Structural Elucidation and Synthesis of 3-Hydroxybenzene-1,2-dicarbaldehyde from Astigmatid Mites

The structure of a novel aromatic compound contained in the unidentified Rhizoglyhus mite (Acaridae: Astigmata) was elucidated, without its isolation, to be 3-hydroxybenzene-1,2-dicarbaldehyde (tentatively named γ-acaridial) by a combination of GC/MS and GC/FT-IR together with knowledge of related mite compounds. The structure was confirmed by a 5-step synthesis, starting from methyl 3-hydroxybenzoate, in a 15% overall yield. The compound is widely distributed not only among Astigmata but also among Oribatida, although its biological function is obscure at present.     

3-(4-Methyl-3-pentenyl)-2(5H)-furanone, alpha,alpha-acariolide and 4-(4-methyl-3-pentenyl)-2(5H)-furanone, alpha,beta-acariolide: new monoterpene lactones from the astigmatid mites, Schwiebea araujoae and Rhizoglyphus sp. (Astigmata: Acaridae)

A new monoterpene lactone from the acarid mite, Schwiebea araujoae, was elucidated without its isolation by GC/FT-IR and GC/MS analyses to be 3-(4-methyl-3-pentenyl)-2(5H)-furanone (1) and tentatively named as alpha,alpha-acariolide. The structure of 1 was identified by its synthesis from alpha-bromo-gamma-butyrolactone via 4 reaction steps. The synthesized compound gave the same GC/MS and GC/FT-IR spectra as those of the natural product. The other monoterpene lactone was likewise elucidated from the unidentified Rhizoglyphus mite to be 4-(4-methyl-3-pentenyl)-2(5H)-furanone (2) and named as alpha,beta-acariolide; it was also identified by its synthesis in 5 reaction steps from the same butyrolactone as the starting material. GC/MS and GC/FT-IR spectra of the preparation were identical to those of the natural product.     

Molecular phylogeny of oribatid mites (Oribatida, Acari): evidence for multiple radiations of parthenogenetic lineages

Nucleotide sequences of the D3 expansion segment and its flanking regions of the 28S rDNA gene were used to evaluate phylogenetic relationships among representative sexual and asexual oribatid mites (Oribatida, Acariformes). The aim of this study was to investigate the hypothesis that oribatid mites consist of species-rich clusters of asexual species that may have radiated while being parthenogenetic. Furthermore, the systematic position of the astigmate mites (Astigmata, Acariformes) which have been hypothesised to represent a paedomorphic lineage within the oribatid mites, is investigated. This is the first phylogenetic tree for oribatid mites s.l. (incl. Astigmata) based on nucleotide sequences. Intraspecific genetic variation in the D3 region was very low, confirming the hypothesis that this region is a good species marker. Results from neighbour joining (NJ) and maximum parsimony (MP) algorithms indicate that several species-rich parthenogenetic groups like Camisiidae, Nanhermanniidae and Malaconothridae are monophyletic, consistent with the hypothesis that some oribatid mite groups diversified despite being parthenogenetic. The MP and maximum likelihood (ML) method indicated that the D3 region is a good tool for elucidating the relationship of oribatid mite species on a small scale(genera, families) but is not reliable for large-scale taxonomy, because branches from the NJ algorithm collapsed in the MP and ML tree. In all trees calculated by different algorithms the Astigmata clustered within the oribatid mites, as proposed earlier.     

7-Hydroxyphthalide: a new natural salicylaldehyde analog from Oulenzia sp. (Astigmata: Winterschmitiidae)

A new salicyl lactone was detected from the unidentified Oulenzia sp. and its chemical structure was elucidated as 7-hydroxyphthalide (7-hydroxy-3H-isobenzofuran-1-one), based on its GC/MS and GC/FT-IR data and SiO2 column behavior. The compound was synthesized by NaBH4 reduction of 3-hydroxyphthalic anhydride. The GC/MS and GC/FT-IR spectra of the natural compound were consistent with those of the synthetic product. Although the compound is known as a medical material, this is the first example of its presence in nature.     

