Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Biomedicines ; 11(10)2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37893241

RESUMO

Endometriosis, which is the presence of endometrial stroma and glands outside the uterus, is one of the most frequently diagnosed gynecologic diseases in reproductive women. Patients with endometriosis suffer from various pain symptoms such as dysmenorrhea, dyspareunia, and chronic pelvic pain. The pathophysiology for chronic pain in patients with endometriosis has not been fully understood. Altered inflammatory responses have been shown to contribute to pain symptoms. Increased secretion of cytokines, angiogenic factors, and nerve growth factors has been suggested to increase pain. Also, altered distribution of nerve fibers may also contribute to chronic pain. Aside from local contributing factors, sensitization of the nervous system is also important in understanding persistent pain in endometriosis. Peripheral sensitization as well as central sensitization have been identified in patients with endometriosis. These sensitizations of the nervous system can also explain increased incidence of comorbidities related to pain such as irritable bowel disease, bladder pain syndrome, and vulvodynia in patients with endometriosis. In conclusion, there are various possible mechanisms behind pain in patients with endometriosis, and understanding these mechanisms can help clinicians understand the nature of the pain symptoms and decide on treatments for endometriosis-related pain symptoms.

2.
Clin Nucl Med ; 48(12): 1105-1106, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37883212

RESUMO

ABSTRACT: Calcification and formation of calculi in the genitourinary system such as the bladder, kidney, and prostate are common processes of aging. Despite being in different parts of the body, these calculi can share risk factors; for instance, bladder and prostate calculi are seen in older men with benign prostatic hyperplasia. There have been increasing reports of detection of calculi using PET tracers such as 18 F-NaF and 18 F-FDG, suggesting their role for detection of extraosseous calcification. In this report, we present simultaneous detection of bladder and prostate calculi with both 18 F-NaF and 18 F-FDG avidity in a 74-year-old man with multiple myeloma.


Assuntos
Calcinose , Cálculos , Doenças Prostáticas , Masculino , Humanos , Idoso , Fluordesoxiglucose F18 , Bexiga Urinária , Tomografia por Emissão de Pósitrons , Próstata , Fluoreto de Sódio
3.
Ecol Appl ; 33(8): e2917, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37661589

RESUMO

Assessing the relative contributions of different pollinator taxa to pollination services is a central task in both basic eco-evolutionary research and applied conservation and agriculture. To that end, many studies have quantified single-visit pollen deposition and visitation frequency, which together determine a pollinator species' rate of conspecific pollen delivery. However, for plant species that require or benefit from outcrossing, pollination service quality further depends upon the ratio of outcross to self-pollen deposited, which is determined by two additional pollinator traits: pollen carryover and movement patterns among genetically compatible plant individuals. Here, we compare the pollination capacities of managed honey bees, native bumble bees, and native mining bees in apple-a varietally self-incompatible commercial crop-when pollen carryover and pollinator movement patterns are considered. We constructed simulation models of outcross pollen deposition parameterized using empirically measured single-visit pollen deposition, visitation frequency, and probabilities of intertree movement exhibited by each pollinator type, as well as pollen carryover patterns simulated based on parameters reported in the literature. In these models, we also explicitly specified the spatial relationships among cross-compatible trees based on field-realistic orchard layout schemes. We found that estimated pollination service delivery was considerably reduced for all pollinator types when pollen carryover and pollinator movement patterns were considered, as compared to when only single-visit pollen deposition and visitation frequency were considered. We also found that the performance of different pollinator types varied greatly across simulated orchard layout schemes and pollen carryover scenarios, including one instance where bumble and mining bees reversed their relative rankings. In all simulations, native bumble and mining bees outperformed managed honey bees in terms of both outcross pollen delivery per unit time and per flower visited, with disparities being greatest under scenarios of low pollen carryover. We demonstrate the degree to which pollination studies may reach inaccurate conclusions regarding pollination service delivery when pollen carryover and pollinator movement patterns are ignored. Our finding of the strong context dependence of pollination efficiency, even within a single plant-pollinator taxon pair, cautions that future studies in both basic and applied pollination biology should explicitly consider the ecological context in which pollination interactions take place.


