Simulium (Rubzovia) paraloutetense Crosskey, 1988

Crosskey, R. W. & BÁez, M., 2004, A synopsis of present knowledge of the Simuliidae (Diptera) of the Canary Islands, including keys to the larval and pupal stages, Journal of Natural History 38 (16), pp. 2085-2117 : 2097-2099

Simulium (Rubzovia) paraloutetense Crosskey

Material from breeding sites

Gran Canaria: Site GC14— 8 larvae (27 March 1994) ( BM / ANN) , 1 pupal cocoon, 29 larvae (29 March 1995) ( RWC) , 3 pupae [pharate adult males] (16 November 1995) ( BM / ANN) and 1 larva (18 March 1997) ( RWC) .

Remarks

Crosskey et al. (1998) have dealt with this very rare endemic species in detail, providing the first description of its aquatic stages and a discussion of its taxonomic affinities, together with an account of its spring habitat in the Barranco de Guayadeque in Gran Canaria (Site 14, the only discovered breeding site). The aquatic stages are easily recognized: the pupal gill has a stout U-like structure (figure 33) and the larva almost completely lacks the postgenal cleft of the cranium (figure 10). The species was the only simuliid occurring at the one known breeding site and was always at very low density. The sum of material found at five prospections of the site between 1994 and 1998 was only 38 larvae, three male pupae (each at pharate adult stage) and one pupal cocoon. Complete extinction of the species, very soon if it has not already occurred, seems certain unless there are any surviving populations in remote mountain springs: recent inspection (by MB) of the site in the Barranco de Guayadeque has shown it to be now dry and destroyed, apparently having been in this degraded state for a considerable time.

P. H. Adler studied the larval polytene chromosomes of S. paraloutetense from a small Carnoy’s-fixed subset of the larvae collected ( RWC) on 29 March 1995. The haploid number 3 (2n~6) is normal, the nucleolar organizer is in chromosome II adjacent to its centromere, the centromeres of chromosomes I and II tend to combine into a partial chromocentre, and sex chromosomes are not differentiated; polymorphisms were not seen in the small sample available (two male and five female larvae). A brief description of the karyotype has been given by Crosskey et al. (1998: 387) and a photograph of the polytene chromosome complement is given here in figure 40. At present there are no cytological data for other western Palaearctic species of the subgenus Rubzovia , namely S. ( R) lamachi Doby and David and S. (R.) knidirii which both occur in Morocco, for comparison with the data on S. (R.) paraloutetense .