The chemical composition of the mandibular gland secretion of Melipona bicolor Lepeletier, 1836 (Hymenoptera, Apidae, Meliponini): a comparative study among castes and sexes

Abstract

A secreção das glândulas mandibulares de operárias recém-emergidas, aprovisionadoras de cria e forrageiras, rainhas virgens e fisogástricas e machos de Melipona bicolor foi analisada através de cromatografia gasosa-espectrometria de massas. Foi verificado que a secreção é composta por uma mistura de hidrocarbonetos, álcoois, ésteres e ácidos. A secreção é casta-sexo específica e difere, também, de acordo com a tarefa desenvolvida pelas operárias e condição fisiológica reprodutiva das rainhas.The mandibular gland secretions of newly emerged, nurse and forager workers, virgin and physogastric queens and males of Melipona bicolor were analyzed by gas chromatography-mass spectrometry. The secretion is composed of a blend of hydrocarbons, alcohols, esters, and acids. The secretion is caste-sex specific and also differs with the tasks performed by the workers and the physiological reproductive condition of the queens.Keywords: GC-MS, mandibular glands, Melipona bicolor, caste, sex, reproductive variation. IntroductionColonies of eusocial bees include males and females, the latter being represented by two castes: workers and queens. The main function of the males is to mate with the queen and, therefore, supply the genetic complementation for female reproduction. The queen influences the behavior and physiology of the infertile females or workers 1,2 that are responsible for every task of colony maintenance, such as nest defense, provisioning, and brood care. In the colony darkness a precise system of chemical communication exists to maintain the interaction among individuals and the organization of the various activities. This chemical communication is based on the production of substances with intra-specific action known as pheromones 4 by numerous exocrine glands dispersed along the bee body. 5The main function of the pheromones produced by the mandibular gland of Apis mellifera honeybee workers is alarm or defense. In contrast, males use their mandibular gland to produce sexual attractants for the queens. The queen produces the "queen substance", 6 a primer pheromone used to prevent worker ovary development and for sexual attraction of males. 1,6,7 Among the workers, there are variations in the composition of the glandular product related to age and type of task performed. Young workers produce mainly 10-hydroxydecenoic acid while older ones, whose task is foraging, produce predominantly 2-heptanone. [8][9][10] In spite of the differences between the glandular products of queens and workers, the same biosynthetic pathways for the production of pheromones is potentially present in both, since it was demonstrated that egg-laying workers of A. mellifera and A. mellifera capensis also produce 9-oxydecenoic acid, which is one of the components of the queen´s mandibular gland secretion. 11Therefore, the presence of the queen in A. mellifera apparently inhibits in workers 12 the production of pheromones typical of the reproductive female.In meliponine bees, mandibular glands occur in queens, workers, and males.13 Whereas ...

Correlation between mandibular gland secretion and cuticular hydrocarbons in the stingless bee Melipona quadrifasciata

“…In response to the same conditions, changes occur in the morphology and secretion composition of the mandibular and other glands (Gracioli-Vitti et al, 2004;Abdalla et al, 2004;Gracioli-Vitti and Abdalla, 2006). When the results of gland secretion are statistically compared, the three classes of workers are quite different, and the statistical evidence shows a significant distinction between the cuticular and secretion composition of newly emerged and forager workers, but some similarity between both compositions in nurse bee workers.…”

“…In Melipona bicolor the morphology of the mandibular gland cells and the composition of their secretion changes according to caste, sex and the temporal activities of workers (Gracioli-Vitti et al, 2004;Gracioli-Vitti and Abdalla, 2006).…”

Stingless Bees: Chemical Differences and Potential Functions in Nannotrigona testaceicornis and Plebeia droryana Males and Workers

“…Thus, the differentiation of the chemistry of workers and males of these two bee species was important to detect signals produced by one and both sexes. The large differences in worker and male head and abdominal and extracts for both species were assigned to the presence of specific glands with different compositions according to sex, caste, or age (Cruz-Landim and Mota 1993;Gracioli-Vitti et al 2004). The chemical signals from the head and abdomen may play important functions in the colonial context as caste and sex recognition.…”

Ultrastructural aspects of the mandibular gland of Melipona bicolor Lepeletier, 1836 (Hymenoptera: Apidae, Meliponini) in the castes

“…The secretion is mainly, lipids as found by gas chromatography and mass spectrometry (Gracioli et al, 2004). This receptacle is enlarged by the branching of the canal procuticle producing invaginations of the secretory cell.…”