Megastigmus schimitscheki Novitzky

Roques, A. & Skrzypczyńska, M., 2003, Seed-infesting chalcids of the genus Megastigmus Dalman, 1820 (Hymenoptera: Torymidae) native and introduced to the West Palearctic region: taxonomy, host specificity and distribution, Journal of Natural History 37 (2), pp. 127-238 : 195-198

Megastigmus schimitscheki Novitzky

(figures 25, 41, 62, 80, 100, 118, 138, 156) Megastigmus schimitscheki Novitzky, 1954: 220–224 . 10 X, 10 W syntypes, Alanya-Ayandere,

Turkey (depository unknown: ‘Novitzky collection’ and ‘Schimitschek collection’

according to Grissell, 1999 [not examined]).

Female

Body length (without ovipositor) 5.0 mm. Body predominantly shining black except a few parts coloured in orange-brown to brown. Head mostly black with the following parts coloured in orange-brown: oral area, a small triangular spot below eye extending along malar sulcus, and a narrow, semi-continuous circumorbital line interrupted by irregular black patches. Antenna brown except scape and pedicel orange beneath. Pilosity black on head, even on lower face. Thorax almost entirely black with a dark orange, quite indistinct spot along posterior margin of lateral panel of pronotum and at basis of forewing. Pilosity black on thorax. Coxae black; femurs mostly dark brown except the distal part orange; remainder of legs orange. Forewing stigma brown, without surrounding infuscation. Propodeum black. First apparent tergum of gaster brown, the following ones brown with a narrow, orangeyellow transverse band posteriorly; lateral parts and sterna orange-yellow except first apparent sternite brown. Ovipositor sheaths black.

Head 1.3× as broad as long in dorsal view. Antennal scape as long as pedicel, anellus and first funicular segment combined; first funicular segment 1.2× longer than the following segments (figure 25). Pronotum and mesoscutum with coarse cross-striae. Scutellum about 1.3× as long as broad, the anterior part reticulatestriate, the frenal area smooth or with only a few short wrinkles extending longitudinally from the frenal line (figure 138). Forewing stigma oval-elongate, about 1.6× as long as wide (figure 62). Propodeum with a median carina. Exserted part of ovipositor 1.1× as long as body. Distal part of dorsal valve of ovipositor with small, blunt teeth, the second median tooth being larger than others (figure 100).

Male

Body length 3.9 mm. Body colour very similar to that of female, predominantly shining black except a few parts coloured in orange-brown to brown. Head with lower face orange, circumorbital area and temple orange-brown, a narrow black line interrupting circumorbital area between gena and temple; remainder of head black. Antenna brown except scape and pedicel orange beneath. Pilosity black on head, even on lower face. Thorax almost entirely black with a dark orange, quite indistinct spot along posterior margin of lateral panel of pronotum and at basis of fore wing. Pilosity black on thorax with five pairs of conspicuous bristles on scutellum. Coxae black; femurs mostly dark brown except the distal part orange; remainder of legs orange. Forewing stigma brown, without surrounding infuscation. Propodeum black. First apparent tergum of gaster brown, the following ones brown with a narrow, orange-yellow transverse band posteriorly; lateral parts and sterna orangeyellow except first apparent sternite brown.

Head about 1.5× as broad as long in dorsal view. Antennal scape smaller than in female, 0.9× as long as pedicel, anellus and first funicular segment combined; first funicular segment slightly longer (1.1×) than the following ones (figure 41). Pronotum and mesoscutum with very coarse cross-striae. Scutellum 1.4× as long as broad, the anterior part reticulate-striate, the frenal area smooth with only a few short carinae extending longitudinally from the frenal line (figure 156). Forewing stigma more rounded than that of female, about 1.5× as long as broad, with a small uncus (figure 80). Propodeum with a median carina, interrupted in the middle in some specimens. Aedeagus conical, medium-sized; phallobase compressed in its medium; digitus with four teeth (figure 118).

