Pollination and fruit set in pumpkin (Cucurbita pepo) by honey bees

Species of Cucurbitaceae are cultivated worldwide and are depend on bee pollination for fruit set. Field and lab experiments were conducted at Cornell University, Ithaca, NY, during 1996 and 1997 to determine "Howden" pumpkin (Cucurbita pepo L.) pollen removal and deposition by honeybees and factors relating to male flower attractiveness. Several parameters were evaluated in flowers at anthesis: (1) removal of pollen from anthers by honey bees, (2) pollen deposition on the stigma by honey bees, (3) amount of pollen on the body of honey bees, (4) fruit set after bee pollination, and (5) male flower nectary's pores and flower attractiveness. Honey bees carried between 1,050 to 3,990 pollen grains and 13,765 were removed from an anther after one visit. The amount of pollen deposited on the stigma by the honey bees varied according to the number of visits, from 53 grains with one visit, to 1,253 grains with 12 visits, and the mean number of grains in each visit varied from 53 to 230 grains. The percentage of established fruits was higher (100%) when the flowers received 12 visits of Apis mellifera, corresponding to a load 1,253 pollen grains. The attractiveness of the male flower for pollen and nectar collection was increased by the degree of opening of the access pore to the nectary in the flower.

Multivariate analysis of pollen frequency of the native species Escallonia pulverulenta (Saxifragaceae) in Chilean honeys

The aim of this work was the identification of geographic zones suitable for the production of honeys in which pollen grains of Escallonia pulverulenta (Ruiz & Pav.) Pers. (Saxifragaceae) can be detected. The analysis of botanical origin of 240 honey samples produced between La Serena and Puerto Mont (the IV and X Administrative Regions of Chile), allowed the detection of pollen grains of E. pulverulenta in 46 Chilean honeys. The geographic distribution of the honeys studied is presented together with their affinities, through factor analysis and frequency tables. The study was based on the presence of E. pulverulenta pollen. Escallonia pulverulenta pollen percentages oscillated between 0.24% and 78.5%. Seventeen of the studied samples were designated as unifloral - i.e. samples showing more than 45% pollen of a determined plant species. Two of these corresponded to E. pulverulenta (corontillo, madroño or barraco) honeys. The remaining unifloral honeys correspond to 8 samples of Lotus uliginosus Schkuhr (birdsfoot trefoil), 2 samples of Aristotelia chilensis (Molina) Stuntz (maqui) and 1 sample of Escallonia rubra (Ruiz & Pav.) Pers. (siete camisas), Eucryphia cordifolia Cav. (ulmo or muemo), Weinmannia trichosperma Cav. (tineo), Rubus ulmifolius Schott (blackberry) and Brassica rapa L. (turnip). Honeys with different percentages of E. pulverulenta pollen - statistically analyzed through correspondence analysis - could be associated and assigned to one of three geographic types, defined on the basis of this analysis. The geographical type areas defined were the Northern Mediterranean Zone (samples from the IV Region), Central Mediterranean Zone (samples from the V to the VIII regions including two samples of unifloral Escallonia pulverulenta honey), and Southern Mediterranean Zone (samples from the IX Region).

Reproductive biology of Protium spruceanum (Burseraceae), a dominant dioecious tree in vegetation corridors in Southeastern Brazil

We investigated the reproductive biology of Protium spruceanum (Benth.) Engler in vegetation corridors of secondary Atlantic forest in Lavras, southern Minas Gerais State, Brazil. The reproductive phenology was investigated fortnightly over a one year period. Floral biology studies involved pollen viability analysis, nectar production, stigmatic receptivity, pollen tube growth, visiting insect species and visit rates. The small, pale yellowish flowers (0.3-0.4 cm diameter) are functionally unisexual and organized in dense inflorescences (ca. 45 flowers). P. spruceanum presented annual flowering between September and November. Staminate flowers supplied a high percentage of viable pollen (90.6%) and relatively abundant nectar (x = 4.5 μL). Pistillate flowers produced only nectar to flower visitors (x = 4.0 μL). The effective pollinators were Apis mellifera and Trigona sp. (Hymenoptera, Apidae). Pollen tubes of cross-pollinated flowers were observed entering the ovaries 48 h after pollination. The fruiting season is from October to March, with a peak in November, coinciding with the rainfall peak. Ecological implications of these findings, and alternative arguments to explain the high genetic diversity at regional landscape are discussed.

