Aphanogmus flavigastris Matsuo

Matsuo, Kazunori, Ganaha-Kikumura, Tomoko, Ohno, Suguru & Yukawa, Junichi, 2016, Description of a new species of Aphanogmus Thomson (Hymenoptera, Ceraphronidae) that parasitizes acarivorous gall midges of Feltiella (Diptera, Cecidomyiidae) in Japan, ZooKeys 596, pp. 77-85 : 78-81

Taxon classification Animalia Hymenoptera Ceraphronidae

Aphanogmus flavigastris Matsuo sp. n.

Ceraphronidae sp.: Abe et al. 2011: 277.

Ceraphronidae sp.: Ganaha-Kikumura et al. 2012: 323.

Etymology.

The specific name, flavigastris , is Latin meaning yellowish gaster, derived from the color of the female metasoma.

Type material.

See Table 1.

Description.

FEMALE. Body length 0.5-0.6 mm (Figs 1, 2). Head dark brown. Scape yellow; pedicel and all flagellomeres yellowish brown. Mesosoma dark brown. Fore wing with an infuscate area. Fore and mid coxae dark brown, sometimes yellowish in apical half; fore and mid femora yellow, sometimes brownish; hind leg and all tibiae yellow. Metasoma yellow, darker dorsally.

Head in dorsal view 1.5-1.7 times as wide as long, 1.2-1.4 times as wide as mesosoma; POL: OOL: LOL = 1.8: 1.5: 1.0. Head in frontal view (Fig. 3) 1.0-1.1 times as wide as high; malar space 0.3-0.5 times as long as eye height; lateral margin of torulus distinctly raised; intertorular carina distinct; frontal depression transversely reticulate; ocellar foveae absent; preocellar pit absent; facial pit absent; preoccipital furrow present and extends from anterior ocellus to occipital foramen; preoccipital carina absent; preoccipital lunula absent; occipital carina present; occipital depression absent; occiput smooth. Antenna (Fig. 4) 10 segmented; scape about 0.6 times as long as height of head, as long as distance between inner orbits; pedicel 2.0-2.5 times as long as flagellomere 1; the following segments gradually widened; flagellomere 7 about 2.0 times as wide as flagellomere 1; club 1 segmented.

Mesosoma 1.2-1.4 times as long as wide; 1.3-1.5 times as high as wide; ventral pronotal pit distinct; mesoscutum reticulate, sparsely setose (Fig. 5); setal base slightly pustulate; median mesoscutal sulcus complete; notaulus absent; parapsidal line absent; interaxillar sulcus present; scutoscutellar sulcus angled medially, foveolate, continuous with interaxillar sulcus; dorsal axillar area and mesoscutellum sculptured as mesoscutum, with distinct lateral carina which connects posterior mesoscutellar sulcus (Fig. 6); mesoscutellum 1.4-1.6 times as long as wide; anterior mesopleural sulcus distinct (Fig. 7); anterior mesopleural area finely reticulate with several setae; dorsal mesometapleural carina straight; anterior mesopleural sulcus perpendicularly intersecting dorsal mesometapleural carina; metapleural carina distinct, extends near dorsal mesometapleural carina.

Fore wing about 3.0 times as long as wide, with a darkly pigmented band (Fig. 8); radial vein 1.4-1.5 times as long as marginal vein. Metacoxa bare dorsally; longitudinal metacoxal carina present at base.

Syntergum with distinct transverse carina anteriorly, smooth, with 2-3 setae anterolaterally, occupying more than half of total length of metasoma; longitudinal striae of syntergum absent.

MALE. Differs from female as follows: Antenna (Fig. 9) 11 segmented; flagellar setae long, about 2.0 times width of flagellomeres.

Distribution.

Japan.

Host insects.

Feltiella acarisuga and Feltiella acarivora . Usually one, occasionally two or three adults emerged from a single host cocoon.

Diagnosis

Evans et al. (2005) proposed the following three species groups based on characteristics of the mesosoma and metasoma:

clavicornis group: mesoscutal median furrow and metasomal basal carina absent. tenuicornis group: mesoscutal median furrow absent, metasomal basal carina present. fumipennis group: mesoscutal median furrow and metasomal basal carina present.

According to the morphological features of these species groups, the new species belongs to the fumipennis group, while Aphanogmus fulmeki and Aphanogmus floridanus that have been known as parasitoids of Feltiella species belong to the clavicornis group and tenuicornis group, respectively. Therefore, the new species can be distinguished from Aphanogmus fulmeki and Aphanogmus floridanus .

Among members of the fumipennis group, the new species shares the following characteristics with species in the Aphanogmus hakonensis complex sensu Polaszak and Dessart (1996): median mesoscutal sulcus present; dorsal axillar area and mesoscutellum with distinct lateral carina; syntergum with distinct transverse carina anteriorly. However, Aphanogmus flavigastris does not belong to the Aphanogmus hakonensis complex based on the following characters: fore wing with a darkly pigmented band (hyaline in Aphanogmus hakonensis complex); antenna of female with flagellomere 2-7 not transverse (transverse in Aphanogmus hakonensis complex).

The new species is most similar to Aphanogmus inamicus as it shares the following characters: median mesoscutal sulcus present; dorsal axillar area and mesoscutellum with distinct lateral carina; syntergum with distinct transverse carina anteriorly; fore wing with a darkly pigmented band; antenna of female with flagellomere 2-7 not transverse. However, Aphanogmus flavigastris can be distinguished from Aphanogmus inamicus by the following characters: club of antenna 1 segmented (3 segmented in Aphanogmus inamicus ); lateral carina on dorsal axillar area and mesoscutellum more raised than that of Aphanogmus inamicus ; longitudinal striae of syntergum absent (present in Aphanogmus inamicus ); mesosoma dark brown (reddish yellow in Aphanogmus inamicus ); infuscate area on fore wing smaller (from marginal vein to posterior margin of fore wing in Aphanogmus inamicus ).

According to a key to the Palaearctic species of Aphanogmus ( Szelényi 1940), the new species runs to Aphanogmus fasciolatus Förster based on the following characters: antenna clavate; club 1 segmented and longer than the preceding two segments combined; ra dial vein longer than marginal vein. However, the new species could be distinguished from Aphanogmus fasciolatus by having longer pedicel that is distinctly longer than flagellomere 1 while Aphanogmus fasciolatus has the pedicel that is shorter than flagellomere 1.

We need to monitor the seasonal abundance of Aphanogmus flavigastris for the successful application of Feltiella species, because its congener Aphanogmus floridanus that attacks Feltiella acarivora has been regarded to act as a negative force in controlling Tetranychus urticae Koch ( Acari: Tetranychidae ) on strawberry in California ( Oatman 1985). Shimoda et al. (2016) recently developed a remarkable system for trapping Feltiella species and other predators of spider mites using pots of Brassica rapa Linnaeus var. perviridis L.H.Bailey ( Brassicaceae ), ‘komatsuna’ in Japanese, which bore Tetranychus urticae . They could rear an unidentified species of Aphanogmus from Feltiella acarisuga with the trapping system. This method may be useful to collect plenty of individuals of Feltiella and its parasitoids from ‘komatsuna’ in the fields. Further field surveys are needed to verify the efficacy of this method as a monitoring tool for Aphanogmus flavigastris .