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Helsinki, Finland

Kaunisto S.,University of Eastern Finland | Kortet R.,University of Eastern Finland | Harkonen S.,Finnish Wildlife Agency | Kaitala A.,University of Oulu | And 2 more authors.
Canadian Journal of Zoology | Year: 2012

Predation is often considered an important factor for population regulation and in some cases for the invasion success of prey. Small mammalian predation may be a major force in the population regulation of many ground-dwelling invertebrate species. The deer ked (Lipoptena cervi (L., 1758)) is an ectoparasitic fly of cervids. The species has a large distribution area and it has relatively rapidly spread in northern Europe during the previous four decades. The factors possibly regulating the distribution and invasion of this fly are poorly known. During the off-host stage of several months, pupae of deer ked are likely exposed to many ground-dwelling predators. To study whether small mammals would feed on deer keds, we conducted experiments by serving pupae of deer ked to wild-captured common shrews (Sorex araneus L., 1758), bank voles (Myodes glareolus (Schreber, 1780)), field voles (Microtus agrestis (L., 1761)), and semi-wild bank voles, and assessed pupal survival. As a control, we provided alternative food including common nutrients used by small mammals in their natural habitats. The results show that variable amounts of pupae of deer ked are consumed by all small-mammal species studied. Surprisingly, insectivorous and most of the time food-constrained shrews consumed less pupae than granivorous-herbivorous voles.

Kaunisto S.,University of Eastern Finland | Valimaki P.,University of Oulu | Kortet R.,University of Eastern Finland | Koskimaki J.,University of Oulu | And 5 more authors.
Biological Journal of the Linnean Society | Year: 2012

The deer ked (Lipoptena cervi) is an ectoparasitic fly on cervids that has expanded its distribution rapidly in Northern Europe. However, the regulating biotic factors such as predation remain unknown. The host-independent pupal stage of the fly lasts for several months. Blackish pupae are visible against snow, especially on the bedding sites of hosts, and are thus exposed to predators. To evaluate the role of predation on the invasion dynamics and evolution of L.cervi, we monitored pupal predation on artificial bedding sites in three geographical areas in Finland during winter. We explored: (1) possible predators; (2) magnitude of predation; and (3) whether predation risk is affected by host-derived cues. We demonstrate that pupae are predated by a number of tit species. Any reddish brown snow discoloration on bedding sites, indicating heavy infestation of the host, serves as an exploitable cue for avian predators, thereby increasing the risk of pupal predation. The ability of tits to use this host-derived cue seems to be dependent on the prevalence of L.cervi and the period of invasion history, which suggests that it may be a learned behavioural response. Predation by tits may potentially affect the L.cervi population dynamics locally. © 2012 The Linnean Society of London.

Brommer J.E.,University of Turku | Brommer J.E.,Novia University of Applied Sciences | Kekkonen J.,University of Helsinki | Wikstrom M.,Finnish Wildlife Agency
Ecology and Evolution | Year: 2015

A heterozygosity-fitness correlations (HFCs) may reflect inbreeding depression, but the extent to which they do so is debated. HFCs are particularly likely to occur after demographic disturbances such as population bottleneck or admixture. We here study HFC in an introduced and isolated ungulate population of white-tailed deer Odocoileus virginianus in Finland founded in 1934 by four individuals. A total of 422 ≥ 1-year-old white-tailed deer were collected in the 2012 hunting season in southern Finland and genotyped for 14 microsatellite loci. We find significant identity disequilibrium as estimated by g2. Heterozygosity was positively associated with size- and age-corrected body mass, but not with jaw size or (in males) antler score. Because of the relatively high identity disequilibrium, heterozygosity of the marker panel explained 51% of variation in inbreeding. Inbreeding explained approximately 4% of the variation in body mass and is thus a minor, although significant source of variation in body mass in this population. The study of HFC is attractive for game- and conservation-oriented wildlife management because it presents an affordable and readily used approach for genetic monitoring that allowing identification of fitness costs associated with genetic substructuring in what may seem like a homogeneous population. The use of Heterozygosity-Fitness Correlation (HFC) to study inbreeding depression is debated, especially regarding the potential of a small set of neutral markers to reflect genome-wide heterozygosity. White-tailed deer in Finland went through an extreme bottleneck and we here show that HFC study is a powerful approach to study inbreeding in this population. © 2015 Published by John Wiley & Sons Ltd.

Kynkaanniemi S.-M.,University of Oulu | Kettu M.,University of Oulu | Kortet R.,University of Oulu | Kortet R.,University of Eastern Finland | And 8 more authors.
Parasitology Research | Year: 2014

Blood-sucking ectoparasites have often a strong impact on the behaviour of their hosts. The annual insect harassment of reindeer (Rangifer tarandus tarandus) has increased in the southern part of the Finnish reindeer herding area because of the recent invasion of a blood-feeding ectoparasitic louse-fly, the deer ked (Lipoptena cervi). We studied the impact of the deer ked on the behaviour of reindeer. Twelve reindeer were infested with a total of 300 keds/reindeer on six occasions in a 5-week period during the deer ked flight season in autumn, while six non-infested reindeer were used as controls. Behavioural patterns indicating potential stress were monitored by visual observation from August to December. The infested reindeer displayed more incidences of restless behaviour than the controls. Shaking and scratching were the most common forms of restless behaviour after infestation of deer keds. Increased grooming was also observed after the transplantation and also later, 1 month after the infestation. Based on the results, the deer ked infestation can cause acute behavioural disturbance in reindeer and, thus, could pose a potential threat to reindeer welfare. Antiparasitic treatment with, e.g. ivermectin, may increase the welfare of parasitized reindeer by reducing deer keds. If the deer ked infestation intensity on the reindeer herding area increases and restless behaviour of reindeer becomes more common, the present results can help in further evaluation of the duration and magnitude of behavioural changes. © 2014 Springer-Verlag.

Kekkonen J.,University of Helsinki | Wikstrom M.,Finnish Wildlife Agency | Ala-Ajos I.,Finnish Wildlife Agency | Lappalainen V.,Finnish Trophy Board | And 2 more authors.
Annales Zoologici Fennici | Year: 2016

White-Tailed deer were introduced to Finland in 1934 from Minnesota, North America. The population has expanded and is now an important wildlife species, managed through hunting. We determined the age of 451 individuals harvested in the 2012 hunting season. Hunters measured their body mass after slaughter and we measured the dimensions of the lower jaw (in both sexes) as well as skull dimensions and antler scores (in males). The sample indicated a deficit of older males in the population. Females seem to gain their size at the age of two while males continue to increase their body size and that of skeletal traits until the age of four. The size traits measured were similar to those in the North American studies. Based on population growth patterns and introduction history, the white-Tailed deer population is performing well in Finland but the potentially skewed sex-specific age distribution warrants further attention. © Finnish Zoological and Botanical Publishing Board 2016.

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