Ovarian ultrastructure in virgin queens of Apis mellifera L. narcotized by CO2.

Ovaries of newly emerged virgin queens, aged 1, 3, 5, and 10 days, were submitted to an atmosphere of CO2 for 1 min, and studied by transmission electron microscopy. Newly emerged control and experimental queens were kept caged during 15 days with six nurse workers (changed every 2 days) and fed with sugar candy and water ad libitum. For the ultrastructural studies, the ovaries were collected when the queens were 3, 5, 10, and 15 days old. The effect of the treatment on the ovary was mainly evaluated by cell death incidence and acid phosphatase detection. Neither the confinement nor CO2 treatment interfered with the pattern of queen ovarian development for up to 5 days; that is, no differences were observed in ovarian ultrastructure or acid phosphatase activity between control and treated queens. Beyond the age of 10 days, treated queens showed a lower rate of cell death than controls, but the positivity to acid phosphatase reaction remained similar in both. The protective effect of CO2 on cells, however, did not persist, and 15-day-old treated queens showed no differences compared to the controls in the rates of cell death or enzyme reactivity. In conclusion, treatment with CO2 did not significantly change the ultrastructure of ovarian cells, or acid phosphatase activity in them, during the caging time of the queens. From an applied perspective, the short-term imprisonment of newly emerged queens outside of the colony, as is done by beekeepers, does not seem to affect their performance in terms of future fertility, although the narcosis, as applied in this study, may negatively affect their long-term performance.

Efeitos da aplicação tópica de hormônio juvenil sobre o desenvolvimento dos ovários de larvas de operárias de Apis mellifera Linnaeus (Hymenoptera, Apidae) / Effect of topic application of juvenile hormone on the ovarian development of worker larvae of Apis mellifera Linnaeus (Hymenoptera, Apidae)

A influência do hormônio juvenil sobre o desenvolvimento do ovário de larvas de operárias de Apis mellifera foi analisada levando em conta a determinação trófica das castas, segundo a qual a alimentação larval é controlada pelas operárias de maneira a promover uma diferenciação de castas controlada pela produção e disponibilidade desse hormônio. A hipótese testada é que a ação do hormônio juvenil seja capaz de proteger ou prevenir a degeneração nos ovários das larvas de operárias. Foi feita aplicação tópica de 1 ml de hormônio dissolvido em hexano na concentração de 1 mg/ml do segundo até o quinto dia de vida larval, e a morfologia dos ovários avaliada nos dias subseqüentes à aplicação até ao sexto dia de vida larval. Como controles foram utilizadas larvas nas quais se aplicou 1 ml de hexano e larvas que não receberam nenhum tratamento. Constatou-se que o efeito do hormônio juvenil varia conforme a idade larval em que é aplicado e que este efeito foi maior quando a aplicação foi feita no terceiro dia de vida larval.

The influence of juvenile hormone (JH) on the ovarian development of worker larvae of Apis mellifera was analyzed, taking into account the trophic determination of the castes. The workers control the larval feeding in order to promote caste differentiation, which is regulated by the production and availability of this hormone. The hypothesis tested was that the action of juvenile hormone is capable of protecting or preventing the degeneration of the ovaries in worker larvae. A preparation of 1 ml of juvenile hormone dissolved in hexane at a concentration of 1 mg/ml was applied topically to 2- to 5-day-old larvae. The morphology of the ovaries was evaluated on the days following the application, until the larvae were 6 days old. The controls consisted of larvae to which 1 ml of hexane was applied, and larvae that received no treatment. The effect of juvenile hormone varied according to the age of the larvae to which it was applied, and this effect was greatest in 3-day-old larvae.

