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Title from PDF of title page (University of Missouri--Columbia, viewed on March 17, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Matthew E. Gompper. Vita. Includes bibliographical references.

2005 – 2007 m. šaltuoju metų periodu (rudenį ir žiemą) buvo tirta rudųjų lapių (Vulpes vulpes L.) ir usūrinių šunų (Nyctereutes procyonoides Grey.) mityba ir morfometrija. Tyrimams buvo naudojamos sumedžiotos lapės ir usūriniai šunys skirti kailių išdirbimui bei iškamšų darymui. Visi tirti gyvūnai buvo pasverti. Iš viso atlikti 5 kūno ir 16 kaukolės matavimų, apskaičiuoti kaukolės, kiaušo ir snukio indeksai. Pas rudasias lapes rasti statistiškai patikimi skirtumai tarp patinų ir patelių buvo pagal visus 5 kūno matmenis. Atlikus kraniometrinę analizę rasti 6 statistiškai patikimi skirtumai tarp usūrinių šunų ir 10 patikimų skirtumų tarp rudosios lapės patinų ir patelių. Atlikus tarprūšinę analizę rasta 15 statistiškai patikimų skirtumų tarp patinų ir tiek pat tarp patelių. Usūrinių šunų kaukolės ir snukio indeksai didesni už lapių, jais galima remtis atskiriant šių gyvūnų kaukoles. Taip pat buvo atlikta skrandžių analizė, apskaičiuotas mitybos objektų aptikimo dažnis ir santykinis tūris, įvertintas tirtų plėšrūnų mitybinių nišų persidengimas. Šaltuoju periodu smulkūs žinduoliai ir kanopinių dvėseliena yra pagrindinis šių plėšrūnų maistas. Labai svarbus usūrinių šunų maisto komponentas yra javai ir vaisiai. Žiemą lapių mityboje dar labiau svarbesni tampa kiškiai ir kanopinių žinduolių arba naminių gyvulių dvėseliena ir skerdiena. Per pus mažiau, šiuo metų laiku lapės minta augalinės kilmės maistu (vaisiai, javai, žoliniai augalai). Mitybinių nišų plotis ir persidengimas... [toliau žr. visą tekstą] / The diet composition of red fox (Vulpes vulpes L.), raccoon dog (Nyctereutes procyonoides Grey.), using stomach analysis, and the morphometrical differences of red fox (Vulpes vulpes L.) were studied in Lithuania. Forty-three males and twenty-eight females of red fox were measured at the 5 measurement points. Furthermore, eighty eight red foxes and forty one raccoon dog skulls were measured at the 16 measurement points, mandibles at the 3 measurement points.5 statistically significant differences in measurements of red fox body were obtained between males and females. Eight skulls and one mandible features of the male foxes were statistically significantly longer compared to the same females foxes features. Five statistically significant differences were found between skull measurement point and one statistically significant difference between mandible measurement points of raccoon dog. Furthermore fifteen significant differences were found between measurements in males and fourteen between measurements in females. The frequency of occurrence and relative capacity were evaluated. In the cold season (November-February), small mammals and carrion of ungulates was the principal food of both predator species. For the raccoon dog plants were an important food component too.

