Phylogenomics offers new insights into the classification of Phytoseiidae (Acari: Mesostigmata)

Abstract

Phytoseiid mites are significant natural predators of harmful mites and constitute one of the largest groups within Gamasina (Acari: Mesostigmata). The currently accepted classification divides the Phytoseiidae family into three subfamilies, primarily based on the pattern of their dorsal setae. However, the phylogenetic relationships among these subfamilies remain unresolved. To address this issue, we sampled forty representative species from the three subfamilies. Using a specific Arachnida reference dataset (orthodb10, n = 2,934), we mined thousands of universal single-copy orthologs from whole-genome sequencing data. We then constructed four amino-acid matrices, taking into account evolutionary rates and the degree of violation of the molecular clock (DVMC). Phylogenetic trees were reconstructed using both concatenated and multispecies coalescent (MSC) analyses. Based on maximum likelihood and Bayesian inference, the majority of the phylogenetic trees supported the hypothesis (P2) of Phytoseiinae + (Typhlodrominae + (Galendromus + Amblyseiinae)). However, when using slowly evolving and non-clock-like genes, the MSC trees supported an alternative hypothesis (P1) of Typhlodrominae + (Phytoseiinae + (Galendromus + Amblyseiinae)). Additional analyses, including model fitness, topology tests, and morphological comparisons, favored the hypothesis P2. Our findings indicate that Typhlodrominae is not monophyletic, and Galendromus and Amblyseiinae are sister groups. Based on these results, we recommend that Galendromus be separated from Typhlodrominae and elevated to a fourth subfamily.