Acute kidney injury after massive attack of Africanised bees

Acute kidney injury (AKI) is a well-documented complication of massive attack by Africanised bees and can be observed 48-72 h after the accident. We report a case of Africanised bees attack followed by severe and lethal AKI. A 56-year-old man was admitted to emergency department after a massive attack of Africanised bees (>1000 bee stings). He was unconscious, presenting with hypotension and tachycardia. Mechanical ventilation, volume expansion and care for anaphylaxis were instituted. The patient was transferred to the intensive care unit (ICU) and after 48 h he developed rhabdomyolysis, oliguria, increased creatinine levels, hyperkalaemia and refractory acidosis. A diagnosis of AKI secondary to rhabdomyolysis and shock was made. The patient was treated with a prolonged course of haemodialysis. However, he progressed to refractory shock and died 5 days after admission.

Pollination of Anemopaegma album (Bignoniaceae) with focus on floral nectar as the mediator of interactions with mutualistic and antagonistic bees

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Techniques for the In Vitro Production of Queens in Stingless Bees (Apidae, Meliponini)

Considering the ecological importance of stingless bees as caretakers and pollinators of a variety of native plants makes it necessary to improve techniques which increase of colonies' number in order to preserve these species and the biodiversity associated with them. Thus, our aim was to develop a methodology of in vitro production of stingless bee queens by offering a large quantity of food to the larvae. Our methodology consisted of determining the amount of larval food needed for the development of the queens, collecting and storing the larval food, and feeding the food to the larvae in acrylic plates. We found that the total average amount of larval food in a worker bee cell of E varia is approximately 26.70 +/- 3.55 mu L. We observed that after the consumption of extra amounts of food (25, 30, 35 and 40 mu L) the larvae differentiate into queens (n = 98). Therefore, the average total volume of food needed for the differentiation of a young larva of F. varia queen is approximately 61.70 +/- 5.00 mu L. In other words; the larvae destined to become queens eat 2.31 times more food than the ones destined to become workers. We used the species Frieseomelitta varia as a model, however the methodology can be reproduced for all species of stingless bees whose mechanism of caste differentiation depends on the amount of food ingested by the larvae. Our results demonstrate the effectiveness of the in vitro technique developed herein, pointing to the possibility of its use as a tool to assist the production of queens on a large scale. This would allow for the artificial splitting of colonies and contribute to conservation efforts in native bees.

Botanical Preferences of Africanized Bees (Apis mellifera) on the Coast and in the Atlantic Forest of Sergipe, Brazil

Pollen analysis in honey can be used as an alternative method to research into flowers visited by bees in an area. This study aimed to indentify the main floral families in honey from apiaries in the Atlantic Forest and Sergipe state coast. Honey samples from these apiaries were studied, as well as plants that grow around them, which can be used as a source of foraging for bees. The palynological technique was used to compare the pollen content of honey samples with the pollen grains from leaves of plants found in the vicinity of the apiaries to assess whether they had been visited by bees. The results of studies in both sites were similar in terms of incompatibility of families found in the apiary vicinity and honey. Thus, it was possible to observe that in honey samples from the coast and in the remaining Atlantic forest, the number of families was greater than the number of families found in the apiary vicinity, which highlights the diversity of plants visited by bees and a possible expansion of the visited area for food search. This diversity suggests an adaptive foraging behavior to plant resources available in the environment, which may facilitate the pollination of these botanical families and consequently improve their genetic quality.

Mixed colonies of two species of congeneric stingless bees (Hymenoptera: Apinae, Meliponini) display environmentally-acquired and endogenously-produced recognition signals

