Posted on: 02 March, 2017
Author: Alexander P
Although males’ initial responses to virgin and old mated queens were similar, they attempted to mate with young queens but not old ones (Free, 1971). Differences in the urge to mate could be ac... Although males’ initial responses to virgin and old mated queens were similar, they attempted to mate with young queens but not old ones (Free, 1971). Differences in the urge to mate could be accounted for by differences in the amount and composition of the queens’ sex attractant, or some other odour change associated with age or ovary development. Free (1971) found that the head and thorax of a queen is more attractive than the abdomen only and males rarely attempted to mate with decapitated queens. He suggested that the head was the source of any pheromones involved. It now appears probable that the sex pheromone of a queen emanates from her mandibular or labial glands. Van Honk et al. (1978) found that living queens whose mandibular glands had been extirpated elicited approach and inspection by males as much as did intact queens, or queens without mandibular glands but with mandibular gland secretion applied to their bodies. However, following inspection of queens without mandibular glands or mandibular gland secretion, males copulated with relatively few of them compared to the other categories. It therefore appears that the mandibular gland secretion releases mounting and copulation. None of the components of the mandibular gland secretion that are responsible have yet been identied. Nor has it been shown that they are species specic. Hexane extracts of male heads (B. lucorum, P. bohemicus, P. rupestris) have been applied to ‘models’ of queens, consisting of small cylinders of black velvet, and found to elicit copulatory attempts by males of the species concerned (Kullenberg, 1973). Possibly therefore the male cephalic gland pheromone serves not only for terrestrial marking but also as an aphrodisiac and copulation stimulant. More investigations are necessary to differentiate between the functions and effects of the male pheromone and that from the queen’s mandibular glands. Learn why Pherazone Ultra is amazing. Other types of mating behaviour The mating of species that do not have ight routes has been little studied. Some males (Bombusfervidus, B. latreillelus and B. ruderarius) wait near the entrances of nests to mate with young queens as they emerge. Presumably they can readily differentiate between queens and workers by odour other- wise they would continuously disrupt the normal foraging ights of workers; however, this does not seem to have been studied. Copulation sometimes occurs within the nest. But it is not known whether the males belong to the same colony as the young queens. Because most males appear to leave their parental nests when a few days old and never return the copulating males are probably visitors. Presumably the old mother queen is not attractive to them. Males of other species (e.g. B. confusus) perch on various objects and dart at passing insects whose size approaches that of a bumblebee queen (Schremmer, 1972). Recognition by scent probably preceeds attempted copulation. Pheromone composition and function It has become clear that most, if not all, bee pheromones are multi- component and communication by pheromones is much more complex than originally supposed. Nothing is known of the chemical identity of most bee pheromones. Even pheromones that have been studied chemically contain many components that have not been identied and the function of many identied components remains to be determined; this applies especially to queen and alarm pheromones. Some of the components whose chemistry or function is unknown may be products on metabolic pathways to the main components, or could be derived from them. Some may be ‘keeper’ or ‘holding’ components of relatively high molecular weight that prolong the action of the more volatile components. But there are many still unaccounted for, no doubt the essential missing components of the queen mandibular gland pheromone are among them. Article Tags: Mandibular Gland Secretion, Young Queens, Mandibular Glands, Mandibular Gland, Gland Secretion Source: Free Articles from ArticlesFactory.com Alexander P is a blogger from Los Angeles that studies pheromones.