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Several phytoseiid mite species are important natural enemies used in biological control strategies. In the present study, Cytb mtDNA sequences of various populations of two species, Phytoseiulus macropolis and P. persimilis, were compared to determine whether the specimens collected in Brazil could belong to P. persimilis as this latter species is reported in South America but not in Brazil. The Cytb marker was used because of its high evolution rate, assumed to capture intraspecific variation. No overlap between intra- and interspecific distances was observed but the distances were quite low for interspecific variation. This can be due to the particular biology of Phytoseiulus species and this shows the difficulty to apply a universal threshold in genetic distances to conclude about the existence of one or several species. Cytb mtDNA sequences were also considered to assess intraspecific variation. The DNA sequences of P. persimilis populations were very similar, probably because they all originated from the West Palearctic region or because of a prevalence of commercialized specimens in natura. For P. macropilis, higher genetic distances were observed and differentiation was noted according to geographic location and, to a smaller extent, pyrethroid resistance. To determine how DNA variation might impact the protein function (CytB fragment considered), the amino acid compositions of the populations studied were compared. No diagnostic mutation was observed between pyrethroid resistant and susceptible populations, whereas four mutations were identified between populations of P. macropilis separated by 1300 km (different climatic conditions). The impact of such mutations is discussed but knowledge is scarce, which makes it difficult to root testable hypotheses. The protein analysis clearly opens new perspectives in Phytoseiidae studies., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

This paper focuses on the differentiation of specimens, identified as Phytoseiulus longipes, collected in four countries: Argentina, Brazil, Chile and South Africa. Two of these populations are known to feed and develop on Tetranychus evansi, whereas the two others do not. As morphologically similar specimens can sometimes belong to different species and because differences in predatory behaviours exist among the four populations considered, we tested for the presence of cryptic species. Morphological and molecular experiments (12S rDNA) were carried out. The four studied populations of P. longipes could be morphologically differentiated thanks to a combination of characters. However, these morphological differences are very small. The two populations that feed and develop on T. evansi (from Argentina and Brazil) are morphologically closer to each other than to the two other populations. Genetic distances among the four populations of P. longipes were very low, suggesting that despite their different feeding habits, all specimens belong to the same species. However, the populations associated with T. evansi showed some genetic differentiation from those that do not use this pest. This is the first time that this type of differentiation has been reported for the family Phytoseiidae. These results are of primary importance to ensure the success of biological control programs and to develop strains adapted to both crops and prey species.