Reproductive compatibility and genetic and morphometric variability among populations of the predatory mite, Amblyseius largoensis (Acari: Phytoseiidae), from Indian Ocean Islands and the Americas

[EN] The red palm mite (RPM), Raoiella indica Hirst (Acari: Tenuipalpidae), is an invasive phytophagous mite that was recently introduced into The Americas. The predatory mite Amblyseius largoensis Muma (Acari: Phytoseiidae) has been the only natural enemy consistently found in association with RPM. This study aimed to determine if A. largoensis populations from the Indian Ocean Islands (La Reunion and Mauritius) and the Americas (Brazil, Trinidad and Tobago and the USA) consist a taxonomic unit or a group of cryptic species. First, the morphological variability among the A. largoensis populations from these areas was evaluated through morphometric analyses of 36 morphological traits. Then, their genetic variability and phylogenetic relationships were assessed based on two target DNA fragments: the nuclear Internal Transcribed Spacer and the mithochondrial 12S rRNA. Finally, reproductive compatibility of the populations from La Reunion and Roraima, Brazil was evaluated. Morphometric differences between the A. largoensis specimens from La Reunion Island and the Americas were observed, most of them on the length of the setae. Molecular analysis indicated that the A. largoensis populations from the Indian Ocean Islands and the Americas belong to the same taxonomic entity, although to two well defined genetic groups. Crossings involving the A. largoensis populations from La Reunion Island and Roraima, Brazil revealed complete reproductive compatibility between these populations. Information on the morphometric and genetic variability among studied A. largoensis populations can be further exploited in future studies to follow colonization of Indian Ocean Islands populations in the Americas, in the case of field releases. (C) 2014 Elsevier Inc. All rights reserved.
We thank the Agricultural Research Centre for International Development (CIRAD), in special Dr. Serge Quilici, for the logistical support in obtaining the population from La Reunion. We are grateful to Serge Kreiter, Gilberto J. de Moraes, Tatiane Marie Martins Gomes de Castro, Ricardo Adaime da Silva, and Farsan Hosein for their assistance in the sample collection. To Jose Wagner Melo and Daniela Duarte Rezende for the support with SAS statistical analyses. To Bruno de Paiva Rocha and Adilson Werneck for graphical abstract edition. Finally we are grateful to Gilberto J. de Moraes for valuable manuscript review. This research was partially funded by the National Council for Scientific and Technological Development (CNPq), Brazil, call CNPq/SDA/MAPA Call 064/2008. Authors D.N., R.S.M. and M.G.C.G. Jr. also thanks CNPq for research and post-doc fellowships.