James W. Amrine

Recommended procedures and techniques for morphological studies of Eriophyoidea (Acari: Prostigmata)

Methods used for sample storage, specimen clearing, slide mounting, species illustration and morphometric description in alpha-taxonomic studies are essential for the Eriophyoidea. Eriophyoid mites are very tiny and delicate, for which truly permanent specimen slides currently cannot be prepared, resulting in eventual loss of material, including type specimens. Often, published descriptions and drawings have not achieved the required level of quality, and thus many relevant taxonomic details have been permanently lost or neglected. These shortcomings can make certain identifications impossible and cause significant confusion. Consequently, there is a considerable need for accurate and uniform descriptive and illustrative data for the Eriophyoidea. Based on their expertise on this topic, the authors provide guidelines and advices, assisted also by illustrations, of the main critical aspects in managing eriophyoid mites in order to supplement and improve techniques for handling and preparation of specimens, and for improving their taxonomic study. The effects of the short- and long-term preservation methods (i.e., fresh, dried and liquid preservative choices) on digesting the internal tissues of the mites are discussed. Clearing and mounting procedures are analyzed, and special tips are suggested for handling mites and designing tools needed during these steps. Methods for recovering specimens from unsuitable slides (i.e., undercleared and overcleared specimens) are proposed and described. Techniques and tricks to produce descriptive line drawings of good quality are highlighted, and the content to include in plates is stressed. Finally, detailed instructions for standardization of measurements are given.

Behavioural studies on eriophyoid mites: an overview

Eriophyoid mites are excellent candidates for ethological research using the approaches of behavioural ecology and sociobiology. These tiny haplodiploid mites are highly specialized plant parasites, producing galls, forming nests, inhabiting refuges or living freely on plants. They reproduce via spermatophores deposited on a substrate and without pairing, which is a fascinating, though still poorly understood, mode of reproduction widespread in some groups of arthropods. Eriophyoid males can be involved in external sperm competition. In some species they also guard pre-emergent females and deposit spermatophores beside them. Although slow-walking, the minute eriophyoid mites can disperse for long distances on air currents or specific animal carriers. After landing on a plant they can distinguish between suitable and unsuitable hosts. Biological observations on a deuterogynous species indicate that parasociality could occur among eriophyoid mites. Many eriophyoids are of economic importance. Knowledge of their behaviour may promote understanding their ecology, may resolve problems in their phylogeny and may help developing methods for their control. In this paper, attention is directed to dispersal modes of eriophyoid mites, their feeding and host acceptance, spermatophore deposition and mating, defence against predators, and social behaviour.

Host-plant specificity and specialization in eriophyoid mites and their importance for the use of eriophyoid mites as biocontrol agents of weeds

Eriophyoid mites, which are among the smallest plant feeders, are characterized by the intimate relationships they have with their hosts and the restricted range of plants upon which they can reproduce. The knowledge of their true host ranges and mechanisms causing host specificity is fundamental to understanding mite-host interactions, potential mite-host coevolution, and diversity of this group, as well as to apply effective control strategies or to use them as effective biological control agents. The aim of this paper is to review current knowledge on host specificity and specialization in eriophyoid mites, and to point out knowledge gaps and doubts. Using available data on described species and recorded hosts we showed that: (1) 80% of eriophyoids have been reported on only one host species, 95% on one host genus, and 99% on one host family; (2) Diptilomiopidae has the highest proportion of monophagous species and Phytoptidae has the fewest; (3) non-monophagous eriophyoids show the tendency to infest closely related hosts; 4) vagrant eriophyoids have a higher proportion of monophagous species than refuge-seeking and refuge-inducing species; (5) the proportions of monophagous species infesting annual and perennial hosts are similar; however, many species infesting annual hosts have wider host ranges than those infesting perennial hosts; (6) the proportions of species that are monophagous infesting evergreen and deciduous plants are similar; (7) non-monophagous eriophyoid species have wider geographic distribution than monophagous species. Field and laboratory host-specificity tests for several eriophyoid species and their importance for biological control of weeds are described. Testing the actual host range of a given eriophyoid species, searching for ecological data, genetic differentiation analysis, and recognizing factors and mechanisms that contribute to host specificity of eriophyoid mites are suggested as future directions for research.

