Sierraphytoptus Keifer 1939

Genus Sierraphytoptus Keifer, 1939:151

Sierraphytoptus Keifer, 1939:151, fig. LI; 1965:8, fig. 4; Newkirk, Keifer 1975:567; Amrine et al., 2003:17, fig. 18. Fragariocoptes Roivainen, 1951:51 [Synonymy by Roivainen (1953, p.85)]; Farkas, 1965:8

Type species: Sierraphytoptus alnivagrans Keifer, 1939, by monotypy.

Diagnosis: opisthosoma diversely annulated; prodorsal shield with four setae – ve and sc; a pair of setae c1 on the dorsal part of opisthosoma; solenidion on leg I, II missing.

Species included: Sierraphytopyus alnivagrans Keifer, 1939, S. ambulans sp. n., S. setiger (Nalepa, 1894)

Distribution and hosts. Mites of the genus are recorded from North America, Asia (Armenia, Ural region and South Siberia of Russia, China) and Europe. Host-plants of these mites include dicots from the orders Fagales (Alnus spp.) and Rosales (Fragaria spp.).

Remarks. The species S. taiwanensus from T. aralioides is removed from the genus because it possesses a solenidion on tibia I, while in Sierraphytoptus it is missing. The tibial solenidion was not measured and figured in the description of S. taiwanensus given by K.W. Huang (2006), but the female (slide # 030416 -01, Taiwan, Nantou Ren-ai 2003/04/16, coll. K.W. Huang) and nymph (slide # 961031-17, Taiwan, Taichung Anmashan, 1996/10/31, coll. C.F. Wang) of this mite do have a tibial solenidion (Fig. 1). Therefore, the morphological features of S. taiwanensus correspond to the diagnosis of the genus Austracus Keifer, 1944 and we transfer it to this genus: Austracus taiwanensus (K.- W. Huang 2006) comb. n.

Mites of the genus Sierraphytoptus were first found by А. Nalepa (1894) inside red galls on leaves of F.

viridis and described under the name Phyllocoptes setiger (Table 1). Later, Liro (1941) found similar mites on F. vesca in Finland. He identified them as P. s e t i g e r and suggested that there were two subspecies, which remained unnamed: one formed red galls on leaves of F. viridis and lived inside them, but the other lived on the lower surface of leaves on F. vesca, causing no visible damage. Liro (1941) also wrote that these subspecies differed in the number of dorsal annuli (Table 1) and that they could be separate species. The same suggestion was made by Bagdasarian (1981), who gave detailed descriptions of vagrant nymphal and female S. setiger from Fragaria sp. in Armenia.

Characteristics Reference

* The data are given according to the figures presented in the cited papers.

Ten years after Liro found phytoptid mites on Fragaria, these mites were recorded in Finland again by Roivainen (1951). He thought these mites were very close to the vagrant mites P. s e t i g e r referred to by Liro, but differed from the mites collected by Nalepa from galls (Table 1). Roivainen (1951) also noted that both forms (gall-forming and vagrant) of the species “ setiger ” have four setae on their prodorsal shield and a pair of subdorsal setae (c1) on the dorsal surface of opisthosoma that did not fit to the characteristics of the genus Phyllocoptes. On this basis he established a new monotypic genus, Fragariocoptes Roivainen, 1951, for the species “ setiger ”. However, by that time the genus Sierraphytoptus Keifer, 1939 had already been established, to which this species could be placed. Therefore Roivainen (1953, p.85) synonymised the genus Fragariocoptes with Sierraphytoptus and transferred the species “ setiger ” into it.

Therefore, previous authors have considered the possibility that S. setiger comprises two species, one forming galls and the other vagrant, but have never split the species. Afterall, another possibility is that both forms represent the deutogyne and protogyne of the same species. For this to be true, we would be able to rear deutogynes from the protogynes. We would also expect to find both forms of mites throughout the year, especially summer.

In North-West Russia there are three species of Fragaria: two widespread (F. vesca and F. moschata Duch.) and one much rarer (F. v i r i d i s) (Tzvelev 2000). It is remarkable that during 2008–2009 we looked for Seirraphytoptus on F. m o s c h a t a many times and never found them. Our field collections found Sierraphytoptus only from lower surface of leaves on F. vesca and from red leaf galls on F. v i r i d i s during spring, summer and autumn. The vagrant and gall-forming mites distinctly differed in their number of dorsal annuli, length and form of body and design of prodorsal shield (Fig. 2, 3; Tables 1, 2). During summer, both forms were numerous and laid eggs intensively. Furthermore, during our field work they were never found simultaneously together either on the leaf surface or in galls.

Moreover, the mites reared in our laboratory revealed no morphologically distinguishable forms of females living on the same species of Fragaria: all the mites on F. v e s c a from Vyritza were of the vagrant type, whereas on F. v i r i d i s from Luga were of the gall-making type. Therefore, the above evidence shows that the two forms are not deutogyne and protogyne.

After morphological analysis and comparison of our original data (Table 2) with published data we conclude that the vagrant mites and mites forming galls from Fragaria spp. are the two separate species: S. ambulans sp. n. and S. setiger.