Per pusantrų metų 26 km ilgio kelyje Vilnius–Dūkštos užregistruota 378 žuvę gyvūnai, iš jų 44 žinduoliai (6 laukinių ir 3 naminių gyvūnų rūšys), 1 paukštis ir 333 varliagyviai (rudosios Rana genties varlės). Rastas 21 suvažinėtas baltakrūtis ežys, 8 katės, 4 šunys, 4 akmeninės kiaunės, 2 rudosios žiurkės, 2 geltonkaklės pelės, 1 lapę, 1 pilkasis kiškis ir 1 karvė. Varliagyviai masiškai žūva migruodami iš žiemojimo vietų į nerštavietes. Tiek 2005, tiek 2006 metais masinis rudųjų varlių žuvimas kelyje Vilnius–Dūkštos užregistruotas balandžio pirmąjį dešimtadienį. Daugiausia žinduolių ant kelio buvo suvažinėta šiltuoju metų laiku – rugpjūčio, gegužės ir rugsėjo mėnesiais. Kadangi gyvūnai ant kelių registruojami rytą, dauguma jų suvažinėjami tamsiu paros metu. Daugiausia žinduolių (27%) suvažinėta tose vietose, kur kelią supa krūmynai, 23% - gyvenvietėse ir miesteliuose, 20% – keliui einant pievomis ir 18% – pamiškėse. Kitų biotopų reikšmė gyvūnų žuvimui kelyje Vilnius–Dūkštos buvo nedidelė – miške užregistruota tik 9% žuvusių žinduolių. Ežiai ir varliagyviai suvažinėjami visame Vilnius–Dūkštos kelio ruože: varliagyviai – ties grioviais, upeliais, laukų pelkutėmis ir ten, kur kelią supa šlapi krūmynai, ežiai – kai kelias eina pievomis ir krūmuotomis vietomis. Ištirtoje kelio atkarpoje trūksta apie susidūrimą su gyvūnais perspėjančių kelio ženklų, pavojingose vietose nėra ribojamas greitis. Šios priemonės leistų sumažinti gyvūnų žuvimą. / Animal roadkills on the road were partly conditioned by overspeeding and insufficient number of the road signs. Our results show, that animal roadkills are quite big compared to the short road segment. In the foreign countries problems of the animal roadkills receive more attention, as except damage done to the nature, there are problems of safety, material losses and possible charges to a road service if warning road signs were absent. Object of this investigation were animals, killed on the road Vilnius–Dūkštos (segment length – 26 km). Aim this work was to evaluate species composition of the killed animals, seasonality and influence of the surrounding habitats. Investigation was done while driving this segment twice per day and registering animals killed. Rules of the road were obeyed – no stops under sign or interrupting other vehicles, thus, not all of the killed animals were collected or pictures taken. Places of the roadkills were mapped. In the period of 2004.11.01–2006.05.01number of killed animals was 378; out of these 44 mammals, 1 bird (young Tawny Owl) and 333 amphibians (common/moor frogs). Biggest number of mammal roadkills was done in the dark period of the day and in August–September, while that of amphibians – in April. No kills were registered in January and February. Species composition of mammals: 21 hedgehogs, 4 stone martens, 2 yellow-necked mice, 2 brown rats, 1 fox, 1 brown hare, 8 cats and 4 dogs. According our results and literature analysis... [to full text]

Per pusantrų metų 26 km ilgio kelyje Vilnius–Dūkštos užregistruota 378 žuvę gyvūnai, iš jų 44 žinduoliai (6 laukinių ir 3 naminių gyvūnų rūšys), 1 paukštis ir 333 varliagyviai (rudosios Rana genties varlės). Rastas 21 suvažinėtas baltakrūtis ežys, 8 katės, 4 šunys, 4 akmeninės kiaunės, 2 rudosios žiurkės, 2 geltonkaklės pelės, 1 lapę, 1 pilkasis kiškis ir 1 karvė. Varliagyviai masiškai žūva migruodami iš žiemojimo vietų į nerštavietes. Tiek 2005, tiek 2006 metais masinis rudųjų varlių žuvimas kelyje Vilnius–Dūkštos užregistruotas balandžio pirmąjį dešimtadienį. Daugiausia žinduolių ant kelio buvo suvažinėta šiltuoju metų laiku – rugpjūčio, gegužės ir rugsėjo mėnesiais. Kadangi gyvūnai ant kelių registruojami rytą, dauguma jų suvažinėjami tamsiu paros metu. Daugiausia žinduolių (27%) suvažinėta tose vietose, kur kelią supa krūmynai, 23% - gyvenvietėse ir miesteliuose, 20% – keliui einant pievomis ir 18% – pamiškėse. Kitų biotopų reikšmė gyvūnų žuvimui kelyje Vilnius–Dūkštos buvo nedidelė – miške užregistruota tik 9% žuvusių žinduolių. Ežiai ir varliagyviai suvažinėjami visame Vilnius–Dūkštos kelio ruože: varliagyviai – ties grioviais, upeliais, laukų pelkutėmis ir ten, kur kelią supa šlapi krūmynai, ežiai – kai kelias eina pievomis ir krūmuotomis vietomis. Ištirtoje kelio atkarpoje trūksta apie susidūrimą