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1.
Zoolog Sci ; 38(2): 122-139, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33812352

RESUMO

We focused on Meloe beetles that have lost all flight ability, and conducted molecular phylogeographic analyses based on their mitochondrial DNA COI and nuclear DNA EF1- α regions. Meloe beetles infiltrate bumblebee nests by attaching to bumblebees as they pollinate flowers and thereafter have a unique and specific life history as they complete their life-cycle within the host nest; flight-based dispersal is achieved by piggybacking on bumblebees. In fact, Meloe beetles, which cannot fly, even inhabit remote islands (i.e., "Oceanic Islands"). Regarding four species, i.e., Meloe coarctatus, Meloe proscarabaeus, Meloe violaceus and Meloe corvinus, the conventional morphological classification system based on morphological characteristics was strongly supported by the molecular markers. On the other hand, for two species, Meloe menoko and Meloe auriculatus, it was found that M. menoko may be evaluated as having a paraphyletic relationship with M. auriculatus. Furthermore, two other cryptic, undescribed species were also discovered in this study. One was collected in the Nikko Highland, and inhabited the area sympatrically with M. coarctatus. The other was collected from Hachijo-jima Island. These cryptic species were highly differentiated, independent lineages in terms of mitochondrial and nuclear gene regions. That is to say, a new level of species diversity was revealed among the Meloe beetle species, known for their unique and strange ecological and ethological characteristics.


Assuntos
Distribuição Animal , Abelhas/parasitologia , Besouros/fisiologia , Voo Animal , Fluxo Gênico , Animais , Besouros/genética , DNA Mitocondrial , Interações Hospedeiro-Parasita , Filogenia , Especificidade da Espécie
2.
Parasitol Res ; 120(2): 715-723, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33452589

RESUMO

Circular RNAs (circRNAs) are a large class of non-protein-coding transcripts that are involved in a diverse spectrum of regulatory mechanisms across a broad range of biological processes. To date, however, few studies on circRNAs have investigated their role in the biology of invertebrate parasites. The ectoparasitic mite Varroa destructor is perceived as the principal biotic threat towards global honey bee health. This parasite cannot be sustainably controlled partially due to the lack of knowledge about its basic molecular biology. In this paper, we unveil the circRNA profile of V. destructor for the first time and report the sources, distribution, and features of the identified circRNAs. Exonic, intronic, exon-intron, and intergenic circRNAs were discovered and exon-intron circRNAs were the most abundant within the largest spliced length. Three hundred and eighty-six (8.3%) circRNAs were predicted to possess translational potential. Eleven circRNAs, derived from six parental genes, exhibited strong bonds with miRNAs as sponges, suggesting an efficient post-transcriptional regulation. GO term and KEGG pathway enrichment analyses of the parental genes of the identified circRNAs showed that these non-coding RNAs were mainly engaged in protein processing, signal transduction, and various metabolism processes. To our knowledge, this is the first catalog of a circRNA profile of parasitiformes species, which reveals the prevalence of circRNAs in the parasite and provides biological insights for future genetic studies on this ubiquitous parasitic mite.


Assuntos
Abelhas/parasitologia , RNA Circular/metabolismo , Varroidae/genética , Animais , Regulação da Expressão Gênica , Interações Hospedeiro-Parasita , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Circular/genética
3.
Sci Rep ; 10(1): 21943, 2020 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-33318550

RESUMO

Formic acid (FA) has been used for decades to control Varroa destructor, one of the most important parasites of the western honey bee, Apis mellifera. The rather unselective molecular mode of action of FA and its possible effects on honeybees have long been a concern of beekeepers, as it has undesirable side effects that affect the health of bee colonies. This study focuses on short-term transcriptomic changes as analysed by RNAseq in both larval and adult honey bees and in mites after FA treatment under applied conditions. Our study aims to identify those genes in honey bees and varroa mites differentially expressed upon a typical FA hive exposure scenario. Five detoxification-related genes were identified with significantly enhanced and one gene with significantly decreased expression under FA exposure. Regulated genes in our test setting included members of various cytochrome P450 subfamilies, a flavin-dependent monooxygenase and a cytosolic 10-formyltetrahydrofolate dehydrogenase (FDH), known to be involved in formate metabolism in mammals. We were able to detect differences in the regulation of detoxification-associated genes between mites and honey bees as well as between the two different developmental stages of the honey bee. Additionally, we detected repressed regulation of Varroa genes involved in cellular respiration, suggesting mitochondrial dysfunction and supporting the current view on the mode of action of FA-inhibition of oxidative phosphorylation. This study shows distinct cellular effects induced by FA on the global transcriptome of both host and parasite in comparison. Our expression data might help to identify possible differences in the affected metabolic pathways and thus make a first contribution to elucidate the mode of detoxification of FA.