Mite species identification in the production of allergenic extracts for clinical use and in environmental samples by ribosomal DNA amplification

The identification of allergy‐causing mites is conventionally based on morphological characters. However, molecular taxonomy using ribosomal DNA (rDNA) may be particularly useful in the analysis of mite cultures and purified mite fractions in the production of allergenic extracts. Full‐length internal transcribed spacers (ITS1 and ITS2) were obtained from Dermatophagoides farinae, Dermatophagoides pteronyssinus, Dermatophagoides microceras and Euroglyphus maynei (Astigmata: Pyroglyphidae), Glycyphagus domesticus and Lepidoglyphus destructor (Astigmata: Glycyphagidae), Tyrophagus fanetzhangorum, Tyrophagus putrescentiae, Tyrophagus longior, Tyrophagus neiswanderi, Acarus farris and Acarus siro (Astigmata: Acaridae), and Blomia tropicalis (Astigmata: Echymopodidae), using mite‐specific primers. Polymerase chain reaction (PCR) products were digested with HpaII and RsaI restriction enzymes in order to produce species‐specific PCR restricted fragment length polymorphism (RFLP) profiles. A semi‐nested re‐amplification step was introduced before the RFLP in order to apply the method to environmental samples. Results demonstrate that rDNA sequences can be used for the unambiguous identification of mite species. The PCR–RFLP system allows the identification of species in purified mite fractions when the availability of intact adult mite bodies for morphological identification is limited. This reliable and straightforward PCR–RFLP system and the rDNA sequences obtained can be of use in the identification of allergy‐causing mite species.     

7-Hydroxyphthalide: A New Natural Salicylaldehyde Analog from Oulenzia sp. (Astigmata: Winterschmitiidae)

A new salicy lactone was detected from the unidentified Oulenzia sp. and its chemical structure was elucidated as 7-hydroxyphthalide (7-hydroxy-3 H-isobenzofuran-1-one), based on its GC/MS and GC/FT-IR data and SiO₂ column behavior. The compound was synthesized by NaBH₄ reduction of 3-hydroxyphthalic anhydride. The GC/MS and GC/FT-IR spectra of the natural compound were consistent with those of the synthetic product. Although the compound is known as a medical material, this is the first example of its presence in nature.     

Identification of the New Hydrocarbon (Z,Z)-1,6,9-Heptadecatriene as the Secretory Component of Caloglyphus polyphyllae (Astigmata: Acaridae)

A new heptadecatriene was isolated from the acarid mite, Caloglyphus polyphyllae, as the major characteristic component which could be used to identify the species chemo-taxonomically. Its structure was elucidated as 1,6,9-heptadecatriene by partial hydrogenation and a subsequent GC/MS analysis of the dimethyldisulfide derivative, together with evidence of the terminal vinyl group and Z-configuration of double bonds that was provided by GC-FT/IR and NMR. The triene was identified as (Z,Z)-1,6,9-heptadecatriene by its synthesis and is revealed to be a new compound as a natural product.     

The phylogenetic relationship between Astigmata and Oribatida (Acari) as indicated by molecular markers

Astigmata comprise a diverse group of acariform mite species with a remarkable range of life histories, most of which involve parasitic or commensal relationships with other organisms. Several authors have suggested that Astigmata evolved as a paedomorphic clade from within Oribatida, and both morphology and gland-chemistry strongly suggest that their sister-clade is within the oribatid subgroup Desmonomata. The biologies of these groups contrast greatly, since oribatid mites are mostly soil-living detritivores and fungivores, and have life cycles that are much longer than those in Astigmata. We tested the hypothesis that Astigmata evolved from within Desmonomata using two molecular markers, the ribosomal 18S region (18S) and the nuclear elongation factor 1 alpha (ef1α) gene. Representative acariform mites included 28 species of Oribatida, eight of Astigmata, two of Prostigmata and two of Endeostigmata; outgroups included members of Opilioacariformes, Parasitiformes and Ricinulei. To minimize the possibility of long-branch attraction artifacts, we limited highly variable sites by removing gaps (18S) and third codon positions (ef1α) from the sequences. Maximum parsimony, neighbor-joining and Bayesian algorithms formed trees that consistently placed Astigmata outside monophyletic Oribatida, usually as sister-group of the endeostigmatid mite Alicorhagia sp. Analyses with and without outgroups resulted in similar topologies, showing no evidence for long-branch artifacts and leaving the conflict with morphological and biochemical data unexplained.     

Feather mites and birds: an interaction mediated by uropygial gland size?

