S. Mahunka szerk.: Folia Entomologica Hungarica 52. (Budapest, 1992)

Notes on the host range and sex-ratio of Ornithomyia fringillina (Diptera: Hippoboscidae) Adatok az Ornithomya fringillina (Diptera: Hippoboscidae) gazdaspektrumának és ivararányának ismeretéhez Hippoboscid flics were collected in the autumn (from 17lh August to 27th September) of 1991 at Fenékpuszta, Hungary. The flies were parasitizing on birds captured in the reeds at the lake Balaton. A group of amateur ornithologists collected the birds by mistnets during their autumn migration. Ringers, collecting biomedical data on the birds, blow into the abdominal plumage, in order to visually estimate their fat reserves. At this point Hippoboscid flies occasionally escape from the birds, typically landing on the ringer himself or on a nearby object. Most of these flies were caught. A total of 93 flies belonging to four species were identified. Ornithomyia fringillina (Curtis, 1836) was the commonest species represented by 67 individuals (72%). The data on the host species of 41 Ornithomyia fringillina are as follows: ReedWarbler SedgeWarbler BeardedTit Great Reed Warbler Swallow Moustachcd Warbler Savi's Warbler Blue-headed Wagtail Acrocephalus scirpaceus A crocephalus sc hoc nob ae nus Panurus biarmicus A crocephalus arundinaceus Hirundo rustica A. (Lusciniola) mclanopogon Locustella luscinioides Motacilla flava flava 17 individuals 8 individuals 6 individuals 3 individuals 3 individuals 2 individuals 1 individuals 1 individuals All individuals (20) of Ornithomyia biloba pufour, 1827) were collected from swallows. Ornithomyia avicularia (Linnaeus, 1758) was represented by three individuals, two of them were collected from Reed Warbler, one from Bearded Tit. One individual of Stenepteryx hirudinis (Linnaeus, 1758) was collected from Sand Martin (Riparia riparia). These data suggest that Ornithomyia fringillina is probably the commonest Hippoboscid fly parasitizing the Passeriform birds in the reeds. Our sample of Ornithomyia fringillina consisted of 9 males and 58 females. There are seven more individuals in the Hungarian Natural History Museum (1 male and 6 females), all of them from Hungary, in 1988. On the base of these data the sex-ratio of this population is estimated to be 1:6.4, significantly differs from 1:1 (chi-square test, p <0.01). Howewer, we may not exclude the possibility that this sex-ratio was influenced by the sampling method. Acknowledgement - The author wishes to thank dr. László Papp and Lajos Rózsa for their valuable help, and to the group of ornithologists led by Sándor Palkó for their generous help in the field. Csaba SZANY1, Budapest