Bdellidae (Trombidiformes: Prostigmata) are moderate to large sized predatory mites that inhabit soil, leaves, leaf litter, and intertidal rocks. They are readily recognized by an elongated, ...snout-like gnathosoma and by elbowed pedipalps bearing two (one in Monotrichobdella Baker & Balock) long terminal setae. Despite being among the first mites ever described, with species described by Carl Linnaeus, the knowledge about bdellids has never been compiled into a taxonomic catalogue. Here we present a catalogue listing 278 valid species; for each species we include distribution information, taxonomic literature, and type depository institutions. The genus Rigibdella Tseng, 1978 is considered a junior synonym of Cyta von Heyden, 1826, and Bdellodes Oudemans, 1937 is considered a junior synonym of Odontoscirus Tohr, 1913. Illustrated keys to subfamilies and genera are presented, as well as keys to species of each genus.
•The northern fowl mite, Ornithonyssus sylviarum, is an economically important ectoparasite of poultry.•Control of northern fowl mite currently depends on spraying chemical insecticides.•Mites are ...resistant to many chemical classes, and control will be impacted by organic production and cage-free housing.•Knowledge gaps remain for this mite, and the development of future control methods will rely on basic and applied research on this ectoparasite.
The northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago, 1877), is found on several continents and has been a major pest of poultry in the United States for nearly a century. Lack of earlier USA reports in the United States suggests an introduction or change to pest status in domestic poultry systems occurred in the early 1900s. Though predominantly a nest-parasite of wild birds, this obligate hematophagous mite is a permanent ectoparasite on domestic birds, especially egg-laying chickens. Economic damage is incurred by direct blood feeding and activation of the of host’s immune responses. This in turn causes decreased egg production and feed conversion efficiency, and severe infestations can cause anemia or death to birds. Here we review the biology, ecology, and recent control measures for the northern fowl mite. Photomicrographs are included of adult males and females, protonymphs, and larvae with key characters indicated. Special emphasis is placed on current knowledge gaps of basic and applied science importance.
Rosacea is a common dermatological condition that predominantly affects the central regions of the face. Rosacea affects up to 3 % of the world's population and a number of subtypes are recognized. ...Rosacea can be treated with a variety of antibiotics (e.g. tetracycline or metronidazole) yet no role for bacteria or microbes in its aetiology has been conclusively established. The density of Demodex mites in the skin of rosacea patients is higher than in controls, suggesting a possible role for these mites in the induction of this condition. In addition, Bacillus oleronius, known to be sensitive to the antibiotics used to treat rosacea, has been isolated from a Demodex mite from a patient with papulopustular rosacea and a potential role for this bacterium in the induction of rosacea has been proposed. Staphylococcus epidermidis has been isolated predominantly from the pustules of rosacea patients but not from unaffected skin and may be transported around the face by Demodex mites. These findings raise the possibility that rosacea is fundamentally a bacterial disease resulting from the over-proliferation of Demodex mites living in skin damaged as a result of adverse weathering, age or the production of sebum with an altered fatty acid content. This review surveys the literature relating to the role of Demodex mites and their associated bacteria in the induction and persistence of rosacea and highlights possible therapeutic options.
Microbiota has diverse roles in the life cycles of their hosts, affecting their growth, development, behavior, and reproduction. Changes in physiological conditions of the host can also impact the ...assemblage of host-associated microorganisms. However, little is known of the effects of host plant–prey–predatory mite interactions on mite microbiota. We compared the microbial communities of eggs and adult females of the two˗spotted spider mite,
Tetranychus urticae
Koch (Acari: Tetranychidae), and of adult females of the predatory mite
Neoseiulus californicus
(McGregor) (Acari: Phytoseiidae) on four different host plants (cotton, maize, pinto bean, and tomato) by metabarcoding sequencing of the V3–V4 region of the 16S ribosomal RNA gene (16S rRNA), using the Illumina MiSeq platform. Only the egg microbiota of
T. urticae
was affected by the host plant. The microbiota of the predatory mite
N. californicus
was very different from that of its prey, and the predator microbiota was unaffected by the different host plant–prey systems tested. Only the microbiota of the eggs of
T. urticae
carried
Serratia
as a high fidelity-biomarker, but their low abundance in
T. urticae
adult females suggests that the association between
Serratia
and
T. urticae
is accidental. Biomarker bacteria were also detected in the microbiota of adult females of
T. urticae
and
N. californicus
, with different biomarkers in each host plant species. The microbiota associated with eggs and adult females of
T. urticae
and adult females of
N. californicus
differed in their functional potential contributions to the host mite.
The presence of Demodex species can be associated with blepharitis. Their pathogenic potential in meibomian gland dysfunction is discussed herein. The purpose of this study was to determine the ...prevalence of Demodex mites in eyelashes of Austrian patients with ocular discomfort and to evaluate associated changes of the lid margins and meibomian glands.
This is a case-control study.
Two hundred twenty-nine consecutive patients with ocular discomfort from an Austrian dry eye clinic were investigated for the presence of Demodex mites on sampled eyelashes. Associations of a mite infestation with individual dry eye and lid parameters were assessed. Lid margins were evaluated for scales, vascularization, Marx line, expressibility and quality of meibum, and drop-out of meibomian glands.
Demodex mites were identified in 40.2% of patients suffering from ocular discomfort (mean mite count 3.3 ± 2.9 per patient). Infestation with mites was associated with the presence of significantly more cylindrical scales (sleeves), a higher Marx line score, and a lower quality of meibum compared with mite-free patients. There were no significant associations with the expressibility and the drop-out of meibomian glands.
