Behavioral responses evoked in honey bee workers by Dufour gland extracts (Hymenoptera : Apidae)

A series of experiments was performed to assess possible roles of the honey bee Dufour gland secretion. Bioassays with extracts of queen and worker glands from two colonies were made under artificial conditions, in which nestmate and non-nestmate forager workers were tested. The results demonstrate that forager workers display behavioral responses when exposed to Dufour gland extracts of nestmates, but remain indifferent when exposed to non-nestmate extracts. Also, the results demonstrate that forager workers are attracted by virgin queen gland extracts, and repelled by forager worker extracts. The data demonstrate that the Dufour gland secretion is colony- and caste-specific. The attractant remains in the nest. The repellent effect of forager worker extracts is interpreted as an alarm-like pheromone. The attractant effect of virgin queen extracts could be useful in the swarming process to attract scout bees to the eventual founder virgin queen or to attract old foragers to the virgin queen that remains in the nest.

Comparative study of the ultrastructure and secretory dynamic of hypopharyngeal glands in queens, workers and males of Sceptotrigona postica latreille (Hymenoptera, Apinae, Meliponini)

The secretory cycle of hypopharyngeal glands (HPGs) in Scaptotrigona postica resembles that of Apis mellifera: in newly emerged workers the HPGs are in prefunctional state, their maximum development happens in the nurse workers and in forager workers they show signs of reabsorption. In S. postica these glands are also present in queens and males where they are more developed in newly emerged individuals. The ultrastructural features of the HPG secretory cycle in workers of S. postica and A. mellifera are alike: granular endoplasmic reticulum well developed, large secretion masses around the intracellular canaliculus in nurse workers and extensive degenerative structures in forager workers. Then it is suggested that the HPG secrete similar substances in both species. A second secretory cycle seems to occur in early foragers, may be with production of enzymes. The role of the HPGs in queens and males remains unknown but one possibility is enzyme production.

In situ localization of heat-shock proteins and cell death labelling in the salivary gland of acaricide-treated honeybee larvae

The effects of the acaricides, rotenone and oxalic acid (OA) on salivary glands of honeybee larvae were evaluated. Immunohistochemical methods were used to detect cell death and heat-shock protein (HSP70 and 90) localizations. Heat-shock proteins (HSP70 and 90) were localized in the cytoplasm and/or the nuclei of secretory gland cells, both under stress and in normal conditions. In rotenone-treated larvae, there were no changes in the normal level of cell death and also there were no morphological alterations in the secretory cells. In the larvae treated with oxalic acid, the salivary gland showed varying degrees of morphological cellular alteration and an increase in the cell death level. The present data suggest that stress-induced HSP70 might have an antiapoptotic effect while the stress-induced HSP90 might have a chaperone function in the larval salivary glands.

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

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Analysis of Mortality in Africanized Honey Bee Colonies with High Levels of Infestation by Varroa destructor

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cephalic salivary gland ultrastructure of worker and queen eusocial bees (Hymenoptera, Apidae)

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

A morphological view of the relationship between indirect flight muscle maturation and the flying needs of two species of advanced eusocial bees

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

Vitellogenin content in fat body and ovary homogenates of workers and queens of Melipona quadrifasciata anthidioides during vitellogenesis

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

Characterization and localization of dynein and myosins V and VI in the ovaries of queen bees

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

Cytoskeletal organization of bee ovarian follicles during oogenesis

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

Bee Visitors of Quaresmeira Flowers (Tibouchina granulosa Cogn.) in the Region of Dourados (MS-Brasil)