Assuntos
Malus , Polinização , Humanos , Abelhas , Animais , Pólen , Plantas , Flores
4.
Am J Nucl Med Mol Imaging ; 13(4): 136-146, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37736491

RESUMO

OBJECTIVE: The glenohumeral (GH) joint is a classic ball-and-socket joint of the shoulder subject to various pathologies including osteoarthritis (OA). Degenerative changes of the OA evident on traditional imaging are proceeded by molecular changes, which if detected early could enhance disease prevention and treatment. In this study, we use 18F-FluoroDeoxyGlucose (FDG) and 18F-sodium-fluoride (NaF)-PET/CT to investigate the effects limb laterality, age, and BMI on the inflammation and bone turnover of the GH shoulder joint. METHODS: FDG and NaF-PET/CT scans of 41 females (mean age of 43.9 ± 14.2 years) and 45 males (mean age of 44.5 ± 13.8 years) were analyzed with a semi-quantitative technique based on predefined region of interest. RESULTS: There was greater FDG uptake in the left side of the GH joint compared to the right in both females (left: 0.79 ± 0.17, right: 0.71 ± 0.2; P < 0.0001) and males (left: 0.76 ± 0.19, right: 0.57 ± 0.18; P < 0.0001). We also observed a strong positive association between BMI and FDG uptakes in females (left: P < 0.0001, r = 0.71, right: P < 0.0001, r = 0.58) and males (left: P < 0.0001, r = 0.56, right: P < 0.0001, r = 0.64). Association between BMI and NaF uptake were found in males as well (left: P = 0.004, r = 0.42, right: P = 0.02, r = 0.35). CONCLUSION: Our study demonstrates the varying effect of limb laterality and BMI on FDG and NaF uptake at the GH joint. Adoption of molecular imaging will require future studies that correlate tracer uptake with relevant medical and illness history as well as degenerative change evident on traditional imaging.

5.
Medicine (Baltimore) ; 101(31): e29726, 2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-35945797

RESUMO

To evaluate the efficacy and safety of a gonadotropin-releasing hormone (GnRH) agonist for treating large-sized submucosal leiomyoma before hysteroscopic myomectomy. The data were retrospectively collected from patients who underwent a hysteroscopic myomectomy for a submucosal leiomyoma >3.5 cm in size from January 2009 to December 2018. The patients were divided into the GnRH group and the control group according to whether they were pretreated before surgery. A total of 61 patients were included in the study, 31 in the GnRH agonist group and 30 in the control group. At diagnosis, the maximum leiomyoma diameter was similar between the 2 groups (4.67 ± 0.6 cm in the GnRH agonist group vs 3.82 ± 0.6 cm in the control group, P = .061). After pretreatment with the GnRH agonist, the maximum diameter was significantly smaller in the GnRH agonist group compared to the control group (3.82 ± 0.6 vs 4.33 ± 0.8 cm, respectively, P = .004). The leiomyoma volume in the GnRH agonist group decreased by 55.6%, from 41.68 ± 15.7 to 23.19 ± 10.4 cm3, which led to significant differences in leiomyoma volume between the 2 groups (23.19 ± 10.4 cm3 in the GnRH agonist group vs 33.22 ± 24.7 cm3 in the control group, P = .042). The GnRH agonist group showed a shorter operation time (37.7 vs 43.9 minutes, P = .040) and less uterine distention media was used (6800 vs 9373.3 mL, P = .037) compared to the control group. Postoperative complications such as estimated blood loss, remnant leiomyoma, and recurrence were similar between the 2 groups. Treatment with a GnRH agonist before hysteroscopic myomectomy for large submucosal leiomyoma might decrease the volume of the leiomyoma, reduce operation time, and the amount of uterine-distension media used without surgical complications.


Assuntos
Leiomioma , Miomectomia Uterina , Neoplasias Uterinas , Feminino , Hormônio Liberador de Gonadotropina , Humanos , Leiomioma/tratamento farmacológico , Leiomioma/cirurgia , Estudos Retrospectivos , Neoplasias Uterinas/tratamento farmacológico , Neoplasias Uterinas/cirurgia
6.
Environ Entomol ; 51(5): 958-968, 2022 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-35964238

