Transeius wainsteini (Gomelauri)

Tixier, Marie-Stephane, Auger, Philippe, Migeon, Alain, Douin, Martial, Fossoud, Amandine, Navajas, Maria & Arabuli, Tea, 2021, Integrated taxonomy supports the identification of some species of Phytoseiidae (Acari: Mesostigmata) from Georgia, Acarologia 61 (4), pp. 824-844 : 833-834

Transeius wainsteini (Gomelauri)

Amblyseius wainsteini Gomelauri 1968: 518 .

Amblyseius (Amblyseius) wainsteini, Wainstein & Vartapetov 1973: 103 .

Typhlodromips wainsteini, Rahmani et al. 2010: 498 .

Transeius wainsteini, Chant & McMurtry 2004: 185 ,

Specimens examined. At Gurjaani (Velistsikhe) (41.8545° N, 45.8035° E): 8 ♀♀ on Populus alba L. ( Salicaceae ), at Telavi (5kms West from Telavi) (41.9283° N, 45.4241° E): 1

♀ on Rubus sp. (Rosaceae) , at Telavi (Rd Tetri Tsklebi to Telavi) (41.8870° N, 45.3636° E):

7 ♀♀ and 2 ♂♂ on Rubus sp. (Rosaceae) , at Telavi (41.9141° N, 45.4579° E): 5 ♀♀ and 3 immatures on Quercus sp. (Fagaceae) .

Previous records. Denmark, Georgia, Germany, Iran, Slovakia, Turkey.

Measurements of females (10 specimens)

Dorsum. Dorsal shield 362 (340–382) long and 170 (155–177) wide, smooth with small striation in the lateral posterial part, with seven solenostomes (gd1, gd2, gd4, gd5, gd6, gd8 and gd9), 17 pairs of dorsal setae and two pairs of sub-lateral setae: j1 26 (22–30), j3 51 (50–55),

j4 8 (7–10), j5 7, j6 8 (7–10), J2 9 (7–10), J5 6 (5–7), z2 22 (17–27), z4 32 (22–35), z5 7 (5–7), Z1 11 (7–12), Z4 63 (60–67), Z5 119 (110–127), s4 68 (65–72), S2 27 (25–32), S4 13 (12–15), S5 9 (7–10), r3 25 (22–27) and R1 17 (15–20) in length. All setae smooth.

Peritreme. Extending forwards to the bases of the setae j1.

Venter. Sternal shield with three pairs of setae and two pairs of poroids; one pair of sternal setae (st4) on small metasternal platelets; posterior margin straight. Distances between st1–st3 65 (62–70), st2–st2 69 (65–72), st5–st5 67 (65–70). Two pairs of metapodal plates, the largest one 24 (22–25) long and 5 (4–5) wide, the smallest one 10 (7–12) long and 2 wide. Ventrianal shield with three pairs of pre-anal setae JV1, JV2, ZV2 and a pair of crescent pre-anal pores (gv3) present, slightly posterior-paraxial to setae JV2. Integument surrounding ventrianal shield with four pairs of setae ZV1, ZV3, JV4 and JV5 ; ventrianal shield 116 (112–125) long, 84 (80–90) wide at level of anterior corners, and 82 (77–90) wide at level of anus. JV5 64 (60–70) long.

Legs. Legs IV with three macrosetae: on the genu 55 (52–57), tibia 41 (35–40) and basitarsus 63 (60–70). SgeII 31 (30–35), SgeIII 32 (30–35), StiIII 26 (25–27). Genu II with seven setae (2–2/0, 2/0–1), Genu III with seven setae (1–2/1, 2/0–1).

Chelicera. Fixed digit 37 long, movable digit 32 long. Dentition not visible because the chelicerae are closed.

Spermatheca. Spermatheca with a cup-shaped calyx 8–10 long and 5 wide, with a well differentiated round and small atrium at the base of calyx.

The table 2 provides measurements of three males.

Remarks. This species was described from Georgia (Manglisi) on Corylus sp. (Betulaceae) and according to Wainstein and Vartapetov (1973), it is quite common across the country. These authors also noted that T. wainsteini feeds on P. citri and T. urticae . The measurements of the Georgian specimens are close to those reported in the original description and in the re-description of Faraji et al. (2011) (from Turkey), except for the setae STIV that were shorter in our specimens (60–70) than in those measured by Faraji et al. (2011) (75–78) ( Table 2). However, the difference is minor and it is the only difference with T. wainsteini studied by Faraji et al. (2011) ; we therefore conclude that the specimens from Georgia belong to Transeius wainsteini ( Table 2).

Differences between Amblyseius swirskii , Amblyseius andersoni (Chant) and T. wainsteini are minor. Amblyseius andersoni differs from A. swirskii and T. wainsteini by longer setae Z5 ( Table 2). The main differences between A. swirskii and T. wainsteini are the measurements of the setae z2, z4, the ratio s4 / S2 and the dentition of the chelicerae.

CytB (8), 12S (5) and COI (8) DNA sequences of Georgian specimens of T. wainsteini were obtained, respectively. Phylogenetic trees are presented in the figure 2. The mean genetic distances between these specimens are 1.6% (0–3.1%) for the CytB mtDNA marker, 0% for the 12S rRNA fragment, and 1.2% (0–3%) for the COI mtDNA marker. The mean genetic distances between T. wainsteini and A. swirskii , observed for the three molecular markers, support that these species are distinct taxa (CytB mtDNA marker: 44.2% (43.7% – 45.1%),

12S rRNA: 19.7%, COI mtDNA: 24.9% (23.8% – 25.9%)). Transeius wainsteini differs from A. andersoni by 26.3 % (25.5% – 27.2%) for the CytB mtDNA, 9.1% (8.8% – 9.4%) for the

12S rRNA marker and 19.9% (18.6% – 21.1%) for the COI mtDNA fragment (Supplementary

Table S3a,b,c). These distances are clearly smaller than those observed between T. wainsteini and A. swirskii , suggesting that T. wainsteini is phylogenetically closer to A. andersoni than to A. swirskii . Interestingly, these genetic relationships do not reflect morphological similarities as (i) A. swirskii and A. andersoni are more similar to each other than to T. wainsteini and (ii) T. wainsteini is morphologically more similar to A. swirskii than to A. andersoni .

The morphological similarities between T. wainsteini and A. swirskii suggest evolutionary convergence especially for the length of setae Z5. Further analyses would be interesting to carry out based, in particular, on the observation of spermatheca structures (atrium, calyx).

A very close relationship between A. andersoni and T. wainsteini is clearly supported by the 12S sequences (9.1%) (Supplementary Table S3b). In the absence of additional parameters (morphology and other molecular markers), this small distance could have wrongly lead to conclusion that they belong to the same species. The maximal intraspecific distance using the

12S rRNA marker for Phytoseiidae , was observed for the species Amblyseius largoensis (7.8%

in Barbosa-Lima et al. 2018) and the minimal interspecific distances observed range between 9.5% and 12.5% (between Neoseiulus californicus and N. fallacis and N. californicus and N. idaeus , respectively) ( Jeyaprakash and Hoy 2002 ; Okassa et al. 2011).

The phylogenetic closeness of A. andersoni and T. wainsteini questions the monophyly of the genus Amblyseius and the validity of the genus Transeius , as already stated by Tsolakis et al. (2012) who showed the proximity between A. andersoni , A. swirskii and Transeius montdorensis (Schicha) . Further phylogenetic analyses would be required including additional Amblyseius and Transeius species, to conclude that Transeius is not a valid genus and that Amblyseius is paraphyletic.