Ocorrência, morfologia e ultra-estrutura da glândula de Dufour de Scaptotrigona postica Latreille (Hymenoptera: Apidae)

Abstract

Neotropical Entomology 34(1): 047-057 (2005) Dufour Gland Occurence, Morphology and Ultrastructure in Scaptogrigona postica Latreille (Hymenoptera: Apidae)ABSTRACT -The Dufour gland is an accessory gland of the bee reproductive female apparatus. In neotropical stingless bees, this gland has been poorly investigated, concerning to developmental, morphological or biochemical characteristics. In order to collaborate with the knowledge of the Dufour gland in stingless bees, a study of its occurrence, morphology and development was performed in Scapatotrigona postica Latreille. The results showed that this gland is absent in workers, although it occurs in workers of many stingless bee species. The glandular cells seem to be very active in virgin queens, presenting a well developed tubular network of smooth endoplasmic reticulum, secretion granules and some polyribosomes in the glandular cell cytoplasm, besides larger nuclei than in physogastric queens. In physogastric queen glands there are two types of cells, both of them apparently not synthetically active. Nevertheless, the physogastric queen glands are clearly able to absorb substances from the haemolymph, probably lipids that do not cross the cells, but pass through the intercellular cell spaces and cuticle, and are released directly to the gland lumen. The very developed double-layered gland basal lamina may actuate in the process of substances uptaking. The secretion, and consequently its function, can be different in these two queen types.KEY WORDS: Exocrine gland, alkaline gland, meliponine RESUMO -A glândula de Dufour é uma glândula acessória do aparelho reprodutivo feminino das abelhas. Nas abelhas neotropicais sem ferrão, tem sido pouca estudada sob todos os aspectos: morfológico, ontogenético e bioquímico. Na tentativa de colaborar com o conhecimento dessa glândula em abelhas sem ferrão, foi realizado um estudo da sua ocorrência, morfologia e desenvolvimento em Scaptotrigona postica Latreille. Os resultados mostraram que ela se encontra ausente nas operárias, como ocorre em muitas outras espécies desse grupo. Nas rainhas, as células glandulares parecem mais ativas nas virgens, possuindo uma desenvolvida rede de retículo endoplasmático liso tubular, grânulos de secreção e polirribossomos dispersos no citoplasma, além de apresentarem núcleos maiores do que os das células glandulares das fisogástricas. Nas rainhas fisogástricas há dois tipos de células glandulares, ambas aparentemente inativas sinteticamente. As glândulas das rainhas fisogástricas são claramente capazes de captar substâncias da hemolinfa, provavelmente lipídios, que não penetram nas células, mas passam pelos espaços intercelulares e, através da cutícula, chegam diretamente à luz da glândula. A bem desenvolvida dupla camada de lâmina basal ao redor da glândula pode atuar no processo de captação de substâncias da hemolinfa. A secreção, e conseqüentemente sua função, pode ser diferente nas duas classes de rainhas.PALAVRAS-CHAVE: Glândula exócrina, glândula básica, meliponíneo Nas abelhas, d...

Chemical composition of the dufour gland secretion in queens of Melipona bicolor (Hymenoptera, Meliponini)

“…Indirect support for this hypothesis is the observation that in Apis mellifera the Dufour gland is most developed when the queens are ready to mate and after mating, when the queen is in active egg-laying activity. 25 In M. bicolor physogastric queens, as in A. mellifera queens, the active compounds would be the esters, which could function as a pheromone to attract workers for provisioning and oviposition processes (POP), as suggested by Velthuis et al 21 In meliponines in general and specifically in M. bicolor the attractiveness of the physogastric queen is a high adaptative process since the queens depend on the workers to oviposite, controlling then her oviposition taxa and the population size, and in M. bicolor the colonies usually have more than one queen (polygyny). In a polygynic colony, the more attractive queen receives more trophic eggs by the workers, which increases the queen ovary development due the richer diet, being the queen able to oviposite more than other less attractive queens.…”

Morphological, chemical and developmental aspects of the Dufour gland in some eusocial bees (Hymenoptera, Apidae): a review

“…In A. mellifera as in other species of bees (Abdalla et al 1999a,b;Abdalla & Cruz-Landim 2001b, 2004b, 2005 this is an additional evidence of the gland lipid uptake capacity (Fig. 4 A-C).…”

“…Measurements of the length and diameter of the Dufour gland of Apis mellifera and statistical analysis of the data. In queens of Scaptotrigona postica Latreille 1807, the uptake substances seem do not cross the glandular cells, conversely they seem to bypass through the intercellular space, being released directly into the subcuticular space (Abdalla & Cruz-Landim 2005). In A. mellifera this does not occur, as showed by the lanthanum nitrate technique in the apical region there are many occlusion septated junctions that function as a barrier against molecule transit from the intercellular space to the gland lumen (Abdalla & Cruz-Landim 2004a).…”

“…Since the pioneer data of de Lello (1971) and Billen (1987), when they definitively disassociated the Dufour gland of bees as a sting associated gland and pointed it on as a reproductive accessory gland, much progress has been done about the knowledge of this gland in bees, especially in Apis mellifera Linné, 1758. In A. mellifera many aspects of its morphology (Abdalla & Cruz-Landim, 2001b,d,;2004a), physiology, secretion cycle and chemical nature were understood (Katazav-Gozansky et al 1997, 2000,01,03,04, Abdalla 2002Abdalla et al 2001;Abdalla & Cruz-Landim 2004a;Martin & Jones 2004) and now this background has been driving the studies of the gland in other species and groups of eusocial bees, as in the neotropical stingless bees or meliponines (Cruz-López et al 2001;Abdalla & Cruz-Landim 2002, 2004b, 2005Patricio et al 2003:04;Abdalla et al 2004).…”

Morphology and ultrastructure of salivary glands of male treehopper <i>Tricentrus brunneus</i> Funkhouser (Hemiptera: Membracoidea)

“…Basal infoldings and apical microvilli greatly increase the effective surface area of cells, and effectively enhance the exchange and transport of substances (O'Donnell & Maddrell 1983). The infoldings can increase the area for transport of water from the hemolymph to the cells, thus changing the concentration of saliva (Serrão & Cruz-Landim 1996, 2000, Abdalla & Cruz-Landim 2005, Serrão et al 2008. The existence of infoldings in cells of different acini of T. brunneus suggests that the dense secretions are diluted to facilitate saliva secretion into the efferent salivary duct.…”