Histology and histochemistry of the ventriculus of Dolichoderus (=Monacis) bispinosus (OLIVIER, 1792) (Hymenoptera : Formicidae)

In this study we histologically and histochemically describe the ventriculus of Dolichoderus bispinosus. The epithelium consists of two basic cell types, highly basophilic generative cells, and digestive cells. The latter present several cytoplasmic vesicles. rich in acidic and neutral polysaccharides, and basic proteins. Also, these. cells exhibit an apocrine secretion pattern. A mass of fibrous material is observed on the surface of the epithelium. Finally, we discuss the results obtained. (c) 2005 Elsevier Ltd. All rights reserved.

Insect Venom Peptides

The insects of the order Hymenoptera ( bees, wasps, and ants) are classified in two groups, based on their life history: social and solitary. The venoms of the social Hymenoptera evolved to be used as defensive tools to protect the colonies of these insects from the attacks of predators. Generally they do not cause lethal effects but cause mainly inflammatory and/or immunological reactions in the victims of their stings. However, sometimes it is also possible to observe the occurrence of systemic effects like respiratory and/or kidney failure. Meanwhile, the venoms of solitary Hymenoptera evolved mainly to cause paralysis of the preys in order to permit egg laying on/within the prey's body; thus, some components of these venoms cause permanent/transient paralysis in the preys, while other components seem to act preventing infections of the food and future progenies. The peptide components of venoms from Hymenoptera are spread over the molar mass range of 1400 to 7000 da and together comprise up to 70% of the weight of freeze-dried venoms. Most of these toxins are linear polycationic amphipatic peptides with a high content of alpha-helices in their secondary structures. These peptides generally account for cell lysis, hemolysis, antibiosis, and sometimes promote the delivery of cellular activators/mediators through interaction with the G-protein receptor, and perhaps some of them are even immunogenic components. In addition to these peptides, the Hymenopteran venoms also may contain a few neurotoxins that target Na+ and/or Ca+2 channels or even the nicotinic ACh receptor. This review summarizes current knowledge of the biologically active Hymenoptera venoms.

Survival of Atta sexdens workers on different food sources

Leaf-cutting ants belonging to the tribe Attini are major herbivores and important agriculture pests in the neotropics, these ants being thought to feed on the sap which exudes from the plant material which they cut and also on the mycelium of a symbiotic fungus that grows on plant material inside their nests in what is called 'the fungus garden'. However, we have found that the survival of Atta sexdens worker ants on leaves, on mycelium. of the ants' symbiotic fungus, Leucoagaricus gongylophorus, or on plant polysaccharides was the same as that of starved A. sexdens, while, conversely, significantly longer survival was achieved by ants fed on the fungus garden material or on some of the products (especially glucose) of the hydrolysis of plant polysaccharides. We found that the fungus garden contained glucose at a higher concentration than that found in leaves or fungal mycelium, and that this glucose was consumed by the ant to the extent that it was probably responsible for up to 50% of the nutritional needs of the workers. The fungus garden contained polysaccharide degrading enzymes (pectinase, amylase, xylanase and cellulase) in proportions similar to that observed in laboratory cultures of L. gongylophorus. It thus appears that A. sexdens workers obtain a significant part of their nutrients from plant polysaccharide hydrolysis products produced by the action of extracellular enzymes released by L. gongylophorus. In this paper we discuss the symbiotic nutrition strategy of A. sexdens workers and brood and the role played by plant polysaccharides in the nutrition of attine ants. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Morphohistological study of the venom gland in workers of the ant Pachycondyla striata F. Smith (Hymenoptera : Ponerinae)

Themorphology of the venom gland in workers of the ant Pachycondyla striata (F. Smith) (Hymenoptera: Ponerinae) consists of an elongated sac that is directly connected to the sting apparatus. Three distinct regions compose this gland: the external secretory portion, composed by a secretory filament that bifurcates to originate another two; the internal secretory portion, which is represented by the convoluted gland from which rises the excretory duct that liberates the venom; and the storage portion, consisting of a large sac-shaped reservoir. The histology showed that the gland possesses a strong musculature on its distal third. Underneath these muscle layers, we noted the presence of an epithelium that envelops the internal wall of the reservoir. The presence of a convoluted gland as well as secretion inside the reservoir was also noted.