Ultrastructural modifications in the venom glands of workers of Apis mellifera L. (Hymenoptera: Apidae) promoted by topical application of juvenile hormone

The present study analyzed, the influence of the treatment with juvenile hormone on the ultrastructure of Apis mellifera L. workers' venom glands. Newly emerged workers received topical application of 1 æl of juvenile hormone diluted in hexane, in the concentration of 2 æg/æl. Two controls were used; one control received no treatment (group C1) and other received topical application of 1 æl of hexane (group C2). The aspect of the glandular cells, in not treated newly emerged workers, showed that they are not yet secreting actively. Cellular modifications happened according to the worker age and to the glandular area considered. The most active phase of the gland happened from the emergence to the 14th day. At the 25th day the cells had already lost their secretory characteristic, being the distal area the first to suffer degeneration. The treatment with juvenile hormone and hexane altered the temporal sequence of the glandular cycle, forwarding the secretory cycle and degeneration of the venom gland.

O presente estudo analisou, através de estudos ultra-estruturais a influência do tratamento com hormônio juvenil sobre as glândulas de veneno de operárias de Apis mellifera L. Para tanto, operárias recém-emergidas receberam aplicação tópica de 1æl de hormônio juvenil, na concentração de 2 æg/æl, sendo usado o hexano como veículo. Foram feitos dois controles, um que não recebeu nenhum tipo de tratamento (grupo C1) e o outro que recebeu aplicação tópica de 1 æl de hexano (grupo C2). O aspecto das células glandulares, em operárias recém-emergidas, mostra que estas não estão ainda secretando ativamente. Observa-se que alterações celulares ocorrem de acordo com a idade da operária e da região glandular considerada no controle C1. Assim, a fase de secreção mais ativa da glândula ocorre entre a emergência e os 14 dias de idade; aos 25 dias as células já perderam sua característica secretora, sendo a região distal a primeira a sofrer degeneração. Os tratamentos com hormônio juvenil e com hexano alteram a cronologia do ciclo glandular, antecipando o início da secreção e da degeneração da glândula.

Cell death and ovarian development in highly eusocial bees (Hymenoptera, apidae): caste differentiation and worker egg laying

The development and functioning of the ovary in highly eusocial bees is one of the most prominent differences between the castes in these insects, with queens having very large ovaries and a high capacity to produce eggs while the workers have small, sub-functional ovaries. The differences in ovary size and function are established during larval and pupal development and are hormonally controlled. Differential cell death has a prominent role in modulating the ovarian differences during development and adulthood. In this review, we discuss the forms of cell death, the types of cells affected and the timing of death in relation to the function of the female castes in the colony.

Morphology and protein patterns of honey bee drone accessory glands.

We used light and transmission electron microscopy to examine the morphology of the accessory glands of immature and mature adult males of Apis mellifera L. We also made an electrophoretic analysis of the protein content of the mature gland. The glands of the immature male actively secrete a mucous substance that can be seen in the lumen of the gland of the mature male. This secretion stains with mercury bromophenol blue and with periodic acid-Schiff reaction, which stain glyconjugates. The protein content was higher in the lumen secretion than in the gland wall extracts. The electrophoresis patterns of the wall extracts were different from those of the secretion found in the gland lumen.

Ocorrência e morfologia de glândulas tegumentares no abdome de Melissoptila richardiae ( Bertoni & Scrottky ) ( Hymenoptera, Apidae, Eucerini ) / Occurrence and morphology of tegumentary abdominal glands in Melissoptila richardiae ( Bertoni & Scrottky ) ( Hymenoptera, Apidae, Eucerini )

Ocorrência e a morfologia de glândulas tegumentares presentes no abdome de fêmeas de Melissoptila richardiae. Os resultados mostram que nesta espécie, células glandulares da classe III são encontradas de duas formas: isoladas nos tergitos e esternitos III e IV e formando um aglomerado de unidades glandulares bilateralmente, entre os segmentos III e IV, os quais liberam seu produto de secreção em um reservatório originado a partir da membrana intersegmental. Os resultados sugerem que o produto secretado é lipídico e, provavelmente volátil.