Genetic Characterization of North American Populations of the Wheat Curl Mite and Dry Bulb Mite

ABSTRACT The wheat curl mite, Aceria tosichella Keifer, transmits at least three harmful viruses, wheat streak mosaic virus (WSMV), high plains virus (HPV), and Triticum mosaic virus (TriMV) to wheat (Triticum aestivum L.) throughout the Great Plains. This virus complex is considered to be the most serious disease of winter wheat in the western Great Plains. One component of managing this disease has been developing mite resistance in wheat; however, identification of mite biotypes has complicated deployment and stability of resistance. This biotypic variability in mites and differential virus transmission by different mite populations underscores the need to better understand mite identity. However, A. tosichella has a history of serious taxonomic confusion, especially as it relates to A. tulipae Keifer, the dry bulb mite. Molecular techniques were used to genetically characterize multiple A. tosichella populations and compare them to populations of A. tulipae. DNA from these populations was polymerase chain reaction amplified and the ribosomal ITS2 region sequenced and compared. These results indicated limited variability between these two species, but two distinct types within A. tosichella were found that corresponded to previous work with Australian mite populations. Further work using sequencing of several mitochondrial DNA genes also demonstrated two distinct types of A. tosichella populations. Furthermore, the separation between these two A. tosichella types is comparable to their separation with A. tulipae, suggesting that species scale differences exist between these two types of A. tosichella. These genetic differences correspond to important biological differences between the types (e.g., biotypic and virus transmission differences). In light of these differences, it is important that future studies on biological response differences account for these mite differences.

Collection and detection of eriophyoid mites

Methods for collecting and detecting eriophyoid mites are crucial components in research, taxonomical and biological studies, and control programs for these organisms. Their small size, their specific host-plant interactions and their hidden life-style make them difficult to find in routine inspections. This review examines successful and unsuccessful approaches for collecting eriophyoid mites, and makes recommendations for their detection, supporting studies in taxonomy, ecology, biology, molecular systematics and population genetics.

Eriophyid Mites (Acari: Eriophyoidea) on Bamboo from China, with Descriptions of Three New Species from the Qinling Mountains

Abstract Three new species of eriophyid mites on bamboo from the Qinling Mountains, northwestern China, are described and illustrated: Tegolophus bashaniae sp. nov. on Bashania fargesii (E. G. Camus) Keng f. et Yi (Poaceae: Bambuseae); Tegolophus fargesiae sp. nov. on Fargesia qinlingensis Yi et J.X. Shao, and Tetraspinus vulgaris sp. nov. on Bambusa vulgaris Schrader ex Wendland. All species are vagrants on leaf surfaces, causing no apparent damage. A key to known eriophyid mites on bamboo from China is provided.

A new species of eriophyoid mite (Acari : Eriophyidae) on sugarcane in Australia

Abstract Seven species of eriophyoid mites (Acari: Eriophyoidea) are known to attack sugarcane plants (Saccharum spp., Poaceae) and related grasses in various parts of the world, but except for unconfirmed reports of Aceria sacchari and Abacarus sacchari, Australia had been thought to be free of these pests. Herein, Abacarus queenslandiensis n. sp. (Eriophyidae), vagrant on leaf surfaces of sugarcane in Australia, is described. Also, Cathetacarus n. gen. is erected for the distinctive mite, Catarhinus spontaneae Mohanasundaram, 1984. In addition, a key to the eriophyoid mites known to occur on sugarcane plants in the world is given.