Assuntos
Abelhas , Formiatos/farmacologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Varroidae/metabolismo , Animais , Abelhas/metabolismo , Abelhas/parasitologia
4.
Exp Appl Acarol ; 82(2): 171-184, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32990837

RESUMO

The devastating effects of Varroa destructor Anderson and Trueman on Western honeybee colonies (Apis mellifera L.) have been well documented. Not only do these mites cause physical damage to parasitized individuals when they feed on them, but they also transmit viruses and other pathogens, weaken colonies and ultimately may cause their death. Unlike the subspecies of European origin, the honeybees of African origin suffer less from mite infestations. Absconding is one of the factors contributing to low V. destructor population in honeybee colonies as it creates a brood-free period. For a long time, researchers hypothesized that absconding was the main mechanism to control the parasite. The effects of V. destructor are well documented under temperate climatic conditions with a break during winter. Therefore, our study aimed at investigating the impact of V. destructor population growth on colony size, absconding and productivity under natural infestation levels of a tropical/subtropical climate with continuous brood production. We measured several characteristics related to the mite populations, the bee colonies and the resources of the bee colonies for a period of 8 months. The seven colonies that absconded during the study period were not influenced by densities of V. destructor. Absconding of the colonies occurred as a result of low numbers of capped brood. Mite densities were generally low throughout the study period (ranged between 26.9 and 59.8 mites per month) but were positively associated with adult bee densities. The amount of open and capped brood was positively associated with densities of V. destructor in the brood and negatively associated with denisities of V. destructor on screen boards, which appeared as extremely important factors that should be monitored regularly alongside colony stores and availability of pollen.


Assuntos
Abelhas/parasitologia , Infestações por Ácaros/veterinária , Varroidae , Animais , Quênia , Densidade Demográfica , Estações do Ano , Clima Tropical
5.
Parasitol Res ; 119(11): 3595-3601, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32935162

RESUMO

Varroosis is the disease caused by the ectoparasitic mite Varroa destructor, one of the most destructive diseases of honeybees. In Spain, there is great concern because there are many therapeutic failures after acaricide treatments intended to control varroosis outbreaks. In some of these cases it is not clear whether such failures are due to the evolution of resistance. Therefore, it is of high interest the development of methodologies to test the level of resistance in mite populations. In this work, a simple bioassay methodology was used to test whether some reports on low efficacy in different regions of Spain were in fact related to reduced Varroa sensitivity to the most used acaricides. This bioassay proved to be very effective in evaluating the presence of mites that survive after being exposed to acaricides. In the samples tested, the mortality caused by coumaphos ranged from 2 to 89%; for tau-fluvalinate, it ranged from 5 to 96%. On the other hand, amitraz caused 100% mortality in all cases. These results suggest the presence of Varroa resistant to coumaphos and fluvalinate in most of the apiaries sampled, even in those where these active ingredients were not used in the last years. The bioassay technique presented here, either alone or in combination with other molecular tools, could be useful in detecting mite populations with different sensitivity to acaricides, which is of vital interest in selecting the best management and/or acaricide strategy to control the parasite in apiaries.


Assuntos
Acaricidas/farmacologia , Resistência a Inseticidas , Varroidae/efeitos dos fármacos , Animais , Abelhas/parasitologia , Bioensaio , Cumafos/farmacologia , Feminino , Infestações por Ácaros , Nitrilos/farmacologia , Piretrinas/farmacologia , Espanha , Toluidinas/farmacologia
6.
Exp Appl Acarol ; 82(1): 1-16, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32809187