Anti-inflammatory and antispasmodic activity of Ipomoea imperati (Vahl) Griseb (Convolvulaceae)

Ipomoea imperati (Convolvulaceae) lives on the sandy shores of the Brazilian coast and in other areas of the world. The anti-inflammatory activity of a methanol-water extract of the leaves of I. imperati was investigated in experimental models of acute and subchronic inflammation. Topical application of the extract (10 mg/ear) inhibited mouse ear edema induced by croton oil (89.0 ± 1.3% by the lipid fraction with an IC50 of 3.97 mg/ear and 57.0 ± 1.3% by the aqueous fraction with an IC50 of 3.5 mg/ear) and arachidonic acid (42.0 ± 2.0% with an IC50 of 4.98 mg/ear and 31.0 ± 2.0% with an IC50 of 4.72 mg/ear). Phospholipase A2, purified from Apis mellifera bee venom, was also inhibited by the extract (5.0 mg/ml lipid and aqueous fraction) in vitro in a dose-dependent manner (85% by the lipid fraction with an IC50 of 3.22 mg/ml and 25% by the aqueous fraction with an IC50 of 3.43 mg/ml). The methanol-water extract of I. imperati (1000 mg/kg) administered by the oral route also inhibited the formation of cotton pellet-induced granulomas (73.2 ± 1.2% by the lipid fraction and 56.14 ± 2.7% by the aqueous fraction) and did not cause gastric mucosal lesions. I. imperati extracts (10 mg/ml) also inhibited in a dose-dependent manner the muscle contractions of guinea pig ileum induced by acetylcholine and histamine (IC50 of 1.60 mg/ml for the lipid fraction and 4.12 mg/ml for the aqueous fraction). These results suggest the use of I. imperati as an anti-inflammatory and antispasmodic agent in traditional medicine.

Superinfection exclusion and the long-term survival of honey bees in Varroa-infested colonies

Over the past 50 years, many millions of European honey bee (Apis mellifera) colonies have died as the ectoparasitic mite, Varroa destructor, has spread around the world. Subsequent studies have indicated that the mite's association with a group of RNA viral pathogens (Deformed Wing Virus, DWV) correlates with colony death. Here, we propose a phenomenon known as superinfection exclusion that provides an explanation of how certain A. mellifera populations have survived, despite Varroa infestation and high DWV loads. Next-generation sequencing has shown that a non-lethal DWV variant 'type B' has become established in these colonies and that the lethal 'type A' DWV variant fails to persist in the bee population. We propose that this novel stable host-pathogen relationship prevents the accumulation of lethal variants, suggesting that this interaction could be exploited for the development of an effective treatment that minimises colony losses in the future.The ISME Journal advance online publication, 27 October 2015; doi:10.1038/ismej.2015.186.

Descriptive Sensory Analysis and Acceptance of Stingless Bee Honey

Stingless bee honey samples were evaluated by sensory descriptive analysis using free choice profile methodology. Appearance, flavor, and aroma were described and the data were treated with Generalized Procrustes Analysis. Individual descriptive terms ranged from 8 to 20. Plotting the samples in a bidimensional plan indicated that appearance attributes (color and viscosity) and sweet, sour and acid flavor were strongly correlated with x axis (Dimension 1) while coconut, wood, acid, sour, and sweet flavor aroma attributes were correlated with y axis (Dimension 2). The affective test was also performed and with the exception of the Melipona scutellaris honey, all the other samples showed good acceptance. Honeys that were described as sweeter and less acid were preferred by nontrained assessors, indicating that the regular consumer recognizes honey produced by Apis mellifera bee as a standard.

