Odontocerum hellenicum Malicky, 1972 (Trichoptera: Odontoceridae) as a host of Agriotypus armatus Curtis, 1832 (Hymenoptera: Ichneumonidae) – the first finding for Serbia

Abstract

Odontocerum Leach, 1815 is а single European caddisfly genus within family Odontoceridae, containing three species, O. albicorne (Scopoli, 1763), O. hellenicum Malicky, 1972 and O. lusitanicum Malicky, 1975. First two species are registered in Serbia, but O. hellenicum has a much narrower area (southeastern part of the country). Species of Odontoceridae, Goeridae and Uenoidae in a pupal stage can be a host for ectoparasitoid wasp Agriotypus armatus Curtis, 1823. Distribution of A. armatus was recorded during the macrozoobenthos research of the streams of Serbia in 2011–2012. The caddisfly species Silo pallipes Fabricius, 1781 (fam. Goeridae) is known to be as the most common host of this parasitoid wasp. Out of eight rivers involved in the study, we recorded parasitized pupae of O. hellenicum only in the Vrla River, which is the first record of this host–parasitoid relation on the territory of Serbia. Among 36 O. hellenicum cases examined, seven cases were empty (19.44%), 27 were non-parasitized (75%) and only two were parasitized (5.56%). Parasitoid wasps we found were in pupal stage. As known so far, O. hellenicum is the second recorded host species for A. armatus in Serbia. Having in mind that Silo pallipes is more common species compared to O. hellenicum, and also the fact that no infected cases of more frequent species O. albicorne were found in our survey, we can assume that A. armatus has a higher preference for the species of Goeridae family in Serbian streams.