dissertations Sirpa Kaunisto An invasive ectoparasite of cervids, the deer ked: | Sirpa 87 | No Kaunisto | dispersion, cold tolerance and predation Ectoparasites inhabit the outer surface of their hosts and consume host re- sources. In general, host-related factors Sirpa Kaunisto (e.g. density) are thought to be the main An invasive ectoparasite cervids, of the deer ked: dispersion, cold tolerance and predation contributors to geographical distribu- tion of arthropod ectoparasites. How- An invasive ectoparasite ever, temperature is known to strongly regulate survival and distribution in of cervids, the deer ked: many species. Also predation may have ecological significance on parasites, dispersion, cold tolerance although it has rarely been acknow- ledged. This thesis provides insights and predation into temperature-related survival, life-history characteristics and biologi- cal relationships (e.g. predation) of an insect ectoparasite that undergoes a range expansion. Publications of the University of Eastern Finland Publications of the University of Eastern Finland Dissertations in Forestry and Natural Sciences No 87 Dissertations in Forestry and Natural Sciences isbn 978-952-61-0947-3 (printed) issnl 1798-5668 issn 1798-5668 isbn 978-952-61-0948-0 (pdf) issn 1798-5676 (pdf) SIRPA KAUNISTO An invasive ectoparasite of cervids, the deer ked: dispersion, cold tolerance and predation Publications of the University of Eastern Finland Dissertations in Forestry and Natural Sciences No 87 Academic Dissertation To be presented by permission of the Faculty of Science and Forestry for public examination in the Auditorium N100 in Natura Building at the University of Eastern Finland, Joensuu, on November, 07, 2012, at 12 o’clock noon. Department of Biology Author’s address: University of Eastern Finland Department of Biology P.O.Box 111 80101 JOENSUU FINLAND email: [email protected] Supervisors: Professor Hannu Ylönen, Ph.D. University of Jyväskylä Department of Biological and Environmental Science P.O.Box 35 40014 JYVÄSKYLÄ FINLAND email: [email protected] Professor Raine Kortet, Ph.D. University of Eastern Finland Department of Biology P.O.Box 111 80101 JOENSUU FINLAND email: [email protected] Docent Sauli Härkönen, D.Sc. Kopijyvä Finnish Wildlife Agency Joensuu, 2012 Fantsintie 13–14 Editors: Profs. Pertti Pasanen, 00890 HELSINKI Pekka Kilpeläinen, and Matti Vornanen FINLAND email: [email protected] Distribution: Eastern Finland University Library / Sales of publications Reviewers: Docent Marko Mutanen, Ph.D. [email protected] University of Oulu www.uef.fi/kirjasto Department of Biology P.O.Box 3000 90014 OULU ISBN: 978-952-61-0947-3 (printed) FINLAND ISSNL: 1798-5668 email: [email protected] ISSN: 1798-5668 ISBN: 978-952-61-0948-0 (PDF) Researcher Bjørnar Ytrehus, Ph.D. Norwegian Veterinary Institute ISSN: 1798-5676 (PDF) Section for Pathology Pb 750 Sentrum N-0106 OSLO NORWAY email: [email protected] Author’s address: University of Eastern Finland Department of Biology P.O.Box 111 80101 JOENSUU FINLAND email: [email protected] Supervisors: Professor Hannu Ylönen, Ph.D. University of Jyväskylä Department of Biological and Environmental Science P.O.Box 35 40014 JYVÄSKYLÄ FINLAND email: [email protected] Professor Raine Kortet, Ph.D. University of Eastern Finland Department of Biology P.O.Box 111 80101 JOENSUU FINLAND email: [email protected] Docent Sauli Härkönen, D.Sc. Kopijyvä Finnish Wildlife Agency Joensuu, 2012 Fantsintie 13–14 Editors: Profs. Pertti Pasanen, 00890 HELSINKI Pekka Kilpeläinen, and Matti Vornanen FINLAND email: [email protected] Distribution: Eastern Finland University Library / Sales of publications Reviewers: Docent Marko Mutanen, Ph.D. [email protected] University of Oulu www.uef.fi/kirjasto Department of Biology P.O.Box 3000 90014 OULU ISBN: 978-952-61-0947-3 (printed) FINLAND ISSNL: 1798-5668 email: [email protected] ISSN: 1798-5668 ISBN: 978-952-61-0948-0 (PDF) Researcher Bjørnar Ytrehus, Ph.D. Norwegian Veterinary Institute ISSN: 1798-5676 (PDF) Section for Pathology Pb 750 Sentrum N-0106 OSLO NORWAY email: [email protected] Opponent: Professor Manfred Milinski, Ph.D. ABSTRACT Max Planck Institute for Evolutionary Biology August-Thienemann-Str. 2 24306 PLÖN Species distributions and invasion success are affected by a GERMANY range of factors, including various environmental conditions email: [email protected] and biological interactions with other organisms. Ectoparasites are parasites that inhabit surface of the host and consume resources of the host from the outside. Host-related factors, such as host availability and host specificity, are thought to be the main contributors to geographical distribution of terrestrial arthropod ectoparasites. In