Parasitic Mite Research Articles

The Beneficial Effect of Pollen on Varroa Infested Bees Depends on Its Influence on Behavioral Maturation Genes.

Honey bees collect nectar and pollen to fulfill their nutritional demands. In particular, pollen can influence longevity, the development of hypopharyngeal glands, and immune-competence of bees. Pollen can also mitigate the deleterious effects caused by the parasitic mite Varroa destructor and related deformed wing virus (DWV) infections. It has been shown that V. destructor accelerates the physiological and behavioral maturation of honey bees by influencing the interaction between two core physiological factors, Vitellogenin and juvenile hormone. In this study, we test the hypothesis that the beneficial effects of pollen on Varroa-infested bees are related to the hormonal control underpinning behavioral maturation. By analyzing the expression of genes associated to behavioral maturation in pollen-fed mite-infested bees, we show that treatment with pollen increases the lifespan of mite-infested bees by reversing the faster maturation induced by the parasite at the gene expression level. As expected, from the different immune-competence of nurse and forager bees, the lifespan extension triggered by pollen is also correlated with a positive influence of antimicrobial peptide gene expression and DWV load, further reinforcing the beneficial effect of pollen. This study lay the groundwork for future analyses of the underlying evolutionary processes and applications to improve bee health.

Decreased Mite Reproduction to Select Varroa destructor (Acari: Varroidae) Resistant Honey Bees (Hymenoptera: Apidae): Limitations and Potential Methodological Improvements.

The invasive parasitic mite, Varroa destructor (Anderson and Trueman), is the major biotic threat to the survival of European honey bees, Apis mellifera L. To improve colony survival against V. destructor, the selection of resistant lineages against this parasite is considered a sustainable solution. Among selected traits, mite fertility and fecundity, often referred to as suppressed mite reproduction are increasingly used in breeding programmes. However, the current literature leaves some gaps in the assessment of the effectiveness of selecting these traits toward achieving resistance. In the population studied here, we show a low repeatability and reproducibility of mite fertility and fecundity phenotypes, as well as a low correlation of these traits with infestation rates of colonies. Phenotyping reliability could neither be improved by increasing the number of worker brood cells screened, nor by screening drone brood, which is highly attractive for the parasite and available early in the season, theoretically allowing a reduction of generation time and thus an acceleration of genetic progress in selected lineages. Our results provide an evaluation of the potential and limitations of selecting on decreased mite reproduction traits to obtain V. destructor-resistant honeybee colonies. To allow for a more precise implementation of such selection and output reporting, we propose a refined nomenclature by introducing the terms of decreased mite reproduction and reduced mite reproduction, depending on the extent of mite reproduction targeted. We also highlight the importance of ensuring accurate phenotyping ahead of initiating long-lasting selection programmes.

Identifying and Assessing Needs of Florida Commercial Beekeepers Using Nominal Group Technique

The importance of honey bees to global agriculture is largely undisputed (Calderone, 2012; Southwick & Southwick, 1992). Simultaneously, commercial beekeeping operations face tremendous industry stressors that have led to increased management requirements and elevated colony losses in Florida and around the United States. in recent decades (Hodges et al., 2001; Kulhanek et al., 2017). The needs of such beekeepers are largely unknown due to a lack of published literature on beekeepers as a whole. Extension professionals and other agricultural educators can create educational programs to address the needs of constituents once they have assessed these gaps between current and desired states. The purpose of this study was to increase understanding of the issues facing commercial honey bee operations to better guide and develop research, instruction, and Extension programs in Florida and beyond. The objectives of this study were to (a) identify the needs of registered commercial beekeepers in Florida, and (b) prioritize registered Florida commercial beekeeper needs. The highest priority need identified by beekeepers in this study was related to controlling the parasitic mite, Varroa, in honey bee colonies. Other priority needs included effective nutritional management as well as control and management of viral infections, bacteria, and Nosema in honey bee colonies.

