Changes in the size of cephalic salivary glands of Apis mellifera and Scaptotrigona postica (Hymenoptera: Apidae) queens and workers in different life phases

The bee species of the Apinae, in addition to the thoracic salivary glands, possess a pair of cephalic glands originating as branches of the excretory duct that crosses the head. These glands are known as cephalic salivary or labial cephalic glands. The degree of development of these glands in newly emerged, nurse and forager workers and virgin and egg-laying queens of Apis mellifera Linnaeus, 1758 and Scaptotrigona postica Latreille, 1807 were evaluated by measuring the secretory alveolar units. The area of the secretory alveoli, measured in total gland preparations, was used to evaluate differences in size. In both species, gland size was found to increase progressively from newly emerged workers to foragers and from virgin to egg-laying queens. A statistical analysis revealed significant differences (p < 0.05) in the area of gland alveoli of workers in different life phases in both species, and between S. postica virgin and egg-laying queens, but not between A. mellifera queens. In the case of workers, this suggests cephalic salivary gland secretion has a function in forager activity and, in queens, a possible pheromonal function

Histologia e ultra-estrutura do vaso dorsal de Scaptotrigona postica (Hymenoptera, Apidae) em oper\ue1rias e rainhas de diferentes idades

O vaso dorsal é um órgão tubular localizado na região mediano-dorsal do corpo dos insetos, abaixo do tegumento. Fez-se um estudo de microscopia de luz e eletrônica de transmissão da porção abdominal do vaso dorsal, o coração, em uma espécie de abelha indígena. Foram estudadas operárias e rainhas em diferentes idades. O coração está localizado no sinus pericárdico. A parede cardíaca é formada por fibras musculares estriadas e apresenta aberturas ou ostíolos providos de válvulas. A fibra cardíaca contém miofibrilas arranjadas irregularmente, núcleos alongados ou redondos, mitocôndrias grandes e numerosas, e depósitos de glicogênio. Em operárias e rainhas longevas, as fibras encontram-se em degeneração, evidenciada por vacúolos autofágicos, alterações mitocondriais e acúmulo de corpos mielínicos. Em conclusão, o coração de Scaptotrigona postica é semelhante ao de outros insetos estudados. As alterações encontradas estão relacionadas ao processo de envelhecimento e mantêm relação temporal com a expectativa de vida da casta

Cephalic salivary glands of two species of advanced eusocial bees (Hymenoptera: Apidae): morphology and secretion

Some adult eusocial bees have a pair of cephalic salivary glands (CSG) in addition to the thoracic labial or salivary gland pairs. This paper deals with variations in morphological features and secretion production of the CSG of females and males of Apis mellifera Linnaeus, 1758 and Scaptotrigona postica Latreille, 1807. The following life stages were studied: newly emerged, nurse, and forager workers; newly emerged and egg-laying queens; and newly emerged and sexually mature males. The histological results showed that the CSG differs between the two species in the following features: while alveoli and duct cells are cuboidal in workers and queens of A. mellifera, they change from cuboidal to flat in S. postica as the workers age. The glands of newly emerged males and females of A. mellifera are similar. However, as males become sexually mature, glands degenerate and practically disappear. The secretion from the glands of females of both species is oleaginous and gradually accumulates in the lumen of the alveoli in the beginning of the adult phase. Consequently, forager workers and egg-laying queens exhibit more turgid alveoli than younger individuals. Sudan black and Nile's blue staining indicated that the CSG secretion consists of neutral lipids. The possible role of gland secretion is discussed taking in account tasks performed by the individuals in the particular phases studied

Ovary development in honeybee (Apis Mellifera L.) workers under co2 narcosis, caged outside of the colony

Exposure of A. mellifera workers to CO2 has been reported to decrease life span, induce behavioral changes, and inhibit the development of some glands and the ovaries. However, the use of CO2 is currently practiced among beekeepers and how the development of workers'ovaries are affected is unknown. The present work aimed to evaluate the effect of CO2 on the ovaries of A. mellifera workers, using a morphological approach. Newly emerged, and 3, 5, and 10-day-old workers were exposed to saturated CO2 for 30 seconds, more than once. The ovaries were examined under light (LM) and transmission electron microscopy (TEM). The ovaries of narcotized, 5-day-old workers exhibited long ovarioles with well-developed germarium, although oogenesis showed little development. While in the control group, the ovaries already exhibited cysts with cystocytes forming rosettes. At 10-days-old, the ovaries feature was variable; some of the ovaries showed ovarioles with many rosette cysts while others showed a high intensity of disorganization due to the beginning of cell death. The ovarioles of the ovaries of 15-day-old treated workers were morphologically varied as oogenesis showed little or no advance. In others cases, a complete disorganization with swollen cells and cell death features were observed. Germ cells of the ovaries of CO2-treated workers exhibited well-structured organelles, such as the Golgi complex, and larger amounts of mitochondria in the cytoplasm than the control group, but there was disorganization of the endoplasmic reticulum membranes. Our findings revealed that the exposure of workers to CO2 promotes impairment of oogenesis and ovarian degradation.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Separation of Scaptotrigona postica Workers into Defined Task Groups by the Chemical Profile on Their Epicuticle Wax Layer

During evolution, the cuticle surface of insects acquired functions in communication, such as inter- and intra-specific recognition, identification of gender, physiological state, and fertility. In eusocial bees, the information in the cuticular surface is important not only to discriminate nestmates from non-nestmates but also to identify an individual's class, life phase or task. A comparative study of the cuticular surface chemical profile of workers of Scaptotrigona postica in different phases of life, i.e., newly emerged workers (NE), brood comb area workers (CA), and forager workers (FO) was undertaken by gas chromatography linked to mass spectrometry. Multivariate statistical analysis was performed to verify how workers are grouped according to their chemical profile and to determine which compounds are responsible for separating them into groups. The cuticle surface of workers contains mainly hydrocarbons and a small amount of oxygenated compounds. Multivariate statistical analysis showed qualitative and quantitative variation in relation to the life phases/tasks performed, and all groups were distinct. The most abundant compound found in NE and CA was n-heptacosane, while in FO, it was (Z)-9-heptacosene. The compounds that differentiate NE from other groups are n-tricosane and n-hexacosane. A (Z)-X-octacosene and n-nonacosane are the chemicals that distinguish CA from NE and FO, while 11- and 13-methylpentacosane, (Z)-X-hexacosene, and (Z)-9-heptacosene characterize FO as distinct from NE and CA. The probable function of alkenes is nestmate recognition, mainly in FO. The results show that the cuticle surfaces of workers are characteristic of the phase of life/task performed by workers, allowing intra-colonial recognition.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Morphomettic changes on honeybee Apis mellifera L. workers fat body cells after juvenile hormone topic application at emergence

The effect of topical application of juvenile hormone (JH) over the lifetime of worker bees was evaluated in Apis mellifera, by measuring the area of the two cell types, trophocytes and oenocytes, found in the fat body. Topical application of 1 mu l of a 1 mu g/mu l solution of JH in acetone to the abdomens of newly emerged workers produced an increase in cell size, in both types of cell of 5-day-old treated workers in relation to the untreated control. The treatment was more effective on the oenocytes, since there were significant differences compared to the averages of the treatments and the interaction of the treatments with the age of the workers. The developmental pattern seemed to differ from the treated group. However, subsequent effects were probably dependent on different, natural variations in hormonal levels. (c) 2007 Elsevier Ltd. All rights reserved