RESUMO

Megachile rotundata (F.) is an important pollinator of alfalfa in the United States. Enhancing landscapes with wildflowers is a primary strategy for conserving pollinators and may improve the sustainability of M. rotundata. Changing cold storage temperatures from a traditionally static thermal regime (STR) to a fluctuating thermal regime (FTR) improves overwintering success and extends M. rotundata's shelf life and pollination window. Whether floral resources enhance overwintering survival and/or interact with a thermal regime are unknown. We tested the combined effects of enhancing alfalfa fields with wildflowers and thermal regime on survival and macronutrient stores under extended cold storage (i.e., beyond one season). Megachile rotundata adults were released in alfalfa plots with and without wildflower strips. Completed nests were harvested in September and stored in STR. After a year, cells were randomly assigned to remain in STR for 6 months or in FTR for a year of extended cold storage; emergence rates were observed monthly. Macronutrient levels of emerged females were assessed. FTR improved M. rotundata survival but there was no measurable effect of wildflower strips on overwintering success or nutrient stores. Timing of nest establishment emerged as a key factor: offspring produced late in the season had lower winter survival and dry body mass. Sugars and glycogen stores increased under FTR but not STR. Trehalose levels were similar across treatments. Total lipid stores depleted faster under FTR. While wildflowers did not improve M. rotundata survival, our findings provide mechanistic insight into benefits and potential costs of FTR for this important pollinator.


Assuntos
Himenópteros , Feminino , Abelhas , Animais , Temperatura , Medicago sativa , Trealose , Nutrientes , Glicogênio , Lipídeos
7.
BMC Pregnancy Childbirth ; 22(1): 113, 2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-35144573

RESUMO

BACKGROUND: In twin pregnancies, the cord prolapse of either fetus during the pre-viable period leads to fetal death but can also cause an intrauterine infection, leading to death or prematu-re birth of the remaining fetus. However, there are no validated protocols to prolong the gestational period or decrease the morbidity and mortality of the remaining fetus. CASE PRESENTATION: The present cases were PPROM and cord prolapse very early during the second trimester (around 17 weeks in the first case and 19 weeks in the second case). The first fetus was evacuated, and cervical cerclage was performed at 23 and 20 weeks in the two cases, respectively. After maintaining the pregnancy, the second baby was born around 27 and 39 weeks in the first and second cases, respectively. The delivery interval between the first and second fetuses was 46 days in the first case and 126 days in the second case. CONCLUSION: If cord prolapse is identified at a pre-viable time in twin fetuses, evacuation and cerclage should be performed as soon as possible after the cord prolapse to reduce intrauterine infection and increase the survival chances of the remaining fetus.


Assuntos
Cerclagem Cervical/métodos , Parto Obstétrico/métodos , Ruptura Prematura de Membranas Fetais/cirurgia , Segundo Trimestre da Gravidez , Gravidez de Gêmeos , Cordão Umbilical/cirurgia , Adulto , Feminino , Humanos , Nascido Vivo , Gravidez , Resultado da Gravidez , Prolapso
8.
Ecol Appl ; 31(8): e02445, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34448315

RESUMO

Pollinators face multiple pressures and there is evidence of populations in decline. As demand for insect-pollinated crops increases, crop production is threatened by shortfalls in pollination services. Understanding the extent of current yield deficits due to pollination and identifying opportunities to protect or improve crop yield and quality through pollination management is therefore of international importance. To explore the extent of "pollination deficits," where maximum yield is not being achieved due to insufficient pollination, we used an extensive dataset on a globally important crop, apples. We quantified how these deficits vary between orchards and countries and we compared "pollinator dependence" across different apple varieties. We found evidence of pollination deficits and, in some cases, risks of overpollination were even apparent for which fruit quality could be reduced by too much pollination. In almost all regions studied we found some orchards performing significantly better than others in terms of avoiding a pollination deficit and crop yield shortfalls due to suboptimal pollination. This represents an opportunity to improve production through better pollinator and crop management. Our findings also demonstrated that pollinator dependence varies considerably between apple varieties in terms of fruit number and fruit quality. We propose that assessments of pollination service and deficits in crops can be used to quantify supply and demand for pollinators and help to target local management to address deficits although crop variety has a strong influence on the role of pollinators.


