Lasioptera foeniculi Dorchin and Freidberg

Dorchin, Netta & Freidberg, Amnon, 2011, The gall midges (Diptera: Cecidomyiidae) of Apiaceae in Israel, Zootaxa 3044, pp. 28-48 : 37-39

Lasioptera foeniculi Dorchin and Freidberg , new species

( Figs. 2, 4, 7 , 15–17, 21 , 24, 27–29 , 51 )

Adult: Head ( Fig. 2 ): General color dark brown, densely covered by white scales. Eye facets circular, gap between eyes on vertex 0–0.5 facet wide. Palpus 4-segmented; palpiger usually well developed; segment 1 as long as or slightly longer than wide; segments successively longer or segments 3–4 same length. Antenna: flagellomeres 11– 13 in both sexes (n=9 Ƥ, 4 3); flagellomeres 1–3 longer than wide, remaining flagellomeres except for apical, rectangular, wider than long; first two flagellomeres partially fused, last flagellomere often longer than preceding, rounded apically, often consisting of 2 fused flagellomeres; each flagellomere except apical with two whorls of circumfila connected by 1–2 longitudinal branches, row of short, curved setae proximal to proximal circumfilum, and several strong setae between circumfila whorls; otherwise evenly covered by microtrichia ( Fig. 4 ). Apical flagellomere often with more than 2 circumfila whorls.

Thorax: General color dark brown, covered by white scales. Wing ( Fig. 7 ): length 0.95–1.27 mm in female (n=11), 0.91–1.16 mm in male (n=4); covered by dark brown hairs, veins faint; C covered by dark brown scales to merging point with R5, M present, Cu unforked. Legs covered by dark brown scales dorsally, white scales ventrally. Tarsal claws toothed; teeth evenly curved. Empodia longer than bend in claws ( Fig. 6 ).

Female abdomen: general color pinkish, covered by white scales; scale pattern on each tergite comprises wide band of black scales on proximal part and thin band of white scales along lateral and posterior margins. Tergites 1– 6 with two sensory setae at mid-anterior part and row of setae along posterior margin; tergite 7 unsclerotized mesolaterally, with two sensory setae anteriorly and 1–2 rows of strong setae along posterior margin ( Fig. 17 ); sclerite 8 divided into two elongate sclerites, each widened posteriorly, with one sensory seta at proximal third and few setae posteriorly ( Fig. 15 ). Sternites weakly sclerotized along posterior half, with two closely adjacent sensory setae anteriorly, few setae mesally, and row of strong setae along posterior margin; sternite 7 less sclerotized laterally and more setose than preceding; sternite 8 undifferentiated from surrounding membrane. Ovipositor ( Fig. 15 ): long (segments 9+10 of abdomen 4.48–5.16 times as long as tergite 6 (n=9)); lateral group of setae on segment 8 comprising relatively few (15-20) short, apically rounded, scale-like setae; lateral plate virtually absent; dorsal part of fused cerci bearing two long, hooked, apically rounded dark setae and at least two fine strongly curved setae anterior to the hooked setae; fused cerci otherwise setulose and with numerous straight, long, fine setae on entire surface.

Male abdomen ( Fig. 16 ): Scale pattern as in female. Tergites 1–6 with two sensory setae anteriorly and row of setae posteriorly; sclerotization of tergites 7–8 reduced to narrow anterior band, with two anterior sensory setae and no posterior setae. Sclerites of sternites 2–7 divided into two bands, anterior longer than posterior, with two closely adjacent sensory setae anteriorly, row of strong setae posteriorly and several strong setae mesally; Sclerotization of sternite 8 reduced to single median band, with anterior sensory setae and row of posterior setae. Terminalia ( Fig. 21 ): gonocoxite with numerous, evenly distributed setae; mediobasal lobe long and narrow, sheathing aedeagus almost to apex, covered by curved setae. Gonostylus narrowed abruptly at distal third, setulose on proximal third, ridged on distal two thirds, with several setae; tooth well developed. Aedeagus blunt apically. Hypoproct entire. Cerci separated to base, setose and setulose.

