Prosimulium rachiliense, DJAFAROV

Adler, Peter H., S, Ümit & Irin, 2014, Cytotaxonomy of the Prosimulium (Diptera: Simuliidae) of Western Asia, Zoological Journal of the Linnean Society 171 (4), pp. 753-768 : 759

PROSIMULIUM RACHILIENSE DJAFAROV CYTOFORM ‘B’

Populations in western Turkey, consisting of 305 analysed larvae, were designated a distinct cytoform of P. rachiliense on the basis of having the Prosimulium standard sequence in all arms (e.g. Fig. 3 ), albeit with a high frequency of IS-20 ( Fig. 4 ), a set of unique autosomal inversions, and sex determination based on chromosome III ( Table 4). All but one of 102 males were heterozygous for a darkly staining band on either side of the centromere; absence of the bands represented the Y chromosome ( Fig. 10A ). All females were homozygous for both bands (X 0 X 0), representing the standard condition. An additional rearrangement, IIIS-2, was coupled with the centromeric rearrangement in eight of ten males in south-western Anatolia (Sites 15 and 16), yielding a second Y chromosome, Y 2 ( Fig. 10A ). Twelve autosomal rearrangements were recorded ( Table 4), each infrequent, with the exception of IS-20, which generally occurred in 75% or more of the homologues at each site, and was fixed in samples from south-western Anatolia. At Site 8, the population consistently had a dearth of IS-20 heterozygotes over a four-year period, and was not in Hardy−Weinberg equilibrium for the inversion ( Table 5). The two early samples (10, 11 April) were predominantly homozygous inverted for IS-20, whereas the two later samples (23, 27 April) were predominantly standard, suggesting some seasonal structuring at Site 8. IS-20 also was not in equilibrium at Site 13a ( Table 5). Ectopic pairing of centromere bands occurred in all larvae, although not in all nuclei. One larva (Site 19) was infected with a probable new species of microsporidium with oval spores .

Figures

Figure 3. Chromosome arm IS of Prosimulium rachiliense cytoform ‘B’ (female), showing the standard sequence. Limits of IS-20 and IS-22 are indicated by arrows and a bracket, respectively, and of IS-18 of Prosimulium rufipes by arrows. Fixed rearrangements are italicized and polymorphic rearrangements are in standard type. Abbreviations: hb, location of heteroband 11hb in Prosimulium sp. nov.; “3”, 3 heavy marker.

Figure 4. Chromosome arm IS of Prosimulium rachiliense cytoform ‘B’ (male). Relative to the standard sequence, IS-20 is present. Limits of inversion IS-21 of cytoform ‘A’ are indicated by a bracket. Fixed rearrangements are italicized and polymorphic rearrangements are in standard type. Abbreviations: C, centromere; “3”, 3 heavy marker.

Figure 10. Chromosome arm IIIS and base of IIIL (male), showing the standard sequence. A, centromere region of Prosimulium rachiliense cytoform ‘B’. The upper homologue carries the standard banding sequence representing the X; the lower homologue shows the Y-linked absence of bands on either side of the centromere. Limits of Y-linked IIIS-2 and autosomal IIIL-20 are indicated by brackets. B, Prosimulium tomosvaryi showing the standard sequence. Abbreviations: bl, blister; C, centromere; ca, capsule; hc, location of extra heterochromatin (83hc).