Assuntos
Malus , Polinização , Animais , Abelhas , Produtos Agrícolas , Frutas , Insetos
9.
Proc Biol Sci ; 288(1947): 20210212, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33726596

RESUMO

While an increasing number of studies indicate that the range, diversity and abundance of many wild pollinators has declined, the global area of pollinator-dependent crops has significantly increased over the last few decades. Crop pollination studies to date have mainly focused on either identifying different guilds pollinating various crops, or on factors driving spatial changes and turnover observed in these communities. The mechanisms driving temporal stability for ecosystem functioning and services, however, remain poorly understood. Our study quantifies temporal variability observed in crop pollinators in 21 different crops across multiple years at a global scale. Using data from 43 studies from six continents, we show that (i) higher pollinator diversity confers greater inter-annual stability in pollinator communities, (ii) temporal variation observed in pollinator abundance is primarily driven by the three-most dominant species, and (iii) crops in tropical regions demonstrate higher inter-annual variability in pollinator species richness than crops in temperate regions. We highlight the importance of recognizing wild pollinator diversity in agricultural landscapes to stabilize pollinator persistence across years to protect both biodiversity and crop pollination services. Short-term agricultural management practices aimed at dominant species for stabilizing pollination services need to be considered alongside longer term conservation goals focussed on maintaining and facilitating biodiversity to confer ecological stability.


Assuntos
Ecossistema , Polinização , Agricultura , Animais , Abelhas , Biodiversidade , Produtos Agrícolas , Insetos
10.
Obstet Gynecol Sci ; 63(6): 700-708, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32814372

RESUMO

OBJECTIVE: This study identified the distribution of lymphocele, as well as the factors associated with lymphocele formation, in patients undergoing pelvic and/or para-aortic lymph node dissection (PLND and/or PALND) for gynecologic malignancies. METHODS: This study was retrospective, and data were collected from patients who underwent surgical procedures including lymphadenectomy due to gynecologic malignancies from March 2013 to May 2016. Lymphocele was defined by postoperative computer tomography within 2 weeks after surgery. RESULTS: A total of 116 patients underwent lymphadenectomy, of whom, 47 (42.0%) developed lymphocele and 14 (12.1%) had symptomatic lymphocele formation. The affecting factors of lymphocele formation were PLND concomitant with PALND and a large amount of blood loss ≥600 mL (P=0.030 and P=0.006, respectively). All clinical factors were not significantly different between patients with symptomatic and asymptomatic lymphocele. Lymphocele developed more frequently in the left side (67.1%) of the body compared to the right side (48.7%), and in the pelvic area (75.9%) compared to the para-aortic area (24.1%, P<0.001, both). CONCLUSION: Lymphocele formation is more prevalent in the left and pelvic area of the body compared to the right and paraaortic side. PLND concurrent with PALND and large amounts of blood loss were significant risk factors for lymphocele formation.

11.
PLoS One ; 15(1): e0227918, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31971987

RESUMO

Bees play a key role in the functioning of human-modified and natural ecosystems by pollinating agricultural crops and wild plant communities. Global pollinator conservation efforts need large-scale and long-term monitoring to detect changes in species' demographic patterns and shifts in bee community structure. The objective of this project was to test a molecular sequencing pipeline that would utilize a commonly used locus, produce accurate and precise identifications consistent with morphological identifications, and generate data that are both qualitative and quantitative. We applied this amplicon sequencing pipeline to native bee communities sampled across Conservation Reserve Program (CRP) lands and native grasslands in eastern North Dakota. We found the 28S LSU locus to be more capable of discriminating between species than the 18S SSU rRNA locus, and in some cases even resolved instances of cryptic species or morphologically ambiguous species complexes. Overall, we found the amplicon sequencing method to be a qualitatively accurate representation of the sampled bee community richness and species identity, especially when a well-curated database of known 28S LSU sequences is available. Both morphological identification and molecular sequencing revealed similar patterns in native bee community structure across CRP lands and native prairie. Additionally, a genetic algorithm approach to compute taxon-specific correction factors using a small subset of the most concordant samples demonstrated that a high level of quantitative accuracy could be possible if the specimens are fresh and processed soon after collection. Here we provide a first step to a molecular pipeline for identifying insect pollinator communities. This tool should prove useful for future national monitoring efforts as use of molecular tools becomes more affordable and as numbers of 28S LSU sequences for pollinator species increase in publicly-available databases.


