An astigmatid defence volatile against a phytoseiid mite

Numerous semiochemicals have been isolated from several species of astigmatid mites with various identified or unidentified functions. Alarm pheromonal activity is widespread with neryl formate and neral, being the most common compounds eliciting alarm response in conspecifics. The cosmopolitan astigmatid mite Suidasia medanensis (= S. pontifica) Oudemans (Acari: Suidasidae) has been reported to use neral as an alarm pheromone, but neral can also act as an allomone towards predators of oribatid mites. Suidasia medanensis can be utilised as a factitious prey for mass‐rearing of the phytoseiid predatory mite Amblyseius (= Typhlodromips) swirskii (Athias‐Henriot) (Acari: Phytoseiidae), which is used for biological control of insect and mite pests in protected crops. This study investigated the potential defence properties of the S. medanensis volatiles against A. swirskii, comparing the repellency to pollen‐reared (naïve) vs. S. medanensis‐reared (experienced) predators using a synthetic blend of the isomers neral and geranial (1:1) as a model compound. In a repellency bioassay, the synthetic blend elicited a significant repellence to A. swirskii with no difference between naïve and experienced predators. During capture success studies, S. medanensis under repeated attack could release sufficient quantities of the defence volatile to deter 1–5 attacks from A. swirskii, whereas hexane‐treated S. medanensis artificially depleted of volatiles were significantly more vulnerable to an attack. This is the first report of an astigmatid defence volatile with repellent activity to a phytoseiid mite and the starting point to understanding semiochemical interactions in any current or novel factitious predator‐prey mass‐rearing system.     

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.     

Ecological and morphological attributes of parthenogenetic Japanese Schwiebea species (Acari: Acaridae)

We examined life history traits and spermathecal morphology of both sexual and thelytokous Schwiebea mite species to determine ecological and morphological attributes during the evolution of parthenogenesis in this lineage. We reconstructed a molecular phylogeny of eight Japanese species using the internal transcribed spacer 1 (ITS1) of the ribosomal DNA (rDNA) and compared the sex ratio, developmental period, and egg number (fecundity) of each species within a species group by rearing them in the laboratory. Habitat preference was also analyzed from both collection and literature data. The reconstructed molecular phylogeny suggested that parthenogenesis evolved independently multiple times in this lineage. There were three clusters in the tree, in each of which the idiosoma, leg, setae, and spermathecal morphology of females was similar or identical; this suggested that mites in the same cluster were sister species. There was no relationship between sexual mode and life history traits or habitat preference. These results suggest that sexual and asexual species use different microhabitats. Because S. similis (sexual), S. elongata (thelytokous), and S. estradai (thelytokous) were in the same cluster and spermathecae of the first two were similar while that of the last was distinctively reduced, we hypothesized that speciation occurred in this order and that spermathecae are reduced and eventually lost during the course of parthenogenetic evolution.     

New feather mites of the family Pterolichidae (Acari: Pterolichoidea) from parrots (Aves: Psittaciformes) in Australia

Abstract Seven new feather mite species of the family Pterolichidae are described from various Australian parrots: Apexolichus lathami sp. n. from the swift parrot, Lathamus discolor (Shaw); Titanolichus platycerci sp. n. and Rhytidelasma punctata sp. n. from the pale-headed rosella, Platycercus adscitus (Latham); R. striata sp. n. from the Australian king-parrot, Alisterus scapularis (Lichtenstein); Lorilichus stenolobus sp. n. and Lorilichus curvilobus sp. n. from the rainbow lorikeet, Trichoglossus haematodus (Linnaeus); Psittophagus galahi sp. n. from the galah, Eolophus roseicapillus (Vieillot). We give a brief overview of taxonomic studies of pterolichid mites living on Psittaciformes, and discuss the main diagnostic characters of different generic groups of these mites.     

