The significance of multicomponent pheromones in denoting specific compositions

Abstract

. Abetract--The chemical composition of Dufour's gland secretions of 13 species of halictine bees was investigated. The secretions were composed of a series of macrocyclic lactones, hydrocarbons and isopentenyl esters. The number and relative intensities of these compounds were unevenly disu'ibuted among the species, i.e. the secretions were species specific. Based on the empirical date, an algorithm was constructed in order to assess how many of the components present in a secretion are required to discriminate between species, non-related conspecific individuals or nestmates. The results demonstrate that the number of components required for recognition increases with the increase in the level of specificity and with the number of individuals to be identified. The number of compounds denoting identity in a species specific blend may be surprisingly low. Using a similar technique, we assessed the number of components a secretion must contain in order to obtain individual recognition at different levels of relatedness. Several predictions regarding the level of recognition that can be attained by a given pheromone in a given population can be made from these theoretical results.

Ontogenetic patterns of volatiles identified in Dufour's gland extracts from queens and workers of the primitively eusocial halictine bee,Lasioglossum malachmum (Hymenoptera: Halictidae)

“…Macrocyclic lactones were found in large amounts in the Dufour's gland of halictine bees (Johansson et al, 1982;Smith et al, 1985;Hefetz, 1987Hefetz, , 1990Hefetz and Graur, 1988). Nevertheless, these prevalent secretions of the large Dufour's gland are not produced at high rates throughout the imaginal life span.…”

“…The oily secretions have been analyzed in several halictine (Johansson etal., 1982;Hefetz, 1987Hefetz, , 1990Hefetz and Graur, 1988) and Colletes bees (Hefetz et al, 1979;Albans et al, 1980;Cane, 1981). Macrocyclic lactones, polymerized by enzymes to form a thin hydrophobic layer (Hefetz et al, 1979;Cane, 1981), were always the dominant compounds used to line the walls of brood cells.…”

“…14, A-1090 Vienna, Austria. Michener and Smith, 1987) In several halictine bees, species-specific composition of Dufour's gland secretion was found (Johansson et al, 1982;Hefetz and Graur, 1988;Teng6 et al, 1992). In the primitively eusocial sweat bee Lasioglossum zephyrum (Halictidae) both males and females discriminate among conspecific females according to genealogical relationship (Greenberg, 1979;Smith 1983).…”

Neural Mechanisms and Information Processing in Recognition Systems

“…Here specificity is highly important and the information conveyed needs to be very accurate. This poses a great evolutionary challenge because the pheromones must be very complex in order to be colony-specific [ 8 ]. The major problem is that, unlike alarm pheromones where trait uniformity is advantageous because all individuals in the population can use and benefit from such uniformity, within-population trait-diversity must be the rule in a nestmate recognition system.…”