Heritability of sting characters in Africanized honeybees

In this paper we proposed to estimate the heritability of seven morphological characters that compose the sting apparatus ofthe Africanized honeybee workers. An experimental design to estimate genetic parameters was based on the method developed by Oldroyd and Moran. This method was modified to eliminate within-colony environmental effects associated with the additive genetic variance. The estimated h2 values ranged from 0.17 ± 0.11 (maximum width of bulb of sting stylet and height of the valve of right lancet) to 0.74 ± 0.30 (length of the lancet).

Dwarf gynes in Nannotrigona testaceicornis (Apidae, Meliponinae, Trigonini). Behaviour, exocrine gland morphology and reproductive status

The behaviour and morphology of dwarf gynes produced in worker-sized cells of normal colonies in Nannotrigona testaceicornis (Meliponinae, Trigonini) were studied. The behaviour of these dwarf virgin queens was the same as observed for normal Trigonine gynes. The glandular equipment is also the same: Dufour glands, fat bodies and spermathecae are present. Despite these similarities, their ovaries are different. The functional significance of dwarf gynes is unknown, but may be a basis for an alternative reproductive strategy.

Estrutura de guildas de polinizacao de Solanum aculeatissimum Jacq. e S. variabile Mart. (Solanaceae)

Some aspects of the reproductive biology of Solanum aculeatissimum and S. variabile (Solanaceae) were considered in this study with special reference to floral visitants and their behavior. The most frequent Solanum visitors are bees of the genus Centris, Epicharis, Bombus, Oxaea and Xylocopa that collect pollen from the anthers by means of body vibration. The behavior of those bees on the flowers and their flight distances makes them important pollinators mainly to Solanum aculeatissimum that bears cross-pollination. The guild of pollination of Solanum aculeatissimum and S. variable is composed by bees of the cited genus and by bees of the genus Thygather, Pseudaugochloropsis and Euglossa.

Phytochemical evidence for the plant origin of Brazilian propolis from Sao Paulo state

Propolis and plant secretions from three species, most frequently mentioned as botanical sources of the bee glue in Brazil (Baccharis dracunculifolia, Araucaria angustifolia and Eucalyptus citriodora) have been investigated using GC-MS. Based on chemical evidence, B. dracunculifolia was shown to be the main propolis source in Sao Paulo state. The antibacterial and antifungal activities of all four materials were also tested, the most active being propolis and Baccharis leaf exudate.

Cell death in ovarioles causes permanent sterility in Frieseomelitta varia worker bees

Frieseomelitta varia worker bees do not lay eggs even when living in queenless colonies, a condition that favors ovary development and oviposition in the majority of highly social bees. The permanent sterility of these worker bees was initially attributed to a failure in ovary morphogenesis and differentiation. Using transmission electron microscopy we found that at the beginning of the pupal phase the ovaries of F. varia workers are formed by four ovarioles, each of them composed of 1) a terminal filament at the apex of the ovarioles, containing juxtaposed and irregularly shaped cells, 2) a germarium with clusters of cystocytes and prefollicular cells showing long cytoplasmic projections that envelop the cystocyte clusters, 3) fusiform interfollicular and basal stalk precursor cells, and 4) globular, irregularly contoured basal cells with large nuclei. However, during the pupal phase an accentuated and progressive process of cell death takes place in the ovarioles. The dying cells are characterized by large membrane bodies, electron-dense apoptotic bodies, vacuoles, vesiculation, secondary lysosomes, enlarged rough endoplasmic reticulum cisternae, swollen mitochondria, pycnotic nuclei, masses of chromatin adjacent to the convoluted nuclear envelope, and nucleoli showing signs of fragmentation. Cell death continues in ovarioles even after the emergence of the workers. Once they become nurse bees, the ovaries have become transformed into a cell mass in which structurally organized ovarioles can no longer be identified. In F. varia workers, ovariole cell death most certainly is part of the program of caste differentiation.