RESUMO

Varroa destructor is one of the greatest threats for the European honeybee, Apis mellifera. Acaricides are required to control mite infestation. Three conventional chemical acaricide substances are used in France: tau-fluvalinate, flumethrin and amitraz. Tau-fluvalinate was used for over 10 years before experiencing a loss of effectiveness. In 1995, bioassay trials showed the first mite resistance to tau-fluvalinate. In some countries, amitraz was widely used, also leading to resistance of V. destructor to amitraz. In France, some efficiency field tests showed a loss of treatment effectiveness with amitraz. We adapted the bioassay from Maggi and collaborators to determine mite susceptibility to tau-fluvalinate and amitraz in France in 2018 and 2019. The lethal concentration (LC) which kills 90% of susceptible mite strains (LC90) is 0.4 and 12 µg/mL for amitraz and tau-fluvalinate, respectively. These concentrations were chosen as the determining factors to evaluate mite susceptibility. Some mites, collected from different apiaries, present resistance to amitraz and tau-fluvalinate (71% of the mite samples show resistance to amitraz and 57% to tau-fluvalinate). As there are few active substances available in France, and if mite resistance to acaricides continues to increase, the effectiveness of the treatments will decrease and therefore more treatments per year will be necessary. To prevent this situation, a new strategy needs to be put in place to include mite resistance management. We suggest that a bioassay would be a good tool with which to advise the policymakers.


Assuntos
Acaricidas , Abelhas/parasitologia , Resistência a Medicamentos , Nitrilos , Piretrinas , Toluidinas , Varroidae , Animais , França
7.
Exp Appl Acarol ; 81(4): 515-530, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32671510

RESUMO

Olfaction is a key sensory modality for many arthropods and could be used as a tool in pest management through manipulation of pest behavior. Management of Varroa destructor, important parasitic mites of honey bees, could be improved through better understanding of the chemical ecology of this host-parasite relationship. We refined techniques of mounting mites to obtain electrophysiological recordings (electrotarsograms) of their responses to synthetic odor stimuli. Results of 271 electrotarsogram recordings from V. destructor revealed responses to 10 odorants relative to solvent controls. Electrotarsogram responses to methyl palmitate, ethyl palmitate, and 2-heptanol were highest at the lowest stimulus loading (10 ng) we tested, suggesting that V. destructor may have acute sensitivity to low concentrations of some odors. Results suggest that odorant origin (e.g., methyl oleate from honey bee larvae, geraniol from adult honey bee alarm pheromone, and α-terpineol, a plant secondary metabolite) can influence the degree of electrophysiological response. Varroa destructor tended to be more responsive to known attractants and repellents relative to previously unexplored odorants and some repellent terpenes. Electrotarsograms offer the potential for screening odors to determine their importance in V. destructor host detection.


Assuntos
Abelhas/química , Odorantes , Feromônios/química , Varroidae/fisiologia , Animais , Abelhas/parasitologia , Interações Hospedeiro-Parasita
8.
Exp Appl Acarol ; 81(4): 495-514, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32700265

RESUMO

Detection and interpretation of chemical cues is essential for Varroa destructor Anderson and Trueman, an important parasite of honey bees (Apis mellifera L.), to complete its life cycle. We collected volatiles from honey bee brood at various developmental stages and screened for V. destructor electrophysiological responses to these with gas chromatography-linked electrotarsal detection. Volatile collections contained several methyl-alkanes that evoked electrophysiological responses from V. destructor. Moreover, odors in honey bee colonies that regulate honey bee colony structure and function were also detected by V. destructor. Collections from mid- to late-stage larvae had detectable levels of low-volatility odors identified as components of the honey bee brood pheromone and branched alkanes likely originating from brood cuticle. Among these, several mid- to heavy-molecular weight compounds elicited high proportional electrophysiological responses by V. destructor relative to their abundance but could not be identified using chemical standards of previously documented honey bee brood odors. We suggest further investigation of these unknown volatiles and future behavioral assays to determine attractiveness/repellency (valence) of those identified through chemical standards.


Assuntos
Abelhas/química , Odorantes , Feromônios/química , Varroidae/fisiologia , Animais , Abelhas/parasitologia , Fenômenos Eletrofisiológicos
9.
Trends Parasitol ; 36(7): 592-606, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32456963

RESUMO

The parasitic mite, Varroa destructor, has shaken the beekeeping and pollination industries since its spread from its native host, the Asian honey bee (Apis cerana), to the naïve European honey bee (Apis mellifera) used commercially for pollination and honey production around the globe. Varroa is the greatest threat to honey bee health. Worrying observations include increasing acaricide resistance in the varroa population and sinking economic treatment thresholds, suggesting that the mites or their vectored viruses are becoming more virulent. Highly infested weak colonies facilitate mite dispersal and disease transmission to stronger and healthier colonies. Here, we review recent developments in the biology, pathology, and management of varroa, and integrate older knowledge that is less well known.


