Ultrastructural and Cytochemical Aspects of Metamorphosis in the Midgut of Apis mellifera L. (Hymenoptera: Apidae: Apinae)

The midgut of Apis mellifera is remodeled during metamorphosis. The epithelium and, to a lesser extent, the muscular sheath degenerate between the end of the last larval instar and the onset of pupation (prepupa).The larval epithelium is shed to the midgut lumen and digested, while a new epithelium is reconstructed from larval regenerative cells. During pupation, some reorganization still occurs, mainly in brown-eyed pupae. In pharate adult, the midgut wall shows the characteristics of adult, although some cells have pycnotic nuclei. The localization of alkaline and acid phosphatases showed that these enzymes were not involved in the reabsorption of the midgut wall.

Influência de cultivares de batata-doce resistentes e suscetíveis a Euscepes postfasciatus fairmaire (Coleoptera: Curculionidae) sobre o parasitismo, sobrevivência e a biologia de Catolaccus grandis burks (Hymenoptera: Pteromalidae)

The influence of four resistant and two susceptible genotypes of sweet potato to Euscepes postfasciatus Fairmaire on parasitism and biology of Catolaccus grandis Burks were evaluated under laboratory conditions. Six sweet potato roots of each genotype were infested with E. postfasciatus adults during 40 days. After this period the larvae were taken, weighted and encapsulated in parafilm. Five larvae were offered in free choice and no choice tests to C. grandis pregnant females for 12h. Five replications were used. The parasitized larvae and the eggs of the parasitoid were counted. Three daily observations were made to determine the developmental time of phases and parasitoid survival. C. grandis females can distinguish E. postfasciatus larvae reared on susceptible and resistant roots, prefering to parasitize larvae reared on susceptible roots. C. grandis survival was higher when the parasitoid was reared on larvae originated from susceptible roots and the number of emerged females was higher on larvae reared on hosts originated from susceptible roots.

Ultramorfologia e Histologia da Glândula Salivar do Tórax de Polistes versicolor (Olivier) (Vespidae), Comparada com a de Outros Hymenoptera

The salivary system of the Hymenoptera consists of the mandible, hypopharynx and thoracic salivary glands. It is very important because it is related to various aspects of the life of the insects, such as pheromone production, feeding the young, food digestion and nest building. Adult Polistes versicolor (Olivier) individuals were dissected, the thoracic salivary glands removed and processed for scanning electronic microscopy and histological examination. The P. versicolor thoracic salivary gland presents alveolar secretory units, consists of pseudoacines and does not have a reservoir. Four types of cells are present in the gland. The T1 and T2 cells make up the pseudoacines and differ mainly by the many secretory vessels in T2. There is a cluster of T3 cells at the base of the gland duct collectors, also with secretory characteristics. The secretion produced in the pseudoacines is conducted by canals and ducts to the outside, and the latter are made of T4 cells. The comparison of these characteristics with those of different Hymenoptera species, already studied, showed that the thoracic salivary gland cannot be used as a single comparison factor in evolutionary studies.

Comparative study of the cuticular hydrocarbon composition of Melipona bicolor Lepeletier, 1836 (Hymenoptera, Meliponini) workers and queens

In social insects, cuticular hydrocarbons are involved in species, kin, caste and nestmate recognition. Gas chromatography and mass spectrometry were used to compare the cuticular hydrocarbon composition of workers, males and queens of Melipona bicolor. The cuticular hydrocarbon composition of this species was found to consist mainly of C23, C25:1, C25, C27:1, C27, C29:1 and C29, which are already present in imagoes that have not yet abandoned the brood cell. This composition varied quantitatively and qualitatively between and within the castes and sexes. The newly emerged workers and young queens (virgins) had similar cuticular hydrocarbon profiles, which were different from those of the males. When the females start executing their tasks in the colony, the cuticular hydrocarbon profile differences appear. The workers have less variety, while the queens conserve or increase the number of cuticular hydrocarbon compounds. The queens have more abdominal tegumentary glands than the workers, which apparently are the source of the new cuticular compounds.

