Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Acari”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1989

Distribution of some anystid mites (Acari: Anystidae) in Australia and Indonesia and their role as possible predators of the cattle tick, Boophilus microplus (Acari: Ixodidae).

The geographic and habitat distributions of Anystis baccarum, A. jabanica, A. salicinus, and A. sp. B Walzia australica Womersley and Chaussieria warregense in Australia and parts of Indonesia are presented. Laboratory trials showed that A. baccarum will feed upon the larvae of the cattle tick Boophilus microplus, whilst A. jabanica also showed some predatory potential. Walzia australica and C. warregense had no effect on survival of tick larvae.

Animals↗
PubMed1989

Susceptibility of Ornithodoros parkeri (Cooley) (Acari: Argasidae) and Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae) to ivermectin.

Ivermectin was injected into hosts and evaluated for effectiveness against the argasid tick Ornithodoros parkeri (Cooley) and the chicken mite Dermanyssus gallinae (DeGeer). O. parkeri second stage nymphs (N2s) showed a marked increase in mortality when fed on mice injected intraperitoneally with ivermectin at a dose between 0.1 and 0.2 mg/kg host body weight. For adult O. parkeri and D. gallinae, 0.4 and 0.5 mg, respectively, per kilogram of host body weight were necessary for an increase in mortality over controls. These latter findings are comparable to those reported for other tick species but differ from those reported for the northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago). Further testing narrowed the effective dose range for O. parkeri adults to between 0.425 and 0.450 mg/kg host body weight. The time interval (4, 8, and 24 h) between ivermectin injection of the host and tick feeding had only a slight influence on the overall effectiveness of the drug. In O. parkeri, doses of 0.0125 to 0.1000 mg/kg body weight did not affect fecundity, hatchability, gross morphology of the reproductive system and synganglion, or histology of the reproductive system. Contrary to reports of irreversibility of effects of ivermectin on gamma aminobutyric acid-mediated neurotransmission, many ivermectin-paralyzed ticks recovered partial mobility over time.

Animals↗
PubMedDate not supplied

[Influence of acari of house dust in the tiology of infantile asthma].

We have studied 61 children with a previous diagnosis of a possible allergic disease showing clear symptoms in relation to the respiratory system (rhinitis, asthma, etc.). In all cases prick tests were carried out with house-dust extracts Dermatophagoides pteronyssinus, D. farinae, T. putrescentiae, A. siro and A. siro + Cheyletus spp. Commercial extracts (Bencard) were used for the former two; the remainder were prepared from the pure culture of the corresponding acari. The technique followed has been described separately. From the results obtained (see Table I) the following conclusions have been reached: 1. The acari of the Dermatophagoides species particularly D. peteronyssinus) are those mainly responsible for the antigenic capacity of house-dust studied in the geographic area of Barcelona and its surroundings. 2. A similarity but no antigenic identity exists between the antigenic extracts of D. pteronyssinus and D. farinae. 3. The many positive reactions shown by many patients to the various species of acari frequently found in house-dust are due not so much to the antigenic similarity of these acari as to the multiple sensitization or special condition of the individual person. 4. The allergens proceeding from different species of the Tyroglyphidae family, possibly possess a certain antigenic relationship. 5. Finally, it can be asserted that despite the important role played by the acari of the Dermatophagoides species among the different allergenic components of house-dust, it is the remaining acarian fauna present in this dust biocenosis that also has a distinct influence.

Acari↗
PubMed1985

Pheromones and other semiochemicals of the acari.