Nestmate recognition is fundamental for the maintenance of social organization in insect nests. It is becoming well recognized that cuticle hydrocarbons mediate the recognition process, although the origin of recognition cues in stingless bees remains poorly explored. The present study investigates the effects of endogenously-produced and environmentally-acquired components in cuticular hydrocarbons in stingless bees. The tests are conducted using colonies of Plebeia droryana Friese and Plebeia remota Holmberg. Recognition tests are performed with four different groups: conspecific nestmates, conspecific non-nestmates, heterospecifics and conspecific, genetically-related individuals that emerge in a heterospecific nest. This last group is produced by introducing brood cells of P. droryana into a P. remota colony, and the resulting adult bees are tested for acceptance 10 days after emergence. For all groups, 15 individuals are sampled for chemical analysis. The results show the acceptance of all conspecific nestmates, and the rejection of almost every conspecific non-nestmate and every heterospecific bee. Genetically-related individuals emerging from heterospecific nests present intermediate rejection (66.7% rejection). Chemical analysis shows that P. droryana individuals emerging in a P. remota nest have small amounts of alkene and diene isomers found in P. remota cuticle that are not found in workers from the natal nest. The data clearly show that the majority of the compounds present in P. droryana cuticle are endogenously produced, although a few unsaturated compounds are acquired from the environment, increasing the chemical differences and, consequently, the rejection percentages.

First record of chemical signals from the queen during the oviposition process in stingless bees

In stingless bees, the cell provisioning and oviposition process consists of several integrated behavioral sequences and several stereotyped queen-worker interactions. This study aims to demonstrate that chemical signals originating from the queen may contribute as cues for the sequence of the oviposition process in Melipona marginata. For this, we analyzed the cell before and after queen laying, and compared them with the cuticular hydrocarbons of the queen's abdomen, using a gas-chromatography and mass spectrometry system.

The Ecological Basis for Biogeographic Classification: an Example in Orchid Bees (Apidae: Euglossini)

Biogeography has been difficult to apply as a methodological approach because organismic biology is incomplete at levels where the process of formulating comparisons and analogies is complex. The study of insect biogeography became necessary because insects possess numerous evolutionary traits and play an important role as pollinators. Among insects, the euglossine bees, or orchid bees, attract interest because the study of their biology allows us to explain important steps in the evolution of social behavior and many other adaptive tradeoffs. We analyzed the distribution of morphological characteristics in Colombian orchid bees from an ecological perspective. The aim of this study was to observe the distribution of these attributes on a regional basis. Data corresponding to Colombian euglossine species were ordered with a correspondence analysis and with subsequent hierarchical clustering. Later, and based on community proprieties, we compared the resulting hierarchical model with the collection localities to seek to identify a biogeographic classification pattern. From this analysis, we derived a model that classifies the territory of Colombia into 11 biogeographic units or natural clusters. Ecological assumptions in concordance with the derived classification levels suggest that species characteristics associated with flight performance, nectar uptake, and social behavior are the factors that served to produce the current geographical structure.

Rapid morphological changes in populations of hybrids between Africanized and European honey bees

African honey bees, introduced to Brazil in 1956, rapidly dominated the previously introduced European subspecies. To better understand how hybridization between these different types of bees proceeded, we made geometric morphometric analyses of the wing venation patterns of specimens resulting from crosses made between Africanized honey bees (predominantly Apis mellifera scutellata) and Italian honey bees (A. mellifera ligustica) from 1965 to 1967, at the beginning of the Africanization process, in an apiary about 150 km from the original introduction site. Two virgin queens reared from an Italian parental were instrumentally inseminated with semen from drones from an Africanized parental. Six F-1 queens from one of these colonies were open mated with Africanized drones. Resultant F-1 drones were backcrossed to 50 Italian and 50 Africanized parental queens. Five backcross workers were collected from each of eight randomly selected colonies of each type of backcross (N = 5 bees x 8 colonies x 2 types of backcrosses). The F-1 progeny (40 workers and 30 drones) was found to be morphologically closer to the Africanized than to the European parental (N = 20 drones and 40 workers, each); Mahalanobis square distances = 21.6 versus 25.8, respectively, for the workers, and 39.9 versus 46.4, respectively, for the drones. The worker progenies of the backcrosses (N = 40, each) were placed between the respective parental and the F-1 progeny, although closer to the Africanized than to the Italian parentals (Mahalanobis square distance = 6.2 versus 12.1, respectively). Consequently, the most common crosses at the beginning of the Africanization process would have generated individuals more similar to Africanized than to Italian bees. This adds a genetic explanation for the rapid changes in the populational morphometric profile in recently colonized areas. Africanized alleles of wing venation pattern genes are apparently dominant and epistatic.