Morphometrical, biochemical and molecular tools for assessing biodiversity. An example in Plebeia remota (Holmberg, 1903) (Apidae, Meliponini)

We see today many efforts to quantify biodiversity in different biomes. It is very important then to develop and to apply other methodologies that allow us to assess biodiversity. Here we present an example of application of three tools with this goal. We analyzed two populations of Plebeia remota from two distinct biomes that already showed several differences in morphology and behavior. Based on these differences, it has been suggested that the populations of Cunha and Prudentopolis do not represent a single species. In order to verify the existence or absence of gene flow between these two groups, we characterized the patterns of mtDNA through RFLP, the patterns of wing venation through geometric morphometry, and the cuticular hydrocarbons through gas chromatography-mass spectrometry. We used bees collected in these two locations and also from colonies which have being kept for around 9 years at Sao Paulo University. We found six different haplotypes in these specimens, of which three of them occurred exclusively in the population of Cunha and three only in the Prudentopolis population. The fact that the populations do not share haplotypes suggests no maternal gene flow between them. The two populations were differentiated by the pattern of the wing veins. They also had different mixtures of cuticle hydrocarbons. Furthermore it was shown that the colonies kept at the university did not hybridize. These two groups may constitute different species. We also show here the importance of using other methodologies than traditional taxonomy to assess and understand biodiversity, especially in bees.

Visitantes florais de Erythrina speciosa Andr. (Leguminosae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Entomofauna visitante das flores de Cassia spectabilis (L.) D C. (Leguminosae)

Realizaram-se estudos sobre sistemas de reprodução de Cassia spectabilis (L.) D C. (Leguminosae) observando-se a diversidade, freqüência e constância dos insetos visitantes em diferentes horários. Também testou-se a influência dos fatores ambientais em relação às visitas. Os resultados de polinização manual sugerem que C. spectabilis é autocompatível, porém, a xenogamia é o sistema de reprodução predominante. As inflorescências foram visitadas por uma grande quantidade de insetos, havendo predominância de abelhas. O horário de maior ocorrência dos insetos nas flores de C. spectabilis foi das 8 às 14 h e de menor ocorrência entre 7 e 8 h e das 17 às 18 h. Quanto ao comportamento dos insetos em relação à flor de C. spectabilis, observou-se que Xylocopa frontalis Olivier, X. suspecta Camargo & Moure, Bombus morio Swederus e Centris scopipes Friese possuem comportamento e morfologia adequados aos polinizadores legítimos; C. similis F., Oxaea flavescens Klug e Epicharis rustica flava Cockerell foram considerados polinizadores ocasionais. Pseudaugochloropsis graminea (F.), Tetragonisca angustula Latreille e A. mellifera L. foram considerados pilhadores. A polinização por vibração é o método usado pelas abelhas para coleta de pólen.

Agentes polinizadores e produção de grãos em cultura de café arábica cv. “Catuaí Vermelho”

Coffee (Coffea arabica L.) plants had the pollination process of their flowers studied in three coffee producing regions in Brazil: the first in Ribeirao Preto, state of São Paulo, in September of 2004, the second in Carmo do Paraiba, in the state of Minas Gerais, in October of 2006, and, the third, in Altinopolis, state of São Paulo, in September of 2007. In all these locations the coffee variety used was the 'Catuai Vermelho'. The pollinator species visiting the flowers, the frequency with which the flowers were visited by the insects, and the type of material collected by them ( nectar and/or pollen) were determined by counts taking place at the first 10 minutes of each hour from 7:00 AM till 6:00 PM during the months mentioned above. To estimate the fructification percentage, 25 branches were identified with color threads and protected with wire frames covered with a nylon fabric to prevent them from being visited by insects. Another group of 25 branches was similarly identified but remained without any covering so that their flowers were thus freely visited by insects. on the average, the most frequent pollinator was the Africanized bee Apis mellifera (73.7%) followed by the bee Trigona spinipes (14.5%), and Tetragonisca angustula (9.5%). The Africanized bee collected nectar and pollen to almost the same extent: 58.5% of the first and 41.5% of the second. To collect nectar, that species increased its visiting frequency up to 1:00 PM. To collect pollen, A. mellifera visited the flowers up to 1:00 PM with frequency peaks between 8:00 and 9:00 AM. T. spinipes collected pollen (58,5%) and nectar (41.5%). T. angustula collected only pollen. The branches freely visited by insects produced 181 grains on the average whereas those covered with the nylon fabric produced only 81 grains, this meaning a reduction of 55.25% in grain production. Coffee grains produced on the freely visited branches had a mean weight (1.13 g) significantly superior to that of those produced on the covered branches (0.94 g).

Antimicrobial activity of propolis and essential oils and synergism between these natural products

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

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.

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)

Invasive Africanized honeybees change the structure of native pollination networks in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)