Research Article
A Comparative Analysis of Key Parameters of the Species of Subgenus Phlebotomus (Diptera, Psychodidae) from Balochistan, Pakistan
Sandflies, Leishmaniasis and Mosquitoes Lab. I Zoology, University of Balochistan, Quetta, Pakistan
Since the classical work of Lewis[1] on sandflies of the Punjab, N.W. F. P. and Sindh Provinces, till after the lapse of about 29 years, no taxonomic studies was ever conducted on the sandflies of the Balochistan Province. To fill this gap of knowledge, taxonomic revision of the sandflies of Balochistan Province was conducted by the author in 1996-2001[2]. During the revision of different genera and subgenera of Phlebotomine sandflies collected from the whole of the Balochistan Province, the author encountered specimens of the three species of the subgenus Phlebotomus (Genus Phlebotomus) namely Ph. papatasi (N=720), Ph. bergeroti (N=30) and Ph. salehi (N=70) in various localities of the Province. Lewis[1] did not report the prevalence Ph. bergeroti and Ph. salehi from Pakistan as his collection did not represent the specimens from Balochistan Province. In view of the insufficient work of Lewis[1], a comparative analysis of forty-five taxonomic characters of the specimens of these three species are given in the present paper. Differential diagnosis of these species is also briefly discussed. This study adds new supportive taxonomic data to earlier works on the identification of sandflies of the subgenus Phlebotomus.
For collection, preservation, dissection and examination of external and internal parts of the body of the sandfly, the conventional methods especially those used by Johnson et al.[3], Lewis[4], Killick-Kendrick[5], Lawyer et al.[6] and Killick-Kendrick et al.[7] were generally followed. Standard taxonomic keys furnished by Lewis[1,8,9] and Artemiev[10] were followed. All the diagrams were drawn with a camera lucida and are to the given scales and the measurements are in millimeter (mm), unless otherwise indicated. All the specimens are housed with the Authors collection of Sandflies, Department of Zoology, University of Balochistan, Quetta.
Key parameters studied: Taxonomic features taken into account in the present study were primarily those of earlier works, but many are modified and others are new. Following, 45 key parameters (27 of male and 18 of female) are taken into consideration and are given in the (Table 1).
Differential diagnosis among species of subgenus phlebotomus: Ph. papatasi Scopoli[11]. The morphology of spermathecae, pharyngeal armature and position of basal and middle spine on style, bigger upper parameral lobe than the paramere and surstyle with 2 or some times 3 stout but similar apical bristles at once differentiates this species from other species of subgenus Phlebotomus.
Ph. bergeroti Parrot[12]: The distance between basal and middle spines are greater or equal to that of between middle and distal spines. Further, 2nd dorsal process of paramere hardly longer than the paramere itself. Apical bristles o f surstyles are long and thin.
Table 1: | Species of subgenus Phlebotomus (Genus Phlebotomus) |
Pharynx of female flies with blunt teeth directed obliquely down to the center.
Ph. salehi Mesghali[13]: Intermediate basal spine of the style is at the same distance from terminal spines and from another basal spine. Distal part of the paramere strongly curved up and has 7-8 hairs at the end. Second dorsal process is rather short, widens at the end and hairs present only at the wider distal part. Female pharyngeal armature consists of small teeth, those in the center are more hard and pigmented than the others and teeth are not pointing backward. Spermathecae become narrower towards its duct.
Comparative note
Ph. papatasi Scopoli[11]: Male flies were with a larger wing and alar index than those of from Sudan[14]. However, A3, labrum, ascoid 4/A4, coxite and aedeagus were measured shorter than those from Sudan. Labrum of male flies was found smaller than those from S. India[15], central Asian countries[16], countries of Eastern Mediterranean region[17], Saudi Arabia[18].The female flies were observed with shorter wing length, alar index, A3, labrum and ascoid 4/ A4 but a greater wing breadth as compared with those from Sudan. However, wings of male and female flies were measured similar as those from India. Characters like ascoid formula (2/3-15) and palpal formula (1,2-4,3,5) were found similar as those from Sudan[14].
Ph. bergeroti Parrot [12]: Female flies were found with a greater alar index and a larger A3 as compared with the published data of this species from Eastern Mediterranean region countries[17]. Further, female flies were observed having a shorter wing, A3 and shorter ascoid 4/ A4, but a larger ä, alar index, labrum and larger A3/ labrum as compared with the published data of this species from Africa (Sudan)[14]. Characters like coxite and style were found larger than those from Iran[19].
Ph. salehi Mesghali[13]: Male flies were found with shorter wing, A3, labrum, toothed area of pharynx, coxite, style, surstyle as compared with those from Iran[13].The cibarium of male flies were observed having several narrow spicules arranged laterally, but unarmed buccal cavity was reported by Mesghali and Rashti[20] in Iranian specimens. The over all figures of pharynx and kind of armature of present specimens showed a notable differentiation as compared with Iranian forms. Similarly, the surstyle of the present form were found armed with four apical bristles and not three as reported in Iranian specimens. The aedeagus were found having curved ends like a birds and not as figured in Iranian forms. Female flies were found with a shorter wing, A3, ascoid 4/A4 and shorter length to breadth ratio of pharynx as compared with Iranian specimens. Similarly, cibarium of female specimens were observed with 5-7 denticles scattered anteriorly and several narrow spicules arranged laterally but Mesghali and Rashti[20] reported 2-3 minute cibarial teeth arranged laterally. Further, the over all figure of pharynx and the kind of pharyngeal armature showed a notable difference as compared with the same structures of Iranian forms. Several punctiform ridges were also observed in posterior pharyngeal armature whereas the figure of pharynx drawn by Mesghali and Rashti[20] did not show such type of armature. Moreover, these Iranian workers neither described nor drawn diagram of papilla on antennal segments in Iranian flies whereas a single papilla on antennal segments (III,IV,V) was observed during present study.
In conclusion, it can be suggested that the data presented here will facilitate the workers in the correct identification of the species of the subgenus Phlebotomus.
The author is grateful to Professors Drs. R. Killick-Kendrick.; David, J. Bradley; R. W. Ashford; R. P. Lane and Dr. David Evans for their encouragement and valuable guidance on sandflies. My sincerest thanks are also due to respected Joanna Kapusta (BMNH), Linda Huddleston (BMNH), Dr. J.-P. Dedet (France) and Dr. Farrokh Modabber (WHO) and Prof. Dr. V. N. Neronov (Russia) for providing me the literature on sandflies.