Phylogeography of the parasitic mite Laelaps agilis in Western Palearctic shows lineages lacking host specificity but possessing different demographic histories

BackgroundLaelaps agilis C.L. Koch, 1836 is one the most abundant and widespread parasitic mite species in the Western Palearctic. It is a permanent ectoparasite associated with the Apodemus genus, which transmits Hepatozoon species via the host’s blood. Phylogenetic relationships, genealogy and host specificity of the mite are uncertain in the Western Palearctic. Here, we investigated the population genetic structure of 132 individual mites across Europe from their Apodemus and Clethrionomys hosts. Phylogenetic relationships and genetic variation of the populations were analyzed using cytochrome c oxidase subunit I (COI) gene sequences.ResultsWe recovered three main mtDNA lineages within L. agilis in the Western Palearctic, which differentiated between 1.02 and 1.79 million years ago during the Pleistocene period: (i) Lineage A, including structured populations from Western Europe and the Czech Republic, (ii) Lineage B, which included only a few individuals from Greece and the Czech Republic; and (iii) Lineage C, which comprised admixed populations from Western and Eastern Europe. Contrary to their population genetic differentiation, the lineages did not show signs of specificity to different hosts. Finally, we confirmed that the sympatric congener L. clethrionomydis is represented by a separated monophyletic lineage.ConclusionDifferences in the depth of population structure between L. agilis Lineages A and C, corroborated by the neutrality tests and demographic history analyses, suggested a stable population size in the structured Lineage A and a rapid range expansion for the geographically admixed Lineage C. We hypothesized that the two lineages were associated with hosts experiencing different glaciation histories. The lack of host specificity in L. agilis lineages was in contrast to the co-occurring highly host-specific lineages of Polyplax serrata lice, sharing Apodemus hosts. The incongruence was attributed to the differences in mobility between the parasites, allowing mites to switch hosts more often.

Redescription of two parasitic feather mites sampled from the last two Crested Ibises, Nipponia nippon (Temminck, 1835) (Pelecaniformes: Threskiornithidae), lived in Japan.

The objective of this paper is to redescribe two feather mites, Compressalges nipponiae Dubinin, 1950 (Caudiferidae) and Freyanopterolichus nipponiae Dubinin, 1953 (Kramerellidae), based on samples collected from the last two individuals of the Crested Ibis Nipponia nippon (Temminck, 1835) from the native Japanese populations, which had been extirpated in 2003. Our study provides detailed description of the leg and idiosomal chaetotaxy, and many morphological structures, which were missed or misinterpreted in the original publications.

Exposure of Apis mellifera to anti-Varroa destructor formic acid treatment induces significant proteomic alterations

The parasitic mite Varroa destructor is a major threat to the health and productivity of Apis mellifera hives and induces its effect by feeding on the fat body of larvae/pupae and transmitting viruses. The effect of the anti-Varroa formic acid containing – Mite Away Quick (MAQ) strips on the proteome of A. mellifera was assessed. Samples of A. mellifera were isolated from hives one week prior to MAQ treatment, during the week of treatment and for two weeks after the end of treatment, proteins were extracted and analysed by label free quantitative proteomics. The results indicated that samples isolated during the week of treatment showed increased abundance of a range of cuticular proteins (+ 2.65 fold to + 6.64 fold) and decreased abundance of proteins that deal with xenobiotics (Cytochrome P450 subunits −11.38 fold to −2.16 fold). Interestingly some proteins associated with the oxidative phosphorylation pathway were increased in abundance (e.g., Cox5a and Cox5b) but others (e.g., Coxfa4) were decreased. The results presented here reveal that the application of MAQ strips caused a dramatic disruption to the proteome of A. mellifera, but the effect is transient and two weeks after the end of treatment the proteome has returned to resemble that of the untreated control. While MAQ strips are effective in reducing Varroa populations, the results presented here indicate they can adversely affect the proteome of A. mellifera and may contribute to the elevated stress in hives previously affected by Varroa parasitisation.

