Neutral Sterols of Cephalic Glands of Stingless Bees and Their Correlation with Sterols from Pollen

Sterols are essential molecules in the membrane lipid composition and precursors of important sterol hormones that regulate many developmental processes. Insects are unable to synthesize sterols de novo and, thus, all phytophagous insects depend on an exogenous source of sterols for growth, development, and reproduction. The sterol requirements of social bees are not fully known due to the fact that there is no well-defined diet available throughout the year with regard to floral resources. Our study aimed to characterize the sterols present in pollen stored in Melipona marginata and Melipona scutellaris colonies, as well as evaluating their presence in the mandibular, hypopharyngeal, and cephalic salivary gland secretions. We analyzed the chemical composition of pollen stored in the colonies and the composition of the cephalic glands of workers in three adult functional phases (newly emerged, nurses, and foragers) by gas chromatography and mass spectrometry. The results showed that the pollen analyzed contained campesterol, stigmasterol, sitosterol, isofucosterol, lanosterol, and small amounts of cholesterol. The glands showed the same compounds found in the pollen analyzed, except lanosterol that was not found in M. scutellaris glands. Surprisingly, cholesterol was found in some glands with relative ratios greater than those found in pollen

Floral Resource Partitioning between Centris (Heterocentris) analis (Fabricius, 1804) and Centris (Heterocentris) terminata Smith, 1874 (Hymenoptera, Apidae, Centridini), in an Urban Fragment of the Atlantic Forest

The knowledge on plant species used for the collection of floral resources is crucial to understanding interactions between plants and bees. The aim of the present study was to identify floral resources used by Centris analis and Centris terminata to provision brood cells and determine the niche breadth and overlap of these two species in a fragment of the Atlantic Forest in Brazil. This study was conducted at the Universidade Federal da Bahia and Parque Zoobotânico Getúlio Vargas, both of which are located in urban areas of the city of Salvador in the state of Bahia. Twelve and eight pollen types were identified in C. analis and C. terminata nests, respectively. The most frequent pollen types were from species of Malpighiaceae and Fabaceae. A larger trophic niche breadth was found in the Parque Zoobotânico Getúlio Vargas for C. analis and in the Universidade Federal da Bahia for C. terminata. Pianka’s index demonstrated trophic niche overlap between C. analis and C. terminata, which was greater in the Parque Zoobotânico Getúlio Vargas. This study is the first to provide data on plants used as food sources by species of the genus Centris in a fragment of the Atlantic Forest situated within urban areas. 

SPACE-TEMPORAL DYNAMICS OF ENDEMIC TREE SPECIES IN SECONDARY FOREST IN THE ATLANTIC FOREST DOMAIN IN BRAZIL

ABSTRACT Understanding the dynamics of endemic tree component species based on natural regeneration (NR) and adult trees (AT) is essential for formulating conservation strategies for protecting these species. The objective of the present study was to identify endemic species in a preserved area of secondary forest in the Atlantic Forest domain in Brazil and to evaluate their dynamics over 24 years. Based on inventories carried out from 1992 to 2016 of the NR (diameter at breast height - dbh ≤ 5 cm) and of the AT (dbh ≥ 5 cm) in ten sites with different characteristics (physiographic, edaphic, and successional), it was possible to, initially, identify 58 species classified as endemic to Brazil (EBR) and/or those exclusive to the Brazilian Atlantic Forest (EAF), among the 226 species in the entire survey. Subsequently, this classification was reassessed based on updated information on its occurrence, and only 38 of these species were maintained as endemic to Brazil and/or to the Atlantic Forest. Some species were recorded in the AT and NR strata, in different sites, throughout the study period, while others occurred in only one level (AT or NR), some with low abundance. Among these endemic species, eight are included in the endangered species lists, and 15 can be classified as rare, as there was only one individual in the survey. Considering the two arboreal strata it was observed that some species were abundant in the forest in all inventories and several sites, while others went throughout the study period with few individuals and, in some cases, disappeared due to mortality. These results contribute to understanding the factors that can affect the local abundance of endemic species over time, allowing the definition of conservation actions for protecting these vulnerable species, thus avoiding their extinction

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Cuticular Hydrocarbons Discriminate Distinct Colonies of Melipona marginata (Hymenoptera, Apinae, Meliponini)

The aim of the present study was to characterize the variation of the chemical profiles among workers in different colonies of the stingless bee Melipona marginata. We used gas chromatography and mass spectrometry (CG-MS) and multivariate analysis of the bees’ chemical from three colonies of two localities in southeast Brazil. The results showed that cuticular hydrocarbon profiles clearly separated distinct colonies. We show here the importance of using the chemical analyses for characterization of colony membership, in addition of the traditional techniques of diversity analyses

Cuticular Hydrocarbons Discriminate Distinct Colonies of Melipona marginata (Hymenoptera, Apinae, Meliponini)

The aim of the present study was to characterize the variation of the chemical profiles among workers in different colonies of the stingless bee Melipona marginata. We used gas chromatography and mass spectrometry (CG-MS) and multivariate analysis of the bees' chemical from three colonies of two localities in southeast Brazil. The results showed that cuticular hydrocarbon profiles clearly separated distinct colonies. We show here the importance of using the chemical analyses for characterization of colony membership, in addition of the traditional techniques of diversity analyses.CNPq [134833/2006-6]CNPqCAPESCapesFAPESPFapesp [Proc. 04/09479-8

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

Characterization of cuticular hydrocarbons of diploid and haploid males, workers and queens of the stingless bee Melipona quadrifasciata

Males, queens and workers of stingless bees show differences in external morphology, behaviour and roles within a colony. In addition, each individual has a cuticular chemical signature responsible for mutual communication that is essential for maintaining the integrity of the colony. In this paper we characterize the cuticular hydrocarbon composition of newly emerged diploid and haploid males, workers and virgin queens of Melipona quadrifasciata by gas chromatography-mass spectrometry (GC/MS) analysis. This is the first time that the cuticular profile of diploid males in a species of stingless bee has been characterized. We found differences in the cuticular hydrocarbon composition among males, workers and virgin queens, recording both qualitative and quantitative differences among individuals of different phenotypes. However, no compound was found exclusively in diploid males. The cuticular chemical profiles of haploid and diploid males were very similar to those of workers. Moreover, the cuticular lipids of males and workers were significantly different from those of queens. Tricosane, pentacosene-2 and 7-methyl-heptacosane were the compounds responsible for this significant separation. This result correlates with the behavioural and morphological differences among these phenotypes.Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)CNPqCNP