Larva (third instar): Ovoid, orange, with dark brown spatula; length: 1.53–1.62 mm (n=6). Integument evenly bumpy except for two narrow anteroventral patches on each segment. Cephalic apodeme about twice as long as head capsule. Antennae about twice as long as wide. Spatula ( Fig. 24 ): with long slender shaft and two pointed anterior teeth separated by triangular notch. On each side of spatula one sternal papilla and four lateral papillae, all asetose. Median pleural papilla asetose. Other pleural papillae and dorsal papillae with long, well developed setae. Terminal segment with two groups of three terminal papillae with long, conspicuous setae ( Fig. 27 ).

Pupa ( Figs. 28–29 ): Brown. Antennal bases developed into very short, blunt horns. Cephalic seta long, situated on elevated base. Prothoracic spiracle thin and elongate, trachea ends at apex. Frons on each side with one pair of lateral and one pair of median papillae, one papilla of each pair with very short seta. Dorsum of abdominal segments covered by tiny, pointed spinules.

Holotype: Ƥ, Israel, Kefar Hahoresh, 19.x.2009, N. Dorchin, reared from fruit gall on Foeniculum vulgare , mounted on permanent microscope slide, deposited in TAUI.

Paratypes: 4 Ƥ, 3 3, Israel, Kefar Hahoresh, 3.x.1997, N. Dorchin (3 Ƥ, 2 3 TAUI, 1 Ƥ, 1 3 ZFMK); 6 larvae (on one microscope slide), Israel, Kefar Hahoresh, 11.x.1997, N. Dorchin ( TAUI); 4Ƥ, 1 3, 4 pupal exuviae (on one microscope slide), same data as holotype (3 Ƥ, 1 3, exuviae TAUI, 1 Ƥ ZFMK). All material from Foeniculum vulgare .

Other material examined. 2 Ƥ, 2 3, Israel, Kefar Hahoresh, 3.x.1997, N. Dorchin, ex. Foeniculum vulgare .

Distribution. This species is currently known only from Israel. Galls were observed in the Upper and Lower Galilee and the Shfela (Nahal Amud, Sede Ya’acov, E’n Alva, Kefar Hahoresh, and Tel Keshet).

Etymology. The species name refers to its host-plant genus, Foeniculum .

Biology. Galls develop in fruits of Foeniculum vulgare ( Fig. 51 ). Thus, this is the only Lasioptera species from Apiaceae that does not develop in stems or umbels. A galled fruit is 2–5 times as large as a normal fruit, contains a single chamber, and larvae develop in it gregariously (up to 12 larvae observed in dissected galls). Mycelia were not observed in the galls. The galls are uncommon but not rare and usually only one or few fruits are galled within a single umbel. They constitute inflated, distorted fruits, usually green but sometimes purplish, and were observed only in September-November. The larvae leave the galls and pupate in the soil. Adults emerged within 10 days. It therefore appears that this species is univoltine or bivoltine - with two generations within a very short time during the fall. Other life-history aspects of this species are unknown. The galls are often attacked by hymenopteran ectoparasitoids that each prey on several gall-midge larvae and may kill all the larvae in a gall.

Remarks. This species is most similar morphologically to Microlasioptera flexuosa ( Winnertz 1853) that develops in stems of Phragmites australis ( Skuhravá and Skuhravý 1981) . The latter species was originally described under Lasioptera but transferred to Microlasioptera by Skuhravá and Skuhravý, who created the genus for it. We do not see the need for a separate genus for the two species and consider them as belonging to Lasioptera . The small number of hooked setae on the female cerci and the absence of the lateral plate represent an extreme situation in the genus, but intermediate states exist between it and the more common situation of an ovipositor with a well developed lateral plate and numerous hooked setae as in L. carophila , for example. An example for such an intermediate state is found in L. hungarica Möhn that is redescribed by Skuhravá and Skuhravý in the same work (1981), including a detailed discussion and illustration of the morphological variability of the ovipositor. Among the distinguishing characters of Microlasioptera , the authors mention the weak wing venation and reduced number of palpal segments (mostly 3 rather than the usual 4). We consider both characters insufficient to justify a new genus.