Potential costs of bacterial infection on storage protein gene expression and reproduction in queenless Apis mellifera worker bees on distinct dietary regimes

Insects are able to combat infection by initiating an efficient immune response that involves synthesizing antimicrobial peptides and a range of other defense molecules. These responses may be costly to the organism, resulting in it exploiting endogenous resources to maintain homeostasis or support defense to the detriment of other physiological needs. We used queenless worker bees on distinct dietary regimes that may alter hemolymph protein storage and ovary activation to investigate the physiological costs of infection with Serratia marcescens. The expression of the genes encoding the storage proteins vitellogenin and hexamerin 70a, the vitellogenin receptor, and vasa (which has a putative role in reproduction), was impaired in the infected bees. This impairment was mainly evident in the bees fed beebread, which caused significantly higher expression of these genes than did royal jelly or syrup, and this was confirmed at the vitellogenin and hexamerin 70a protein levels. Beebread was also the only diet that promoted ovary activation in the queenless bees, but this activation was significantly impaired by the infection. The expression of the genes encoding the storage proteins apolipophorins-I and -III and the lipophorin receptor was not altered by infection regardless the diet provided to the bees. Similarly, the storage of apolipophorin-I in the hemolymph was only slightly impaired by the infection, independently of the supplied diet. Taken together these results indicate that, infection demands a physiological cost from the transcription of specific protein storage-related genes and from the reproductive capacity. (C) 2012 Elsevier Ltd. All rights reserved.

A method for harvesting unfermented pollen from stingless bees (Hymenoptera, Apidae, Meliponini)

Pollen traps used for harvesting pollen from Apis mellifera do not work for stingless bees, as most species have small entrances and rapidly deposit large quantities of propolis at any barrier in front of the nest. Some stingless beekeepers harvest pollen by removing it directly from pollen pots, but this pollen is normally fermented and unpalatable. The aim of this study was to test a new method for harvesting pollen from stingless bee colonies before it begins to ferment. Colonies of Scaptotrigona depilis were removed and replaced by empty hives, which were occupied by the returning foragers and used for storing pollen and nectar. After one week, the pollen and honey were harvested directly from the storing pots and weighed. On average, the colonies produced 8.7 g of honey and 54.2 g of unfermented pollen (n = 10). This method is a viable option for harvesting unfermented pollen from stingless bees, especially with species that harvest large amounts of pollen. The unfermented pollen of S. depilis was well received in taste tests, receiving higher scores than fermented pollen, and similar scores to A. mellifera pollen, so could have great commercial possibilities. It is also a good method for studying the foraging of stingless bees because the amount of harvested food can be easily and precisely quantified.

Composition and antioxidant activity of honey from Africanized and stingless bees in Alagoas (Brazil): a multivariate analysis

The purpose of this study was to evaluate the antioxidant activity of honey from different entomological sources which were harvested in the dry season of 2008-2009 from distinct mesoregions of the State of Alagoas in the North East of Brazil. Honey produced by five different species of bees, even from the same region and season, showed a statistically significant difference (p <0.05) in the content of phenols, flavonoids and antioxidants, with higher levels of these compounds found in honey produced by Plebeia spp. and A. mellifera. Honey from stingless bees was quite different from that of A. mellifera, especially from the Plebeia spp. A dendrogram of the five species of bees showed the formation of 3 groups, one being formed by Apis mellifera, one by the genus Melipona (M. subnitida, M. quadrifasciata and M. scutellaris) and another formed by Plebeia spp.

Variation morphogeometrics of Africanized honey bees (Apis mellifera) in Brazil

The morphometrics of the honey bee Apis mellifera L., 1758 has been widely studied mainly because this species has great ecological importance, high adaptation capacity, wide distribution and capacity to effectively adapt to different regions. The current study aimed to investigate the morphometric variations of wings and pollen baskets of honey bees Apis mellifera scutellata Lepeletier, 1836 from the five regions in Brazil. We used geometric morphometrics to identify the existence of patterns of variations of shape and size in Africanized honey bees in Brazil 16 years after the classic study with this species, allowing a temporal and spatial comparative analysis using new technological resources to assess morphometrical data. Samples were collected in 14 locations in Brazil, covering the five geographical regions of the country. The shape analysis and multivariate analyses of the wing allowed to observe that there is a geographical pattern among the population of Apis mellifera in Brazil. The geographical variations may be attributed to the large territorial extension of the country in addition to the differences between the bioregions.

