Natural history of Oxyrrhexis zgphyrus sp.n. (Hymenoptera: Ichneumonidae), a parasitoid of Enoplognatha serratosignata (Araneae: Theridiidae), with notes on taxonomy and other hostspecies of Oxyrrhexis

摘要

Oxyrrhexis zephyms sp.n., belonging to the Polysphincta genus-group, is described. Like all other species of this group, the new species is a koinobiont ectoparasitoid of spiders. It has been reared from the ground-living theridiid Enoplognatha serratosignata (L. Koch, 1879) in Norway. Chablisea shaanxiensis (Liu, He et Chen, 2009) comb.n. is proposed, ex Oxyrrhexis; thus Oxyrrhexis still comprises only four known species worldwide, but now with two species in the West Palaearctic. Oxyrrhexis carbon-ator (Gravenhorst, 1807), as its subspecies texana (Cres-son, 1870), is reported as new to the state of Alaska. Steatoda bipunctata (Linnaeus, 1758) is reported as the host of O. carbonator in Europe and, based on a large reared material from Finland, Sweden and Norway, this seems to be the only host of the nominate subspecies, at least in northern Europe. Parasitised hosts and the cocoons of the new species and O. carbonator are figured. The host record for the new species together with the data presented and discussed in this paper strongly support the hypothesis of Oxyrrhexis being a genus specialised in attacking the spider family Theridiidae. Literature records of other spider families and non-spiders as hosts for O. carbonator are considered erroneous.