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Browsing by master's degree program "Ekologian ja evoluutiobiologian maisteriohjelma"

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  • Palonen, Aura (2020)
    Early life conditions have long-term effects on the fitness and survival of individuals. Foetal development is an especially crucial period and even small changes may have large impacts on the development of individuals. Mammal foetuses may be exposed to additional testosterone either from their male littermates or their mother. This additional prenatal androgen exposure leads to masculinization of female features and behavior. In males the effects of additional prenatal androgen exposure are less drastic due to their own testosterone production. The anogenital distance, defined as the distance between the anus and genitalia, has been used to determine the sex of young mammals since males have longer anogenital distances than females. An elongated anogenital distance is an indicator of additional prenatal androgen exposure in females, and in some species also in males. It correlates with for example increased aggressiveness in both females and males. In females a longer anogenital distance has also been connected to delayed puberty and decreased fertility. I studied the effects of additional prenatal androgen exposure on weight and important life-history traits in banded mongooses (Mungos mungo) with data from a long-term study. Banded mongooses are small co-operatively breeding mammals living in family groups of 10-30 individuals across sub-Saharan Africa. Breeding is extremely synchronized within groups and in most cases all pregnant females give birth on the same day. The resulting communal litter is cared for by most adults in the group regardless of relatedness. Adults escort the pups until three months of age, providing the pup with food, grooming and protection. This early life care has long-term fitness benefits for the pups. Pregnant females may change the phenotype of their offspring via maternal effects. When the competition faced by breeding females is more intense, they compensate by investing more resources to their foetuses, making them bigger. Using the anogenital distance as a proxy for additional prenatal androgen exposure, I measured its effects on weight at early life and maturity, the amount of care received as pups and whether the individual reproduced in its lifetime or not. I hypothesized that a longer anogenital distance may be an indicator of increased competitiveness in the banded mongoose. It could lead to a cumulative advantage since more aggressive individuals may be able to access more food and care, which leads to higher maturity weight and lifetime reproductive success. I also measured the effects of resource abundance and intensity of competition during gestation on the anogenital distance of the pups. I hypothesized that mothers may prepare their offspring for future competitive environment by exposing them to androgens during gestation. In males a longer anogenital distance predicted higher weight both at early life and maturity. Higher weight at the beginning of the escorting increased the amount of care received, which in turn increased weight at maturity. A longer anogenital distance therefore has both direct and indirect fitness benefits in male banded mongooses. In females, a longer anogenital distance predicted lighter weight at maturity, suggesting that it may have negative effects on female growth and development. This study offers evidence that additional prenatal androgen exposure has long-term fitness consequences on banded mongooses and that these consequences are sex specific. Future research should focus on confirming the connection between additional prenatal androgen exposure and longer anogenital distance in this species, as well as assessing the effects of prenatal androgen exposure on survival, puberty and growth of especially female individuals.
  • Zavattoni, Giorgio (2022)
    Populations of forest grouse – capercaillie (Tetrao urogallus), black grouse (Lyurus tetrix) and hazel grouse (Tetrastes bonasia) - have been declining through all of Europe. Habitat loss, fragmentation and degradation are recognized to be the most important ultimate causes behind this trend. In Fennoscandia, there is a general consensus that forestry practices have a primary role, even though the mechanisms are still not fully understood. Nest predation is generally thought to be an important proximate cause of the declines, but how nest predation relates to habitat changes remains poorly understood. I combined long-term data provided by the Natural Resources Institute Finland (LUKE) from inventory studies, both for grouses and predators, with an artificial nest experiment. I investigated a) how predation rate varies with forest age and landscape structure; b) what is the possible role of non-native mesopredator species as predators; c) how nest predation rate relates to larger scale reproductive success. In spring 2021, I placed 141 nests with two hen eggs each, in the regions of Kainuu and North Karelia for 14 days with camera traps. The nests were equally divided between mature forests (>80 years), young forests (<40 years) and edges of mature forests (in a mature forest 5m from a clearcut or a field). I found that the overall predation rate was low (~13 %) and similar in the three sites, but predation time was faster in mature forests, suggesting that when these are scarce, they can act as an ecological trap by increasing nest detectability. However, nest predation decreased with the increasing of mature forests in the landscape around the nest, supporting the hypothesis that on a larger scale forestry may increase generalist predator densities. Areas with higher predator densities suffered higher nest losses. The main predators were pine martens, badgers and magpies, followed by bears and ravens. No nests were predated by raccoon dogs or American minks. There was no correlation between areas with higher nest predation and areas where grouse had lower reproductive success which may result from other factors, e.g., chick predation. My results add to the diverse outcomes of several studies of grouse nest predation in Europe, which together indicate large variation in nest predation, no consistency in predatory species, and weak effects of landscape composition on nest predation.