The prevalence of Demodex mites in patients with ocular discomfort is high. The mean mite count per patient in this Austrian dry eye unit population is lower compared with previously published data from Asian regions. The infestation of the eyelids with Demodex species is associated with changes of the anterior and posterior lid margin, suggesting a pathogenic role in blepharitis and meibomian gland dysfunction.
Predatory mites (Acari: Phytoseiidae) are the most important beneficial arthropods used in augmentative biological pest control of protected crops around the world. However, the genomes of mites are ...far less well understood than those of insects and the evolutionary relationships among mite and other chelicerate orders are contested, with the enigmatic origin of mites at one of the centres in discussion of the evolution of Arachnida.
We here report the 173 Mb nuclear genome (from 51.75 Gb pairs of Illumina reads) of the predatory mite, Neoseiulus cucumeris, a biocontrol agent against pests such as mites and thrips worldwide. We identified nearly 20.6 Mb (~ 11.93% of this genome) of repetitive sequences and annotated 18,735 protein-coding genes (a typical gene 2888 bp in size); the total length of protein-coding genes was about 50.55 Mb (29.2% of this assembly). About 37% (6981) of the genes are unique to N. cucumeris based on comparison with other arachnid genomes. Our phylogenomic analysis supported the monophyly of Acari, therefore rejecting the biphyletic origin of mites advocated by other studies based on limited gene fragments or few taxa in recent years. Our transcriptomic analyses of different life stages of N. cucumeris provide new insights into genes involved in its development. Putative genes involved in vitellogenesis, regulation of oviposition, sex determination, development of legs, signal perception, detoxification and stress-resistance, and innate immune systems are identified.
Our genomics and developmental transcriptomics analyses of N. cucumeris provide invaluable resources for further research on the development, reproduction, and fitness of this economically important mite in particular and Arachnida in general.
•Concurrence of ocular and facial demodicosis is relatively common•Demodex mites on facial skin may serve as reservoir and hinder ocular eradication•Tea tree oil-based eye therapy reduced symptoms ...and total mite count in all patients•Topical ivermectin enhances eradication in the eyes of facial demodicosis patients•Combined ophthalmological and dermatological therapy may be beneficial
To determine the association between ocular and facial demodicosis, and the effect of facial treatment on ocular demodicosis.
Prospective clinical cohort study.
Ocular demodicosis outpatients from a tertiary medical center were enrolled from April to December 2020. The diagnosis was based on epilation of four eyelashes from each upper eyelid. High ocular Demodex load (ODL) was defined as ≥8 mites per eye. Facial infestation was assessed by direct microscopic examination, with facial Demodex overgrowth (FDO) defined as a density >5 mites/cm2. All patients were prescribed three months of ocular treatment, and FDO patients received dermatologic treatment.
Eighty-nine patients were enrolled. Among those that completed the treatment course, 39 presented high ODL. Lower cylindrical sleeve counts were found in low ODL patients (low ODL vs. high ODL: 8 vs. 14, P = 0.009). FDO was less prevalent in this group (49% vs. 77%, P = 0.012). The Ocular Surface Disease Index score decreased in patients without FDO (20.0 ± 17.1 to 14.0 ± 16.6, P = 0.027) after three months of topical tea tree oil treatment. Topical ivermectin treatment on the facial skin provided a higher ocular Demodex eradication rate in FDO patients (76% vs. 16%, P < 0.001).
Concurrence of ocular and facial demodicosis is common, especially in cases of severe ocular demodicosis. While ocular treatment alone is effective for patients with ocular demodicosis only, co-treatment with topical ivermectin on the facial skin enhances ocular Demodex eradication in patients with comorbid facial Demodex overgrowth.
Many blood-feeding arthropods use volatile organic compounds (VOCs) to detect their vertebrate hosts. The role of chemical interactions in mediating the behavior of hematophagous insects and ticks ...has been investigated before but remains poorly understood in hematophagous mesostigmatic mites. The poultry red mite
Dermanyssus gallinae
is an obligatory blood-sucking mesostigmatic mite that feeds on birds and causes damage in poultry farms. We characterized the attractive response of
D. gallinae
to candidate VOCs previously reported from the odor emitted by living hens. We performed
in-vitro
choice-test bioassays as well as semi-field and field trials using baited and unbaited traps, in the presence and absence of hens. Among different tested combinations of VOCs, a blend of 5 VOCs (mix1.0) was significantly attractive to our reference population of
D. gallinae in vitro
, whereas the same individual compounds tested alone were not attractive. Ammonia was attractive on its own and increased the mix1.0 attractiveness. The attractiveness of mix1.0 was confirmed at ‘natural’ spatial scales in the absence of hens both at the lab and on the farm that provided the reference population. The presence of hens inhibited the mix1.0 attractiveness. The attractive power of mix1.0 was not found in other farms. This research is an important step to advance our understanding of host-parasite interactions in hematophagous mesostigmatic mites and paves the way for developing alternative control tools against
D. gallinae
by interfering with chemical interactions. Moreover, it underlines the importance of assessing kairomonal activity on different pest populations when developing attract-and-kill systems.
Abstract
The two most economically important poultry ectoparasites are the northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), and the poultry red mite, Dermanyssus gallinae (De ...Geer). Both mites are obligate blood feeders but differ in where they reside. Sampling methods thus focus on-host, especially the vent feathers, for northern fowl mite and off-host, especially cracks and crevices near the nighttime roosting areas, for poultry red mite. Much remains unknown, however, about the basic biology and ecology of both mites. Here we discuss mite detection, quantification, and decision making and provide thoughts on future directions for research.
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