Assuntos
Abelhas/parasitologia , Interações Hospedeiro-Parasita , Varroidae/fisiologia , Acaricidas/farmacologia , Animais , Resistência a Medicamentos , Varroidae/efeitos dos fármacos , Varroidae/virologia
10.
Res Vet Sci ; 131: 215-221, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32408232

RESUMO

This paper describes the global distribution and temporal trend of Varroa spp. during 13 years (2005-2018) using the information retrieved from the OIE World Animal Health Information Database (WAHIS). During the period of study 53.4% of the countries reported the presence of the mite at least once. Countries were classified in five categories: 22% as Enzootic, 18% as Epizootic, 9% as Free, 12% and 26% respectively as disease Present or Absent at least once since 2005. Twelve percent of the countries were not able to provide any information on the presence of the disease. The average percentage of countries reporting the disease present was stable along the study, but it was observed a statistically significant increasing trend in the number of outbreaks reported per year. The number of outbreaks were different among the climate regions. Based on the seasonality analysis, the second semester of each year was the period characterized by the highest number of outbreaks reported.


Assuntos
Abelhas/parasitologia , Estações do Ano , Varroidae/fisiologia , Animais , Interações Hospedeiro-Parasita , Fatores de Tempo
11.
Proc Natl Acad Sci U S A ; 117(21): 11559-11565, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32393622

RESUMO

Pathogens pose significant threats to pollinator health and food security. Pollinators can transmit diseases during foraging, but the consequences of plant species composition for infection is unknown. In agroecosystems, flowering strips or hedgerows are often used to augment pollinator habitat. We used canola as a focal crop in tents and manipulated flowering strip composition using plant species we had previously shown to result in higher or lower bee infection in short-term trials. We also manipulated initial colony infection to assess impacts on foraging behavior. Flowering strips using high-infection plant species nearly doubled bumble bee colony infection intensity compared to low-infection plant species, with intermediate infection in canola-only tents. Both infection treatment and flowering strips reduced visits to canola, but we saw no evidence that infection treatment shifted foraging preferences. Although high-infection flowering strips increased colony infection intensity, colony reproduction was improved with any flowering strips compared to canola alone. Effects of flowering strips on colony reproduction were explained by nectar availability, but effects of flowering strips on infection intensity were not. Thus, flowering strips benefited colony reproduction by adding floral resources, but certain plant species also come with a risk of increased pathogen infection intensity.


Assuntos
Abelhas , Brassica napus , Flores , Infecções Protozoárias em Animais , Animais , Comportamento Apetitivo/fisiologia , Abelhas/parasitologia , Abelhas/fisiologia , Brassica napus/microbiologia , Brassica napus/parasitologia , Crithidia/patogenicidade , Ecossistema , Flores/parasitologia , Flores/fisiologia , Larva/fisiologia , Polinização/fisiologia , Infecções Protozoárias em Animais/fisiopatologia , Infecções Protozoárias em Animais/transmissão
12.
Exp Appl Acarol ; 80(4): 463-476, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32249394

RESUMO

The parasitic mite Varroa destructor Anderson and Trueman continues to devastate western honey bee (Apis mellifera L.) colonies throughout most of the world where they are managed. The development of a method to rear Varroa in vitro would allow for year-round Varroa research, rapidly advancing our progress towards controlling the mite. We created two separate experiments to address this objective. First, we determined which of four in vitro rearing methods yields the greatest number of Varroa offspring. Second, we attempted to improve the rearing rates achieved with that method. The four methods tested included (1) rearing Varroa on honey bee pupae in gelatin capsules, (2) rearing Varroa on in vitro-reared honey bees, (3) group rearing Varroa on honey bee pupae in Petri dishes, and (4) providing Varroa a bee-derived diet. The number of reproducing females and the number of fully mature offspring were significantly higher in the gelatin capsules maintained at 75% RH than in any other method. A 2 × 3 full factorial design was used to test combinations of gelatin capsule size (6 and 7 mm diameter) and relative humidity (65, 75, or 85%) on Varroa rearing success. Varroa reproduction and survival were significantly higher in 7-mm-diameter gelatin capsules maintained at 75% RH than in those maintained in 6-mm capsules and at the other humidities. By identifying factors that influence Varroa reproductive success in vitro, this work provides an important foundation for the development of future rearing protocols.