su gyvūnais perspėjančių kelio ženklų, pavojingose vietose nėra ribojamas greitis. Šios priemonės leistų sumažinti gyvūnų žuvimą. / Animal roadkills on the road were partly conditioned by overspeeding and insufficient number of the road signs. Our results show, that animal roadkills are quite big compared to the short road segment. In the foreign countries problems of the animal roadkills receive more attention, as except damage done to the nature, there are problems of safety, material losses and possible charges to a road service if warning road signs were absent. Object of this investigation were animals, killed on the road Vilnius–Dūkštos (segment length – 26 km). Aim this work was to evaluate species composition of the killed animals, seasonality and influence of the surrounding habitats. Investigation was done while driving this segment twice per day and registering animals killed. Rules of the road were obeyed – no stops under sign or interrupting other vehicles, thus, not all of the killed animals were collected or pictures taken. Places of the roadkills were mapped. In the period of 2004.11.01–2006.05.01number of killed animals was 378; out of these 44 mammals, 1 bird (young Tawny Owl) and 333 amphibians (common/moor frogs). Biggest number of mammal roadkills was done in the dark period of the day and in August–September, while that of amphibians – in April. No kills were registered in January and February. Species composition of mammals: 21 hedgehogs, 4 stone martens, 2 yellow-necked mice, 2 brown rats, 1 fox, 1 brown hare, 8 cats and 4 dogs. According our results and literature analysis... [to full text]

The red fox occurs across a very broad range of habitats, and displays great behavioural flexibility under different environmental conditions. In Australia, mounting concern over the impacts of foxes on livestock and native fauna has highlighted a need for more information on fox ecology under Australian conditions as a fundamental step towards developing more strategic means of managing foxes. This study explores ranging behaviour, dispersal, use of dens, activity rhythms, population dynamics and diet in the absence of management in productive agricultural land in the central tablelands of New South Wales. The study was conducted from June 1994 to June 1997 on private property near Murringo, NSW Australia (34°15� S, 148°30� E). The site was primarily sheep and cattle grazing land and had a history of no fox management. Rainfall was considerably below average for much of the study. A total of 83 foxes were trapped over 3931 trapnights, of which 50 were fitted with radio-collars (23 adult and 6 juvenile females, 12 adult and 9 juvenile males) and 26 released with eartags only (all juveniles: 10 females, 16 males). Thirty-three foxes were radio-tracked using fixed towers between March 1995 and December 1996, with between 11 and 28 foxes tracked at any time. Mean home range size was 446.1 ha ± 69.8 se using 95% Minimum Convex Polygons (MCP), and 276.4 ha ± 36.3 se using 95% kernel utilisation distributions. Male home ranges defined by MCP were significantly larger than female ranges, but no significant difference was found using 95% kernels. Core ranges were estimated to be 133.4 ha ± 23.7 se using 50% MCP and 59.8 ha ± 6.1 se using 95% kernels, with no significant difference between sexes. No significant differences were found between range sizes of adults and juveniles or between years or seasons. While most home ranges were steady for the duration of the study, some foxes were observed to shift range location and 4 foxes displayed nomadic behaviour for at least some of the study. There was a high incidence of overlapping home ranges, most commonly between females or males and females but occasionally between males, but core areas were usually separate. Fully overlapping core areas were observed in 1995 but not in 1996. Juvenile foxes were significantly more likely to disperse than adults, and usually travelled further (juveniles 61.1 km 31.6 ± se; adults 5.9 km 1.1 ± se). Males and females were equally likely to disperse, and there was no significant difference in the distance travelled. The furthest distances were 285 km and 140 km, but mean distance of dispersal excluding these animals was 12.3 