Apis mellifera (Hymenoptera, Apini) Ovary Development in Queens and in Workers from Queenright and Queenless Colonies

A morphological study of the development of the ovaries in workers from queenright and queenless colonies and queens of Apis mellifera is presented and discussed. The mating stimulates the ovary development and the egg-laying. Mating prevention or egg laying prevention provokes reabsorption in the queens ovaries, characteristic of the queen stage or ovariole development. Ovary development was observed in queenless and in queenright colonies but the queen's presence, the worker's age and the type of tasks done by them interfere with their development.

Electrophoretical Protein Profile in Apis mellifera (Hymenoptera; Apidae) Hypopharyngeal Glands under Juvenile Hormone Effect When the Colony is Grown in the Absence of Brood

Twelve-day-old and 25-day-old Apis mellifera workers were treated or not treated with juvenile hormone at the moment of emergence and reared in the colony without brood. Having the brood interference apart, the hormone effect on the hypopharyngeal glands protein expression was determined through the electrophoretical protein profiles of the both groups of bees. In those conditions, the hormone induced changes that were different from the control. Protein bands of 66 and 48 kDa were intensified in the 12-day-old bees, whereas band of 42 kDa was reduced in the 25-day-old bees. That indicated a different effect of the juvenile hormone in the function of bee aging, which promoted a glandular protein activation in the young bees and, in contrast, an inhibitory action in the 25-day-old bees workers.

Foraging Behavior and Subtask Hierarchical Structure in Acromyrmex spp. (Hymenoptera: Formicidae)

This study considers the function and complexity of tasks during foraging of three Acromyrmex species. Foraging was classified as a team task composed of 2 or 3 processes: recruitment, selection, and collection. Each process was subdivided into different subtasks. Points were attributed to subtasks considering their hierarchical level to compare the complexity of foraging among species. Total scores obtained were 19 for A. balzani and 14 for A. crassispinus and A. rugosus, indicating different degrees of social complexity for grass-cutting and leaf-cutting ant species. Acromyrmex balzani, a grass-cutting ant species, shows a behavioral repertoire composed of more variable subtasks during foraging.

Non-Specific Interaction between Ants (Hymenoptera; Formicidae) and Fruits of Syagrus romanzoffiana (Arecaceae) in an Area of the Brazilian Atlantic Forest

On the forest floor of a fragment of the Atlantic Forest which is considered to be in a stage of recuperation, located in southeastern Brazil, we recorded 54 species of ants interacting with the fruits of Syagrus romanzoffiana (Arecaceae). Myrmicinae was the subfamily which was the richest in species, followed by Ponerinae, Formicinae, Ecitoninae, Dolichoderinae, Pseudomyrmecinae and Cerapachyinae. The fruits of S. romanzoffiana can be classified according to whether or not they are preyed by the squirrel Sciurus ingrami, and the ant fauna that visits the fruits has an average similarity. Regarding diversity, the data suggest that there is no significant difference between ant assemblages at preyed and non-preyed-upon fruit falls. The results also indicate that there is no specific interaction between the ant fauna that visits the fruits of S. romanzoffiana, as it consists largely of species with omnivorous feeding habits.

Juvenile Hormone Effect on the Venom Gland Secretory Cycle in Workers of Apis mellifera (Hymenoptera, Apidae)

The present investigation analyzed the influence of Juvenile Hormone (JH) on the venom glands of Apis mellifera workers through protein dosage and electrophoresis of venom gland extracts of newly emerged workers which were treated with 1 μl JH dissolved in hexane, in concentration of 2μg/μl. Newly emerged workers non-treated and treated with 1 μl hexane were the controls. Both JH and hexane provoke quantitative changes on the gland protein titre and on the protein electrophoretic profile. The disappearance of protein bands in the venom gland extracts of 14 day-old treated workers, a situation normally found only in 35 day-old non-treated workers, suggests that the JH treatment induces a precocious maturation of the worker venom gland.

