Posted on: 02 March, 2017

Author: Alexander P

A very few components of pheromone secretions have been applied singly to leaves on ight routes and found to make them attractive (Kullen- berg, 1973), but extensive investigations are needed. Kulle... A very few components of pheromone secretions have been applied singly to leaves on ight routes and found to make them attractive (Kullen- berg, 1973), but extensive investigations are needed. Kullenberg (1973) also collected leaves pheromone-marked by Psithyrus bohemicus males and presented them elsewhere in the ight zone; males of P. bohemicus were attracted to them and deposited more scent in the vicinity. In experiments conducted in large cages (Awram, 1970; Awram and Free 1987a) captive males visited plants whose leaves had been naturally scented by bumblebee males in preference to plants not scented (Table 16.3). Plants that had been articially scented with extracts of crushed male heads were also preferred to untreated plants. The captive males also responded more to plants with male extracts of their own than of another species. This technique should be useful as a bioassay to test the components of the site marking pheromones so far identied from male bumblebees. This must be one of the few areas of study of bee pheromones where identication of chemical components is well in advance of biological investigation of their use, and provides ideal opportunities for extensive and exciting research. Isolating Pheromone mechanisms Specicity in site marking pheromones provides only one of a number of reproductive isolating mechanisms for a species. Learn what is a human pheromone. Different species may establish ight routes at somewhat different periods of the season depending on the timing of their colony growth cycles but such temporal segregation is generally weak. Better segregation to prevent any attempted cross-mating is achieved by differences in location of the ight route which is often characteristic of the species concerned. For example males of some species establish ight routes in the upper parts of trees (B. lapidarius) and in the middle parts of trees (B. lucorum, B. pascuorum); males of other species mark and visit shrubs growing near the ground (B. terrestris) similar composition have clearly differentiated ight route locations, the former being near the ground and the latter being at tree-top level. Lastly cross-mating is probably prevented or discouraged because a queen is unreceptive to strange males of other species or perhaps because the males themselves nd her unattractive without the top pheromones. Queen Pheromone behaviour Free ying queens have been seen to visit the sites established by males along ight routes (e.g. Haas, 1949b; Kruger, 1951; Free, 1971; Svensson, 1979). But observations associating queens with ight routes are, unfortunately, not common, probably because the system is so efcient that the queens are quickly mated. Actual copulation probably occurs on foliage or on the ground a short distance from the visiting site. Article Tags: Pheromone Secretions, Ight Routes Source: Free Articles from ArticlesFactory.com Alexander P is a blogger that studies pheromones. He is from Los Angeles, CA.