The subfamily Tetrastichinae is one of the largest and most widespread of all parasitic Hymenoptera groups. The World fauna of the Tetrastichinae currently includes about 2000 recognized species from 110 genera; 453 species from 19 genera have been recorded from Russia (Yegorenkova, Kostjukov, 2019). Hosts for Tetrastichinae have been found in 100 families of insects in 10 different orders, plus spider eggs, mites, and even nematodes. There are also species that are phytophagous (some of them gall-inducers) or inquilines (LaSalle, 1994).

In his reclassification of the European Tetrastichinae Graham (1987) described nine new genera, including Anaprostocetus Graham, 1987, with type species A. dehraensis Graham, 1987. Anaprostocetus acuminatus (Ratzeburg, 1848) was redescripted and transferred by him from the genus Aprostocetus Westwood, 1833. At present, Anaprostocetus comprises seven species: A. acuminatus (Europe, Turkey, Georgia, China, Japan, North America, India and Russia – new record), A. dehraensis, A. areos Narendran et Fousi, 2005, A. keralicus Narendran et Girish Kumar, 2005, A. sringeriensis Narendran et Santhosh, 2005 (India), A. cenxiensis Sheng, 1995 (China), and A. ankarensis Gençer, 2010 (Turkey) (Domenichini, 1966; Graham, 1987; LaSalle, 1994; Sheng, 1995; Ikeda, 1997; Narendran et al., 2005; Gençer, 2010; Doganlar, 2011; Kostjukov et al., 2017).

About forty A. acuminatus females were collected by me in August of 2018 in the environs of St. Petersburg. Specimens were swept from Salix fragilis L. with injuries by a tenthredinid sawfly. The newly collected specimens differ in some morphological features from the specimens examined by Graham (1987); additional measurements and a photograph of female genitalia (Fig. 1, 7) are given.

MATERIALS AND METHODS

All the collected specimens are deposited in the Zoological Institute of the Russian Academy of Sciences, St. Petersburg (ZISP).

The morphological terminology follows that of Graham (1987, 1991). The abbreviations F1–F3 are used for funicular segments.

The photographs of specimens were taken with a combination of a stereomicroscope (Olympus SZX10) and a digital camera (Olympus OM-D). Some parts of specimens were slide-mounted in Canada balsam and photographs were taken from them using a ZEISS SteREO Discovery.V12 modular stereo microscope and an AxioCam MRc5 camera.

RESULTS

Family EULOPHIDAE

Subfamily TETRASTICHINAE

Genus ANAPROSTOCETUS Graham, 1987

Anaprostocetus Graham, 1987 : 84.

Type species: Anaprostocetus dehraensis Graham, 1987 (original designation).

Descriptive note. Propodeum as long as, or longer than dorsellum, with sharp paraspiracular carinae, plicae absent; surface between paraspiracular carinae with strong, slightly raised reticulation (Fig. 1, 5). Hind coxa with a curved subdorsal carina on its outer surface. Antenna of female with funicle and clava each with three segments (Fig. 1, 4), with three discoid anelli, of which the third tends to be slightly larger than the others. Antenna of male with ventral plaque of scape in upper half, two discoid anelli, four funicular segments, and a three-segmented clava; segments of flagellum with compact subbasal whorls of long dark setae. Vertex having ocelli enclosed in an area marked by impressed lines (Fig. 1, 6) (Graham, 1987).

Body dark green with metallic green to bluish luster. Antennae brown to fuscous. Coxae usually colored similar to the body or dark brown; femora varying from brown to yellow or colored proximally similar to the body. Tegula varying from black to pale yellow. Wings hyaline, venation varying from pale yellow and brownish yellow to testaceous. Body length 1.8–3.9 mm.

Fig. 1.
figure 1

Anaprostocetus acuminatus (Ratzeburg), 1848, females: (1) habitus, lateral view; (2) habitus, dorsal view; (3) gaster, dorsal view; (4) antenna; (5) propodeum, dorsal view; (6) head, dorsal view; (7) genitalia.

