Molecular and cytogenetic differentiation within the Lariophagus distinguendus (Förster, 1841) species complex (Hymenoptera, Pteromalidae)

Abstract

Several strains of the apparently well-known cosmopolitan synanthropic parasitoid of coleopteran stored-product pests, <i>Lariophagusdistinguendus</i> (Förster, 1841) from Western Europe, were studied using DNA sequencing and chromosomal analysis. The presence of at least two cryptic species with different COI sequences and chromosome numbers (n = 5 and 6) was supported. The species with n = 6 is associated with the drugstore beetle <i>Stegobiumpaniceum</i> (Linnaeus, 1758), whereas the other one with n = 5 mostly develops on the granary weevil <i>Sitophilusgranarius</i> (Linnaeus, 1758). A phylogenetic study revealed that the karyotype with n = 6 represents an ancestral character state in this complex. Consequently, the chromosome set with n = 5 which is characteristic of a particular internal clade, apparently originated via chromosomal fusion which was probably preceded by a pericentric inversion. If this is true, inverted chromosome segments could accumulate a number of genetic loci responsible for certain interspecific differences.