Effects of pesticides on honey bees (Apis mellifera L.): study of a specific route of exposure and evaluation of biochemical-physiological changes in the assessment of the pesticides toxicity

In this study, some important aspects of the relationship between honey bees (Apis mellifera L.) and pesticides have been investigated. In the first part of the research, the effects of the exposure of honey bees to neonicotinoids and fipronil contaminated dusts were analyzed. In fact, considerable amounts of these pesticides, employed for maize seed dressing treatments, may be dispersed during the sowing operations, thus representing a way of intoxication for honey bees. In particular, a specific way of exposure to this pesticides formulation, the indirect contact, was taken into account. To this aim, we conducted different experimentations, in laboratory, in semi-field and in open field conditions in order to assess the effects on mortality, foraging behaviour, colony development and capacity of orientation. The real dispersal of contaminated dusts was previously assessed in specific filed trials. In the second part, the impact of various pesticides (chemical and biological) on honey bee biochemical-physiological changes, was evaluated. Different ways and durations of exposure to the tested products were also employed. Three experimentations were performed, combining Bt spores and deltamethrin, Bt spores and fipronil, difenoconazole and deltamethrin. Several important enzymes (GST, ALP, SOD, CAT, G6PDH, GAPDH) were selected in order to test the pesticides induced variations in their activity. In particular, these enzymes are involved in different pathways of detoxification, oxidative stress defence and energetic metabolism. The results showed a significant effect on mortality of neonicotinoids and fipronil contaminated dusts, both in laboratory and in semi-field trials. However, no effects were evidenced in honey bees orientation capacity. The analysis of different biochemical indicators highlighted some interesting physiological variations that can be linked to the pesticide exposure. We therefore stress the attention on the possibility of using such a methodology as a novel toxicity endpoint in environmental risk assessment.

Sublethal effects of a common neonicotinoid pesticide, thiamethoxam, on honey bees: impact on locomotion and thermoregulation

Neonicotinoids have been pointed to as a factor responsible for the increased honey bee colony losses in the last decades. Many studies have investigated the effects of the first marketed neonicotinoid, imidacloprid, while fewer have focused on thiamethoxam. One recent study showed that sublethal doses of thiamethoxam lead to colony failure by decreasing forager homing flight success. We thus decided to investigate the mechanism which caused this phenomenon. Our hypothesis was that this effect was caused by impairment of forager locomotion abilities. Therefore we tested the effects of sublethal acute and chronic exposures to thiamethoxam on forager walking (Chapter 2) and flight (Chapter 3) performances. The acute treatment (1.34 ng/bee) affected walking locomotion firstly triggering hyperactivity (30 min post-treatment) and then impairing motor functioning (60 min post-treatment). 2-day continuous exposures to thiamethoxam (32.5, 45 ppb) elicited fewer effects on walking locomotion, however both exposure modes elicited an increased positive phototaxis. Similarly, in flight experiments, the single dose (1.34 ng/bee) elicited hyperactivity shortly after intoxication (increased flight duration and distance), while longer and continuous exposures (32.5, 45 ppb) impaired forager motor functions (decreased flight duration, distance, velocity). It is known that flight muscles temperature needs to be precisely regulated by bees during flight. Therefore, we further hypothesized that the impaired flight performances of neonicotinoid intoxicated bees were caused also by thermoregulation anomalies. We tested the effects that acute thiamethoxam exposures (0.2, 1, 2 ng/bee) elicit on forager thorax temperature (Chapter 4). Foragers treated with high doses exhibited hyperthermia or hypothermia when respectively exposed to high or low environmental temperatures. In summary, we show that sublethal doses of thiamethoxam affected forager walking and flight locomotion, phototaxis and thermoregulation. We also display the intricate mode of action of thiamethoxam which triggered, at different extents, inverse sublethal effects in relation to time and dose.