Components of pollination effectiveness in Psychotria suerrensis,a tropical distylous shrub

In this paper I report components of effectiveness for pollinators of a tropical distylous shrub, Psychotria suerrensis (Rubiaceae), which is visited by a variety of bees, wasps, and butterflies, and by two species of hummingbirds. In the field, I measured the following components of effectiveness: frequency of visits, evenness of visits across plants, and diurnal pattern of visits. I also used flight-cage experiments to compare pollentransfer abilities of euglossine bees and heliconiid butterflies. Euglossine bees visited more frequently, visited earlier in the day, and visited a higher proportion of plants in the population than did other taxa. In flight cage experiments, bees and butterflies transferred similar amounts of pollen overall, but bees transferred significantly more inter-morph (compatible) pollen. For each component measured, euglossine bees appeared to be the most effective pollinators.     

Effects of itraconazole on the sporocysts wall of the entomopathogenic fungi Ascosphaera apis as revealed by the scanning electron microscope

The young sporocysts had a wrinkled sporocyst wall, numerous papillae on the wall surface and the wall was granular and porous. In the itraconazole-treated culture, the walls of the young sporocysts were also wrinkled, but the characteristic papillae were replaced by larger lumps which were densely packed and coated the entire surface of the sporocyst wall. The mature sporocysts walls were smooth and possessed numerous papillae. In the itraconazole-treated culture, the walls of mature sporocysts walls were also smooth but possessed densely packed larger lumps instead of papillae. At higher magnification, each of the lumps were found to consist of numerous globules. No pores were observed as they were in the normal sporocyst wall.     

On a simplified model for pattern formation in honey bee colonies

We present a simplified version of a previously presented model (Camazine et al. (1990)) that generates the characteristic pattern of honey, pollen and brood which develops on combs in honey bee colonies. We demonstrate that the formation of a band of pollen surrounding the brood area is dependent on the assumed form of the honey and pollen removal terms, and that a significant pollen band arises as the parameter controlling the rate of pollen input passes through a bifurcation value. The persistence of the pollen band after a temporary increase in pollen input can be predicted from the model. We also determine conditions on the parameters which ensure the accumulation of honey in the periphery and demonstrate that, although there is an important qualitative difference between the simplified and complete models, an analysis of the simplified version helps us understand many biological aspects of the more complex complete model. Corresponding author     

Contrasting breeding systems in twoEriotheca (Bombacaceae) species of the Brazilian cerrados

The pollination biology and breeding systems ofEriotheca pubescens andE. gracilipes have been studied. These two species occur as trees in cerrado vegetation, the neotropical savannas of Central Brazil, with partially sympatric distributions. They have similar phenology and floral structure, although the flowers ofE. pubescens are larger. Both species have nectar flowers pollinated by largeAnthophoridae bees but the main pollinators of each species differ in size. The species have markedly different breeding systems: late-acting self-incompatibility inE. gracilipes and apomixis stimulated by pollination inE. pubescens.     

Caste-specific modulation of juvenile hormone III content and ecdysteroid titer in postembryonic development of the stingless bee,Scaptotrigona postica depilis

Summary Juvenile hormone III content and ecdysteroid titer were analyzed for larval and pupal development of the stingless bee,Scaptotrigona postica depilis. Castespecific differences in juvenile hormone III content were detected at three developmental phases: at the transition from the fourth to the fifth larval stadium, in the spinning phase of the fifth larval stadium, and shortly after the imaginal moult. During the fifth larval stadium, juvenile hormone content closely reflects corpora allata activity. Juvenile hormone synthesis may thus be responsible for the elevated hormone titer in spinning-phase queen larvae, a phase of known sensitivity for induction of queen characters by exogenous juvenile hormone. For ecdysteroids, two phases of caste-specific differences were found: in the pre-pupal phase, and shortly after the imaginal moult. In both periods the titer in queens is distinctly higher compared to workers.Abbreviations Im imago 1 day after eclosion - L3, L4, L5 larval instars 3, 4, and 5 - L5F1, L5F2 substages of feeding phase in fifth larval instar - L5S1, L5S2, L5S3 substages of spinning phase in fifth larval instar - PP1, PP2 substages of prepupal phase - Pw white eyed pupa - Pp pink eyed pupa - Pr red eyed pupa - Pd dark eyed pupa - Pdl, Pdm, Pdd dark eyed pupa with progressive tanning of cuticle - RIA radioimmunoassay     