Bacterially expressed dsRNA induces Varroa destructor gene knockdown by honey bee-mediated oral administration

The ectoparasite Varroa destructor causes serious losses of Apis mellifera colonies and negatively impacts the beekeeping industry around the world. New control methods have been proposed based on the RNA interference technique. Previous reports showed that parasitized honey bees fed with double-stranded RNA (dsRNA) synthesized in vitro reduce the transcription levels of target genes in Varroa mites. An efficient and inexpensive alternative to produce dsRNA is the use of bacteria capable of achieving high levels of in vivo synthesis. In the present study, dsRNA synthetized in vivo was used to induce gene silencing in V. destructor and evaluate their effect on the survival of both honey bees and the parasitic Varroa mites. The results evidenced that dsRNA fed to the bees engendered gene silencing in mites, inhibiting expression levels of target genes by 50%. Indeed, a reduction of 50% in Varroa survival was observed when bacterially expressed dsRNAs were administered to mite-parasitized bees. Worker bees that were fed with Varroa-targeted dsRNA by oral route showed no survival differences compared to control bees, fed with sucrose or dsRNA-GFP solutions. Our results demonstrated that specific dsRNA over-expressed in bacteria is capable of reducing mite survival by bee-mediated oral administration. This study provides an efficient and low-cost method for dsRNA production to control parasites and honey bee diseases.

An RNA Interference Tool to Silence Genes in Sarcoptes scabiei Eggs.

In a quest for new interventions against scabies—a highly significant skin disease of mammals, caused by a parasitic mite Sarcoptes scabiei—we are focusing on finding new intervention targets. RNA interference (RNAi) could be an efficient functional genomics approach to identify such targets. The RNAi pathway is present in S. scabiei and operational in the female adult mite, but other developmental stages have not been assessed. Identifying potential intervention targets in the egg stage is particularly important because current treatments do not kill this latter stage. Here, we established an RNAi tool to silence single-copy genes in S. scabiei eggs. Using sodium hypochlorite pre-treatment, we succeeded in rendering the eggshell permeable to dsRNA without affecting larval hatching. We optimised the treatment of eggs with gene-specific dsRNAs to three single-copy target genes (designated Ss-Cof, Ss-Ddp, and Ss-Nan) which significantly and repeatedly suppressed transcription by ~66.6%, 74.3%, and 84.1%, respectively. Although no phenotypic alterations were detected in dsRNA-treated eggs for Ss-Cof and Ss-Nan, the silencing of Ss-Ddp resulted in a 38% reduction of larval hatching. This RNAi method is expected to provide a useful tool for larger-scale functional genomic investigations for the identification of essential genes as potential drug targets.

Demodex bialoviensis sp. nov. (Acariformes, Demodecidae) a new, specific parasite of the European bison Bison bonasus (Artiodactyla, Bovidae).

Sixteen species of parasitic mites of the family Demodecidae have been described in ungulates (Ungulatomorpha), particularly among domestic animals and livestock. Specific synhospital species have been found in seven host species. Demodex bisonianus, occurring in the Meibomian glands of the eyelids, was described in the European bison Bison bonasus. Together with Trypanosoma wrublewskii and Bisonicola sedecimdecembrii, it is one of the three known specific parasite species of European bison. The European bison is not only a rare and endangered mammal, but its biology has been shaped by its recent restitution from extinction from a small pool of individuals kept in breeding facilities. This could have been the reason for the extinction of the majority of specific parasites. The present study reports the finding of a new specific parasite species, Demodex bialoviensis sp. nov., associated with the nasal skin region, in European bison from the Białowieża Forest (Poland). It is the second species of Demodex reported in this host species, however occurring in a different location.

Effects of neonicotinoids on honey bee autogrooming behavior against the tracheal mite Acarapis woodi.

The European honey bee, Apis mellifera, is the most common and important pollinator of crops worldwide. Honey bees are damaged by destructive parasitic mites, but they also have evolved a behavioral immune system to remove them. Exposures to neonicotinoids, however, can cause significant behavioral effects because these compounds alter the central role of nicotinic acetylcholine receptor in insect brains. In this study, we assessed the effects of three neonicotinoids that have a high toxicity to bees-imidacloprid, thiamethoxam, and clothianidin-on the behavioral immune system of honey bees. We used A. mellifera and the endoparasitic mite Acarapis woodi as a behavioral immune system model because A. mellifera can effectively remove the mite by autogrooming. Our results did not demonstrate an effect of neonicotinoid application on whether bees show autogrooming or on mite removal, but the time to initial autogrooming became shorter and the number of autogrooming attempts increased. As opposed to previous studies, our findings indicate that the honey bee response to parasitic mites becomes more sensitive after exposure to neonicotinoids.Clinical Trials Registration: Not applicable.