Full size image

Distribution. Europe, Russia (Leningrad Province) (new record), Turkey, Georgia, China (Guangxi), Japan (Hokkaido, Honshu), North America (Canada), and India (Kerala, Karnataka) (Domenichini, 1966; Graham, 1987; LaSalle, 1994; Ikeda, 1997; Narendran et al., 2005; Gençer, 2010; Doganlar, 2011; Kostjukov et al., 2017).

Hosts. Tenthredinidae (Hymenoptera) (Graham, 1987) and Cecidomyiidae (Diptera) (Doganlar, 2011).

Remarks. This genus is not difficult to distinguish from the similar Aprostoceus, by the following features: outer surface of hind coxa with a fine curved dorsal carina; propodeum with a sharp curved paraspiracular carina on either side; surface between the two carinae with distinct, slightly raised reticulation; vertex having ocelli enclosed by an impressed line.

Anaprostocetus acuminatus (Ratzeburg, 1848) (Fig. 1, 1–7)

Entedon acuminatus Ratzeburg, 1848 : 169. Syntypes: ♀♀, Germany, Mecklenburg (British Museum Natural History, London) (not examined; destroyed).

Geniocerus acuminatus (Ratzeburg): Kurdjumov, 1913 : 251.

Aprostocetus acuminatus (Ratzeburg): Graham, 1961 : 46.

Tetrastichus acuminatus (Ratzeburg): Domenichini, 1966a : 181; 1966b : 16.

Anaprostocetus acuminatus (Ratzeburg): Graham, 1987 : 84; LaSalle, 1994 : 134.

Material. Russia. St. Petersburg: Pushkin District, Tyarlevo, swept from Salix fragilis, 3.VIII.2018 (O. Kosheleva), 7 ♀; same data, 6.VIII.2018 (O. Kosheleva), 4 ♀; 10.VIII.2018 (O. Kosheleva), 2 ♀; 14.VIII.2018 (O. Kosheleva), 30 ♀.

Distribution. See distribution of the genus.

Host. Euura atra (Jurine) (Ratzeburg, 1848; Domenichini, 1966a), Eu. laeta (Brischke) (Hymenoptera: Tenthredinidae) (Graham, 1987), Dasineura oleae (F. Loew), and Lasioptera oleicola Skuhravá (Diptera: Cecidomyiidae) (Doganlar, 2011).

COMMENTS

The redescription of this species was based on 6 males and numerous females from Great Britain, Sweden, France, Germany, Italy, Austria, Czechoslovakia, and Hungary. The type specimens were subsequently destroyed (Graham, 1987). The newly collected specimens of Anaprostocetus acuminatus correspond to the redescription by Graham (1987) in most characters, but differ in the features given in Table 1. They also exhibit variations in the structure of the gaster and coloration of the legs and tegulae, and in the size (see Table 1).

Table 1. Differences in diagnostic features between females of Anaprostocetus acuminatus (Ratzeburg) from different parts of the range (see Fig. 1, 1–7)
Full size table

Some additional features of A. acuminatus were reported by Ikeda (1997). Japanese specimens differ from those examined by Graham (1987) in the smaller body length (1.9–3.2 mm); in the number of the adnotaular setae on mesoscutum varying from 6 in a single row to about 20 in two rows; longer thorax and propodeum, which are slightly longer than dorsellum to nearly twice as long as the latter (see Table 1).

These variations are possibly due to features of the bionomics of their hosts and can be attributed to intraspecific variability. In addition, similar to the Russian specimens, the wasps from Japan have the clava distinctly shorter than F2 plus F3. According to Graham (1987), the clava of A. acuminatus is distinctly longer than F2 plus F3, but E. Ikeda (1997) reports, based on the information received from J. LaSalle, that the specimens examined by M. Graham have the clava distinctly shorter than F2 plus F3.