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

Abstract

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.

Daily production of spermatophores, sperm number and spermatophore size in two eriophyoid mite species

“…This 'live' method of measurement guaranteed quick and precise estimation of male size without the long process of 'conventional' clearing and mounting of specimens on slides (for conventional methods see e.g. de Lillo et al 2010).…”

“…The glycerin medium was also used to measure the diameter of a spermatophore head. To estimate the widths of female genital coverflaps and the length of female legs (for details see de Lillo et al 2010), I made permanent mounts of females of both species in a Heinze-PVA medium. I measured only one, left or right hind leg of each female.…”

Transmission of grapevine Pinot gris virus by Colomerus vitis (Acari: Eriophyidae) to grapevine

“…Tissues were washed with a watery bleach and detergent solution in order to extract mites, which were concentrated on a sieve (25-lm mesh size) [19]. An aliquot of active mites from each collected population was used for morphological identification at the species level, according to current procedures [20]. To assess the presence of GPGV in mites, pools of 5-15 C. vitis individuals were placed live in Eppendorf tubes at ?4-5°C for about 24 h and then stored at -80°C before RNA extraction.…”

<strong>Two new genera and four new species of Diptilomiopidae from Thailand</strong>

“…The morphological terminology used herein follows Lindquist (1996) and the genus was identified using the generic key by Amrine et al (2003). Slides were mounted and specimens were measured following de Lillo et al (2010). Specimens were examined with a Zeiss Imager M2 research microscope with Phase Contrast Light Microscopy (PC LM) and Differential Interference Contrast Light Microscopy (DIC LM) using 100x oil objectives.…”