A new needle stonefly with parasitic mites from the Eocene Baltic amber

A new needle stonefly with parasitic mites from the Eocene Baltic amber

Surveillance of synthetic acaricide efficacy against Varroa destructor in Ontario, Canada

Abstract The parasitic mite Varroa destructor (Mesostigmata: Varroidae) is the main culprit of honey bee (Hymenoptera: Apidae) colony mortality in Ontario, Canada. Most beekeepers use synthetic acaricides to control V. destructor infestations in their colonies, but the use of these products increases the risk of V. destructor developing resistance to the active ingredients, which is a growing concern. This study sought to determine the efficacy of three synthetic acaricides approved for use in Canada for control of V. destructor infestations, amitraz (Apivar™), tau-fluvalinate (Apistan®), and flumethrin (Bayvarol®), using the Pettis test. The mite mortality rate in populations of V. destructor differed for the acaricides tested. Amitraz caused a significantly higher mite mortality rate (92%) than flumethrin (78%) and tau-fluvalinate (72%) did. Amitraz was classified as “mostly effective” (90–97%), whereas flumethrin and tau-fluvalinate were classified as “minimally effective” (< 80%) for V. destructor control in the mite populations studied. Variation in mite mortality due to acaricide exposure was observed between apiaries and regions. The results highlight the importance of periodically assessing the varroacidal activity of acaricides to inform decisions to control the parasite when implementing integrated pest management strategies.

Mites and helminths infestation in Lebanese broiler farming systems.

This study aims at the identification of endo- and ectoparasites in broiler farms while assessing their prevalence in semi-open and closed rearing systems in Lebanon. Seventeen semi-open and six closed broiler farms were investigated in various Lebanese provinces between March and September 2020 and 2021. Intestinal and composite litter samples were collected and observed for morphological identification of prevalent parasites. Results notably revealed the prevalence of mites in all of the surveyed farms. Moreover, mixed mite-helminth infestation was recorded in 100% of the semi-open farms and 50% of the closed ones. The northern fowl mite Ornithonyssus sylviarum was the predominant chicken parasitic mite in both systems. The poultry red mite Dermanyssus gallinae, was present in 6% of the semi-open farms and was not detected in closed farms. The mammalian itching mite Sarcoptes scabiei and the grain mite Acarus siro were also identified and had similar prevalence pattern as the red poultry mite. Eggs and/or larvae stages of one parasitic helminth species, Ascaridia galli, were detected in half of the semi-open and closed farms while adult worms were not present. This study documents for the first time the prevalence of specific endo- and ectoparasites in Lebanese broiler farms, reflecting managerial problems and poor biosecurity practices. Nevertheless, the identification of specific parasites in this work paves the way towards implementing proper control methods against these overlooked, yet devastating, organisms.

Understanding the Enemy: A Review of the Genetics, Behavior and Chemical Ecology of Varroa destructor, the Parasitic Mite of Apis mellifera.

Varroa destructor (Mesostigmata: Varroidae) is arguably the most damaging parasitic mite that attacks honey bees worldwide. Since its initial host switch from the Asian honey bee (Apis cerana) (Hymenoptera: Apidae) to the Western honey bee (Apis mellifera) (Hymenoptera: Apidae), Varroa has become a widely successful invasive species, attacking honey bees on almost every continent where apiculture is practiced. Two haplotypes of V. destructor (Japanese and Korean) parasitize A. mellifera, both of which vector various honey bee-associated viruses. As the population of Varroa grows within a colony in the spring and summer, so do the levels of viral infections. Not surprisingly, high Varroa parasitization impacts bees at the individual level, causing bees to exhibit lower weight, decreased learning capacity, and shorter lifespan. High levels of Varroa infestation can lead to colony-wide varroosis and eventually colony death, especially when no control measures are taken against the mites. Varroa has become a successful parasite of A. mellifera because of its ability to reproduce within both drone cells and worker cells, which allows populations to expand rapidly. Varroa uses several chemical cues to complete its life cycle, many of which remain understudied and should be further explored. Given the growing reports of pesticide resistance by Varroa in several countries, a better understanding of the mite’s basic biology is needed to find alternative pest management strategies. This review focuses on the genetics, behavior, and chemical ecology of V. destructor within A. mellifera colonies, and points to areas of research that should be exploited to better control this pervasive honey bee enemy.

