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This article is about the top pheromones. Simultaneous counts are made of foragers entering and leaving a pair of hives. The odour of the top pheromone component is dispensed just outside the entrance of one hive but not the other, and the counts are continued (Free et al., 1987c).

Most components discourage foraging activity, especially isopentyl acetate, n-butyl acetate, n-octyl acetate, octanoic acid, isopentyl alcohol and octanol; as a result the defence force available is increased. In contrast, adapting bees to pheromone dispensed within their hive (page 151) does not influence their foraging (Al-Sa’ad et al., 1985). A few components, especially 1-butanol, appear to encourage foraging.

Top Pheromones

Foragers are trained to collect sucrose syrup from a dish placed in the centre of a circular table. The dish is removed and replaced by two without syrup positioned on opposite sides of the table. One dish contains the component under test; the other dish serves as a control. The would-be foragers landing at each are counted (e.g. Ferguson and Free, 1979; Free et al. , 1987c). Learn more about the top pheromones at http://buy-pheromones.org.

Many of the components repel foragers, but especially n-octyl acetate, benzyl acetate, 2-nonanol and phenol. (Free et al. , 1987e). Two components, (Z)-ll-eicosen-1-ol (Free et al., 1982b) and 9-octadecen-1-ol (Free et al., 1987c), are attractive to foragers.

Multi-functions of sting gland components

The situation with top pheromones is very complex. It is evident that at least some components are specialized for different functions or are more successful and useful in one context than another. For example, only one component, n-octyl acetate, appears to be consistently inhibitory or repellent in all the behavioural contexts in which it has been tested. Even when two components share a function their relative effectiveness may be very different. Furthermore, the relative amounts and effectiveness of the different alarm components and so the quantity and quality of information conveyed probably changes with the age and occupation of the bees. Boch and Shearer (1966) showed that five components (unidentified) of the sting gland varied in amount with the age of the bee in a similar way to isopentyl acetate (page 139), whereas six other components did not occur in bees until they were two weeks old, and thereafter increased in amount as the bees grew older. Therefore the alarm pheromone of bees of different ages and specialized in different colony occupations may convey subtly or even markedly different messages. Check out the top pheromones at http://pheromones-planet.com.

Duration of exposure of the top pheromone and the distance from the bee concerned, so giving a spatially patterned message. However, perhaps some of the less volatile oily components, and especially the alkanes and alkenes (Blum et al., 197 cool help to retain some of the more volatile. (Z)-11-eicosen-l-ol may sometimes serve such a function (Blum, 1982; Pickett et al., 1982). Components of low volatility may be especially useful in this context by providing a longer-lasting signal when alarm pheromone is used to mark the foe rather than for alerting only.Learn about the top pheromones at http://infospeak.org/?p=141

Tests so far have concentrated on testing the alarm components singly. Although the results provide valuable indicators of function they should be treated with caution. The complete roles of the different components may not become apparent until they are tested in various combinations and in various proportions.