Molecular Correlation between Larval, Deutonymph and Adult Stages of the Water Mite Arrenurus (Micruracarus) Novus.

Pedro María Alarcón-Elbal,Ricardo García-Jiménez,Jose Luis Horreo,Antonio G. Valdecasas,María Luisa Peláez

doi:10.3390/life10070108

Pedro María Alarcón-Elbal, Ricardo García-Jiménez + Show 3 more

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https://doi.org/10.3390/life10070108

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Abstract

The systematics of many groups of organisms has been based on the adult stage. Morphological transformations that occur during development from the embryonic to the adult stage make it difficult (or impossible) to identify a juvenile (larval) stage in some species. Hydrachnidia (Acari, Actinotrichida, which inhabit mainly continental waters) are characterized by three main active stages—larval, deutonymph and adult—with intermediate dormant stages. Deutonymphs and adults may be identified through diagnostic morphological characters. Larvae that have not been tracked directly from a gravid female are difficult to identify to the species level. In this work, we compared the morphology of five water mite larvae and obtained the molecular sequences of that found on a pupa of the common mosquito Culex (Culex) pipiens with the sequences of 51 adults diagnosed as Arrenurus species and identified the undescribed larvae as Arrenurus (Micruracarus) novus. Further corroborating this finding, adult A. novus was found thriving in the same mosquito habitat. We established the identity of adult and deutonymph A. novus by morphology and by correlating COI and cytB sequences of the water mites at the larval, deutonymph and adult (both male and female) life stages in a particular case of ‘reverse taxonomy’. In addition, we constructed the Arrenuridae phylogeny based on mitochondrial DNA, which supports the idea that three Arrenurus subgenera are ‘natural’: Arrenurus, Megaluracarus and Micruracarus, and the somewhat arbitrary distinction of the species assigned to the subgenus Truncaturus.

Highlights

The systematics of many groups of organisms has traditionally been based on the adult stage [1]
We identified the adult and deutonymph water mite specimens as A. novus, a broadly distributed species found from the Western Palearctic to the Afrotropic, commonly in standing waters [2,25]
Arrenurus subgenera are ‘natural’—Arrenurus, Megaluracarus and Micruracarus—and the somewhat arbitrary distinction of the species assigned to the subgenus Truncaturus

Summary

Introduction

The systematics of many groups of organisms has traditionally been based on the adult stage [1].For species showing a deep morphological transformation from the embryonic to the adult stage, due to a change in habitat or different behavior (parasitic and free-living stages) it may be difficult, if not impossible, to identify the juvenile stage without a previous correlation with the corresponding adult.Members of the clade Hydrachnidia (Acari Actinotrichida) mainly inhabit continental waters [2]and are characterized by three main active life stages—larval, deutonymph and adult—with intermediate dormant stages [3]. The systematics of many groups of organisms has traditionally been based on the adult stage [1]. For species showing a deep morphological transformation from the embryonic to the adult stage, due to a change in habitat or different behavior (parasitic and free-living stages) it may be difficult, if not impossible, to identify the juvenile stage without a previous correlation with the corresponding adult. Members of the clade Hydrachnidia (Acari Actinotrichida) mainly inhabit continental waters [2]. Are characterized by three main active life stages—larval, deutonymph and adult—with intermediate dormant stages [3]. Deutonymphs and adults share a characteristic morphology and may be identified through diagnostic characters. Larval morphology is very different from that of the two other stages. The standard procedure to match the larvae of a species with its corresponding adult

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Conclusion