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No description available.

No description available.

The purpose of the work leading to the writing of the thesis was two fold: (1) to survey birds of Northern California for hemoprotozoa of the genera Haemoproteus, Leucocytozoon, and Trypanosoma, and (2) to construct an up-to-date check-list of the Haemoproteus, Leucocytozoon, and Trypanosoma parasites of birds of North America.

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This thesis investigates the impact of avian malaria (Haemosporidia) parasites on the outcome of interspecific competition between two closely related bird species, pied (Ficedula hypoleuca) and collared (F. albicollis) flycatchers. I further investigated how variation in timing of breeding, life history strategies and immune competence genes (MHC genes) modulate the fitness effects of malaria parasites in one of the two species i.e. collared flycatchers. Collared flycatchers colonized the Baltic island Öland in the late 1950-ties and has since then been expanding their breeding range while competitively excluding pied flycatchers from the favourable habitats (deciduous forests). I investigated the underlying mechanisms behind this exclusion by combining detailed long-term breeding data with modern molecular genetic techniques identifying both the presence/absence and lineage specificity of haemosporidian blood parasites. I found that the rapid decline of pied flycatchers can be explained by the combined effects of competition over nestling sites, hybridization and haemosporidian infections. Haemosporidian infections have a negative impact on survival of pied flycatcher females but no detectable effect on collared flycatchers’ longevity or reproductive success. This may be due to the fact that collared flycatchers carry (and are potentially exposed to) a higher diversity of parasites than pied flycatchers, which in turn may select for a higher diversity of MHC genes and hence a better overall protection from the negative impact of parasites. Indeed, functional MHC diversity correlates negatively with malaria prevalence among collared flycatchers from Gotland. Moreover, I found that both, malaria infection intensity and immunoglobulin level influences how infected collared flycatchers respond to increased nestling food-demands. The latter results mean that there is variation in allocation strategies (i.e. in resource allocation between reproductive effort and immune competence) within the collared flycatcher population. Hence, this population has the ability to respond to novel selection pressures in terms of optimal allocation of resources into immune functions. In summary, my results show that local parasites may facilitate the expansion of a new colonizer. This is important in the context of global climate change that will probably increase the colonization rate of southern species and lead to novel host-parasite interactions.

The present study demonstrates that blue grouse on Vancouver Island are infected with two species of Haemoproteus, probably two species of Leucocytozoon and a species of Trypanosoma. Haemoproteus dendragapi n.sp. is described from the Nanaimo Lakes Area. The growth rate of H. canachites gametocytes is much more rapid than that described by Fallis in Ontario. The very young tissue stages of H. canachites are described from lung preparations of grouse chicks. The life cycle of Leucocytozoon bonasae has been completed by using a new vector, Cnephia minus. As reported by Fallis in Ontario, Simulium aureum has been found to be a vector of L. bonasae on Vancouver Island. This study has verified Woodcock's often ignored hypothesis that the morphology of the gametocyte-host cell complex changes with age of infection. A probable new species of Leucocytozoon is described from the Campbell River Area. In-vitro culture of the trypanosome from grouse blood has been carried out. A yearling blue grouse has been successfully infected by inoculation of metacyclic trypansomes from the culture. / Science, Faculty of / Zoology, Department of / Graduate