km ± 4.3 se (n = 13). Thorough surveys across a 16.4 km² area located 200 dens, with 68 of these active in 1995 and 96 active in 1996. Density of breeding foxes was estimated to be 0.55 and 0.52 adult foxes/km² in 1995 and 1996 respectively based on natal den counts. Density estimates based on active den counts, which include non-breeding foxes, were 0.91and 1.30 foxes/km² in 1995 and 1996 respectively. These estimates appear lower than other studies in similar habitats but this is likely due to using a half home range boundary strip around the surveyed area in the present study. Application of mark-recapture analysis found very high �recapture� rates of dens and gave a similar estimate of the total number of dens to that observed directly. Natal dens were regularly distributed across the study area, whereas active dens tended to be in clusters. There was a high turnover of which dens were used each year, but the total number of natal dens was similar across years (16 in 1995 and 17 in 1996). Natal dens were more likely to be used on repeat occasions than other dens, but not necessarily by the same vixen. Litter size based on sightings of emergent cubs was 2.8. Foxes were predominantly nocturnal, with a major peak in activity about an hour after sunset. A new method of analysing activity rhythm data using Fourier series to mathematically describe animal movements was developed, that allowed systematic identification of the cyclical components underlying overall movement patterns. General fox behaviour could be clearly described by a 24-hour and a 12-hour cyclical component when corrected for variation in daylength. The rising and setting of the sun appeared to be a major trigger underlying movement patterns. Seasonal and sex differences were observed in patterns of activity. The annual rate of increase of the fox population was found to vary around a mean of zero between June 1994 and June 1997. A major drop in fox numbers as estimated by spotlight counts occurred in the second half of 1995, but numbers recovered by the end of 1996. Kaplan-Meier analysis of radio-tagged foxes found annual adult survival was generally very high (0.56-0.96) with lowest survival between July and October. Causes of mortality were human-related outside the site and apparently of natural causes within the site. However foxes dying of natural causes outside the site were unlikely to be found. There was no overall movement of foxes into or out of the site. Immigration was detected following the drop in fox numbers in late 1995, but there was no evidence of immigration prior to this period although emigration occurred. A sensitivity analysis was conducted on the effects of a small change in life history parameters on finite rate of increase using published data as well as adult mortality data from the present study. The two most influential life-history parameters were adult and juvenile survival, while changes in fecundity and age at first reproduction had much less impact on finite rate of increase. In terms of management, in which fertility control is being considered as an alternative to lethal control, this implies that a small change in fecundity may cause less change in the rate of increase of foxes than lethal control. Foxes were culled in June 1997 on completion of the study. Estimated density using a Petersen estimate was 2.4-5.3 foxes/km² and index-manipulation-index was 1.4-3.2 foxes/km². The different methods used to cull foxes appeared to target different age groups within the population, and were generally biased in favour of younger foxes. Success at killing animals was low, leading to large standard errors in the population estimates. Stomachs of foxes shot in the Orange district were found to contain predominantly rabbit and carrion, with invertebrates present when abundant. These findings were not strictly representative of the diet of foxes in the study area, where rabbits were scarce. Foxes scavenged heavily on lamb carcasses within the study site. The quantity of fresh lamb carrion removed from a lambing paddock in winter 1996 was estimated to support 13-24 foxes, with available fresh lamb theoretically able to support 240-440 foxes. Density based on removal of fresh carcasses was estimated to be 0.83-1.5 foxes/km².