Morphology and ultrastructure of the male accessory glands of Achroia grisella (Fabricius)(Lepidoptera, Pyralidae)

The adult male reproductive system of Achroia grisella consists of paired testes in a common oval sheath, paired deferent ducts, accessory glands, seminal vesicles and a single ejaculatory duct. In this work, we used light and transmission electron microscopy to study the morphology of the male reproductive accessory glands of A. grisellla. The accessory gland consisted of glandular cells with a well-developed rough endoplasmic reticulum and Golgi apparatus, although no secretion was seen in the cells. Histochemical analysis showed that the accessory gland secretion consisted of glycoproteins. The variable morphological appearance of the secretion (globular, amorphous and fibrillar) present in the gland lumen and its staining properties, which changed along the gland tract, suggested that the secretion underwent some form of processing that was possibly associated with its maturation before release from the gland. We suggest that the accessory gland secretion may have a role in the maintenance of spermatozoa and/or in plug formation, as already reported for other lepidopteran species.

Tegumentary epithelial glands in the abdomen of virgin and physogastric queens of the stingless bee Scaptotrigona postica Latreille (Meliponini: Trigonina)

In the eusocial worker bees, portions of the epithelium of the abdominal epidermis may become hypertrophied and glandular, and produce the wax used to build the brood alveoli. In meliponine bees, the presence of similar epithelium was already observed in the queens, but its function is still unknown. Would this epithelium have homologous function in the workers? May the queens display other functions, besides reproduction, related to those considered exclusive of workers? In order to contribute to solve these questions, a histological and ultrastructural study of the tegumentary epithelial glands of the third tergite was carried out in virgins and physogastric queens of Scaptotrigona postica Latreille. The glandular tegumentary epithelium was easily discernible in the third tergite of the queens, being much more developed in physogastric than in virgin queens. The ultrastructural differences in the smooth endoplasmic reticulum between the queens, additionally to the histological and morphometrical data, indicate that this epithelium may have functional differences between the queen types. As already known, the virgin queens may produce wax and build brood alveoli, but the role of this epithelium in physogastric queens is totally unknown. A hypothesis considered in the present study is that the epithelium may be involved in production of pheromones, which may play roles in the social interaction of the laying queen.

Nas operárias das abelhas eussociais, regiões do epitélio tegumentar do abdome podem hipertrofiar-se e tornarem-se glandulares, sendo responsáveis pela produção de cera usada na contrução dos alvéolos de cria. Nos meliponíneos, epitélio com essas características também foi observado nas rainhas, porém sua função ainda continua desconhecida. Teria esse epitélio função homóloga nas operárias? As rainhas, além da função reprodutiva, desempenhariam funções na colônia até então consideradas exclusivas das operárias? Para tentar colaborar no esclarecimento dessas questões realizou-se um estudo histológico e ultra-estrutural das glândulas epiteliais tegumentares do terceiro tergito em rainhas virgens e fisogástricas de Scaptotrigona postica Latreille. Os resultados morfológicos mostraram que o epitélio glandular existe e é facilmente discernível no terceiro tergito das rainhas, sendo muito mais desenvolvido nas fisogástricas do que nas virgens. A ultra-estrutura mostrou que há diferenças no tipo de organização do retículo endoplasmático liso entre as rainhas, o que, juntamente com os resultados da histologia e morfometria, indicam poder haver diferenças funcionais desse epitélio entre elas. Como já observado na literatura, nas rainhas virgens tal epitélio pode estar envolvido na produção de cera e confecção de alvéolos de cria, porém sua função nas rainhas fisogástricas é totalmente desconhecida. A hipótese lançada no presente estudo é de que esse epitélio pode estar envolvido na produção de feromônios que irão atuar nas interações sociais da rainha poedeira.

Ocorrência, morfologia e ultra-estrutura da glândula de Dufour de Scaptotrigona postica Latreille (Hymenoptera: Apidae) / Dufour gland occurence, morphology and ultrastructure in Scaptogrigona postica Latreille (Hymenoptera: Apidae)

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.

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.

