Altitudinal Variability in Wing Patterns of Phyllonorycter salictella (Zeller, 1846) (Lepidoptera: Gracillariidae)

Individual variability of wing patterns is not frequent in European species of the genus Phyllonorycter Hubner, 1822. It is unusually distinct in Phyllonorycter salictella (Zeller, 1846) which causes some taxonomic ambiguities and oversights. We found on numerous material of adults reared from overwintering pupae collected in the Czech and Slovak Republics since 1950 that this variability is related with altitude (temperature). Adults with the distinct generotypic (plesiomorphic) wing patterns dominated in submountain populations while individuals with the strongly reduced (apomorphic) wing drawings were represented quite negligibly. This ratio was reversed in lowland populations. The observed variability is continuous between extreme variants, it is regionally and trophic unaffected, and more pronounced in males than in females. The results support the view that the questionable taxa such as Phyllonorycter viminiella (Sircom, 1848) and P. heringiella (Gronlien, 1932) represent only individual (local or regional) forms of the above species.