Chromosomal variability ofDrosophila polymorphapopulations from Atlantic Forest remnants of continental and insular environments in the State of Santa Catarina, Brazil

Abstract

In the present study, we investigated chromosomal polymorphism for paracentric inversions found in Drosophila polymorpha populations common in five fly communities (one continental and four insular) collected in Atlantic For- est remnants in Santa Catarina, Brazil, during a one-year sampling. Our analyses showed that the more polymorphic the populations, the greater the abundance of flies. The insular populations were more polymorphic than the continental one, probably because the greater environmental heterogeneity found in the islands provided more niches for fly colonisation and was more suitable for supporting a community. Stochastic effects, however, need to be taken into account to under- stand the low polymorphism found at the continental site, since the D. polymor- pha sample collected there was small. We also present here the occurrence of six previously undescribed paracentric chromosomal inversions in heterozygosis, increasing to 7 the number of variants identified in the D. polymorpha polytene chromosomes.