Simulium (Wilhelmia) sergenti Edwards, 1923

Crosskey, Roger W. & Crosskey, Margaret E., 2000, An investigation of the black ¯ y fauna of Andalusia, southern Spain (Diptera: Simuliidae), Journal of Natural History 34 (6), pp. 895-951 : 937-938

26. Simulium (Wilhelmia) sergenti Edwards

Spain references: SeÂguy (1925, as ariasi , synonym, original description), SeÂguy (1930, as ariasi ,

no locality), Carlsson (1969, as Wilhelmia mediterranea [mm, in part, misidenti®ed]),

Beaucournu-Saguez (1975a), GonzaÂlez PenÄa et al. (1987), GonzaÂlez PenÄa (1990),

GonzaÂlez (1997).

Andalusia records

Authors’ material. Site 20: 2 pupae, 4 larvae. Site 24: 1 (l1). Site 26: 3 pupae, 1 larva. Site 35: 1m (1), 31 pupae, 43 larvae. Site 36: 1 (l1), 1m (1), 2 pupae, 3 larvae. Site 44: 1m. Site 45: 1m (1), 15 pupae, 2 larvae. Site 79: 1 (l 1), 42 pupae, 53 larvae. Site 94: 1 (l 1), 7 pupae, 13 larvae. Site 95: 1 (l1), 24 pupae, 58 larvae. Site 98: 7 pupae, 16 larvae. Site 100: 2 (l1), 3m (1), 21 pupae, 16 larvae. Site 113: 1 (l1), 4 larvae.

Other specimens seen. CaÂdiz : 2 l(pinned, genitalia on slides), Algeciras , 26± 30.iv.1925 (Zerny) ( BMNH) [New record]; Granada: 1m, Orgiva, RõÂo Guadalfeo, 300 m [VF68], 14.iv.1966 (Langemark) and 2m, same locality, 7.iv.1966 (Lyneborg and Langemark) ( ZMC: specimens referenced RG3, RG5 and RG6 ) [ mediterranea , part, in Carlsson, 1969] .

Previous reports. JaeÂn: Arroyo de los Chopos, 6 km E of AnduÂjar and stream 5 km E of AnduÂjar, on AnduÂjar-BaileÂn road, [VH11], RõÂo Rumblar, 12 km W of BaileÂn [VH21], RõÂo GuadalbulloÂn, 13 km S of JaeÂn [VG47] (ref. Beaucournu-Saguez, 1975a). MaÂlaga: Arroyo de la Venta (UF3394), RõÂo Campanillas (UF6565), RõÂo Grande (UF4866), RõÂo Guadalhorc e (UF4772, UF5667, UF7106), RõÂo Guadiaro (TF9253), RõÂo Turon (UF3684) (refs GonzaÂlez PenÄa et al., 1987; GonzaÂlez PenÄa, 1990).

Remarks

This is a species of very restricted distribution, occurring only in central and southern parts of the Iberian peninsula and in the countries of the Maghreb ( Morocco to Tunisia). It is not widely known and there is little associated literature. It nearly always occurs together with other species of the subgenus Wilhelmia , especially S. pseudequinum but also at times with S. lineatum and S. equinum . The pupa diOEers from that of other Wilhelmia species by the distinctive gill (®gure 50): this has only four tubes in addition to the basal arms, two of them enormous and the other two very small and so delicate that they are often broken oOE and seemingly absent. This unique gill structure makes it possible to recognize the larvae of the species when mixed with larvae of other Wilhelmia , even the quite early instars when the pupal gill histoblast is white: observed in situ the histoblast shows only two incipient gill tubes between the developing basal arms instead of the three seen in larvae of S. pseudequinum , S. lineatum and S. equinum .

Species of subgenus Wilhelmia are mammalophilic and females are attracted to cattle and other livestock as a blood source. Identi®cation to species of non-reared females presents a di culty, as there seem to be no external characters by which they can be readily diOEerentiatedÐthough general observation of the shape of the cerci and paraprocts suggests that the exact form of these lobes may be found to provide reliable speci®c characters when adequately studied. The spermatheca, however, is known to diOEer in size and shape between some Wilhelmia species (Rivosecchi et al., 1988) and on this account one of us (RWC) has examined this structure in pharate and reared females of S. sergenti to see its size and shape and to determine whether the four Wilhelmia species in Andalusia can be distinguished as wild-caught ¯ies. The conclusionÐtaking our data into account with that of Rivosecchi et al.Ð is that females of S. pseudequinum and S. equinum are not separable from one another, that females of S. sergenti and S. lineatum together are separable on spermathecal shape from the S. pseudequinum / S. equinum pair, and that S. sergenti and S. lineatum are separable from one another on spermathecal size. The following key is provided accordingly:

1 Spermatheca large, ovoid or slightly pear-shaped. Sclerotized capsule size: length at

least 0.10 mm, diameter at least 0.08 mm. Edge of capsule at clear duct base smooth, uncrimped..................... 2

± Spermatheca small, subglobular (often resembling an unopened mushroom) (®gures 48,

49, insets). Sclerotized capsule size: length 0.05±0.07 mm, diameter 0.06±0.08 mm. Edge

of capsule at clear duct base crimped, often strongly so (®gure 49, inset).....

............. S. (W.) pseudequinum and S. (W.) equinum

2 Spermatheca very large (®gure 51, inset). Sclerotized capsule size: length 0.14±0.18 mm,

maximum diameter 0.10±0.13 mm .......... S. (W.) lineatum

± Spermatheca smaller (®gure 50, inset). Sclerotized capsule size: length 0.10±0.12 mm, maximum diameter 0.08±0.09 mm .......... S. (W.) sergenti