Distribution and frequency of Culex pipiens and Culex torrentium (Culicidae) in Europe and diagnostic allozyme markers .

摘要

The morphologically similar Culex pipiens sensu lato and Cx. torrentium are sympatric inmuch of Central, Eastern and Northern Europe. Since morphological separation of females ofthese mosquitoes is extremely difficult and uncertain, diagnosis depends upon timeconsuming microscopic examination of male hypopygial characters. Consequently thepossible, or even probable, occurrence of Cx. torrentium has been ignored in numerous fieldstudies which have recorded (perhaps erroneously) presence of Cx. pipiens only. As aconsequence, knowledge of the true geographical distribution, frequency of occurrence andecological characteristics of these mosquitoes is deficient or confused.In this study, the species diagnostic enzyme markers, adenylate kinase (AK) and 2-hydroxybutyrate dehydrogenase (HBDH) were shown to discriminate between Cx. pipiensand Cx. torrentium larvae as well as male and female adults. Diagnostic allele and genotypedifferentiations were quantified. In total, 4,040 mosquitoes of Cx. pipiens sensu lato and Cx.torrentium from Germany and other countries were studied.Culex torrentium was shown to be frequently encountered in Central Europe. Thoughgenetically and reproductively separated from Cx. pipiens, it exhibits similar ecologicalcharacteristics, and there is a high degree of association between these taxa in the breedingsites.Of 2052 specimens collected from ovitraps in South-West Germany, 54.8% were identified asCx pipiens and 45.2% as Cx. torrentium. In 712 samples taken from natural and artificialbreeding sites, 59% were identified as Cx. pipiens and 41% as Cx. torrentium. In contrast, ofadult specimens caught in CO2-traps, only 3.9% were Cx. torrentium, and the other 96.1%were Cx. pipiens, indicating selective attraction exerted by the CO2-traps. Both species werealso found in other parts of Germany.Neither Cx. torrentium nor Cx. quinquefasciatus were detected in samples obtained fromTurkey, Cyprus, Greece, Serbia and South Eastern France, though all these contained Cx.pipiens. It was only in samples from Germany and Luxembourg that Cx. torrentium wasfrequent.