In contrast to the exceptional diversity of semiochemical-regulated behavior in the insects, chemical communication in the Acari is restricted to a few limited roles. These include clustering, mate-finding processes, host- and food-finding processes, and dispersal. No evidence of pheromones regulating oviposition, necrophoric behavior, recognition of hive mates, or many other processes found in numerous insect groups has been reported in the Acari. Perhaps the most noteworthy feature of acarine pheromones or allomones is the use of the same or similar molecules by many species. Metastriate ixodids use volatile phenols to regulate courtship behavior and, in at least one species, feeding site selection and attachment as well. Argasid ticks use a water- or saline-soluble assembly pheromone, which appears to represent a single type of compound, if not the identical compound in all cases. Acarid mites use terpenoids as alarm pheromones and allomones, while certain phytoseiid and tetranychnid mites use terpene alcohols as arrestant sex pheromones. Another notable feature of acarine pheromones is the use of multicomponent signals to regulate different events in the behavioral process. Thus, two separate sex pheromones are necessary to successfully complete courtship in certain Dermacentor ticks, while three pheromones appear necessary to complete feeding-site selection, attachment, and clasping in certain Amblyomma species. In other cases, a combination of chemical and physiological signals is used to regulate courtship. Although the same or similar compounds may be used for chemical communication, no universal model describes the behavior of all species in an acarine family or order. Species-specific differences in perception of pheromone concentration, molecular composition, aphrodisiacs, and other selective signals facilitate species isolation, even though the initial steps in the behavior are similar in all species. This combination of unity and diversity allows economy in the biosynthesis of semiochemicals without compromising species integrity. In the brief period following the pioneering discoveries of pheromones in ticks (8) and mites (16, 17), evidence of a variety of acarine semiochemicals has been obtained, several pheromones and allomones have been identified, a sex pheromone gland has been described, and considerable effort has been directed to understanding the regulation of pheromone activity. Nevertheless, our knowledge of communication in this large and exceptionally diverse group is meager.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1975

Neurosecretory system of the American Dog Tick, Dermacentor variabilis (Acari: Ixodidae). ii. Distribution of secretory cell types, axonal pathways and putative neurohemal-neuroendocrine associations; comparative histological and anatomical implications.

Histological observations using specialized techniques reveal neurosecretory cells in 18 centers throughout the rind (cortex) of the central nerve mass or synganglion of Dermacentor variabilis. Many cells contribute to complicated networks of neurosecretory pathways and tracts in pre- and post-esophageal portions of the synganglion. The four types of neurohemal-neuroendocrine associations found in Dermacentor resemble structures found in soft ticks (Argasidae) and in other Arachnida, but are more diverse than those described from any other single species. Neurosecretory terminals are distributed diffusely and in two concentrated associations within the perineurium of the synganglion and major peripheral nerves. Terminals are also distributed in the perineurial layers of lateral segmental organs which lie in the general hemocoel at the level of the pedal nerves. A retrocerebral organ complex surrounds the esophagus at its junction with the midgut. The complex includes dorsal and ventro-lateral lobes (containing neurosecretory terminals and intrinsic secretory cells1 and the proventricular (neurohemal) plexus. This plexus seems to be a modified (concentrated) cardioglial association. Cardioglial associations are also formed by the neurosecretory innervation of vascular walls of the dorsal aorta and circulatory sinuses which envelope the synganglion and major peripheral nerves. Inferential considerations of neurosecretory and endocrine interactions in the Acari are based on these anatomical and histological data which also provide the basis for evolutionary considerations of anatomical relationships and specializations in the neurosecretory systems of other Arachnida.

Acari↗
PubMed1992

The colonisation of new houses by house dust mites (Acari: Pyroglyphidae).

House dust mites, Dermatophagoides species (Acari: Pyroglyphidae), produce allergens, known for the provocation of asthma and other allergic reactions. To determine the time needed for complete colonisation of a new house by house dust mites, dust samples were collected from carpets of houses varying from 2 weeks to 2 years in age. In contrast to the expectation, no relation was found between age of the houses on the one hand and average levels of mite-allergens Der pI and Der pII and mite numbers on the other. However, presence of dogs appeared to be positively related to allergen levels. Furthermore, carpets in bedrooms appeared to contain more allergens than carpets in living-rooms. Finally, the age of the mattress was not related to allergen levels of bedroom floors.

