Gypsy moth (Lymantia dispar) refugia in Croatia? - evidence from molecular data

The gypsy moth, Lymantria dispar L., is a herbivore insect native to Europe, Asia and the norhern parts of Africa and is invasive to North America. Its caterpillars are polyphagous, recorded to feed on more than 300 plant species and populations periodically outbreak, causing substantial ecological and socioeconomical damages. Due to position in southeastern Europe, whole surface of Croatia lays outside borders of permafrost of last ice age. Today, gypsy moth inhabits whole area of Croatia, but populations are developing in two different regions separated by Dinaric Alps. Thus, one population developes in continental lowland forest where main host species are Quercus robur and Q. petraea, while coastal populations developes in mediteranean forests where main hosts are Q. ilex and Q. pubescens. Gypsy moth survey data revealed diferences in outbreaks between continental and coastal regions, the fact that encouraged us to investigate spatial genetic structure using molecular markers with aim to investigate possible genetic differences between populations. We performed collection of caterpillars on four different sites, two in continent and two in coastal region. Total genomic DNA was extracted using SIGMA extraction kit, COI marker amplification was carried out with conventional PCR, followed by sequencing. Obtained sequences were manually checkeed and alligned using ClustalW. Haplotypes containing 676bp were determined and cladogram was constructed using TCS genealogical software and molecular indices were calculated using DnaSP and MEGA5 phylogenetic software. Haplotype network and distribution map were also constructed. All tests revealed sigificant genetic differentiation between separated population and higher genetic variability in coastal region indicating that this area could have acted as refugia during last Ice Age and Dinaric Alps probably posed migratory barrier causing differentiation between populations. To confirm this hypothesis, these data have to be compared on wider European scale.