Regression of the lateral oviducts during the larval-adult transformation of the reproductive system of Melipona quadrifasciata and Frieseomelitta varia

Toward the end of the larval phase (pre-pupa), the reproductive systems of Melipona quadrifasciata and Frieseomelitta varia workers are anatomically similar. Scanning electron microscopy showed that during this developmental phase the right and left ovaries are fused and form a heart-shaped structure located above the midgut. Each ovary is connected to the genital chamber by a long and slender lateral oviduct. During pupal development, the lateral oviducts of workers from both species become extremely reduced due to a drastic process of cell death, as shown by transmission electron microscopy. During the lateral oviduct shortening, their simple columnar epithelial cells show some signs of apoptosis in addition to necrosis. Cell death was characterized by cytoplasmic vesiculation, peculiar accumulation of glycogen, and dilation of cytoplasmic organelles such as mitochondria and rough endoplasmic reticulum. The nuclei, at first irregularly contoured, became swollen, with chromatin flocculation and various areas of condensed chromatin next to the nuclear envelope. At the end of the pupal phase, deep recesses marked the nuclei. At emergence, worker and queen reproductive systems showed marked differences, although reduction in the lateral oviducts was an event occurring in both castes. However, in queens the ovarioles increased in length and the spermatheca was larger than that of workers. At the external anatomical level, the reproductive system of workers and queens could be distinguished in the white- and pink-eyed pupal phase. The metamorphic function of the death of lateral oviduct cells, with consequent oviduct shortening, is discussed in terms of the anatomical reorganization of the reproductive system and of the ventrolateral positioning of adult worker bee ovaries. (C) 2000 Wiley-Liss, Inc.

Protein requirements in larvae and adults of Scaptotrigona postica (Hymenoptera: Apidia, Meliponinae): Midgut proteolytic activity and pollen digestion

The number and degree of digestion of pollen grains in the midgut and rectum, the midgut proteolytic activity and the time of pollen grain passage through the digestive tract in the stingless bee Scaptotrigona postica (Latreille) have been analyzed. The results show similar protein requirements among larvae, nurse bees and queens, as well as between forager bees and old males, but these requirements are higher in individuals from the former groups than in those from the latter. Although protein requirements have been demonstrated to vary according to a bee's activity in the colony, they are similar among bees from different castes or sexes. These changes in feeding behavior are related to the bee's function and to less competition for nourishment among individuals of the colony. It is also noted that pollen grains took between 6 and 28 h to pass through the digestive tract. Pollen grains are irregularly accumulated in the various regions of the midgut, which may reflect functional differentiation throughout the midgut. © 2001 Elsevier B.V.

Exocrine glands of Schwarziana quadripunctata (Hymenoptera, Apinae, Meliponini)

This article describes the location, anatomy, histology and ontogeny of adult Schwarziana quadripunctata exocrine glands. These glands appear either as individualized organs (salivary gland system and Dufour gland) or as epidermis differentiation (tegumentary glands). Variations in the occurrence and degree of development among colony components with regard to their degree of maturity are also described.

Avaliação do colesterol plasmático em coelhos com hipercolesterolemia induzida e tratados com extrato etanólico de própolis

The propolis (bee glue) is a product rich in flavonoids, which are known for antioxidant activities, a protective action to the lipoproteins LDL-cholesterol against lipid peroxidation. Because they have antioxidant properties, we investigated the effect of the ethanolic extract propolis on the plasma level of cholesterol in rabbits (Oryctolagus cuniculus) submitted to hypercholesterolaemia. The animals were divided into 4 groups. G 1=received commercial feed and water, G 2=received enriched feed and water, G 3=received enriched feed and ethanol, G 4=received enriched feed and ethanolic extract of propolis. The hypercholesterolaemia was induced with commercial feed enriched with egg yolk. The animals received the ethanolic extract propolis at the concentration of 100 mg/kg daily. Weekly, after fast of 14 hours, the samples of blood were collected from the marginal vein of the ear. The plasma was used for the estimation total cholesterol. From the results obtained, we verified that the ethanolic extract propolis significantly reduced the plasma level cholesterol (109,59 mg/dL, p<0,05), compared to the animals treated with ethanol (331,38 mg/dL), and also to those receiving the commercial feed only, with cholesterol at 269,74 mg/dL.

Enzymatic activity of hypopharyngeal gland extracts from workers of Apis mellifera (Hymenoptera, Apidae, Apinae)

This research presents a comparative study of enzymatic activity of the hypopharyngeal gland extracts from workers of Apis mellifera in three physiologic stages: newly emerged, nurse and forager workers, with the objective of contributing to the comprehension of the gland function. In order to determinate the enzymes present in the extracts, the Api Zym kit (Bio Mérieux) was used to test the activity of 19 different enzymes. The enzymes found in larger amounts only in the hypopharyngeal glands from certain individuals were the following: in newly emerged workers, the N-acetyl-down double arrow sign-glucosaminidase that may be digesting the chitin of some food ingested by the bee; in forager workers, the acid phosphatase that is likely acting in authophagic processes, the a-glucosidase, in the processing of nectar into honey, and the down double arrow sign-glucosidases, in the pollen digestion.