Red foxes (Vulpes vulpes) have been identified as a key predator of the threatened piping plover (Charadrius melodus) along the U.S. Atlantic coast. However, little is known about coastal red fox ecology, making it difficult to create effective red fox management strategies in these settings. Here, we quantify aspects of red fox population, spatial, and dietary ecology and interactions with threatened piping plovers on Fire Island, New York. We conducted remote camera surveys, scat and sign surveys, den monitoring, and GPS tracking of red foxes on the island in 2015–2018. We used these data to estimate red fox occupancy, reproduction, survival, and population density. We used GPS data to investigate red fox space use, habitat selection, and responses to piping plover nest exclosure setup, pre-hatch pipping, and hatching. We used fecal dietary analyses and data from den prey item surveys to quantify the frequency of piping plover predation and to identify major prey items of red foxes on the island. Red fox occupancy remained high even after substantial decreases in abundance, population density, annual reproduction, and seasonal survival following 2 sarcoptic mange outbreaks. Within their home ranges, red foxes selected areas that were closer to vegetation during the daytime and twilight hours, but farther from vegetation at night. We did not find clear evidence that red foxes in our study area keyed in on piping plover nest exclosure setup, pipping, or hatching at the spatial scales considered in our comparisons, although fox penetration of and digging at exclosures was an issue in 2015 at Smith Point County Park. Items from Orders Rodentia (rodents, 43% of scats), Coleoptera (beetles, 38%), and Decapoda (crabs and other crustaceans, 29%) were most frequently found in 293 red fox scats examined. Skates (Family Rajidae, 89% of dens with food items) and Atlantic surf clams (Spisula solidissima, 67%) were found most frequently outside of dens. We did not find any identifiable piping plover remains in red fox scats or outside of dens. Our results suggest that direct interactions between red foxes and piping plovers during our study period and in our study area were less frequent than expected, but concurrent work by collaborators documented that the trap success of red foxes was negatively related to piping plover reproductive output during our study period. Lethal removal of red foxes is unlikely to eliminate them from shorebird nesting areas unless complete eradication of foxes from the island can be achieved. We recommend strategic vegetation management in and around piping plover nesting areas to reduce daytime resting areas and hunting cover for red foxes, and continued use of nest exclosures. We also recommend further investigation into indirect impacts of red foxes on piping plover populations, and into the possibility that anthropogenic food resources could be subsidizing the island's red fox population. / Doctor of Philosophy / Red foxes have been identified as a key predator of the piping plover, a small migratory shorebird that breeds along the U.S. Atlantic coast and is considered 'threatened' (at risk of becoming endangered and eventually disappearing) within the United States. The lack of information about red fox ecology in coastal settings has been a challenge for wildlife biologists tasked with reducing predation on piping plovers. We investigated red fox ecology, behavior, and interactions with piping plovers on Fire Island, New York. We used trail cameras, collected scat (feces), monitored dens, and tracked red foxes on the island with global positioning system (GPS) collars in 2015–2018. We used these data to estimate red fox distribution, litter sizes, survival rates, and population sizes. We used GPS data to estimate red fox territory sizes, describe habitat selection, and investigate responses to piping plover nest exclosure setup, pipping (a period before hatching during which chicks vocalize inside the eggs), and hatching. We dissected red fox scats and recorded prey items found outside of dens to determine what red foxes on the island were eating. The proportion of each study area used by red foxes remained high even after substantial decreases in abundance, population density, annual reproduction, and seasonal survival following 2 parasitic disease (sarcoptic mange) outbreaks. Within their territories, red foxes selected areas that were closer to vegetation during the daytime and twilight hours but farther from vegetation at night. We did not find clear evidence that red foxes in our study area keyed in on piping plover nest exclosure setup, pipping, or hatching, although fox penetration of and digging at exclosures was an issue in some years at a site not included in those comparisons. Rodents, beetles, and crustacean remains were found most frequently in red fox scats. Skates and surf clams were found most frequently outside of dens. We did not find any identifiable piping plover remains in red fox scats or outside of dens. Our results suggest that that direct interactions between red foxes and piping plovers may be less frequent than previously believed, but concurrent work by collaborators documented that the trap success of red foxes was negatively related to piping plover reproductive output during our study period. Lethal removal of red foxes is unlikely to eliminate red foxes from shorebird nesting areas unless all foxes on the island are removed. We recommend strategic vegetation removal in and around piping plover nesting areas to reduce daytime resting spots and hunting cover for red foxes, and continued use of nest exclosures. We also recommend further investigation into indirect impacts of red foxes on piping plover populations, and into the possibility that anthropogenic food resources could be subsidizing the island's red fox population.

