the morphological variations of culex pipiens larvae (diptera: culicidae) in yazd province, central iran

background: culex pipiens complex shows variations in morphological and biological characters including differ­ent biological forms and has medical and veterinary importance. because of having morphological variations, some­times it is not easy to separate this species from cx. quinquefasciatus and cx. torrentium . the aim of this study was to   identify the   culex pipiens complex species in order to use in control programs in the future. methods: this study was carried out in two randomly selected rural villages in yazd county, eastern iran using dip­ping technique from april to october 2009. the data were analyzed using spss software version 16. results: average of siphon index in fourth-instrar larvae was 3.86±0.03, the minimum and maximum were calculated 2. 43 and 5.14, respectively. siphon/saddle index was measured as average, minimum and maximum 3.2±0.2, 2.78, and 4.42 respectively. in our study, only 4 specimens had single seta 1 on segments iii and vi (2.5%) and the remaining beard double seta (97.5%). the maximum 3-6 branches seta 1a-s and 1b-s (95%) were observed on siphon. conclusion: more populations of culex pipiens from different areas of iran need to be studied to gain complete informa­tion about the taxonomy and ecology of the species in the country.