorb from the hive atmosphere and food supply are also important in contributing toward recognition.
The workers of a colony may also become conditioned to the blend and quantity of queen pheromone components provided by their own queen. Thus when given the choice, a swarm whose queen has been removed prefers an alien queen that is the most similar in age and reproductive status to their original queen; a swarm previously headed by a mated laying" queen prefers an old virgin queen to a young virgin queen (Ambrose et al. , 1979).
Mutual recognition by Pheromones
When a colony rears a new queen without swarming the old queen may be killed by the workers immediately, or she can remain alive for several months, and mother and daughter may be found on the same comb without signs of antagonism. In all other circumstances in which more than one queen are present in close proximity, they are hostile to each other. It is well known that when two virgin queens meet on the comb they will know ght until one is killed, and that the rst virgin queen to emerge in a queenless colony will sting and kill any others that are still in their cells. It is uncertain whether a queen actively seeks her rivals or whether meeting is by chance; it should be possible to determine in an observation hive the distance from which a virgin queen moves directly toward a queen cell or toward a caged adult queen.
The means by which queens recognize each other has not yet been fully determined. They tend to be more aggresive to each other when of a similar age and physiological condition (Szabo and Smith, 1973). Some of the sensilla on the antennae of queens specialize in 9-ODA perception (Kaissling and Renner, 1968); perhaps queens use their ability to detect 9-ODA to discover any new and potentially hostile queens in their colony, but this presupposes that their sensilla do not become adapted to 9-ODA. However, removal of their mandibular glands does not inuence their aggressiveness or ghting ability (Velthuis, 1967; Szabo and Smith, 1973), suggesting that mandibular gland pheromone is not directly involved. Furthermore, queens whose mandibular glands have been removed and whose abdominal tergites have been covered with nail polish do not ght, suggesting that mutual recognition may be by pheromone secreted from the tergite glands (Velthuis, 1967). The effect of covering the tergite glands of otherwise intact queens has yet to be determined.
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ABOUT THE AUTHOR
Alexander is a blogger from Los Angeles who studies pheromones.