I studied aspects of the ecology of the Murray River turtle, Emydura macquarii, to determine the impact of the introduced red fox, Vulpes vulpes. The fox is one of Australia's worst vertebrate pests through its predation on livestock and native mammals, but their impact on reptilian communities is not known. I conducted a large-scale mark-recapture study to evaluate population growth of E. macquarii in the Albury region of the upper Murray River by determining growth, reproduction and survival. The study was conducted downstream of the first, and largest, impoundment on the Murray River, Lake Hume. Emydura macquarii predominantly inhabit the lagoons in the upper Murray River, as the mainstream and Lake are possibly too cool to maintain metabolic processes. They are easily captured in hoop traps and the use of live decoys maximises trap success. Over 2000 hatchling turtles were marked and released into two lagoons between January 1997 and January 1998. Growth of these individuals is rapid over the first few years but declines towards maturity, and is indeterminate after maturity. Although growth annuli are not well defined, even on young individuals, the von Bertalanffy model describes the growth of both male and female E. macquarii. Male turtles mature at 5-6 years and females mature at 10-12 years. Female turtles may maximise reproductive potential by delaying maturity and producing one relatively large clutch (mean = 21 eggs) per year, which is positively correlated with body size (PL). Although primarily related to body size, clutch size varies annually because of environmental conditions. If winter and summer rainfalls are below average and temperatures are above average, E. macquarii may reduce clutch size to increase the chance of the eggs surviving. Nesting predominantly occurs during the first major rain-bearing depression in November. Habitat variables, including distance from water, nearest nest, and tree, and soil type were measured for each nest to determine characteristics that attract predators. Nests close to the shoreline and trees are heavily preyed on, and nests constructed in sand are less likely to be destroyed by predators. Foxes detect nests through a combination of chemical cues from eggs and slight soil disturbances, whereas birds only destroy nests observed being constructed during the day. Female turtles alter nesting behaviour and construct nests much further away from water when foxes were removed and as a result, nests are less dense and away from trees. Thus in high predation risk areas, turtles minimise emergence and search times to reduce the risk of direct predation by foxes. Predation is reduced when nests are in lower densities and away from trees, because predators increase search efforts when nests are in higher densities and birds are more likely to destroy nests close to trees. Reproductive success is further reduced in high predation risk areas because more nests are constructed in sandy substrates where clutch success is reduced compared to incubation in more dense substrates. Where predators are a significant source of mortality, prey may use indirect methods, such as chemical recognition, to avoid encounters. Nesting turtles did not avoid areas where fox odour was present, suggesting that they assess predation pressure from foxes by other mechanisms, such as visual recognition. However, an innate response occurs to the odour of a once common predator on the Murray River, the eastern quoll (Dasyurus viverrinus), whereby turtles recognise and avoid nesting in areas where quoll odour is present. Therefore nesting turtles show a similar avoidance response to two different predators, using different mechanisms of detection. Similarly, predation risk may influence hatching times and nest emergence. The rate of embryonic development of E. macquarii may increase or eggs may hatch early so that the clutch hatches synchronously, thereby reducing the risk of predation through group emergence from the nest. Emydura macquarii reach densities of over 100 turtles.ha-1, with the majority of the population consisting of sexually mature individuals. Emydura macquarii has a Type III survival curve where mortality is extremely high in the egg stage (93% nest predation), remaining high over the hatchling stage (minimum survival rate- 10%), but decreasing rapidly throughout the juvenile stage (~70% juvenile survival). Adult survival is extremely high, with greater than 95% of adults surviving each year. Foxes through nest predation cause most mortality but a small proportion (~3%) of nesting adult females are killed by foxes each year. A removal program evaluated the impact of foxes. In 1996, fox numbers were monitored around four lagoons by spotlighting and non-toxic bait uptake. Foxes were removed from around two of the lagoons throughout 1997 and 1998, using spotlight shooting and 1080 bait poisoning. Fox numbers were continually monitored around all four lagoons during the study. Nest predation rates remained around 90% in all sites where foxes were present, but fell to less than 50% when foxes were removed. At the same time, predation on nesting female turtles was eliminated where foxes were removed. Demographic models using staged based survival schedules, together with growth and fecundity values for E. macquarii show a decline of 4% per year in these populations. Elasticity analyses shows that survival of adult female E. macquarii has the major influence on population stability and a reduction of nest predation alone is unlikely to address the population decline. Management options, such as reducing foxes prior to nesting around key lagoons, will stabilise the population decline, and eliminating foxes completely from certain areas with high dispersal potential, will promote recruitment of juvenile E. macquarii.