Allergens↗
PubMed1992

Control of the straw itch mite (Acari: Pyemotidae) with sulfur in an insect rearing facility.

The ectoparasitic mite Pyemotes tritici (Lagrèze-Fossat & Montané) (Acari: Pyemotidae) caused paralysis and reduced longevity in eucalyptus longhorned borer, Phoracantha semipunctata F., under laboratory rearing conditions. Application of dusting sulfur to logs that contained pupating borers greatly reduced densities of mites on emerging adult beetles and increased beetle survivorship. Uniform application to all logs in a glasshouse effectively eradicated the mite infestation. A bioassay showed that sulfur may physically impede the dispersal of immature mites by adhering to the cuticle, but sulfur vapor did not act as a toxin.

Animals↗
PubMed1990

Taxonomic relationships of the subgenus Rhipistoma (Acari: Ixodidae: Haemaphysalis).

The possible evolution of the haemaphysalid subgenus Rhipistoma (Koch) (Acari: Ixodidae, Haemaphysalis) is postulated. H. hispanica and H. caucasica seem to be the most primitive species of the subgenus, closely related to a common ancestor, as can be deduced from the palpal outline and from the combination of spines and spurs on the coxae and palpi. However, H. adleri, H. asiatica, H. fossae, H. eupleres, and H. obtusa compose a group of phylogenetically more-advanced species, based on the development of complex palpal structures in the adults, but which have also retained some of the more primitive characteristics in the immature stages. An evolutionary line containing many species seems to have developed from the subgroup H. hispanica (bequaerti, cooleyi, hyracophila, calcarata, and houyi), as inferred from the morphological features of the palpi. The data from lemuris suggest a distant relationship with the H. asiatica group. H. bartelsi and H. koningsbergeri seem to have evolved from a common ancestor of the subgenus (or even from the subgroup hispanica) because they share primitive morphological characteristics. Also, H. heinrichi and H. indica may be considered as two modern members within the indica subgroup, from which H. canestrinii seems to have originated. The data from the canestrinii group suggest the existence of a relationship between the indica-heinrichi-canestrinii subgroup, spinulosa subgroup and leachi subgroup, because they share many morphological features. H. bartelsi and H. koningsbergeri would remain as two species of a primitive pathway from the common ancestor of the subgenus, evolving to the canestrinii subgroup. H. erinacei and its subspecies form a group with several primitive features, linking it to the subgenus Ornithophysalis. Also, H. pedetes and H. zumpti are two very similar species that appear to have evolved from an arinacei-like ancestor. It seems possible that the leachi and spinulosa subgroups have evolved from a complex of species included today in the spinulosa and canestrinii subgroups.

Animals↗
PubMed1990

Bioenergetic consequences of alopecia induced by Dermacentor albipictus (Acari: Ixodidae) on moose.

Fasting metabolic rates, respiration rates, respiratory minute volumes, and fasted weights were measured on three yearling moose (Alces alces (L.)) (Artiodactyla: Cervidae) infested with 50,000 winter ticks. Dermacentor albipictus (Packard) (Acari: Ixodidae), and on two uninfested controls. Infestations produced no detectable effects on fasting metabolic rates or weight changes. The influence of tick-induced alopecia on lower critical temperatures could not be assessed because of warm temperatures during the winter and spring trials. Destruction of winter hair accompanied a reduction in respiratory minute volumes and respiration rates of heat-stressed moose.

Alopecia↗
PubMed1991

Laboratory biology of Hyalomma truncatum (Acari: Ixodidae).