External and internal structure of Atta bisphaerica Forel (Hymenoptera: Formicidae) nests

This work was carried out to determine the internal and external structures of Atta bisphaerica (Forel) nests. Six nests were excavated and during excavation, all data referring to chambers and tunnels were recorded. Three nests had been internally cement-moulded, which enabled a better view of the chamber and tunnel structures. Atta bisphaerica nests presented a similar structural pattern, varying only in the number of chambers as a function of external mound area. Chambers were spherical with two communication tunnels. Internal tunnels had an elliptical section, sometimes circular, indirectly linked to chambers through ramifications and directly through short tunnels. Entrance holes were linked to the area of highest chamber concentration by tunnels from the elliptical section, which led to the nest in a radial manner. Knowledge of the colony's three-dimensional architecture permits successful application of chemical control processes, reduces the quantity of product applied, and consequently diminishes costs and environmental damage.

Male behavior in colonies of the social wasp Polistes lanio (Hymenoptera, Vespidae)

Sixteen post-emergent colonies of Polistes lanio were studied while producing males in the course of the colonial cycle. Individually, they remained in the nest only 10.5 days (5-31, n=165). Twelve different male behaviors were observed: remaining immobile on the nest (82,8%), giving alarm (4,8%), flying out from the nest (2,4%), copulating on the nest (2,4%), being dominated (1,6%), self-grooming (1,2%), checking cells (1,2%), adult-adult trophallaxis (receiving food) (0,8%), larva-adult trophallaxis (0,8%), chewing prey and giving it to the larvae (0,8%), returning to the nest without food (0,8%), and fanning the nest (0,4%). In comparison to the behavioral repertory of females (28 items), they performed fewer tasks and remained immobile most of the time on the nest. Their behavior was largely related to self maintenance, but also included giving chewed prey to the larvae, giving alarm signals and fanning the nest.

The ant (Hymenoptera: Formicidae) community in two species of the Euphorbiaceae, Alchornea sidifolia and Croton floribundus, in an area of the Atlantic Forest of Brazil

The number of individuals and species richness of ants were investigated in two species of Euphorbiaceae found in three areas of differentiated flora. These areas form part of a fragment of the Atlantic Forest located in the Serra do Itapety, in the state of São Paulo, Brazil. Fifty eight ant species were sampled, belonging to 23 genera and 6 sub-families; 40% of the species are arboreal. The sub-family Myrmicinae was the richest in species, with Pheidole being the most diverse genus and Crematogaster the most commonly-occurring. In the three study areas, no significant differences were found between the number of individuals and the species richness of ants collected on the trunks of Euphorbiaceae. C. floribundus Spreng and A. sidifolia Muell. Arg. are similar with respect to the number of ant species sampled; the number collected being 40 and 47, respectively.

Histochemistry and protein profile of the mandibular glands of workers of the ant Atta sexdens rubropilosa (Hymenoptera: Formicidae)

Insect mandibular glands are always associated to the mandibles; they are part of the salivary glandular system. The mandibular glands are composed by a reservoir associated to the secretory cells, with each secretory cell connected to the reservoir by means of individual canaliculi. These glands play an important role in the production of pheromones, which are compounds involved in defense, communication, and reproduction of the colony. Mandibular glands of soldiers and major and minor workers of the ant Atta sexdens rubropilosa were processed for different histochemical tests, total protein content, and protein electrophoretic profile determination. The histochemical tests detected the presence of lipids, DNA/RNA, polysaccharides, and proteins at different regions of the gland. The protein electrophoretic profiles showed that the total protein content as well as the number of peptides of each caste follow a progressive order in relation to the size of the individual. Thus, we suggest that the production of secretion is directly linked to the task that the individual performs in the colony.

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

We describe differences in the chemical composition of the Dufour gland secretion of virgin and physogastric queens of Melipona bicolor through gas chromatography and mass spectrometry. The Dufour gland secretion of virgin queens consists only of hydrocarbons, while that of physogastric queens contains, besides these, a variety of other compounds, such as isobutyrate and acetate esters. Such differences may indicate the queen fecundity condition and the oxygenated compounds of the physogastrics secretion may help to increase their attractiveness.