Lasioptera foeniculi differs from M. flexuosa in the smaller number of antennal flagellomeres in females (11– 13 versus 17–20, respectively), the constant number of 4 palpal segments (as opposed to usually 3 in M. flexuosa ), and the number of hooked setae on the female fused cerci (always 2 in L. foeniculi , 2–4 in M. flexuosa ), although these characters vary often within the same species in the Lasiopterini . Larvae of the two species exhibit better differences: in M. flexuosa , the group of lateral papillae closest to the spatula (basically numbering 3 papillae in Lasiopteridi but usually only 1 in Lasioptera ) has been completely lost whereas in L. foeniculi one of these is still present. It is noteworthy that according to Skuhravá and Skuhravý (1981), all lateral papillae in M. flexuosa are asetose but Möhn (1968, under L. flexuosella ) showed that two of them are setose. Both descriptions agree that the spatula is very weakly sclerotized, often without a visible shaft. By contrast, in L. foeniculi the spatula is well developed. Apart from developing in different host plants and galls, the two species differ also in their life history, as L. foeniculi pupates in the soil whereas M. flexuosa pupates inside the gall.

Figures

FIGURES 1 – 7. Lasioptera spp. 1. L. carophila, head. 2. L. foeniculi, head. 3. L. umbelliferarum, flagellomeres. 4. L. foeniculi, flagellomeres. 5. L. carophila, acropod. 6. L. foeniculi, acropod. 7. L. foeniculi, wing. Scale bars = 0.1 mm (fig. 7, 1 mm).

FIGURES 8 – 15. Lasioptera spp. female abdomen. 8. L. carophila, tergite 7. 9. L. carophila, one of two sclerites of tergite 8. 10. L. eryngii, tergite 7. 11. L. eryngii, one of two sclerites of tergite 8. 12. L. umbelliferarum, tergite 7. 13. L. umbelliferarum, one of two sclerites of tergite 8. 14. L. carophila, ovipositor. 15. L. foeniculi, ovipositor. Scale bars = 0.1 mm.

FIGURES 16 – 21. Lasioptera spp. 16. L. foeniculi, male abdomen (terminalia removed). 17. L. foeniculi, female tergite 7. 18. L. carophila, male terminalia, dorsal. 19. L. carophila, male aedeagus and mediobasal lobes, ventral. 20. L. umbelliferarum, male terminalia, dorsal. 21. L. foeniculi, male terminalia, dorsal. scale bars = 0.1 mm.

FIGURES 22 – 29. Lasioptera spp. 22. L. carophila, larval spatula and associated papillae. 23. L. umbelliferarum, larval spatula and associated papillae. 24. L. foeniculi, larval spatula and associated papillae. 25. L. carophila, larval anal segment. 26. L. umbelliferarum, larval anal segment. 27. L. foeniculi, larval anal segment. 28. L. foeniculi, pupal exuviae, ventral. 29. L. foeniculi, pupal exuviae, lateral. Scale bars = 0.1 mm.

FIGURES 50 – 57. Galls. 50. Lasioptera carophila, umbel and umbelule galls on Foeniculum vulgare. (photo: Israel (Roly) Netiv). 51. Lasioptera foeniculi, fruit galls on Foeniculum vulgare. 52 – 53. Lasioptera umbelliferarum, stem galls on Bilacunaria boissieri. 54 – 55. Schizomyia botellus, jointed bud galls on Deverra triradiata. 56 - 57. Schizomyia buboniae, berry-like bud galls on Deverra tortuosa.