Caracterização das glândulas mandibulares nas diferentes classes de adultos de Scaptotrigona postica Latreille (Hymenoptera: Apidae) / Characterization of the mandibular glands in different adult types of Scaptotrigona postica Latreille (Hymenoptera: Apidae)

As glândulas mandibulares de operárias recém-emergidas, nutridoras e campeiras, rainhas virgens e fisogástricas, e machos maduros de Scaptotrigona postica Latreille foram estudadas histológica e morfometricamente. Estas glândulas apresentam diferenças histológicas características para cada idade e/ou função do indivíduo. De acordo com a morfometria conclui-se que as glândulas mandibulares possuem um ciclo secretor determinado, no qual a secreção começa a ser produzida nas operárias recém-emergidas, e acumula-se no citoplasma e reservatório da glândula das operárias nutridoras. Nas operárias campeiras o citoplasma encontra-se bastante vacuolizado, o que foi interpretado como resultado da eliminação da secreção. Rainhas fisogástricas apresentaram as maiores áreas celulares e nucleares, ao oposto dos machos, os quais apresentaram as menores áreas.

The mandibular glands of newly-emerged, nurse and forager workers, virgin and physogastric queens, and mature males of Scaptotrigona postica Latreille were studied under histological and morphometrical analyses. These glands present differences in their histology, according to the age and/or function of the individuals. The morphometric results showed that the mandibular glands have a very markedly secretory cicle, in which the secretion starts to be produced in newly emerged workers, being accumulated into the cytoplasm and reservoir in the nurses. In forager workers the cytoplasm presents many vacuoles, which are remaining of the secretion releasing. Physogastric queens showed the largest cellular and nuclear areas. On the contrary, the males presented the smallest ones.

Comparative anatomy of the male reproductive internal organs of 51 species of bees / Anatomia comparada dos órgãos do aparelho reprodutor masculino de 51 espécies de abelhas

A anatomia dos órgãos internos do aparelho reprodutor de machos (ARM) adultos e pupas foi comparada em 51 espécies de abelhas, incluindo representantes de seis famílias. Foram obtidos quatro tipos diferentes de ARM. O tipo I está presente em machos das famílias mais basais (Colletidae,Andrenidae e Halictidae) e é caracterizado por três túbulos seminíferos por testículo, o qual é quasetotalmente envolvido pela membrana escrotal. O tipo II é um tipo intermediário entre os tipos I e III e estápresente em Mellitidae e Megachilidae, como também em alguns Apidae estudados, sendo caracterizado por possuir dutos deferentes pós-vesiculares fora da membrana escrotal e possuir três ou quatro túbulos seminíferos por testículo, exceto Apis mellifera L., a qual possui secundariamente um número aumentado de túbulos. O tipo III foi achado somente nos Apidae estudados e é caracterizado por apresentar os testículos e dutos genitais (exceto o duto deferente pós-vesicular) encapsulados separadamente, as glândulas acessórias são bem desenvolvidas e o duto ejaculador é calibroso, apresentando fissuras em sua parede externa, as quais podem ocorrer também no tipo II. O tipo IV está presente exclusivamente na tribo Meliponini e é caracterizado pela ausência de glândulas acessórias.

The anatomy of the internal organs of the male reproductive apparatus (MRA) of adults and pupae was compared among 51 species of bees, including representatives of six families. Fourdifferent types of MRA were found. The type I is present in males of the less derived families (Colletidae, Andrenidae, and Halictidae) and is characterized by three seminiferous tubules per testis, which are almost completely enveloped by the scrotal membrane. The type II is an intermediary between types III and I and is present in Melittidae and Megachilidae, as well as in some Apidae studied, being characterized by post-vesicular deferent ducts outside the scrotal membrane and by three or fourseminiferous tubules per testis, except for Apis mellifera L., which has a secondarily increased number of tubules. Type III was only found in the Apidae studied and is characterized by separately encapsulated testes and genital ducts (except for the post-vesicular deferent duct). Accessory glands are well developed, and the ejaculatory duct is thickened with fissures in its wall, which may also occur in the type II. Type IV is present exclusively in the tribe Meliponini, and is characterized by the absence of accessory glands.