Juvenile hormone promotes changes in the expression of hypopharyngeal gland proteins of worker Apis mellifera (Hymenoptera: Apidae)

The present investigation compares the protein electrophoreses profiles of the hypopharyngeal glands of 12 and 25 day old Apis mellifera workers, some of which were experimentally treated with an analogue of juvenile hormone in the moment of the emergence while others were not treated. According to the evaluation of the presented variations by four main bands, it is concluded that the analogue juvenile hormone changes the glandular genetic expression pattern, promoting the disappearance of two from the four main bands in 25 day old workers. The effect of this hormone is discussed as an hypopharyngeal maturation inductor, in synergetic action with the bee age acting early in the glandular cycle.

Mating influence in the ovary differentiation in adult queens of Apis mellifera L. (Hymenoptera, Apidae)

The present results show that in the ovarioles of a newly emerged (0 day) queen of A. mellifera only two regions may be distinguished: a proximal, short germarium and a very long distal, terminal filament. As the queen matures and gets ready for the nupcial flight, the germarium increases in lenght, advancing towered the distal end, as the terminal filament shortens. The ovarioles of queens ready to mate (6 to 8 days old) have, already one or two ovarian follicles, i.e. a very short proximal vitellarium, but a real vitellogenesis only starts after the fecundation. If the queen does not mate the ovarioles structure is disrupted (12-16 days old). In mated queen eggs the ovarioles present three differentiated regions, from the apice to the basis: a short terminal filament, a medium size germarium, and a very long basal vitellarium. As the eggs are laid, the emptied follicle collapses, degenerates and produces a corpus luteum.

Cell nucleus activity during post-embryonic development of Apis melliferaL. (Hymenoptera: Apidae). Intranuclear acid phosphatase

We report nuclear acid phosphatase activity in the somatic (intra-ovariolar and stromatic) and germ cells of differentiating honey bee worker ovaries, as well as in the midgut cells of metamorphosing bees. There was heterogeneity in the intensity and distribution of electron dense deposits of lead phosphate, indicative of acid phosphatase activity in the nuclei of these tissues, during different phases of post-embryonic bee development. This heterogeneity was interpreted as a variation of the nuclear functional state, related to the cell functions in these tissues.

Contribuição ao protocolo de controle de qualidade da própolis e de seus extratos

A quality control protocol for the analysis of propolis and its extracts is proposed in the present work. Propolis of Apis mellifera L. bees collected in beehives of an apiary located in the northwest of the Paraná State was triturated and submitted to the following analysis: particles medium size determination, loss of dry, ashes drift, waxes drift, drift of extractive (in water and in ethanol) and total flavonoids drift determination. Propolis ethanolic extracts (96 °GL) at 10% (w/w) and at 30% (w/w) were prepared and submitted to the determination of the pH, relative density, dry residue, alcoholic drift and total flavonoids drift determination. Propolis was analyzed, through High Performance Liquid Cromatography (HPLC). Comparing the obtained results with other works, it was observed that is possible to establish the intervals of values for parameters in order to evaluate the quality of a propolis sample and its extracts.

Spermiophagy in the spermatheca of Melipona bicolor lepeletier, 1836 (Hymenoptera, Apidae, Meliponini)

The presence of spermatozoa in vesicles in the cytoplasm of the epithelial cells that constitute the spermathecal wall of Melipona bicolor queen (Meliponini) is discussed in relation to the organ structure. The epithelial wall is lined by an apparently continuous cuticle in the luminal surface that should be a non-transposable barrier to the luminal spermatozoa. However, some spermatozoa were seen crossing the cuticle through interruptions that was first interpreted as sectioning defects. Nevertheless, the sperm cells in well-structured cytoplasmic vesicles, bound by membranes and sometimes associated to multivesicular bodies, as well as cytoplasmic structures representative of intracellular digestion and the occurrence of the phenomenon in two of the three spermathecae studied, suggest a real spermiophagic hole in the spermathecal epithelial cells.