Tuesday, January 3, 2017

How Pheromones Alter Behavior

Free er al. (1987a) observed that the number of bees in the queen’s court, and the number that licked and palpated the queen, decreased during the course of the winter irrespective of any increase in egg laying, suggesting a decrease in her pheromone production. Perhaps while relatively inactive in a winter cluster, the workers’ pheromones requirements are also diminished.

Pain et al. (1972) attempted to determine an annual cycle in the emission of queen pheromone by confining the queen at intervals in a filter paper cylinder and then determining the cylinder’s attractiveness to worker bees. Unfortunately, the results are difficult to interpret as the amount deposited could depend both on the amount that had accumulated on the queen’s integument and on the amount she secreted, but they indicate that maximum production for the year occurred in June. Learn more about pheromones at http://www.brownpapertickets.com/blogcomments/103946

Pheromone transfer from the queen’s court

There is frequent and extensive transfer of food within the honeybee colony (Nixon and Ribbands, 1952; Free, 1957). Food is passed directly from one pheromone supplier to another worker bee to another as well as from workers to drones and the queen. A bee which is begging for food attempts to thrust its tongue between the mouthparts of another bee, and a bee which is offering food opens its mandibles and moves its still folded tongue slightly downwards and forwards from its position of rest; it is conceivable that pheromones are involved as signals in both circumstances.

The food given is water, nectar or honey regurgitated from the honey stomach, but it may also on some occasions consist of, or contain, glandular secretions. It was supposed that workers obtained pheromone by licking the queen’s body, and that the pheromone became distributed among workers in regurgitated food. Butler (1954a) found that workers seen to lick the queen tended to offer food to other bees within the next five minutes, whereas those that merely palpated her with their antennae did not. He transferred groups of 20 bees from a queenright to a queenless colony at five-minute intervals and found that the queenless part was prevented from rearing queen cells (see page 32); he thought this was because the transferred bees carried queen pheromone in their honey stomachs. Learn about effects of pheromones on behavior.

Food transfer. The worker on the right giving food to the worker on the left (Apis mellifera) However, it is doubtful whether pheromones could act chemically after ingestion. There is evidence that if the queen’s pheromone is mixed with food containing sugar in concentrations higher than 5—l0% it loses its inhibiting effect (Verheiien-Voogd, 1959; Van Erp, 1960; Pain, 196la,b). Furthermore, even if distribution of pheromones in food does occur, it has become doubtful whether they could be disseminated effectively and quickly enough by this method alone. (Verheiien-Voogd, 1959; Allen, 1965a; Velthuis, 1972; Butler, 1973). For example, Allen (1957) found that at any one time in the summer.

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