Electrophoretic protein pattern and acid phosphatase activity in the midgut extracts of Apis mellifera L. (Hymenoptera: Apidae) during metamorphosis / Padrão eletroforético de proteínas e atividade de fosfatase ácida em extratos do intestino médio de Apis mellifera L. durante a metamorfose

The electrophoretic pattern of proteins and the activity of acid phosphatase were described in the midgut extracts during the post-embryonic stages of Apis mellifera L. in order to stablish a correlation with the metamorphosis events. The results show the greatest variation in proteic electrophoretical bands during prepupal stage and the smallest variation during the brown eyed pupae stage. The acid phosphatase activity was higher during the larval last instar and lower in white eyed pupae. The greatest variety of bands during the prepupal stage coincides with the histolysis of the larval midgut epithelium and the lowest variability in the brown eyed pupa coincides with the end of the midgut differentiation. In another hand, the greatest phosphatase activity in the last larval stage must reflect this enzyme actuation in the histolysis of the larval epithelium

Foram pesquisadas variações no padrão eletroforético das proteínas e da atividade da fosfatase ácida contidas em extratos do intestino médio de Apis mellifera L. durante o último estágio larval e pupação com a finalidade de estabelecer um paralelo entre os resultados e os eventos da metamorfose. Verificou-se maior variedade de bandas protéicas durante o estágio de pré-pupa e menor na pupa de olho marrom. A atividade da fosfatase ácida foi maior durante o último estágio larval e menor na pupa de olho branco. A maior variedade de bandas protéicas na pré-pupa coincide com a histólise do epitélio larval e reconstituição do epitélio pupal, enquanto a menor variabilidade na pupa de olho marrom coincide com o fim da diferenciação do intestino médio. A maior atividade fosfatásica no último estágio larval pode ocorrer em razão da sua função na histólise do epitélio

Occurrence, morphology and ultrastructure of the Dufour gland in Melipona bicolor Lepeletier (Hymenoptera, Meliponini)

The occurrence, morphology and ultrastructure of the Dufour gland in Melipona bicolor Lepeletier, 1836 are presented. The Dufour gland is not present in workers. In virgin queens the gland cells show characteristics of low activity, which are described in the text. In physogastric queens the gland epithelium is higher and the cells more active than in virgin queens, showing numerous basal plasmic membrane invaginations impregnated by an electrondense material, increased apical invaginations and accumulation of substances that will be released to the gland lumen in the subcuticular space. Therefore, the data show that the Dufour gland is more developed in physogastric than in virgin queens, indicating a possible involvement of the Dufour gland in the reproduction of this species.

Ocorrência e morfologia de glândulas tegumentares no abdome de algumas abelhas (Hymenoptera: Apidae): um estudo comparado / Ocurrence and morphology of tegumentar glands in the abdomen of some bee species (Hymenoptera: Apidae): a comparative study

No presente trabalho foi estudada a ocorrência, distribuição e morfologia de glândulas tegumentares do abdome em Exomalopsis auropilosa Spinola, Centris fuscata Lepeletier, Epicharis flava Friese e Xylocopa (Neoxylocopa) suspecta Moure & Camargo. Os resultados mostraram a ocorrência de glândulas epiteliais (classe I) e unicelulares (classe III) com distribuição dorsal (tergais) e ventral (esternais) sem que se pudesse caracterizar um padrão relacionável com a posição filogenética ou grau de sociabilidade. No entanto, verificou-se uma tendência para maior número de glândulas em espécies com algum grau de sociabilidade como E. auropilosa e X. suspecta.

The present paper describes the presence, distribution and morphology of the abdominal tegumentar glands of Exomalopsis auropilosa Spinola, Centris fuscata Lepeletier, Epicharis flava Friese and Xylocopa (Neoxylocopa) suspecta Moure & Camargo. The studied bees have epithelial glands (class I) and unicellular glands (class III) distributed dorsally (tergal) and ventrally (esternal) without any pattern that could be correlated to the phylogenetic position. However, there is a tendency toward increased number of glands or more developed glands in the species with some degree of sociality as E. auropilosa and X. suspecta.