A survey of lifespan in Winterschmidtiidae (Sarcoptiformes: Astigmata)

The Winterschmidtiidae are a family of over 140 species of fungivorous, saprophagous, predatory and/or parasitic mites in insect/vertebrate nests, in decaying organic matter, in soils and on plants worldwide. In this review, I provide a survey of the immature developmental time, adult longevity and lifespan of the Winterschmidtiidae as part of the series on the lifespans in the Acari. The complete life cycle in this family includes five immature stages (the egg, larva, protonymph, deutonymph and tritonymph) and adult male/female, with deutonymphs lost in some genera such as Czenspinskia and Oulenziella. Development or lifespan data have been reported for only three species (< 3%) of the Winterschmidtiidae, and the experimentally measured lifespans of one to two months most likely reflect those of the summer generation. Afrocalvolia nataliae has two generations per year: the summer generation, which has no deutonymph stage, is mainly devoted to feeding and reproduction and lasts for one month only; the winter generation, however, has a deutonymph stage to resist the cold conditions and lasts for as long as 11 months.

Genital nodular scabies in Indonesian adolescent boy

<p class="abstract">Scabies is an infection caused by infestation and sensitization to the parasitic mite <em>Sarcoptes</em> <em>scabiei</em> <em>var</em>. <em>hominis</em>. World Health Organization (WHO) in 2017 declared that scabies was included as Neglected Tropical Diseases (NTD) and become a significant health concern in many developing countries. According to the Global Burden of Disease Study in 2015, Indonesia was the first place among 195 countries with the greatest scabies burden. Nodular scabies is an uncommon clinical variant in classical scabies cases, characterized by persistent pruritic nodules due to immune response against the mites and their products (eggs and scybala). This variant was occurring in about 7% of scabies patients. The incidence and prevalence of nodular scabies are still unknown. Nodular scabies is usually found in young children and affect the male genitalia, especially in the scrotum. The diagnosis of nodular scabies generally can be made clinically and supported by a history of receiving adequate anti-scabies treatment. Active infestation form or atypical manifestations of nodular scabies might be confused the diagnosis. Diagnostic tools such as dermoscopic and skin biopsy may aid in differentiating them. Histopathology features also can rule out the differential diagnosis. Corticosteroid (topical or injection) and topical inhibitor calcineurin (tacrolimus) was reported effective in treating nodular scabies. We reported an Indonesian adolescent boy who has been diagnosed with scabies complained of persistent pruritic nodules on his genital for several months despite adequate anti scabies therapy being given. Intralesional corticosteroid injection was the options treatment of this case due to the nodular lesion being resistant with topical corticosteroids, while topical tacrolimus is difficult to obtain in our region.</p>

Resistance to amitraz in the parasitic honey bee mite Varroa destructor is associated with mutations in the β-adrenergic-like octopamine receptor

Varroa destructor is considered a major reason for high loss rate of Western honey bee (Apis mellifera) colonies. To prevent colony losses caused by V. destructor, it is necessary to actively manage the mite population. Beekeepers, particularly commercial beekeepers, have few alternative treatments other than synthetic acaricides to control the parasite, resulting in intensive treatment regimens that led to the evolution of resistance in mite populations. To investigate the mechanism of the resistance to amitraz detected in V. destructor mites from French and U.S. apiaries, we identified and characterized octopamine and tyramine receptors (the known targets of amitraz) in this species. The comparison of sequences obtained from mites collected from different apiaries with different treatment regimens, showed that the amino acid substitutions N87S or Y215H in the OctβR were associated with treatment failures reported in French or U.S. apiaries, respectively. Based on our findings, we have developed and tested two high throughput diagnostic assays based on TaqMan technology able to accurately detect mites carrying the mutations in this receptor. This valuable information may be of help for beekeepers when selecting the most suitable acaricide to manage V. destructor.

Metabarcoding prey DNA from fecal samples of adult dragonflies shows no predicted sex differences, and substantial inter-individual variation, in diets.