Dufour glands in the hymenopterans (Apidae, Formicidae, Vespidae): a review

Anexas ao aparelho do ferrão dos himenópteros aculeados encontram-se as glândulas de veneno e as de Dufour. A glândula de veneno é originada das glândulas associadas ao ovopositor dos himenópteros ancestrais não aculeados, já a glândula de Dufour é menos derivada, homóloga das glândulas colateriais dos outros insetos, sendo encontrada em todas as fêmeas dos himenópteros. Nestes insetos sua função é, em grande parte, desconhecida, mas, em formigas, parece estar envolvida com a comunicação e a defesa e, nas abelhas não sociais, com a construção e a proteção do ninho. Nas vespas pode estar relacionada ao reconhecimento parental. Foram observadas diferenças morfológicas e na composição química da secreção da glândula de Dufour entre as espécies, bem como na mesma espécie, entre as castas dos himenópteros sociais e entre indivíduos da mesma casta desempenhando diferentes funções ou pertencentes a ninhos diferentes. Portanto, nos himenópteros, sua função original de produzir substâncias para proteger os ovos ou favorecer a ovoposição parece ter sido substituída ou complementada com a função de produzir semioquímicos com função na comunicação.

General morphology and ultrastructure of the venom apparatus and convoluted gland of the fire ant, Solenopsis saevissima

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Behavior of Ectatomma brunneum (Formicidae: Ectatomminae) Preying on Dipterans in Field Conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The functional morphology of the metapleural gland of the leaf-cutting ant Atta laevigata (Formicidae: Attini)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A new strategy of endosymbiont midgut bacteria in ant (Ponerinae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chemical communication in isoptera

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Secretory Profile of Metapleural Gland Cells of the Leaf-Cutting Ant Acromyrmex coronatus (Formicidae: Attini)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Accessory Nuclei in the Oocytes of Pachycondyla (Neoponera) villosa (Hymenoptera: Ponerinae) as a Source of Annulate Lamellae

In insects' oocytes, structures called accessory nuclei can be observed. They are similar to the nucleus of the oocyte and have been detected in Hymenoptera as well as in other groups, with their source and functions still under discussion (Cassidy & King 1972). Through the use of histochemical techniques as well as ultrastructural ones, it was possible to observe several accessory nuclei surrounding the oocyte nucleus in the immature oocytes of Pachycondyla (Neoponera) villosa ants. Morphologically they were seen to be round and smaller than the germinal vesicle. When using these histochemical techniques, the only positive reaction was for proteins. Ultrastructurally they have the same morphology as the oocyte nucleus and a fine and electrondense granulation was observed inside them. The function of accessory nuclei in P (Neoponera) villosa is probably as a source of anullate lamellae and as an RNA reservoir in the oocytes. In mature oocytes (stage III), these structures are not observed, suggesting that they disappeared before this stage by releasing their contents into the oocytes' cytoplasm, according to Camargo-Mathias and Caetano (1993).

Morpho-physiological analysis of the insect fat body: A review

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Proteomic View of the Venom from the Fire Ant Solenopsis invicta Buren

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On the morphology of the worker immatures of the leafcutter ant Atta sexdens linnaeus (Hymenoptera: Formicidae)

Leafcutter ants of the genus Atta Fabricius are serious agricultural pests. Morphological studies of immature stages within this group are few, and the data provided for species of considerable importance are usually incomplete. In this study, the immatures of Atta sexdens Linnaeus are described and compared using light and scanning electron microscopy. Only specimens from founding stage colonies (i.e., lacking adult workers) were used. The existence of four larval instars was estimated by a frequency plot of maximum head widths, and the larvae of different instars differed from each other mainly by their bodily dimensions. Worker larvae belonged to two distinct morphological castes: (1) gardeners and nurses and (2) within-nest generalists. The worker larvae described in this study differed from a previous description of the same species by the following traits: the existence of a genal lobe, the number of clypeal hairs, the presence of two hairs on the ninth abdominal somite, the presence of hairs on the anterior surface of the labrum, and the shape of the maxillary palpus. This study provides a comparative analysis of immature stages of A. sexdens that may be relevant to future morphological and biological studies of the Attini. Microsc. Res. Tech. 75:10591065, 2012. (c) 2012 Wiley Periodicals, Inc.