Feather mites (Arachnida: Acari: Astigmata) feed mainly on secretions of the uropygial gland of birds. Here, we use analyses corrected for phylogeny and body size to show that there is a positive correlation between the size of this gland and mite abundance in passerine birds at an interspecific level during the breeding season, suggesting that the gland mediates interactions between mites and birds. As predicted on the basis of hypothesized waterproofing and antibiotic functions of uropygial gland secretions, riparian/marsh bird species had larger glands and higher mite loads than birds living in less mesic terrestrial environments. An unexpected pattern was a steeper relationship between mite load and gland size in migratory birds than in residents. If moderate mite loads are beneficial to a host but high loads detrimental, this could create complex selection regimes in which gland size influences mite load and vice versa. Mites may exert selective pressures on gland size of their hosts that has resulted in smaller glands among migratory bird species, suggesting that smaller glands may have evolved in these birds to attenuate a possible detrimental effect of feather mites when present in large numbers.     

(E)-2-(2-Hydroxyethylidene)-6-methyl-5-heptenal (alpha-acariolal) and (E)-2-(2-hydroxyethyl)-6-methyl-2,5-heptadienal (beta-acariolal), two new types of isomeric monoterpenes from Caloglyphus polyphyllae (Acari: Acaridae)

The opisthonotal gland secretion of the acarid mite, Caloglyphus polyphyllae, contained two new monoterpenes, (E)-2-(2-hydroxyethylidene)-6-methyl-5-heptenal (1) and (E)-2-(2-hydroxyethyl)-6-methyl-2,5-heptadienal (2), to which we have given the trivial names alpha- and beta-acariolal in relation to alpha- and beta-acaridial (3 and 4), respectively. Elucidation of the structure of 1 was established mainly from 1H-NMR and GC/MS spectral data after partial purification, together with the fact that 1 was recovered in the more-polar fraction from a silica gel column than alpha- and beta-acaridial (3 and 4) present in the secretion. Compound 2 was obtained in the same fraction as a mixture with 1. Based on the facts that 2 had the same molecular weight by GC/MS and the same polarity as that of 1, compound 2 was assumed to be a structural analog of 1. The structures of compounds 1 and 2 were confirmed by their synthesis in nine and ten respective steps starting from alpha-bromo-gamma-butyrolactone.     

Ecdysial cleavage lines of acariform mites (Arachnida, Acari)

Among mites the ancestral ecdysial cleavage line, or line of dehiscence (a), is inferred by outgroup comparison to be prodehiscent: U-shaped, passing around the front of the mite just above the insertions of the appendages, such that the mite ecloses anteriorly. From preserved and living individuals and exuviae, we found prodehiscence (or its slight variations) to be widespread in Acariformes. It appears to be pervasive in endeostigmatic mites, eupodine Prostigmata, and basal taxa in the Oribatida (Enarthronota, Palaeosomata); it is dominant in cleutherengone Prostigmata and is present in at least one anystine family (Caeculidae). Three general modes of dehiscence are considered to be derived within acariform mites. (1) Merodehiscence is a transverse splitting of the dorsal cuticle at or near the juncture of proterosoma and hysterosoma; it evolved separately in thrcc groups of Prostigmata (Tetranychidae, an undefined subgroup within Cheylctidae, and active instars of Parasitengona) and in a genus of Astigmata (Histiogaster). (2) Trarnsdehiscence is a transverse splitting of the dorsal hysterosomal cuticle anterior to the opisthosomal glands; it occurs in middle-derivative oribatid mites (the paraphyletic Desmonomata), and new observations show it to be widespread in Astigmata, lending support to the hypothesis that the latter group evolved from within Desmonomata. (3) Circumdehiscence is a circumferential splitting of the hysterosomal cuticle that may be incomplete anteriorly; it has long been known to characterize the monophyletic oribatid taxon Brachypylina, but it is convergent with a similar dehiscence in an unrelated family, Lohmanniidae. Transdehiscent and circumdehiscent mites eclose posteriorly. Astigmata exhibit the greatest variety of modes of dehiscence, including the three derived modes and a probable reversal to prodehiscence in Algophagidae. Furthermore, heteromorphic deutonymphs (hypopi) may ecdyse differently from other immature instars of the same species.     