The life cycle of Hyalomma truncatum Koch (Acari: Ixodidae) required an average of 108 d at 26 +/- 1 degree C. 92-96% RH, and a 12:12 (L:D) photoperiod to complete. Mean weights of unfed larvae, nymphs, and females were 0.02, 0.19, and 11.1 mg, respectively. Weight of larvae, nymphs, and females increased 20-, 91-, and 48-fold, respectively, as a result of feeding on guinea pigs. All stages exhibited host-seeking behavior less than 1 d after emergence. The mean (+/- SE) feeding period of larvae, nymphs, and adults was 3.8 (+/- 0.1), 7.7 (+/- 0.3), and 8.3 (+/- 0.3) d, respectively. Larvae and nymphs molted an average of 11.0 (+/- 0.3), and 30.7 (+/- 0.2) d after engorgement, respectively. The female/male sex ratio, as determined from emerged adults, was 1.4:1. Oviposition started an average of 11.9 (+/- 0.8) d after engorgement, and a mean of 6.701 eggs per female was deposited. A total of only 48% of the eggs enclosed after a mean incubation of 35 (+/- 1.1) d. Females converted 56% of their engorged weight into eggs and produced an average of 12,614 (+/- 2.0) eggs/g of engorged body weight. On the first day of oviposition, an egg less than 24 h old weighed an average of 44.8 (+/- 1.5) micrograms. Egg weight was significantly (P less than 0.01) lower during peak egg production (days 2-8 after onset of oviposition) than during reduced egg production (days 14-20 after onset of oviposition).

Animals↗
PubMed1992

Ewingana (Doreyana) baekelandae, sp. n., a parasite of molossid bats in Spain (Acari: Myobiidae).

Ewingana (Doreyana) baekelandae sp. n. (Acari: Myobiidae) is described on the basis of several adults and immatures collected on Tadarida (T.) teniotis from the province of Teruel, Spain. The species is a Palearctic representative of the evolutive line nanula Fain and digitata Fain. Differences within these species are observed in the female genito-anal area and in the shape and size of leg I, both in adults and in immatures.

Animals↗
PubMed1992

Molecular approach in spider mites (Acari: Tetranychidae): preliminary data on ribosomal DNA sequences.

DNA sequence data were used to examine phylogenetic relationships between six species of economically important Tetranychidae mites: Eotetranychus carpini (Oudemans), E. pruni (Reck), Tetranychus pacificus McGregor, T. mcdanieli McGregor, T. turkestani Ugarov & Nikolski and T. urticae Koch. With primers directed toward conserved elements flanking the target region, the Polymerase Chain Reaction was used to amplify the ITS2 spacer of the ribosomal DNA molecule. The nucleotide sequence of a 300-bp fragment of the ITS2 was determined by direct sequencing and nucleotide divergence used for intra-generic comparison in mites. The resulting phylogenetic tree expressing interspecific relationships in genus Tetranychus agrees with morphological data. The study demonstrates the usefulness of the approach in the assessment of the systematics and evolution of the group.

Acari↗
PubMed1979

Fate of fragments and properties of translocations of holokinetic chromosomes after X-irradiation of mature sperm of Tetranychus urticae Koch (Acari, Tetranychidae).

After irradiation of mature sperm in males of Tetranychus urticae, early cleavage stages were scored for chromosome fragments. As expected from the presumed holokinetic nature of the chromosomes, the majority (94.29%) of the fragments pass mitosis without difficulty. A minority of the fragments is affected by loss (4.76%) or missegregation (0.95%), leading to loss of fragments from cells in a large fraction of fragment-containing eggs after a few divisions. Lethality induced by the irradiation treatment can probably be ascribed to these losses. When meiotic configurations of F1 females are analysed, translocations turn out to be the most frequent type of aberration, often accompanied by recessive lethal mutations, thus adding an extra amount of lethality to the already high number of non-viable haploid offspring of heterozygous F1 females. The frequently occurring infecundity of the F1 females may be caused by mechanical problems in early stages of meiosis (before oviposition), when multivalents are not able to perform the specific turning movements typical for this type of chromosome. According to calculations, univalents in meiotic stages are thought to represent translocated chromosomes rather than independent fragments.

Acari↗