Variation

The above description is based on a female and a male emerged from Cedrus libani, Sultandagi , Turkey (May 1997, Turkey, J. P. Fabre leg.) deposited at MNHN. In other specimens we examined, body length varied from 4.8 to 5.3 mm in females, from 3.0 to 4.2 mm in males. Very little variation in colour was observed. The dark orange spots on lateral panel of pronotum and at wing base were absent in about 30% of the examined specimens, and were not observed on the material used by Novitzky (1954) for the original description, nor on that described by Hussey (1957). The circumorbital line could also disappear, especially in females. The carina on propodeum was frequently interrupted in the middle .

Sex ratio

Novitzky (1954) assumed the sex ratio to be balanced in native countries. Fabre et al. (1994) measured a ratio of 730 W:825 X when summing emergences from 18 locations in Turkey, but the sex ratio largely varied between locations. In southeastern France, the introduced populations showed a ratio of 433 W: 602 X at Mt Ventoux.

Hosts

Observed in seeds of the cedar species (Cedrus spp., Pinaceae) originating from the eastern part of the Mediterranean Basin: C. libani (Novitzky, 1954; Schimitschek, 1955; Çanakçioglü, 1959, 1969, 1990; Lessmann, 1962; Ozkazanç, 1979; Fabre et al., 1994; AR; USNM) and C. brevifolia (Hussey, 1957; USNM). In France, it shifted on to another introduced cedar, C. atlantica, and a Spanish fir, Abies pinsapo (Fabre et al., in preparation). Records on cypress (Schimitschek in Schwenke, 1982) probably represented misidentifications.

Distribution

Originates from southeastern Europe and Asia Minor. Present in Cyprus (Hussey, 1957); Greece: Crete and islands of the eastern Aegean Sea (Schimitschek, 1955); Lebanon (Novitzky, 1954; Fabre et al., 1994; AR); Syria (Novitzky, 1954; USNM); and Turkey (Acatay, 1961; Novitzky, 1954; Çanakçioglü, 1959, 1969, 1990, 1993; Lessmann, 1962; Ozkazanç, 1979; Fabre et al., 1994; AR). Recently introduced to Mt Ventoux, southeastern France (probably in 1994 with seed lots of C. libani from Turkey; J. P. Fabre, personal communication), where it is gradually invading the naturalized stands of cedars and Spanish fir.

Comments

Two other chalcid species were observed to attack seeds of Cedrus spp. in the West Palearctic, M. pinsapinis , and more scarcely M. suspectus . Females are easily differentiated by the face coulour, which is entirely yellow in M. pinsapinis and yellow with black markings in most specimens of M. suspectus . Confusion may exist with the darkest specimens of M. suspectus , whose face can show extended black markings, but M. schimitscheki differs by the three pairs of coxae being entirely black. Similarly, males of M. schimitscheki can be recognized from those of the two other species by the coxae being entirely black. A total of six other species compete for seeds of Abies pinsapo . Diagnostic characters are given in the chapter regarding M. milleri .

Material examined

France: 602 X, 433 W, ex. Cedrus atlantica, Mt Ventoux (84), May to June 1998 ( JPF) ; 54 X, ex. Abies pinsapo, Mt Ventoux (84), April 1995 ( JPF) ; 1 W, ex. A. pinsapo, Mt Ventoux (84), April 1997 ( JPF) . Lebanon: 2 X, 2 W, ex. C. libani, Barouk Forest, 1981 , G. Riom ( AR) . Syria: 1 X, ex. C. libani (USNM) . Turkey: 1 X, ex. C. libani, Y. Gokdere , 3 June 1998 ( JPF) ; 12 X, 15 W, ex. C. libani , seed lot to be introduced in France from Yenice (37°30∞N, 35°00∞E), 1994 ( AR) ; 33 X, 55 W, ex. C. libani, Sultandagi , May to June 1997 ( JPF) ; 13 X, 12 W, ex. C. libani, Aykiriçay , May to June 1997 ( JPF) .