Bulb mite,Rhizoglyphus robini (Astigmata: Acaridae) as an experimental animal

Rhizoglyphus robini Claparède (Acari: Astigmata: Acaridae) is proposed as a model laboratory animal for biological, ecological, physiological and toxicological studies. The mite is easy and inexpensive to rear, quite fecund, convenient to manipulate, and may rapidly be raised to gram quantities. Examples are presented of its use in soil pest ecology and control studies, and in physiological, biochemical and toxicological investigations. Efforts to explore the induction of detoxification systems by various chemicals, and a demonstration of its control by solarization, are also described.     

Sperm structure and phylogeny of Astigmata

The Astigmata, a large and variable group, is still a subject of taxonomic dispute. Particularly, their origin from ancestors of the lower oribatid mites (e.g., Malaconothroidea) seems well documented by many lines of evidence. The structure of spermatozoa has been successfully applied to phylogenetic investigations in many animal groups. The aim of our study was to provide new data on spermatozoon structure in Astigmata and to consider its appropriateness in phylogenetic studies. The study reveals information on spermatozoa in 17 species of Astigmata (11 species studied for the first time) extending our knowledge to 18 species (one species known only from the literature) representing 12 families and 7 superfamilies. Spermatozoa have the same basic structure in all species: cells are multiform and the chromatin forms thin threads embedded directly in the cytoplasm; the acrosome is absent. The cytoplasm in most species contains electron-dense lamellae, varying in both number and arrangement within the cell. In Sarcoptoidea, electron-dense tubules in contact with lamellae margins were also observed in Psoroptidae (Psoroptes equi), whereas in two representatives of Sarcoptidae (Notoedres cati and Sarcoptes scabiei), only electron-dense tubules were found. In two species, Canestrinia sellnicki (Canestrinioidea: Canestriniidae) and Scutulanyssus obscurus (Analgoidea: Pteronyssidae), neither lamellae nor tubules were present. The mitochondria in a spermatozoon are usually gathered at the cell periphery and their structure is usually modified to form so-called mitochondrial derivatives. The chromatin threads are an autapomorphy strongly supporting the monophyly of Astigmata. As spermatozoa vary considerably between species in Astigmata, we deduce that sperm structure may be useful for phylogenetic analyses within the group. Several conclusions concerning the affinities within Astigmata are presented. Spermatology seems to be unhelpful, however, in questions on the origin of Astigmata (particularly for Astigmata-Oribatida relationships), since their sperm do not possess synapomorphies with sperm of the remaining groups of Acariformes, i.e., Endeostigmata, Prostigmata, and Oribatida.     

Vertical transmission in feather mites: insights into its adaptive value

1. The consequences of symbiont transmission strategies are better understood than their adaptive causes. 2. Feather mites are permanent ectosymbionts of birds assumed to be transmitted mainly vertically from parents to offspring. The transmission of Proctophyllodes doleophyes Gaud (Astigmata, Proctophyllodidae) was studied in two European populations of pied flycatchers, Ficedula hypoleuca Pallas (Passeriformes, Muscicapidae). 3. The vertical transmission of this mite species is demonstrated here with an acaricide experiment. This study also compared (for two distant populations during 4 years) patterns in reductions in mite intensity in adult birds, from egg incubation to chick‐rearing periods, with the predictions of three hypotheses on how host survival prospects and mite intraspecific competition might drive feather mites' transmission strategy. 4. The results are in agreement with previous studies and show that feather mites transmit massively from parents to chicks. 5. The magnitude of the transmission was closer to that predicted by the hypothesis based on intraspecific competition, while a bet‐hedging strategy is also partially supported.     

House dust mite fauna in western Anatolia, Turkey

House dust mites play an important role in the pathogenesis of allergic diseases. Many factors may influence mite growth. The presence of mites is related to mean temperature and humidity as well as altitude. The aim of this study was to analyze the mite fauna in 5 regions of western Anatolia, Turkey, that have similar climatic properties with low mean temperature and humidity, but differ in altitude. During the period October-November 2004, house dust was collected from 290 homes in 5 different cities. House dust mites were isolated in 67 (23.1%) of 290 samples. The family Pyroglyphidae (Astigmata) was present in all positive samples. This study suggests that the selected western Anatolian regions that share similar environmental conditions host similar dust mite populations.     