Assuntos
Abelhas/parasitologia , Varroidae/crescimento & desenvolvimento , Animais , Feminino , Pupa/parasitologia , Reprodução
13.
Vet Clin North Am Exot Anim Pract ; 23(2): 285-297, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32327036

RESUMO

Most honeybee diseases are not newly emerging diseases; however, honeybee veterinary medicine and disease understanding are emerging concepts for veterinarians in the United States. Beekeepers in the hobby and commercial sectors need a prescription or veterinary feed directive from a veterinarian to obtain medically important antibiotics for administration to their honeybees. Medically important antibiotics such as oxytetracycline, lincomycin, and tylosin were removed from over-the-counter availability for use in honeybees. There are many other aspects of beekeeping that allow veterinarians to build a strong veterinarian-client patient relationship, and fulfill an integral role alongside apiarists.


Assuntos
Abelhas/microbiologia , Doenças Transmissíveis Emergentes/veterinária , Nosema/fisiologia , Varroidae/fisiologia , Animais , Criação de Abelhas , Abelhas/parasitologia , Doenças Transmissíveis Emergentes/microbiologia , Doenças Transmissíveis Emergentes/parasitologia
14.
Appl Environ Microbiol ; 86(12)2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32276975

RESUMO

Pollination provided by managed honey bees as well as by all the wild bee species is a crucial ecosystem service contributing to the conservation of biodiversity and human food security. Therefore, it is not only the health status of honey bees but also the health status of wild bees that concerns us all. In this context, recent field studies suggesting interspecies transmission of the microsporidium parasite Nosema ceranae from honey bees (Apis mellifera) to bumblebees (Bombus spp.) were alarming. On the basis of these studies, N. ceranae was identified as an emerging infectious agent (EIA) of bumblebees, although knowledge of its impact on its new host was still elusive. In order to investigate the infectivity, virulence, and pathogenesis of N. ceranae infections in bumblebees, we performed controlled laboratory exposure bioassays with Bombus terrestris by orally inoculating the bees with infectious N. ceranae spores. We comprehensively analyzed the infection status of the bees via microscopic analysis of squash preparations, PCR-based detection of N. ceranae DNA, histology of Giemsa-stained tissue sections, and species-specific fluorescence in situ hybridization. We did not find any evidence for a true infection of bumblebees by N. ceranae Through a series of experiments, we ruled out the possibility that spore infectivity, spore dosage, incubation time, or age and source of the bumblebees caused these negative results. Instead, our results clearly demonstrate that no infection and production of new spores took place in bumblebees after they ingested N. ceranae spores in our experiments. Thus, our results question the classification of N. ceranae as an emerging infectious agent for bumblebees.IMPORTANCE Emerging infectious diseases (EIDs) pose a major health threat to both humans and animals. EIDs include, for instance, those that have spread into hitherto naive populations. Recently, the honey bee-specific microsporidium Nosema ceranae has been detected by molecular methods in field samples of bumblebees. This detection of N. ceranae DNA in bumblebees led to the assumption that N. ceranae infections represent an EID of bumblebees and resulted in speculations on the role of this pathogen in driving bumblebee declines. In order to address the issue of whether N. ceranae is an emerging infectious agent for bumblebees, we experimentally analyzed host susceptibility and pathogen reproduction in this new host-pathogen interaction. Surprisingly, we did not find any evidence for a true infection of Bombus terrestris by N. ceranae, questioning the classification of N. ceranae infections as EIDs of bumblebees and demonstrating that detection of microsporidian DNA does not equal detection of microsporidian infection.