Supplementary description of Novophytoptus stipae Keifer 1962 (Acariformes, Eriophyoidea) with LT-SEM observation on mites from putatively conspecific populations: cryptic speciation or polyphagy of novophytoptines on phylogenetically remote hosts?

Abstract Supplementary descriptions of an infrequently encountered species Novophytoptus stipae Keifer 1962 (Eriophyoidea, Phytoptidae) from Achnatherum speciosum (Poaceae) based on topotypes recovered from dry plant material from California is given. Comparison of topotypes of N. stipae with fresh Novophytoptus mites from Juncus tenuis and J. balticus (Juncaceae) collected in West Virginia and Ohio failed to reveal distinct morphological differences sufficient enough to establish new taxa. All studied mites are considered belonging to one species, N. stipae. This is putatively an example of polyphagous eriophyoid species inhabiting phylogenetically remote hosts. Remarks on polyphagy and dispersal modes in eriophyoids are addressed. Uncommon features of the gnathosoma and the anal region of novophytoptines were discovered under LT-SEM. These findings emphasize peculiarities of novophytoptines in relation to their endoparasitic life style and underline numerous gaps in our knowledge on anatomy and functioning of the organism of eriophyoid mites.

Reconditioning of the Nalepa collection of eriophyoid mites (Acariformes, Eriophyoidea)

Abstract Alfred Nalepa (19.XII.1856–11.XII.1929), an Austrian acarologist, described about 460 eriophyoid species. He reported new taxa in short communications usually published in “Anzeiger der Kaiserlichen Akademie der Wissenschaften in Wien” and later prepared detailed descriptions for separate publication. For most Nalepan species the date of the first listing in Anzeiger is the valid date of the taxon name. His archive, library and collection are kept in the Natural History Museum of Vienna, Austria (NHMW). The collection consists of 24 boxes with 1073 vials containing plant material with extracted mites collected during 1887–1929. All boxes are labeled according to the first letters of the host-plant names and are sorted alphabetically; the vials are numbered and labeled. A jotter, presumably representing the hand-written catalog of the vial collection, and work diaries, containing indications of numbers of the vials, were found in the Nalepa archives. Nalepa used picric acid, hydrochloric acid, ethanol, formalin and creosote for preservation of mites. In all vials the preservative totally evaporated so that only dry sediment remains at the bottom of the vials. A solution containing ethanol, ether and acetic acid was found to be appropriate for dissolving the sediment. A simple, fast protocol for recovering mites from vials and making good slides was developed. It includes four steps: 1) opening the vial; 2) dissolving the sediment; 3) treating mites in lactic acid; 4) slide mounting. All digital data obtained from the Nalepa archives (database of the vials, copies of the jotter, reprints and drawings of mites) will be available for scientists at the web site of NHMW http://www.nhm-wien.ac.at/en/nalepa.

Eriocaenus (Acari: Trombidiformes: Eriophyoidea), a new genus from Equisetum spp. (Equisetaceae): morphological and molecular delimitation of two morphologically similar species.

Surveys conducted on horsetails, Equisetum spp. (Equisetaceae), in Serbia led to the discovery of a new eriophyoid mite genus while searching for a classical biological control agent against these weeds in New Zealand. Eriocaenus gen. n. is described based on the type species Aceria equiseti Farkas, 1960 (transferred to Eriophyes by Farkas 1965; herein reassigned to the new genus) and Eriocaenus ramosissimi n. sp., a new species discovered on Equisetum ramosissimum Desf. in Serbia. Eriocaenus equiseti (Farkas, 1960), previously only known from Hungary, was found in Serbia for the first time on Equisetum arvense L. and Equisetum telmateia Ehrh., and is redescribed. Species descriptions include line drawings as well as phase contrast (PCLM), differential interference contrast (DIC) and scanning electron (SEM) micrographs. The differential diagnosis between the two Eriocaenus species is supplemented by molecular differentiation of 28S rDNA sequences including D2 fragments for both mites.