Aceria varia ( Nalepa, 1892 )

Mehri-Heyran, Hosein, Lotfollahi, Parisa, de, Enrico, Lillo & Azimi, Solmaz, 2020, Redescription of Aceria varia and Tegoprionus dentatus (Trombidiformes: Eriophyoidea: Eriophyidae) from Iran, Persian Journal of Acarology 9 (2), pp. 129-139 : 130-133

Aceria varia ( Nalepa, 1892) ( Fig. 1 )

Female (measured specimens n = 10)

Body vermiform, 177–205 (excluding gnathosoma), 35–38 thick, 33–37 wide. Gnathosoma projecting obliquely downwards, chelicerae 17–22, palp 19–25, palp coxal setae ep 2, dorsal palp genual setae d 5–6, unbranched. Prodorsal shield 25–28 including frontal lobe, 29–34 wide, subcircular; with a flexible distally pointed or rounded frontal lobe, 5–7, over gnathosomal base. Shield pattern distinct, consisting of short median line at the basal third of shield, complete admedian lines, short first submedian lines on anterior half of the shield, quite complete second submedian lines bent laterally on its anterior half and numerous short lines on the outer side of the shield. Tubercles of scapular setae sc on rear shield margin, 15–18 apart, setae sc 31–35, directed divergent posteriorly. Legs with all usual segments and setae. Leg I 27–30, trochanter 5–8, femur 9–11, genu 5–7, tibia 5– 7, tarsus 6–8, tarsal solenidion 6–7 distally enlarged and tapered, empodium simple, 5–7, 5-rayed; femoral setae bv 7–10, genual setae l" 18–21, paraxial tibial setae l' 5–7, located in basal third of tibia, paraxial fastigial tarsal setae ft ' 10–14, antaxial fastigial tarsal setae ft" 18–22, paraxial unguinal tarsal setae u' 2–3. Leg II 25–28, trochanter 5–7, femur 10–12, genu 5–6, tibia 4–7, tarsus 5–7, tarsal solenidion  7–9 distally tapered, empodium simple, 5–7, 5-rayed; femoral setae bv 6–9, genual setae l" 6–10, paraxial fastigial tarsal setae ft' 5–6, antaxial fastigial tarsal setae ft " 21–24, paraxial unguinal tarsal setae u' 2–3. Coxisternal region. Prosternal apodeme 6–9, anterior setae on coxisternum I 1b 5–7, 8–11 apart; proximal setae on coxisternum I 1a 13–17, 8–10 apart; proximal setae on coxisternum II 2a 31–37, 18–20 apart; 8–9 microtuberculated semiannuli between coxae and genital coverflap plus 2–3 transversal rows of lined granules at the base of the coverflap. Coxae with distinct granules. External genitalia 10–11, 18–21 wide, coverflap with 14–15 longitudinal ridges; setae 3a 15–19, 13–15 apart. Internal genitalia: spermathecae relatively big, ovoid, oriented postero-laterad; spermathecal tubes relatively short; transverse genital apodeme trapezoidal, distally folded. Opisthosoma dorsally arched, with 73–86 dorsal semiannuli, 64–80 ventral semiannuli. Microtubercles: circular, spiny on rear margin of last 4 dorsal semiannuli, elongated and linear on last 5 ventral semiannuli. Setae c2 21–24 on ventral semiannulus 12–14, setae d 46–60 on ventral semiannulus 24–27; setae e 15–17 on ventral semiannulus 39–45; setae f 20–24 on ventral semiannulus 59–71; 5 annuli posterior to setae f. Setae h2 89–108 apically very fine, h1 9–10.

Male (measured specimen n = 1)

Similar in shape and prodorsal shield arrangement to female. Body smaller than female, 143, 32 wide; palp genual setae d 5; prodorsal shield 26, 29 wide; setae sc 26, 29 apart. Opisthosoma with 79 dorsal semiannuli and 69 ventral semiannuli; 11 semiannuli between coxae and genitalia, with microtubercles similar to those of female. Setae: 1b 5, 1a 9, 2a 30, c2 24, d 45, e 15, f 15, h1 8, h2 76. Male genitalia 10 wide, setae 3a 15, 14 apart.

Nymph (measured specimens n= 3)

Body vermiform, 128–141 (excluding gnathosoma), 32 wide, 29–31 thick; palp genual setae d 4. Prodorsal shield 21–23 including frontal lobe, 28 wide. Tubercles of sc setae on rear shield margin, 18 apart, setae sc 22–24, directed posterior. Opisthosoma with 72–76 dorsal and 60–62 ventral semiannuli, circular microtubercles set on rear part of semiannuli. Setae: 1b 3–5, 1a 7–9, 2a 16–20, c2 10–13, d 24–30, e 11–12, f 13–16, h2 99–114, h1 5–8. Setae 3a 7–10, 7 apart on semiannulus 11 after coxae.

Type host plant Populus tremula L. ( Salicaceae ), European Aspen.

Type locality Lorraine, France .

Relation to the host plant

Causing spots on leaves which were silver-red at first and later brown; causing erinea on the undersurface of the leaves, with or without slight bulges on the opposite side of the lamina ( Boczek 1969).

Material examined

2 females and 2 males, mounted singly on separate microscope slides (PA-IWA-OK17M-1-4), from P. alba in Ozmanake Sofla village (36° 95' 50.5'' N, 46° 05' 39.3'' E, 1353.3 m above sea level) on 1 July 2017 ; 25 females, 7 males and 7 nymphs mounted singly on separate microscope slides (PA-IWA-UD17M-1-39) from P. alba in Uch Tappeh Kord village (37° 01' 91.1'' N, 46° 01' 28.0'' E, 1250.5 m above sea level) on 2 July 2017; Miandoab region, West Azerbaijan province, Iran, coll. H. Mehri-Heyran.

Other material

Mites preserved in Oudemans' fluid ( Walter and Krantz 2009) (vials coded PA-IWA-OK17M; PA-IWA-UD17M) as extracted from the same samples like the examined specimens.

Remarks

Until now five Aceria species have been recorded on P. alba ( Table 1). Apart A. parapopuli , the descriptions of the other species appear to be not consistent with the current descriptive standard ( de Lillo et al. 2010). The prodorsal shield ornamentation of Iranian specimens is closer to A. varia according to the drawing by Nalepa (1892) and Boczek (1969). The main differences between the Iranian specimens and Nalepa's (1892) description regards the shape of the frontal lobe (evident in the Iranian specimens and neglected in the given descriptions, but the previous authors might have not seen the lobe due to the less sharpening of the available instruments) and the length of setae e (as long as setae d in the original description but in the Iranian specimens setae d is longer (46–60) than setae e (15–17)). Iranian specimens have been found vagrants on the P. alba leaves, while A. varia causes erinea on the undersurface of the leaves and bulges on the opposite side of the lamina on P. tremula according to Boczek (1969), whereas it is related to felty silver surface on the underside of the leaves of P. alba in Poland ( Szulc 1966). Therefore, in absence of further data and with the will to be quite conservative, the Iranian specimens were redescribed as A. varia according to the observed similarities with the previously described species.

Figures

Figure 1. Schematic drawings of Aceria varia (Nalepa) – AD. Prodorsal shield; ADL. Latero-dorsal view of anterior body region of a female; CG. Female coxigenital region; em. Empodium; GM. Male genital region; IG. Internal female genitalia; LO. Lateral view of annuli; L1. Leg I; PM. Lateral view of posterior opisthosoma. Scale bar: 10 µm for AD, AL, CG, GM, IG, PM; 5 µm for LO, L1; 2.5 µm for em.