Assuntos
Abelhas/parasitologia , Interações Hospedeiro-Patógeno , Nosema/fisiologia , Animais , Trato Gastrointestinal/parasitologia , Especificidade da Espécie
15.
Exp Appl Acarol ; 80(4): 477-490, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32253641

RESUMO

Acarapis woodi, a parasitic mite of honey bees, was first detected in Japan in 2010. Infestation was mostly observed in the Japanese honey bee (Apis cerana japonica) and was rare in the European honey bee (Apis mellifera). By 2014, the mites had spread throughout central and eastern Japan. In the current study, we investigated the subsequent expansion of the mite to western Japan. Our research revealed that the mites were distributed across most of Japan by 2018, except for Wakayama and Kochi prefectures. Many small remote islands more than 20 km away from mainland Japan are still free of A. woodi, but bees on some of these islands were infested. About 40% of colonies of the Japanese honey bee in Japan were infested by the mites, and average mite prevalence of the infested colonies was about 50% during the 6-year study. There was no trend of decline in the infested colony proportion or in the mite prevalence. In addition, the observation of Japanese honey bee colonies by hobby beekeepers for two signs of mite infestation, K-wing and crawling bees, was an effective means for estimating infestation by tracheal mites.


Assuntos
Abelhas/parasitologia , Infestações por Ácaros/veterinária , Ácaros , Animais , Japão/epidemiologia , Infestações por Ácaros/epidemiologia , Prevalência , Traqueia/parasitologia
16.
Sci Rep ; 10(1): 5956, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32249797

RESUMO

The main biological threat to the western honeybee (Apis mellifera) is the parasitic mite Varroa destructor, largely because it vectors lethal epidemics of honeybee viruses that, in the absence of this mite, are relatively innocuous. The severe pathology is a direct consequence of excessive virus titres caused by this novel transmission route. However, little is known about how the virus adapts genetically during transmission and whether this influences the pathology. Here, we show that upon injection into honeybee pupae, the deformed wing virus type-A (DWV-A) quasispecies undergoes a rapid, extensive expansion of its sequence space, followed by strong negative selection towards a uniform, common shape by the time the pupae have completed their development, with no difference between symptomatic and asymptomatic adults in either DWV titre or genetic composition. This suggests that the physiological and molecular environment during pupal development has a strong, conservative influence on shaping the DWV-A quasispecies in emerging adults. There was furthermore no evidence of any progressive adaptation of the DWV-A quasispecies to serial intra-abdominal injection, simulating mite transmission, despite the generation of ample variation immediately following each transmission, suggesting that the virus either had already adapted to transmission by injection, or was unaffected by it.


Assuntos
Vetores Aracnídeos/virologia , Abelhas/parasitologia , Pupa/parasitologia , Quase-Espécies/genética , Vírus de RNA/genética , Varroidae/virologia , Animais
17.
Eur J Protistol ; 73: 125688, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32143143

RESUMO

The molecular divergence, morphology and pathology of a cryptic gregarine that is related to the bee parasite Apicystis bombi Lipa and Triggiani, 1996 is described. The 18S ribosomal DNA gene sequence of the new gregarine was equally dissimilar to that of A. bombi and the closest related genus Mattesia Naville, 1930, although phylogenetic analysis supported a closer relation to A. bombi. Pronounced divergence with A. bombi was found in the ITS1 sequence (69.6% similarity) and seven protein-coding genes (nucleotide 78.05% and protein 90.2% similarity). The new gregarine was isolated from a Bombus pascuorum Scopoli, 1763 female and caused heavy hypertrophism of the fat body tissue in its host. In addition, infected cells of the hypopharyngeal gland tissue, an important excretory organ of the host, were observed. Mature oocysts were navicular in shape and contained four sporozoites, similar to A. bombi oocysts. Given these characteristics, we proposed the name Apicystis cryptica sp. n. Detections so far indicated that distribution and host species occupation of Apicystis spp. overlap at least in Europe, and that historical detections could not discriminate between them. Specific molecular assays were developed that can be implemented in future pathogen screens that aim to discriminate Apicystis spp. in bees.


Assuntos
Apicomplexa/classificação , Abelhas/parasitologia , Animais , Apicomplexa/citologia , Apicomplexa/genética , DNA de Protozoário/genética , Europa (Continente) , Corpo Adiposo/parasitologia , Oocistos/citologia , Especificidade da Espécie
18.
Sci Rep ; 10(1): 4667, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170145

RESUMO

Interactions between stressors are involved in the decline of wild species and losses of managed ones. Those interactions are often assumed to be synergistic, and per se of the same nature, even though susceptibility can vary within a single species. However, empirical measures of interaction effects across levels of susceptibility remain scarce. Here, we show clear evidence for extreme differences in stressor interactions ranging from antagonism to synergism within honeybees, Apis mellifera. While female honeybee workers exposed to both malnutrition and the pathogen Nosema ceranae showed synergistic interactions and increased stress, male drones showed antagonistic interactions and decreased stress. Most likely sex and division of labour in the social insects underlie these findings. It appears inevitable to empirically test the actual nature of stressor interactions across a range of susceptibility factors within a single species, before drawing general conclusions.