Sexes often differ in foraging and diet, which is associated with sex differences in size, trophic morphology, use of habitats, and/or life history tactics. Herein, strikingly similar diets were found for adult sexes of a dragonfly (Leucorrhinia intacta), based on comparing 141 dietary taxa identified from the metabarcoding of mitochondrial DNA archived in feces. Arthropods in > 5% of samples included five species of dipterans, two hemipterans, two spider species and one parasitic mite. The mite was not traditional prey as its presence was likely due to DNA contamination of samples arising through parasitism or possibly via accidental consumption during grooming, and therefore the mite was excluded from diet characterizations. Common prey species were found with statistically indistinguishable frequencies in male and female diets, with one exception of an aphid more often found in male diets, although this pattern was not robust to corrections for multiple statistical tests. While rare prey species were often found in diets of only one sex, instances of this were more frequent in the more oft-sampled females, suggesting sampling artefact. Sexes did not differ in the mean prey species richness in their diets. Overall, sexes showed statistically indistinguishable diets both on a prey species-by-species basis and in terms of multivariate characterizations of diet composition, derived from presence-absence data of prey species analyzed via PERMANOVA and accumulation curves. Males and females may have similar diets by being both opportunistic and generalist predators of arthropods, using the same foraging habitats and having similar sizes and flight agilities. Notably, similarities in diet between sexes occur alongside large interindividual differences in diet, within sexes. Researchers intending on explaining adaptive sex differences in diet should consider characteristics of species whose sexes show similar diets.

Parasitism, seasonality, and diversity of trombiculid mites (Trombidiformes: Parasitengona, Trombiculidae) infesting bats (Chiroptera) in Poland

The study aims to ascertain the diversity of trombiculid species associated with Chiroptera in Poland, and for the first time in the case of research on Central European Trombiculidae, we use both DNA and morphology in an integrative taxonomic approach to determine species identities of trombiculids. The research was carried out from 2015 to 2019. In total, 2725 larvae were collected from 300 specimens of bats belonging to 11 species. Deutonymphs were obtained through laboratory rearing of larvae; few larvae and deutonymphs were collected also from bats' daily roosts. The presence of trombiculid larvae on hosts was observed between July and April of the following year, with the highest numbers recorded in autumn, during bat swarming. Male bats were infested more often than females (16.4 vs. 6.6%). The highest infestation rate was recorded for Barbastella barbastellus, Myotis nattereri and Plecotus auritus, and the highest prevalence of chiggers (> 30%) for Myotis bechsteinii and P. auritus. The larvae found on bats occupied the areas with free access to the host’s skin: auricles, tragus, and snout. Morphological identification of specimens to the species level was hindered by the mosaic distribution of diagnostic traits. Morphological analyses indicated the presence of Leptotrombidium russicum and Leptotrombidium spp. in the examined material, whereas molecular analyses additionally suggested three other potential species assigned to the same genus based on the assessed scope of intrageneric variation (ASAP method). We argue that the identification of the parasitic larvae (chiggers) using morphological characters does not address the question of actual species boundaries, which, in turn, affects the inferences about host specificity and host range.

Species and prevalence of parasitic mites on tree geckos in Purwokerto, Central Java

Parasitic mite infections are very common on virtually all organisms including tree geckos. This research was aimed to determine the species and prevalence of parasitic mites infecting tree lizards in Purwokerto, Central Java. This research employed a survey method with a purposive random sampling technique. One hundred individuals of tree lizards were obtained from trees in 4 different sub-districts in Purwokerto. The results showed that from 3 species of tree geckos namely, Hemidactylus platyurus, H. frenatus and H. garnotii, only the last one was not infected by parasitic mites. The prevalence of parasitic mites in H. garnotii was 0%, while in H. frenatus and H. platyurus were 27% and 29%, respectively. The total prevalence of parasitic mites on tree geckos in Purwokerto, Central Java, was 28%. The results showed that there were 5 (five) species of parasitic mites belonging to the genus Geckobia, namely G. keegani, G. gleadovania, G. turkestana, G. simplex and G. diversipilis. The prevalence of G. gleadovania in H. frenatus geckos was 100%, while in H. platyurus geckos, the prevalence of infection by G. diversipilis was also 100%. The most infected body part was the trunk where the prevalence was 57%.