Morphological evidence for the evolutionary origin of Astigmata (Acari: Acariformes)

A century ago, Antonio Berlese first discussed the close phylogenetic relationship between the large mite groups Oribatida and Astigmata. Since then, information having phylogenetic value has greatly increased and the paradigms within which we interpret it have changed. Herein I refine the general hypothesis that Astigmata originated within oribatid mites and suggest Malaconothridae as a possible sister group. Among the 14 apomorphies used to support the origin of Astigmata within oribatid mites are possession of lateral opisthosomal glands, regression of hysterosomal setal pair f1, paired prelarval denticles, partially internalized chelicerae with incomplete adaxial walls, an atelobasic rutellum, pretarsal condylophores that articulate posteriorly with the tarsus, a dorsally fused palp tibia and tarsus and transdehiscent ecdysis. A further 13 apomorphies support the origin of Astigmata at some level within Malaconothroidea. These include absence of an oblique labiogenal articulation, presence of a distal rutellar lamella, shortening of the palp tarsus, larval regression of hysterosomal seta f2, loss of the bothridial seta in all instars, and several losses and modifications of leg setae. The hypothesis brings to light evolutionary questions that were previously obscured by incorrect or inappropriate classifications. The nomenclatural problems that arise from it are best solved by considering Astigmata as a subgroup within Oribatida.     

Sex allocation by a mite parasitic on insects: local mate competition,host quality and operational sex ratio

The aim of this study was to test the predictions of local mate competition (LMC), host quality (HQ) and operational sex ratio (OSR) models, using a non-arrhenotokous parasitic mite, Hemisarcoptes coccophagus (Astigmata: Hemisarcoptidae). The life-history pattern of this mite meets the assumptions of these sex allocation models. Mating group size (LMC model), HQ and OSR affected the sex allocation of H. coccophagus females. Only young mite females adjusted the sex ratio of their progenies according to the predictions of LMC and HQ models; the sex allocation of old females was contrary to these predictions. We explain these patterns by the dynamic nature of the mite's population structure. When parents are young, their population distribution is patchy and progeny matings are local; hence sex allocation is in accordance with LMC theory. When parents become older, their populations shift towards panmixis; factors which had operated previously no longer exist. Consequently, females adjust the sex ratio of late progenies so that it can compensate for the earlier sex allocation, in order to make their total sex ratio unbiased, as expected in panmictic populations. Our data, expressed as the cumulative sex ratio, support this hypothesis.     

Mating frequency as an indication of food quality for the bulb mite,Rhizoglyphus robini Claparède

Mating frequency of the bulb mite, Rhizoglyphus robini Claparède (Astigmata: Acaridae) was recorded for 23 days on 6 concentrations of peanut extract. The largest numbers of couplings and of adults were obtained on the undiluted (100%) extract, and the fewest on the most diluted (10%) diet. Good association between mating frequency and adult numbers was also observed on several other foods.     

The feather mite (Astigmata) fauna of some passerine birds (Passeriformes) in the south of Western Siberia

Feather mites (Astigmata) are specialized parasites living on the plumage and skin of birds. The paper presents data on infestation of some passerines (Passeriformes) by feather mites in the south of Western Siberia (Omsk and Tyumen Provinces). We found 24 species of feather mites belonging to the families Analgidae, Dermoglyphidae, Pteronyssidae, Trouessartiidae, and Proctophyllodidae on 16 bird species. Among them, 19 species are common parasites of the passerine birds examined; five species were detected on atypical hosts. Ten mite species were recorded for the first time on the passerine species examined. Analysis of the distribution of abundant and common mite species on their hosts has demonstrated that the majority of the bird parasites possess a specific distribution pattern in the host plumage with preference for certain feather types. We have also obtained new data on host associations of several mite species.     

Carcases and mites

Mites are involved in the decomposition of animal carcases and human corpses at every stage. From initial decay at the fresh stage until dry decomposition at the skeletal stage, a huge diversity of Acari, including members of the Mesostigmata, Prostigmata, Astigmata, Endeostigmata, Oribatida and Ixodida, are an integral part of the constantly changing food webs on, in and beneath the carrion. During the desiccation stage in wave 6 of Mégnin’s system, mites can become the dominant fauna on the decomposing body. Under conditions unfavourable for the colonisation of insects, such as concealment, low temperature or mummification, mites might become the most important or even the only arthropods on a dead body. Some mite species will be represented by a few specimens, whereas others might build up in numbers to several million individuals. Astigmata are most prominent in numbers and Mesostigmata in diversity. More than 100 mite species and over 60 mite families were collected from animal carcases, and around 75 species and over 20 families from human corpses.