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 ...