general, temperature is known to strongly regulate species distributions. However, direct temperature effects on the capacity of ectoparasites to disperse have received less attention. Also other external environmental factors and for example predators may play greater roles than commonly thought in the distribution of terrestrial ectoparasite fauna. In this thesis, I study the life-history characteristics and ecological relationships of an invasive insect ectoparasite, the deer ked (Lipoptena cervi L. 1758, Diptera; Hippoboscidae), to understand if these variables could affect distribution capacity of the species. I focus on temperature and predation as potential constraints for the deer ked’s distribution. The deer ked is a blood-feeding ectoparasite infesting several cervid species. This louse fly can be categorized as an invasive species in Finland, owing to its relatively rapid range expansion towards west and north during the previous five decades. The life cycle of the deer ked can be divided into on-host and off-host stages. In this thesis, my primary focus is on the off-host strategies such as free-living pupal stage and winged adults that have recently emerged from the pupariae and not been contact with host. Pupal and adult characteristics of the deer ked were estimated along species’ distribution range in Finland. Results show that diapausing pupae were smaller in the northern Central Finland than in the southern Finland. This may suggests plastic changes in the life-history characteristics of the deer ked. Small adults emerged earlier from smaller pupae, suggesting lower metabolic reserves of small individuals to sustain long Opponent: Professor Manfred Milinski, Ph.D. ABSTRACT Max Planck Institute for Evolutionary Biology August-Thienemann-Str. 2 24306 PLÖN Species distributions and invasion success are affected by a GERMANY range of factors, including various environmental conditions email: [email protected] and biological interactions with other organisms. Ectoparasites are parasites that inhabit surface of the host and consume resources of the host from the outside. Host-related factors, such as host availability and host specificity, are thought to be the main contributors to geographical distribution of terrestrial arthropod ectoparasites. In general, temperature is known to strongly regulate species distributions. However, direct temperature effects on the capacity of ectoparasites to disperse have received less attention. Also other external environmental factors and for example predators may play greater roles than commonly thought in the distribution of terrestrial ectoparasite fauna. In this thesis, I study the life-history characteristics and ecological relationships of an invasive insect ectoparasite, the deer ked (Lipoptena cervi L. 1758, Diptera; Hippoboscidae), to understand if these variables could affect distribution capacity of the species. I focus on temperature and predation as potential constraints for the deer ked’s distribution. The deer ked is a blood-feeding ectoparasite infesting several cervid species. This louse fly can be categorized as an invasive species in Finland, owing to its relatively rapid range expansion towards west and north during the previous five decades. The life cycle of the deer ked can be divided into on-host and off-host stages. In this thesis, my primary focus is on the off-host strategies such as free-living pupal stage and winged adults that have recently emerged from the pupariae and not been contact with host. Pupal and adult characteristics of the deer ked were estimated along species’ distribution range in Finland. Results show that diapausing pupae were smaller in the northern Central Finland than in the southern Finland. This may suggests plastic changes in the life-history characteristics of the deer ked. Small adults emerged earlier from smaller pupae, suggesting lower metabolic reserves of small individuals to sustain long non-feeding pupal stage. Despite of the different temperature bedding sites increased the predation risk of deer ked pupae by origins and different invasion history of the individuals, the local tit (Paridae) species. The predation pressure on deer ked adult emergence period was relatively synchronized, when pupae can be notable during winter because almost 35% of all pupae were reared under identical temperature and light pupae used in the study were predated upon, even within a conditions. The deer ked had relatively high cold tolerance in all relatively short time interval (5 days). The ability of tits to use free-living stages. The supercooling point, SCP (i.e. temperature the snow discolouration cue was likely dependent on infestation where the spontaneous freezing of body fluids begins)