An enigmatic lineage of mites from Baltic amber shows a unique,possibly female‐controlled,mating

It is generally assumed that male control over mating and a lack of precopulatory female choice are prevalent in many animals and in astigmatan mites in particular. We show that several morphological structures of females of some astigmatan mites are indicative of precopulatory female choice: (1) copulatory tubes acting like intromittent organs; (2) specialized structures assisting male–female attachment and possibly allowing indirect mate selection in immature females; and (3) a unique, pad‐like terminal opisthosomal organ used to cling to the male during copulation in Glaesacarus rhombeus (= Acarus rhombeus Koch et Berendt, 1854) belonging to an extinct family, Glaesacaridae, from the Upper Eocene Baltic amber. An exceptionally well‐preserved copulating pair from amber provides insight into the function of this organ and reproductive behaviour in this mite. Female control over mating may reduce the timing of insemination, harassment by males, and damage caused by copulation. As a consequence, this can lessen male–male aggression, select against precopulatory guarding, and reduce the risk of predation. By contrast to extant taxa, males of G. rhombeus do not have any apparent specialized structures aiding clinging to the female during copulation, suggesting that this mating system is either an earlier step in the evolution of the female‐dominated mating system and/or a remarkable example of imbalanced female counteradaptations against the male's reproductive interest that may occur during an arms race between the two sexes. We offer an approach that can falsify the hypothesis assuming precopulatory female choice and discuss an alternative hypothesis suggesting that these female structures evolved in response to the need to reduce damage associated with mating or precopulatory guarding. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 661–668.     

Gallilichus jonesi sp. n. (Acari: Ascouracaridae): A new species of feather mite from the quills of the Australian brush-turkey (Aves: Megapodiidae)

Adults, nymphs, larvae and eggs of Gallilichus jonesi sp. n. are described. These mites inhabit the quills of large wing and tail feathers of the megapode Alectura lathami Gray, where they appear to consume the spongy medulla inside the quill. This is the first record of Gallilichus for Australia, and the first observation of quill mites associated with the Megapodiidae. Two nymphal morphologies of G. jonesi were observed and are presumed to represent male and female, but because pharate adults were not found, definitive assignment of morphs to sexes was not possible. The only other species in the genus Gallilichus occurs in the feathers of domestic chickens. The implications of these host-associations for elucidating relationships between the megapodes and other galliform birds are discussed.     

Four new feather mite species of the genus Proctophyllodes Robin(Astigmata:Proctophyllodidae) from China

Four new species of the feather mite genus Proctophyllodes are described from the birds of the order Passeriformes in China:P.flexuosa sp.nov.from Eophona migratoria Hartert(Chongqing),P.brevis sp.nov.from Passer montanus(Linnaeus)(Anhui and Chongqing),P.garrula sp.nov.from Garrulax poecilorhynchus Gould(Anhui),P.canora sp.nov.from Garrulax canorus(Linnaeus)(Guizhou).     

A new species of the feather mite genus Titanolichus Gaud & Atyeo, 1996 (Acari: Astigmata: Pterolichidae) from the endangered orange-bellied parrot Neophema chrysogaster (Aves: Psittaciformes) from Australia

Abstract  Titanolichus seemani sp. n., a new species of the genus Titanolichus Gaud & Atyeo, 1996, is described from a museum skin of the endangered orange-bellied parrot Neophema chrysogaster (Latham) (Aves: Psittaciformes) from Australia. We also redescribe the type species Titanolichus chiragricus (Mégnin & Trouessart) from the ground parrot Pezoporus wallicus (Kerr), provide a key for all known species of Titanolichus and point out some problems in the systematics of this genus.     

A method for both mass and individual rearing of fungivorous astigmatid mites (Acari)

Several species of common fungi were assessed as food for fungivorous astigmatid mites. Hypocrea nigricans, Botrytis cinerea and Flammulina velutipes were generally good food sources for most mites examined. Fungal mycelia growing on PDA (potato dextrose agar) medium were not only nutritionally adequate but the system also maintained high humidity through the water-based agar medium. Among acarid mites, most species of Rhizoglyphinae could be reared easily with the method. Although filter-feeding histiostomatid mites do not feed directly on hyphae, some species were successfully maintained with the same method through multiple generations. Presumably, these mites obtained sufficient nutrition from the agar medium and fungal metabolites leaching into it. Most species ultimately produced dispersing heteromorphic deutonymphs on these media. Individual mites were also maintained in isolation within glass rings on fungal colonies. Using this technique, we were able to compare developmental periods, fecundity and survival periods of mites reared under different conditions.     

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.