Phorytocarpais kempersi (Oudemans, 1902)

Phorytocarpais kempersi

Among the species we studied, P. kempersi is the most widespread and common mite species found in all five larger regions (Azov-Black Sea Basin, Caspian Sea region, Pacific Ocean region, Arctic Ocean, Baltic Sea region). Of all 154 mite specimens used, 35 sequences of

ITS gene fragments were obtained, representing 7 genotypes ( Table 1). The variability of ITS genotypes of P. kempersi is presented in Figure 2 View Figure 2 . Other mite species from the family Parasitidae with known ITS sequences (representatives of the genera Pergamasus Berlese ,

1903 and Poecilochirus G. & R. Canestrini, 1882) are separated from P. kempersi by a hiatus. The bootstrap values at the node separating the ITS sequences of P. kempersi from the representatives of the closest genera Pergamasus and Poecilochirus are 99% ( Figure 2 View Figure 2 ). At the same time, the intraspecific variability of P. kempersi across a huge part of its distribution (from Iceland to the Kuril Islands) does not exceed 1%, allowing an unambiguous identification of the species. To characterize the intraspecific variation of P. kempersi and to compare data from geographically distant parts of its range, we obtained a median network of genotypes ( Figure 3 View Figure 3 ). There the central position is occupied by the genotype marked with the Roman numeral (I), found in four large regions. All this allows us to consider it ancestral. All other genotypes appear to be associated with it, directly or indirectly. The closely related genotype (II), found in five large regions, is the most common one in the Caspian Sea region. The remaining genotypes are found only in particular regions. The genotypic diversity of the entire sample P of. kempersi and local populations of this species in individual large regions are presented in Tables 4 and 5. In the most remote, Far Eastern populations (Pacific coast), only two widespread genotypes were found.

types of two members of the genus Pergamasus , Parasitidae , and Poecilochirus monospinosus Wise, Hennessey & Axtell, 1988 , Parasitidae , were used as out-groups to root the tree. The sequence taken

from GenBank is marked with GenBank ID number. The length of the aligned sequences is 575 nucleotide sites. The newly obtained sequences are denoted by color labels according to large regions Sample characteristics are given in Table 1.

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Genotypes (III), (IV) and (VII) are revealed only on the shores of the Caspian Sea, and genotype (V) only in the Iceland region ( Table 1). The greatest divergence from the ancestral genotype is observed in mites with genotype (VI). As this genotype was found in closely located areas on the coast near the town of Anapa, Black Sea and on Cape Kazantip, Azov Sea, the early formation of a locally adapted population seems to take place. If adaptation does occur,

it occurs at a very early stage, since the value of the test (Tajima’s D) for selective neutrality corresponds to the model of random accumulation of mutations in the absence of selective pressure on the population ( Table 4). A comparison of P. kempersi populations from different geographic regions shows the absence of fixed region-specific nucleotide substitutions ( Figure 3 View Figure 3 ), this also being consistent with the model of random accumulation of mutations.