Assuntos
Abelhas/genética , Conservação dos Recursos Naturais , Ecossistema , Pradaria , Animais , Abelhas/fisiologia , Biodiversidade , Produtos Agrícolas , Humanos , Polinização/genética , Análise de Sequência de DNA
12.
Science ; 363(6424): 282-284, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30655441

RESUMO

Land-use change threatens global biodiversity and may reshape the tree of life by favoring some lineages over others. Whether phylogenetic diversity loss compromises ecosystem service delivery remains unknown. We address this knowledge gap using extensive genomic, community, and crop datasets to examine relationships among land use, pollinator phylogenetic structure, and crop production. Pollinator communities in highly agricultural landscapes contain 230 million fewer years of evolutionary history; this loss was strongly associated with reduced crop yield and quality. Our study links landscape-mediated changes in the phylogenetic structure of natural communities to the disruption of ecosystem services. Measuring conservation success by species counts alone may fail to protect ecosystem functions and the full diversity of life from which they are derived.


Assuntos
Abelhas/classificação , Produção Agrícola , Filogenia , Polinização , Agricultura , Animais , Biodiversidade , Malus , New York
13.
Eur J Obstet Gynecol Reprod Biol ; 231: 85-92, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30336309

RESUMO

OBJECTIVE: To compare the efficacy of levonorgestrel releasing intrauterine system (LNG-IUS) with other treatments as a postoperative maintenance therapy for endometriosis in terms of pain reduction, recurrence prevention, side effects and patients' satisfaction. STUDY DESIGN: We searched MEDLINE, EMBASE, and the Cochrane Library from January 1986 until February 2018. Two evaluators independently extracted and reviewed prospective and retrospective articles based on pre-determined selection criteria. Outcomes were expressed as mean difference (MD), risk ratios (RR) or odds ratios (OR) in a meta-analysis model, using Revman software. RESULTS: Among the 962 studies, 7 studies were selected: 7 studies included 4 randomized controlled trials with 212 patients, 1 prospective cohort study with 88 patients, and 2 retrospective studies with 191 patients. A meta-analysis showed that LNG-IUS was significantly effective in reducing pain after surgery (MD = 12.97, 95% confidence interval (CI): 5.55-20.39), with a comparable effect to gonadotropin-releasing hormone analogues (MD = -0.16, 95% CI: -2.02 to 1.70). LNG-IUS was also effective in decreasing the recurrence rate (RR = 0.40, 95% CI: 0.26-0.64), with an effect comparable to OC (OR = 1.00, 95% CI: 0.25-4.02) and danazol (RR = 0.30, 95% CI: 0.03-2.81). Furthermore, patients' satisfaction with LNG-IUS was significantly higher than that with OC (OR = 8.60, 95% CI: 1.03-71.86). However, vaginal bleeding was significantly higher in the LNG-IUS group than in the gonadotropin-releasing hormone analogue group (RR = 27.0, 95% CI: 1.71-425.36). CONCLUSION: Our meta-analysis found a positive effect of LNG-IUS as a postoperative maintenance therapy for endometriosis on pain relief, prevention of dysmenorrhea recurrence, and patients' satisfaction.


Assuntos
Endometriose/tratamento farmacológico , Endometriose/cirurgia , Dispositivos Intrauterinos Medicados , Levanogestrel/administração & dosagem , Cuidados Pós-Operatórios , Dismenorreia/prevenção & controle , Endometriose/terapia , Feminino , Humanos , MEDLINE , Manejo da Dor , Satisfação do Paciente , Estudos Prospectivos , Ensaios Clínicos Controlados Aleatórios como Assunto , Recidiva , Estudos Retrospectivos , Prevenção Secundária , Hemorragia Uterina
14.
Glob Chang Biol ; 23(11): 4946-4957, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28488295

RESUMO

Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in-field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes.


Assuntos
Agricultura/métodos , Artrópodes , Biodiversidade , Ecossistema , Animais
16.
Ecol Evol ; 5(17): 3531-40, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26380684

RESUMO

Bees are important pollinators of agricultural crops, and bee diversity has been shown to be closely associated with pollination, a valuable ecosystem service. Higher functional diversity and species richness of bees have been shown to lead to higher crop yield. Bees simultaneously represent a mega-diverse taxon that is extremely challenging to sample thoroughly and an important group to understand because of pollination services. We sampled bees visiting apple blossoms in 28 orchards over 6 years. We used species rarefaction analyses to test for the completeness of sampling and the relationship between species richness and sampling effort, orchard size, and percent agriculture in the surrounding landscape. We performed more than 190 h of sampling, collecting 11,219 specimens representing 104 species. Despite the sampling intensity, we captured <75% of expected species richness at more than half of the sites. For most of these, the variation in bee community composition between years was greater than among sites. Species richness was influenced by percent agriculture, orchard size, and sampling effort, but we found no factors explaining the difference between observed and expected species richness. Competition between honeybees and wild bees did not appear to be a factor, as we found no correlation between honeybee and wild bee abundance. Our study shows that the pollinator fauna of agroecosystems can be diverse and challenging to thoroughly sample. We demonstrate that there is high temporal variation in community composition and that sites vary widely in the sampling effort required to fully describe their diversity. In order to maximize pollination services provided by wild bee species, we must first accurately estimate species richness. For researchers interested in providing this estimate, we recommend multiyear studies and rarefaction analyses to quantify the gap between observed and expected species richness.