L'échinococcose alvéolaire, qui peut être fatale si le diagnostic est tardif, est une zoonose émergente. Elle est due à un cestode, Echinococcus multilocularis, dont le cycle fait intervenir le renard roux, Vulpes vulpes, comme hôte définitif et les campagnols prairiaux (Microtus arvalis et Arvicola terrestris) comme hôtes intermédiaires. Relativement peu de données sont actuellement disponibles sur les facteurs écologiques qui peuvent moduler l'intensité de la transmission du parasite entre ses hôtes aux fenêtres d'observation régionales et locales. Dans ce contexte, nous avons conduit une étude du fonctionnement du cycle d'Em à différents niveaux de perception, dans le département français des Ardennes, considéré comme une région de nouvelle endémie. La prévalence vulpine, estimée à 53 % pourrait être expliquée par une densité relativement élevée de renards et une importante consommation de M. arvalis de leur part. A une étendue régionale (900 km²) et un grain local (1 km²), la prévalence vulpine et la distribution des charges parasitaires apparaissent très hétérogènes, avec un gradient croissant nord-sud très marqué. La majorité de la biomasse parasitaire est concentrée sur quelques individus et sur quelques kilomètres carrés. Les caractéristiques du paysage et les densités de rongeurs hôtes intermédiaires semblent influencer les prévalences vulpines. Enfin, à une étendue locale (90 km²) et un grain micro-local (1000 m²), les lisières semblent particulièrement favorables à la transmission parasitaire, puisque c'est dans ce milieu que coïncident des densités élevées de fèces de renards et de rongeurs et, donc, que les contacts entre oeufs et hôtes intermédiaires sont les plus probables.

<p>The genetic basis for behavioural traits is largely unknown. The overall aim of this thesis was to find genes with importance for behavioural traits related to fear and anxiety. Microarray analysis was used to screen expression profiles of brain regions important for emotional behaviour in dogs, wolves, foxes and mice. In a first experiment, dogs and their wild ancestors the wolves were compared. Our results suggested that directed selection for behaviour might have resulted in expression changes in few genes acting on several brain functions, possibly affecting behaviour. However, the observed expressional differences were confounded with environmental effects. This was addressed in a second study on domesticated silver foxes. By correlating behaviour and brain gene expression in foxes selected for tameness to non-selected foxes raised in the same environment, we found large behavioural differences but only few genes with differential expression in the brain. Fifteen of the 40 genes showing evidence of expression difference were related to haem or haemoglobins. Further studies showed an additive genetic effect on brain gene expression, similar to the additive genetic inheritance of behaviour, indicating an involvement in domestication. Transcriptional profiling was also used for finding genes involved with the sleep disorder narcolepsy. Narcoleptic Doberman pinschers homozygous for the canarc-1 mutation were compared to their unaffected heterozygots revealing reduced expression of three genes, TAC1, PENK and SOCS2, with relevance to the narcoleptic phenotype. Finally gene expression was investigated in relation to anxiety-related traits in a mouse model. Surprisingly, as in the fox study, genes coding for haemoglobins indicated differential expression in the brain between animals with different anxiety levels. Our combined results suggest that genes like haemoglobins, best known for their function in oxygen transport in blood, may also participate in brain functions related to decreased anxiety in domestic animals. </p>