<p>Abstrakt: Jag har undersökt hur älvreglering påverkar mängden knott (Tvåvingar: <i>Simuliidae</i>) längs flera norrlandsälvar och vilka konsekvenser denna påverkan får för den landlevande fågelfaunan. Studien visar att utbyggnad av älvar har en negativ effekt på mängden knott. Det fanns sju gånger högre tätheter av knott längs "orörda älvar" jämfört med utbyggda älvar.</p><p>Skillnaden i antal knott mellan älvtyperna var mycket större för knotthanar än för knotthonor, vilket förklaras av att honorna är rörligare eftersom de flyger och letar efter blod. Knott lever av blod från ett flertal däggdjur och fåglar och visar en stor variation i värd-specificitet mellan olika arter. Jag fann en högre frekvens av haemosporida blod parasiter (<i>Leucocytozoon</i>) i fåglar längs "orörda" Vindelälven jämfört med den reglerade Umeälven. Detta mönster stämmer väl överens med tätheten fågelparasiterande knott som är lägre längs Umeälven. Knott attackerade främst värdar som var stora och vanliga. Fågelsamhällets sammansättning skiljde sig mellan orörda och utbyggda älvdalar. Tätheten av icke insektsätande fåglar tenderade att minska, efter häcksäsongen, längs orörda älvar medan den ökade längs utbyggda älvar. Den insektsätande fågeln svartvit flugsnappare (<i>Ficedula hypoleuca Pallas</i>) uppvisade större häckningsframgång längs orörda älvar jämfört med utbyggda älvar. Detta är förmodligen en effekt av den större mängden insekter som finns längs orörda älvar.</p> / <p>The effects of river regulation on blackfly (Diptera: <i>Simuliidae</i>) abundances and consequences for the avifauna in terrestrial environments were studied along multiple rivers in northern Sweden. I found that impoundment of rivers has detrimental effect to blackfly abundances. The densities of large-river breeding blackfly species were several-fold higher along free-flowing than along regulated rivers. The difference in abundances was much larger in males than blood-seeking females. Blackflies attacked a variety of mammalian and avian hosts and showed different levels of host-specificity between species. I found higher prevalence of haemosporidian blood parasites (<i>Leucocytozoon</i>) in birds along the free-flowing Vindel River in comparison to the regulated Ume River, where the lower densities of ornithophilic blackflies were reduced. Blood-seeking blackflies predominantly attacked large and/abundant hosts.</p><p>Assemblages of birds differed between valleys of regulated and free-flowing rivers. Densities of noninsectivorous birds tended to decrease along free-flowing rivers in the post-breeding season, but increased along regulated rivers at the same time. Insectivorous European pied flycatcher (<i>Ficedula hypoleuca Pallas</i>) showed greater fledging success along free-flowing than regulated rivers, which probably reflects the higher insect abundances found along freeflowing rivers.</p>

Abstrakt: Jag har undersökt hur älvreglering påverkar mängden knott (Tvåvingar: Simuliidae) längs flera norrlandsälvar och vilka konsekvenser denna påverkan får för den landlevande fågelfaunan. Studien visar att utbyggnad av älvar har en negativ effekt på mängden knott. Det fanns sju gånger högre tätheter av knott längs "orörda älvar" jämfört med utbyggda älvar. Skillnaden i antal knott mellan älvtyperna var mycket större för knotthanar än för knotthonor, vilket förklaras av att honorna är rörligare eftersom de flyger och letar efter blod. Knott lever av blod från ett flertal däggdjur och fåglar och visar en stor variation i värd-specificitet mellan olika arter. Jag fann en högre frekvens av haemosporida blod parasiter (Leucocytozoon) i fåglar längs "orörda" Vindelälven jämfört med den reglerade Umeälven. Detta mönster stämmer väl överens med tätheten fågelparasiterande knott som är lägre längs Umeälven. Knott attackerade främst värdar som var stora och vanliga. Fågelsamhällets sammansättning skiljde sig mellan orörda och utbyggda älvdalar. Tätheten av icke insektsätande fåglar tenderade att minska, efter häcksäsongen, längs orörda älvar medan den ökade längs utbyggda älvar. Den insektsätande fågeln svartvit flugsnappare (Ficedula hypoleuca Pallas) uppvisade större häckningsframgång längs orörda älvar jämfört med utbyggda älvar. Detta är förmodligen en effekt av den större mängden insekter som finns längs orörda älvar. / The effects of river regulation on blackfly (Diptera: Simuliidae) abundances and consequences for the avifauna in terrestrial environments were studied along multiple rivers in northern Sweden. I found that impoundment of rivers has detrimental effect to blackfly abundances. The densities of large-river breeding blackfly species were several-fold higher along free-flowing than along regulated rivers. The difference in abundances was much larger in males than blood-seeking females. Blackflies attacked a variety of mammalian and avian hosts and showed different levels of host-specificity between species. I found higher prevalence of haemosporidian blood parasites (Leucocytozoon) in birds along the free-flowing Vindel River in comparison to the regulated Ume River, where the lower densities of ornithophilic blackflies were reduced. Blood-seeking blackflies predominantly attacked large and/abundant hosts. Assemblages of birds differed between valleys of regulated and free-flowing rivers. Densities of noninsectivorous birds tended to decrease along free-flowing rivers in the post-breeding season, but increased along regulated rivers at the same time. Insectivorous European pied flycatcher (Ficedula hypoleuca Pallas) showed greater fledging success along free-flowing than regulated rivers, which probably reflects the higher insect abundances found along freeflowing rivers.