Náttúrufræðingurinn

Volume

Náttúrufræðingurinn - 2021, Page 62

Náttúrufræðingurinn - 2021, Page 62
Náttúrufræðingurinn 62 inn samfelldu lagi af mítlum og mítla- eggjum. Í þessu sambandi er athygl- isvert að það er neikvætt samband á milli smits snípuluddu á rjúpum og smits kláðamítlanna M. borealis og M. islandicus,14 og snípuluddur virðast forðast kláðarjúpur. Við fundum húðmítlana P. pari og M. avus eingöngu á snípuluddum af rjúpum. Hvorug þessara tegunda er þekkt sníkjudýr á rjúpu10,29 og báðar eru nýjar í fánu Íslands. P. pari er vel þekkt sníkjudýr á fjölda fuglategunda víða um heim, meðal annars á spörfuglum, svo sem barrmeisu (Parus ater), flot- meisu (P. major), söngþresti (Turdus philomelos), mistilþresti (T. viscivorus) og maríuerlu.20,30 M. avus sækir á spör- fugla erlendis, svo sem gráspör (Passer domesticus), svartþröst (T. merula) og álmtittling (Emberizia cirlus) en einnig á vaðfugla, svo sem hrossagauk.20 Það á við um báðar þessar tegundir að líklega hafa snípuluddurnar náð í þær af öðrum tegundum fugla en rjúpu. ÁLYKTANIR Lúsflugur af ættkvíslinni Ornithomya eru sérhæfð sníkjudýr með áhuga- verðan lífsferil. Eini ílendi fulltrúi ætt- kvíslarinnar á Íslandi er snípuludda (O. chloropus). Snípuludda sníkir fyrst og fremst á ýmsum tegundum mófugla og er mjög algeng og útbreidd á Íslandi frá miðju sumri og fram á haust. Lúsflugur eru smitferjur fyrir ýmsar tegundir ytri sníkjudýra en í þessari rannsókn fund- ust eingöngu þrjár tegundir húðmítla sem nýttu sér snípuluddu til dreifingar, allt ósérhæfðar tegundir með tilliti til hýsla. SUMMARY The hippoboschid Ornithomya chloropus in Iceland: life cycle and phoresy Feather mites (Astigmata: Analgoidea) and chewing lice (Phthiraptera) are prevalent ectoparasites of birds. It is important to know both transmissions pathways and host specificity when studying host-parasite interactions. The life cycle of both feather mites and chewing lice is simple and transmission most often direct between conspecifics but louse flies (Hippoboscidae) can also function as vectors for ectoparasites. This role of the louse fly was the impetus for our study, and we wanted to answer what parasites use the louse fly Orni- thomya chloropus for transmission in Iceland and to describe the life cycle of the fly. We collected and examined 650 louse flies from 13 avian host species in Iceland 1999–2011. The hosts included six species of shorebirds (Golden Plover Pluvialis apricaria, Ringed Plover Cha- radrius hiaticula, Whimbrel Numenius phaeopus, Black-tailed Godwit Limosa limosa, Snipe Gallinago gallinago, and Redshank Tringa totanus), two species of passerines (Redwing Turdus iliacus and Pied Wagtail Motacilla alba), two falcon species (Gyrfalcon Falco rusti- colus and Merlin Falco columbarius), Rock Ptarmigan Lagopus muta, Grey- lag Goose Anser anser and Arctic Tern Sterna paradisaea. All fly specimens were identified to Ornithomya chloro- pus. The flies were collected between 16 June and 11 October, the active period is thus at least four months. Sex ratio was slightly female biased in June through August (55.6–69.0% females) but in Sep- tember and October females dominated in the samples (92.7 and 96.3% females respectively). Louse flies are larvipa- rous and female flies „give birth“ to a prepupae. Maturing larvae can be seen through the skin of the abdomen of the mother. We found no female flies car- rying maturing larvae in June or July, but 18.5–29.4% of female flies in August through September. There is most likely only one generation of O. chloropus per year in Iceland and the over-wintering stage is a pupa. We searched for pho- ronts on all the specimens and found three species of avian skin mites (Epi- dermoptidae): Myialges borealis (prev- alence 24.3%), Promyialges pari (4.3%) and Microlichus avus (0.3%). The mites were most prevalent in August and Sep- tember. M. borealis was a hyperparasite on O. chloropus with gravid females – usually surrounded by eggs – attached to the abdomen of the louse fly. Flies infested with M. borealis were collected from four species of hosts, Rock Ptarmi- gan, Gyrfalcon, Merlin, and Redwing. Mean intensity of M. borealis was 11.0 mites per infected fly (95% c.l. 9.7–12.5). Adult females of P. pari – usually sur- rounded by eggs and freshly hatched larvae – were found loosely attached to the underside of the wing of the louse fly and apparently not a hyperparasite. Mean intensity was 1.6 mites (95% c.l. 1.1–3.1). Two adult M. avus females were found on louse flies. Both were loosely attached to the flies; one was found on the abdomen among M. borealis and the other on the wing among P. pari. Both M. avus and P. pari are new species records for Iceland. However, their avian hosts are not known. All flies carrying these two mites were caught on Rock Ptarmi- gan but neither species are known Rock Ptarmigan parasites. We did not find any chewing lice phoronts.

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