17.
Nat Commun ; 6: 7414, 2015 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-26079893

RESUMO

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.


Assuntos
Abelhas , Biodiversidade , Conservação dos Recursos Naturais , Produtos Agrícolas , Polinização , Animais , Produtos Agrícolas/economia
18.
Proc Biol Sci ; 282(1809): 20150299, 2015 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-26041355

RESUMO

Wild bee communities provide underappreciated but critical agricultural pollination services. Given predicted global shortages in pollination services, managing agroecosystems to support thriving wild bee communities is, therefore, central to ensuring sustainable food production. Benefits of natural (including semi-natural) habitat for wild bee abundance and diversity on farms are well documented. By contrast, few studies have examined toxicity of pesticides on wild bees, let alone effects of farm-level pesticide exposure on entire bee communities. Whether beneficial natural areas could mediate effects of harmful pesticides on wild bees is also unknown. Here, we assess the effect of conventional pesticide use on the wild bee community visiting apple (Malus domestica) within a gradient of percentage natural area in the landscape. Wild bee community abundance and species richness decreased linearly with increasing pesticide use in orchards one year after application; however, pesticide effects on wild bees were buffered by increasing proportion of natural habitat in the surrounding landscape. A significant contribution of fungicides to observed pesticide effects suggests deleterious properties of a class of pesticides that was, until recently, considered benign to bees. Our results demonstrate extended benefits of natural areas for wild pollinators and highlight the importance of considering the landscape context when weighing up the costs of pest management on crop pollination services.


Assuntos
Abelhas/efeitos dos fármacos , Biota/efeitos dos fármacos , Inseticidas/toxicidade , Polinização/efeitos dos fármacos , Agricultura , Animais , Malus/crescimento & desenvolvimento , New York
19.
Ecol Lett ; 16(11): 1331-8, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23968538

RESUMO

Climate change has the potential to alter the phenological synchrony between interacting mutualists, such as plants and their pollinators. However, high levels of biodiversity might buffer the negative effects of species-specific phenological shifts and maintain synchrony at the community level, as predicted by the biodiversity insurance hypothesis. Here, we explore how biodiversity might enhance and stabilise phenological synchrony between a valuable crop, apple and its native pollinators. We combine 46 years of data on apple flowering phenology with historical records of bee pollinators over the same period. When the key apple pollinators are considered altogether, we found extensive synchrony between bee activity and apple peak bloom due to complementarity among bee species' activity periods, and also a stable trend over time due to differential responses to warming climate among bee species. A simulation model confirms that high biodiversity levels can ensure plant-pollinator phenological synchrony and thus pollination function.


Assuntos
Abelhas/fisiologia , Biodiversidade , Malus/fisiologia , Polinização/fisiologia , Animais , Mudança Climática , Estudos Retrospectivos , Especificidade da Espécie
20.
Ecol Lett ; 16(5): 584-99, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23489285

RESUMO

Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch connectivity and habitat aggregation) and farm management (organic vs. conventional and local-scale field diversity), and their interactions, on wild bee abundance and richness for 39 crop systems globally. Bee abundance and richness were higher in diversified and organic fields and in landscapes comprising more high-quality habitats; bee richness on conventional fields with low diversity benefited most from high-quality surrounding land cover. Landscape configuration effects were weak. Bee responses varied slightly by biome. Our synthesis reveals that pollinator persistence will depend on both the maintenance of high-quality habitats around farms and on local management practices that may offset impacts of intensive monoculture agriculture.


Assuntos
Agricultura , Abelhas/fisiologia , Ecossistema , Modelos Teóricos , Polinização , Animais , Clima , Produtos Agrícolas , Flores , Densidade Demográfica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...