Ontogenetic patterns of volatiles identified in Dufour's gland extracts from queens and workers of the primitively eusocial halictine bee,Lasioglossum malachmum (Hymenoptera: Halictidae)

Summary Ontogenetic patterns of volatile compounds identified in Dufour's gland extracts from queens and workers of the primitively eusocial sweat beeLasioglossum malachurum (K.) were compared. Only young unmated queens showed high proportions of isopentenyl esters, while macrocyclic lactones were dominant in old breeding queens, spring queens, and workers. In young queens the relative and absolute amounts of volatiles changed one day after mating. A discriminant analysis revealed significant differences in odor patterns of unmated and mated young queens. The fat body was the largest in young females, while eggs could be recorded only in breeding queens. Possible functions of different odor components in the investigated female groups are discussed.     

Review on the sublethal effects of pure and formulated glyphosate on bees: Emphasis on social bees

Bees are declining worldwide, and the use of pesticides has been linked to this problem. Studies show that even herbicides can negatively impact bees, causing death or compromising health. As a result, concern about the use of glyphosate (GLY) has increased, as it is the most sold pesticide. Studies have shown that exposure of bees to GLY can trigger sublethal effects. Considering the speed with which information is published, reviews become important for the integration of knowledge, aiding understanding of the topic. Therefore, the present study aimed to review the literature on the sublethal effects of GLY and the different commercial formulations on bees. After the literary review, it was observed that the exposition, acute and chronic, of larvae and adults of social and solitary bees, to GLY and its formulations, can trigger alterations in gene expression, enzyme functioning, oxidative metabolism, cell/tissue structure, intestinal microbiota diversity, learning, food consumption, flight and vertical displacement capacity, circadian cycle and body development of these insects. The most used species in the studies was Apis mellifera L. Studies are still necessary to understand the sublethal effects of GLY on bees, in the medium and long term, on colony homeostasis, especially about the information on the toxicity of some surfactants present in the different commercial formulations.     

Quality Assessment of Bee Pollen-Honey Mixtures Using Thin-Layer Chromatography in Combination with Chemometrics

The aim of this study is to develop a rapid, effect-directed screening method for quality assessment of bee pollen-honey mixtures. The comparative antioxidant potential and phenolic content of honey, bee pollen, and the bee pollen-honey mixtures, was performed using spectrophotometry. The total phenolic content and antioxidative activity of bee pollen-honey mixtures with 20 % bee pollen share were in the range 3.03–3.11 mg GAE/g, and 6.02–6.96 mmol TE/kg, respectively, while mixtures with 30 % bee pollen share contained 3.92–4.18 mg GAE/g, and 9.69–10.11 mmol TE/kg. Chromatographic fingerprint of bee pollen-honey mixtures was performed by high-performance thin-layer chromatography with conditions developed by authors and reported for the first time. Fingerprint analysis hyphenated with chemometrics enabled authenticity assessments of honey in mixtures. Results indicate that bee pollen-honey mixtures represent a food with highly, both, nutritious characteristics and health-promoting effect.     

Number of adult female mites Varroa jacobsoni Oud. on hive debris from honey bee colonies artificially infested to monitor mite population increase (Mesostigmata: Varroidae)

Six honey bee colonies hived in Langstroth nuclei were each artificially infested with 100 phoretic Varroa mites. Hive debris on bottom inserts was inspected every 3–4 days. The adult Varroa mites were compared with mounted specimens and catalogued into lightly pigmented and darkly pigmented females. After 4 months, an acaricide treatment was used to estimate the final mite population. Based on light and dark adult counts, we propose a balancing equation that follows the Varroa population increase at 7 day intervals and allows the calculation of experimental population growth rates. The calculated Varroa finite rate of increase is =1.021. Exponential and logistic growth models fitted to the balancing equation data gave R ²=0.986 and R ²=0.991, respectively. To develop a more precise model it would be necessary to follow the population growth beyond our experimental data.