Assuntos
Antibiose , Comportamento Animal , Simbiose , Animais , Abelhas/parasitologia , Abelhas/fisiologia , Biodiversidade , Meio Ambiente , Interações Hospedeiro-Parasita , Nosema , Característica Quantitativa Herdável , Especificidade da Espécie , Estresse Fisiológico
19.
Exp Appl Acarol ; 80(3): 399-407, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32072354

RESUMO

Apiculture in the Pacific island country of Papua New Guinea (PNG) is under significant pressure from emerging parasitic mites, Varroa jacobsoni and Tropilaelaps mercedesae. Although numerous mite control products exist, beekeepers in PNG have limited resources and access to these products and their effectiveness under local conditions is untested. Here we determined the effectiveness of two brood manipulation strategies-queen caging and queen removal-for managing V. jacobsoni and T. mercedesae in comparison to the chemical miticide Bayvarol®. Our results found Bayvarol was the most effective control strategy for V. jacobsoni, maintaining high efficacy (> 90%) over 4 months with significantly reduced levels of V. jacobsoni compared to untreated control hives. In contrast, T. mercedesae were significantly reduced by the brood manipulation strategies over 2 months, but not significantly by Bayvarol compared to the controls. These results highlight that a combination of strategies is likely needed to effectively manage both mite pests in PNG. We discuss how these findings are relevant to informing best practice for honey bee biosecurity and how these strategies can be implemented to improve the effectiveness of mite management for PNG beekeepers.


Assuntos
Criação de Abelhas/métodos , Abelhas/parasitologia , Ácaros , Controle de Ácaros e Carrapatos/métodos , Varroidae , Animais , Papua Nova Guiné
20.
PLoS One ; 15(2): e0229030, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32078633

RESUMO

While many studies have examined the effects of neonicotinoid insecticides and the parasitic mite Varroa destructor on honey bees (Apis mellifera), more information on the combined effects of such stressors on gene expression, including neural related genes, and their impact on biological pathways is needed. This study analyzed the effects of field realistic concentrations of the neonicotinoid clothianidin on adult bees infested and not infested with V. destructor over 21 consecutive days and then determined bee survivorship, weight, deformed wing virus (DWV) levels and gene expression. V. destructor parasitism with or without clothianidin exposure was significantly associated with decreased survivorship, weight loss and higher DWV levels, while clothianidin exposure was only associated with higher levels of DWV. Expression analysis of the neural genes AmNlg-1, BlCh and AmAChE-2 showed that V. destructor caused a significant down-regulation of all of them, whereas clothianidin caused a significant down-regulation of only AmNrx-1 and BlCh. An interaction was only detected for AmNrx-1 expression. RNAseq analysis showed that clothianidin exposure resulted in 6.5 times more up-regulated differentially expressed genes (DEGs) than V. destructor alone and 123 times more than clothianidin combined with V. destructor. Similar results were obtained with down-regulated DEGs, except for a higher number of DEGs shared between V. destructor and the combined stressors. KEGG (Kyoto Encyclopedia of Genes and Genomes) biological pathway analysis of the DEGs showed that the stressor linked to the highest number of KEGG pathways was clothianidin, followed by V. destructor, and then considerably fewer number of KEGG pathways with the combined stressors. The reduced numbers of DEGs and KEGG pathways associated with the DEGs for the combined stressors compared to the stressors alone indicates that the interaction of the stressors is not additive or synergistic, but antagonistic. The possible implications of the antagonistic effect on the number of DEGs are discussed.


Assuntos
Abelhas/efeitos dos fármacos , Abelhas/genética , Abelhas/parasitologia , Regulação da Expressão Gênica/efeitos dos fármacos , Guanidinas/farmacologia , Interações Hospedeiro-Parasita/efeitos dos fármacos , Interações Hospedeiro-Parasita/genética , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Tiazóis/farmacologia , Animais , Biologia Computacional , Perfilação da Expressão Gênica , Estimativa de Kaplan-Meier
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