Tiphiidae

Abstract: In this study, three new species of the subgenus Jaynesia Allen from China are described and illustrated, namely T. hohehotensis sp. nov. from Inner Mongolia, T. displicata sp. nov. from Sichuan, and T. rotunda sp. nov. from Gansu. A key to all known species of Jaynesia is also provided.

Abstract: We tabulated flowering plant species visited by 151 species of parasitic Hymenoptera. These data were extracted from records of C. Robertson who collected >15,000 insect visitors of flowering plants in central Illinois during a 33-yr period. Species diversity of parasitoids was highest on plant species of the Apiaceae and Asteraceae. The most abundant parasitoids were 2 tiphiid and a scoliid species. Parasitoid species in 6 dominant families (Ichneumonidae, Braconidae, Chrysididae, Tiphiidae, Pteromalidae, and Eucoilidae) showed similar preferences for 10 plant species. Most parasitoid species visited a limited range of host plants, which may have implications for conservation biological control and conservation biology.

Abstract: Imidacloprid, a relatively long residual neonicotinoid soil insecticide, is often applied to lawns and golf courses in spring for preventive control of root-feeding white grubs. We evaluated effects of such applications on spring parasitism of the overwintered third-instar Japanese beetle, Popillia japonica Newman, by Tiphia vernalis Rohwer, an introduced solitary ectoparasitoid. Natural rates of parasitism on a golf course rough were significantly lower in plots treated with full or one-half label rates of imidacloprid in early May compared with untreated turf. Parasitism also was reduced when female T. vernalis were exposed to imidacloprid residues on turf cores in the laboratory. Such exposures did not affect wasp mortality, longevity, survival, or developmental period of Tiphia larvae feeding on hosts in treated turf. They did, however, reduce wasps' ability to parasitize hosts in nontreated soil for at least 1-2 wk postexposure. In Y-trail choice tests, wasps that previously had been exposed to treated turf failed to respond normally to host frass trails in the soil. Female wasps did not avoid imidacloprid residues, imidacloprid-treated host frass, or host grubs that had previously been exposed to treated soil. This study indicates that applying imidacloprid in early spring can interfere with biological control by T. vernalis, whereas postponing preventive grub treatments until June or July, after the wasps' flight period, will help to conserve T. vernalis populations.

Abstract: Cues used in below-ground host-searching behaviour and host discrimination were examined for Tiphia vernalis Rohwer and Tiphia pygidialis Allen (Hymenoptera: Tiphiidae), ecto-parasitoids of root-feeding larvae of the Japanese beetle, Popillia japonica Newman, and masked chafers, Cyclocephala spp. (Coleoptera: Scarabaeidae), respectively. Response to potential stimuli was compared in dual choice tests in an observation chamber filled with soil. Each wasp showed species-specific, directed movement along residual body odor trails made by dragging its respective host through the soil. Presence of a grub was not necessary for wasps to follow such trails. Frass from either host- or non-host grubs elicited trail-following, but each Tiphia species followed frass trails from its respective host when a choice was presented. Frass trails elicited stronger responses than body odor trails. The combination of host frass and body odor elicited the strongest trail-following responses. Our results suggest that once in the soil, Tiphia spp. locate their hosts using contact kairomones present in grub body odor trails and frass.