Integrative taxonomy demonstrates the unexpected synonymy between two predatory mite species: Cydnodromus idaeus and C. picanus (Acari:Phytoseiidae)

Abstract

Species of the mite family Phytoseiidae are well known as predators of mite pests all over the world. Their identification is thus of great interest for biological control. The specimens examined in this study belong to the species Cydnodromus idaeus (described from Brazil) and C. picanus (described from Chile). They were collected together on the same plant in Argentina. These species are mainly differentiated by the presence/absence of the dorsal solenostomes (gland openings) gd2. Some morphometric differences were observed between the Argentinian specimens and the type material of C. idaeus and C. picanus; however, they were not sufficient to support a species separation. Morphological and molecular analyses with two mtDNA (12S rRNA, CytB) and a nuclear DNA (ITS) marker showed no difference between Argentinian specimens with and without the solenostome gd2. Also, molecular differentiation between these latter specimens, C. picanus and C. idaeus, was very low, suggesting that all these individuals belong to the same species. Biological experiments confirm these results, as 75% of the progeny resulting from females with gd2 had gd2 present whereas all the descendants resulting from the females without gd2 had gd2 present too. The presence/absence of this solenostome seems thus to be variable within a species and cannot be used diagnostically. We conclude that all specimens from Argentina belong to C. idaeus and that C. picanus is a junior synonym of C. idaeus. The present results were unexpected as the presence/absence of solenostomes is used in Phytoseiidae identification keys and as one of a suite of diagnostic characters for discriminating between species. The consequences of these findings for the taxonomy of Phytoseiidae are discussed.

An unexpected occurrence of Amblyseius swirskii Athias-Henriot in La Réunion Island (Acari: Phytoseiidae)

“…Furthermore, such distances clearly correspond to intraspecific distances reported for other species of Phytoseiidae (e.g. Okassa et al 2009Okassa et al , 2011Tixier et al 2011Tixier et al , 2012Tixier et al , 2014. The molecular results thus confirm that the specimens collected in La Réunion Island belong to A. swirskii.…”

“…A mitochondrial DNA markers (12S rRNA) was used to allow efficient molecular species diagnosis (see e.g. Okassa et al, 2009Okassa et al, , 2011Tixier et al 2011Tixier et al , 2012Tixier et al , 2014. Primers for the amplification of the DNA fragments were as follows: 12S rRNA, 5'-3' TACTATGTTACGACTTAT and 3'-5' AAACTAG-GATTAGATACCC (Jeyaprakash and Hoy 2002).…”

Statistical approaches to assess intraspecific variations of morphological continuous characters: the case study of the family Phytoseiidae (Acari: Mesostigmata)

“…We compiled morphological measurements of 14 Phytoseiidae species included in five genera ( Euseius Wainstein, Neoseiulus Hughes, Phytoseiulus Evans, Kampimodromus Nesbitt, and Typhlodromus ( Typhlodromus ) Scheuten) and two sub‐families (Amblyseiinae Muma and Typhlodrominae Scheuten), for a total of 1081 specimens (Table 1). Morphological data are taken from published studies carried out in our lab to differentiate morphologically related species (Tixier et al., 2006a, 2008b, 2010, 2011, 2012; Okassa et al., 2009, 2010, 2011). The measurements were made on adult females mounted on slides in Hoyer’s medium and observed with a phase and differential interference contrast microscope (Leica DMLB; Leica Microsystèmes SAS, Reuil‐Malmaison, France) (400× magnification).…”

Piecing together an integrative taxonomic puzzle: microsatellite, wing shape and aedeagus length analyses of Bactrocera dorsalis s.l. (Diptera: Tephritidae) find no evidence of multiple lineages in a proposed contact zone along the Thai/Malay Peninsula

“…Few papers follow the recommended protocols for integrative taxonomy, which include stating the species definition used, developing testable hypothesis/es relevant to that definition, and then testing the hypothesis with at least three independent lines of research; only after which are interpretations of species limits made (Schlick‐Steiner et al , 2010). Some papers broadly follow this approach (Heethoff et al , 2011; Tixier et al , 2011; Tosevski et al , 2011), but they remain uncommon. Here we contribute to integrative taxonomy studies with a pair of pest Diptera which are of international importance as agricultural and quarantine pests.…”