Abstract
Frequently, DNA studies on parasitic Hymenoptera have revealed host specific cryptic species from complexes previously thought of as single generalist species. The parasitic Hymenoptera genus, Pteromalus, involves members that attack fruit flies (Diptera: Tephritidae) with variable degrees of host specificities, but with one species, P. albipennis, particularly standing out as a generalist. Many members of the genus are also very close morphologically, and the status of some of the species has therefore earlier been questioned. These trends indicate a potential presence of cryptic species, or the opposite, that several nominal species exist within the boundaries of a single species. To test these assumptions, species of Pteromalus were investigated based on morphological determinations, sequence data and their host fruit fly relations. The insects were hatched from different Asteraceae plants, and sequence analyses of the Pteromalus specimens were conducted based on two loci, the mitochondrial COI and nuclear ITS2 regions. Despite large intraspecific genetic variation in the two loci, no clear indication on cryptic species was revealed. This indicates that the observed polymorphism is caused by other factors, such as population size, speciation in reverse, Introgressive hybridization or Wolbachia infection. In two cases, sequence analyses were not able to distinguish between species of Pteromalus, suggesting that what is currently recognized as seven valid species rather exists within the boundaries of two. These results indicate that the two species, P. intermedius and P. albipennis, not constitute complexes of host specific cryptic species, but possess broader ranges of host fruit fly preferences than previously expected.