This research was developed in the center-urban area at the city of Dourados (MS), in Tibouchina granulosa trees, a plant popularly known as quaresmeira in Brazil. The floral visitors of this species were recorded in three daily periods: 7 - 8 a.m., 1 - 2 p.m. and 4 - 5 p. m. Bee visitors of those plants were collected with an entomological net when they landed on the flowers. The bees were anesthetized in a closed camera containing etila acetate, conserved in Dietrich ' s fixative and, soon afterwards, transferred to 70% ethyl alcohol for subsequent identification. Almost 300 specimens of Africanized Apis mellifera, Trigona spinipes and Tetragonisca angustula were collected. The presence of these three species of bees in the flowers of T. granulosa suggests that they can be considered the main floral visitors of that vegetal species. T. angustula workers did not visit the flowers of T. granulosa between 7 and 8 a.m., but they were the main floral visitors from 4 to 5 p.m. The workers of T. spinipes presented a very aggressive behavior against the Africanized A. mellifera workers on the quaresmeira flowers, defending the food sources with strength and efficiency and provoking a drastic reduction in the number of honeybee visits between 1 and 2 p.m. Nevertheless, they did not interfere in the opportunistic activity of foraging by T. angustula workers, mainly between 4 and 5 p.m. The most important result of this research was the detection of the Competitive Exclusion Principle between A. mellifera and T. spinipes species in relation to the foraging behavior, when they exploit the floral resources of T. granulosa.

Occurrence and morphometry of the hypopharyngeal glands in Scaptotrigona postica Lat. (Hymenoptera, Apidae, Meliponinae)

As compared to Apis mellifera where only workers have hypopharyngeal glands, in Scaptotrigona postica, these glands occur in workers, queens and males. They are composed of two long axial ducts with many unicellular secretory alveoli interconnected by secretory canaliculi. The axial ducts are longer in miles than in workers, but the alveolar areas of queens and males are generally smaller. In workers the alveoli have their greatest size in the nurses or middle-aged individuals while in queens and males they are larger in newly emerged individuals. The results indicate that the glands in workers may produce food for the brood as in A. mellifera, since they are well developed in the nurse workers. However, the function of the glands in queens and males remains to be clarified since these individuals have no part in brood care.

Effect of topical application of juvenile hormone (JH) in honeybee worker larvae on the development of the Dufour's and Koschewnikow's glands

In order to investigate the action of the juvenile hormone (JH) on honeybee caste differentiation two exocrine glands, Koschewnikow and Dufour glands, were chosen for study. Two combs (I & II) were taken from a single posture of a queen to use for this research. In comb I the larvae were treated with a topical application of JH in Acetone, and those from the comb II (control group) received only Acetone. Immediately after the emergence of the workers, their glands were dissected and prepared for microscopic measurements. The results showed cell area reduction in the Koschewnikow gland induced by the JH application. The results for the Dufour gland displayed taller epithelial cells with the JH application. The difference in glandular responses to the JH relates to gland function, hormone targets, and individual homeostasis.

Oral Toxicity of Fipronil Insecticide Against the Stingless Bee Melipona scutellaris (Latreille, 1811)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pollination of Adenocalymma bracteatum (Bignoniaceae): Floral Biology and Visitors

Adenocalymma bracteatum is a shrub of dense foliage and yellow flowers, easily found on grasslands areas in Central Brazil. The aim of this study was to determine the reproductive biology and the flower visitors of A. bracteatum in a pasture area nearby Ivinhema city, MS (Brazil). The flowering peak occurs in winter. The flower reflects ultraviolet light. Anthesis begins at 6:30h, and pollen and nectar are the resources to visitors. We captured 1,038 floral visitors. The bees Apis mellifera (L.), Trigona sp., Trigona spinipes (Fabricius), (Hymenoptera: Apoidea) and the ant Cephalotes sp. (Hymenoptera: Formicidae) were the main visitors. The reproductive tests indicate that A. bracteatum is self compatible, justifying its expansion in altered environments; however, the largest reproductive success was dependant on cross-pollination and self-pollination, evidencing the pollinators importance. Adenocalymma bracteatum presents melittophilous syndrome and bumblebees were the main pollinators in the area. The correlations observed between the climatic variables and the main pollinator species were low or medium.