Obtaining molecular data for all life stages of Typhlodromus (Typhlodromus) exhilaratus (Mesostigmata: Phytoseiidae): consequences for species identification

Abstract

Several species of the family Phytoseiidae are known to control mite pests in many crops worldwide. However, biological control success greatly depends on the accurate identification of these predatory mites. Species diagnostics is essentially based on the morphological characters of females. Thus, when only immature stages and/or males are collected, their identification is poorly supported. Molecular tools could be of great help to overcome these difficulties, as molecular sequences are assumed to be identical for the life stage considered. However, one of the essential points is to extract a sufficient DNA amount from a single specimen of immature stages (eggs, protonymphs, deutonymphs) and males (less than 300 μm in length) to amplify and sequence DNA. The markers used were two mitochondrial DNA fragments (12S rRNA and Cytb mtDNA) and the species studied were Typhlodromus (Typhlodromus) exhilaratus and T. (T.) phialatus, two cryptic species, reported to control mite pests in crops of southern Europe and commonly found on the same plants. Despite a low quantity of DNA extracted, particularly for the egg, larva and protonymph stages, DNA was amplified and sequences were obtained from all the life stages considered with the two mtDNA fragments. Sequences from all the developmental stages of T. (T.) exhilaratus were identical and well differentiated from those of its sister-species. However, contaminations were observed especially for eggs and DNA amplified with the Cytb mt marker. Utility of the present results are discussed and protocol improvements are proposed.

Revealing the Hyperdiverse Mite Fauna of Subarctic Canada through DNA Barcoding

“…Some Mesostigmata are more heavily sclerotized than the other lineages, perhaps also reducing DNA recovery. Okassa et al [44] reported problems in recovery of Cyt B sequences in their work on phytoseiid mites when DNA concentrations were less than 2.33 ng/ul. A shift to smaller elution volumes might improve success by producing higher DNA concentrations.…”

Feeding design in free-living mesostigmatid chelicerae (Acari: Anactinotrichida)

“…Ologamasids are rare and low in diversity in northern areas arising from the Laurasian 'supercontinent' but are a dominant groups of predatory mites in southern areas arising from the Gondwanan 'supercontinent' (including the Antarctic Peninsula). Bar-coding and Next Generation Sequencing (Navajas and Fenton 2000;Klompen 2010;Okassa et al 2012) offer the ability to construct unbiased trees of identity by descent on which biomechanical characteristics of species can be overlain. What might they reveal for mesostigmatids?…”

Towards resolving the double classification in Erythraeus (Actinotrichida: Erythraeidae): matching larvae with adults using 28S sequence data and experimental rearing

“…Since the seminal paper by Hebert et al (2003), this is broadly referred to as DNA barcoding, although in its strict sense, this term only applies to when certain standard genetic markers are being used (mitochondrial COI in animals). Larvaladult matching using DNA has been successfully applied to fish (Hubert et al 2010; Baldwin and Johnson 2014 and references therein), amphibians (Vences et al 2005), various invertebrate groups (Jousson et al 1999;Locke et al 2011;Okassa et al 2012;Alcántar-Escalera et al 2013) including crustaceans (Feller et al 2013), and a range of insect groups such as beetles (Miller et al 2005;Caterino and Tishechkin 2006;Ahrens et al 2007;Levkanicova and Bocak 2009;Lefort et al 2012), Lepidoptera (Prado et al 2011), Diptera (Pfenninger et al 2007;Sutou et al 2011), caddisflies (Johanson 2007;Zhou et al 2007;Waringer et al 2008), mayflies (Gattolliat and Monaghan 2010), stoneflies (Mynott et al 2011;Avelino-Capistrano et al 2014), and hemipterans (Zhang et al 2008;Zhang and Weirauch 2011) to name a few. The main challenge is the unavailability of reference sequences of adults (Pfenninger et al 2007) or insufficient field sampling of both life instars.…”