Light and electron microscopic aspects of glands and pseudoglandular structures in the legs of bees (Hymenoptera, Apinae, Euglossini)

The presence of glands and pseudoglandular structures in the legs of male and female of Euglossine bees was studied. Insect gland cells belonging to class I or class III are present in all pairs of legs and in all leg segments. Pseudoglandular structures are present in the male pretarsus, which lacked a typical tarsal gland. A special, probably absorptive epidermis, is present in addition to class III glandular cells in this segment. The basitarsus epidermis has special features which differed from other bees, and males have a tibial organ in the hind pair of legs. Light, scanning and transmission electron microscopy of the component parts of these structures showed that the tibial organ consists of three morphologically distinct parts, which could be distinguished in Euglossa cordata, Eulaema mandibularis and Eufrisea violacens. However, in Exaerete smaradigina, zone III was absent and there was a poorly defined zone IV.

Spermiogenesis in Palembus dermestoides (Coleptera: Tenebrionidae) with emphasis on the formation of mitochondrial derivatives

The testes of Palembus dermestoides are formed by six follicles coated and interconnected by a peritoneal sheath. Long, cylindrical and slightly twisted spermatophores were observed. Spermiogenesis followed the usual sequence for insects. During spermiogenesis, the nucleus was transferred to the cell periphery and the mitochondria were grouped at the posterior pole of the cell. Two mitochondrial derivatives and two paracrystalline electrondense bodies were present close to the axoneme. The mitochondrial derivatives were surrounded by a single row of microtubules in immature spermatozoa. The axoneme had the typical 9+9+2 microtubular pattern of insects.

Replacement of larval by adult Malpighian tubules during metamorphosis of Melipona quadrifasciata anthidioides Lep. (Hymenoptera, Apidae, Meliponinae): morphological studies

In Melipona quadrifasciata anthidioides a stingless bee, the malpighian tubules (Mt) of the larvae are totally reabsorbed during pupation and replaced by others that will function in the adult. The dye exclusion test shows generalized celular death in the larvall tubules present in prepupae. The results obtained with the acid phosphatase reaction corroborate these findings. Between the end of larval phase and emergence of adult, the insect does not have functional malpighian tubules, but develops waste storaging cells, the urate cells, for nitrogenous waste inactivation. the morphology of degeneration of the larval and the arising of the adult Mt, as well as that of the urate cell on light microscopy are described. The apparent change in the connection point between intestine and malpighian tubules of larva and adult is also discussed.

Microorganisms of the digestive tract of Brazilian termites (Isoptera, Termitidae)

The hundgut microbiota of the termites Armitermes euamignathus, Cornitermes cumulans and Anoplotermes sp. was examined using transmission electron microscopy. A great variety of bacterial forms were detected and they comprise bacillus, spirochetes and coccus. Negatively stained preparations of the hindgut content showed more than six different bacterial morphotypes including bacteria devoid of flagellum and flagellate. The number of flagella and their distribution in the bacterial surface is also variable.

Presença de material eletrodenso sob a membrana vitelina do ovo de Scaptotrigona postica latr. (Hymenoptera, Meliponinae) durante a fase inicial da embriogenese / Presence of electrodense material under the viteline membrane of Scaptotrigona postica Latr. egg (Hymenoptera, Meliponinae) during the embryogenesis initial fase

The present paper reports the presence of an electrondense material of unknown nature distributed under the viteline membrane of Scaptotrigona postica egg. The dorsal side layer is thicker then the ventral one. In eggs newly oviposited the material is gradually distributed inside the plasmalema invaginations. Later on (12 hs after oviposition) when a blastoderm is already formed around the egg, the material moves to the intercellular space. On the sequence of the development there was no more indication of the material under the membrane.