  • Pääkkö, Henna (2021)
    Animal personality is described as consistent behavioural variation between individuals over long periods of time. Behaviours often connected to animal personality are such as boldness, aggressiveness, and anxiety. In this thesis, the focus was on the behaviours along the shy-bold axis, containing various degrees of boldness expressing behaviour. The study was conducted by using long-term data from the past 30 years on the banded mongoose (Mungos mungo) population in the Mweya Peninsula in the Queen Elizabeth National Park in Uganda. In particular, I used the data on regular weighing events done within the population. As the weighing is not forced on these individuals, the participation percentage on these events can be used to describe an individual’s boldness. I used the participation percentage as a boldness index (values between 0 and 1) for each individual to describe their position on the shy-bold axis. This index was then used to analyse the differences between sexes, and the fitness effects boldness had on the individuals of this population by using proxies of survival, weight at sexual maturity and lifetime reproductive success (LRS). To determine long-term consistency between individuals, I analysed the repeatability of the boldness index. The repeatability of these values showed we can consider this behaviour as an animal personality. From the fitness analyses, it was concluded that boldness had significant positive effects on the fitness proxies used, proposing that bold individuals have higher fitness in this population. While sex did not affect an individual’s boldness, it had significant interactions with boldness, affecting the strength of fitness effects on individuals in weight at sexual maturity and LRS.
  • Haapalainen, Samuli (2021)
    Biodiversity is decreasing globally due to human activity. At times, on-time monitoring of the state of habitats and biodiversity is challenging. One useful way to study these is to use certain species as indicators for the state of habitats and biodiversity. One group that are often used, are birds. They are easy to detect and they have specialized to most terrestrial ecosystems. Changes in the population sizes of different bird species can reflect changes in different habitats and their biodiversity. Therefore, it is essential that different bird monitoring practices produce reliable and comparable results. I compared datasets produced by two different Finnish bird census programs in my thesis. The census programs were national breeding bird survey program and Hanko Bird Observatory´s migratory bird census program. Both programs produce data on population abundances and changes in population sizes. Because methods between these programs differ greatly, their data may differ for some species. I compared the datasets by comparing population change indexes of the same species. I also tested whether species traits would be associated with the comparability of the datasets. These traits were mean body size, migratory behavior, favored habitats, and number of sightings for each species. I made models for all combinations of traits. I used a generalized linear model in my analysis. I compared the models by using Akaike´s information criterion (AIC) with correction for small sample sizes (AICc). My results showed that both national breeding bird survey program and Hanko Bird Observatory´s migratory bird census program produce parallel population trends for species. From the tested species traits, only migratory behavior was associated with comparability of the datasets. The datasets were highly comparable for long- and short-distance migratory birds but only moderately comparable for resident birds. This is likely due to migratory bird census program recording the local population dynamics of resident birds of Hanko peninsula. These local population trends may differ from the national trends of the same species. The breeding bird survey program should better reflect the national population trends. My results also showed that more numerous common bird species are declining faster than uncommon species. This is an alarming scenario because it points at extensive habitat degradation and biodiversity loss. Also, population trends of species favoring mires and mountains were clearly declining compared to species favoring other environments. This may be due to endangering of mire and mountain habitats due to climate change and human land use such as peatland drainage. Strong declines of species may also be explained by changes in the wintering areas of these species. Finnish breeding bird survey program and Hanko Bird Observatory´s migratory bird census program both produce overall comparable data on population trends of birds. They could be used to complement one another and to provide supporting evidence on the validity of bird population trends. Producing quality bird census data is highly important in tracking the state of biodiversity and when deciding on conservation acts. The data on the census programs provide support for the research on state of Finnish and European habitats and biodiversity.
  • Heikkilä, Sofi (2020)
    Conservation actions towards large carnivores have been successful in Europe, and the formerly lawfully persecuted species have started to reclaim their historical range. Coexistence with the predators is needed if their conservation should continue to succeed, as Europe does not host wilderness areas large enough to separate large carnivores from humans. As the importance of top-down regulation in ecosystems is recognized, the protection of these predators becomes essential. In Finland, all four large carnivore species, brown bear, grey wolf, Eurasian lynx and wolverine, have established populations, though their presence is not easily accepted by some. Large carnivores pose a threat to livestock and cause fear in the locals living in their territories. Wolf – hunting dog conflict is especially prominent in Finland south of reindeer husbandry area and the poaching of wolves hinders the population’s management. Attitudes towards large carnivores are often influenced by personal background, such as education level, ecological knowledge and respondent’s position in possible human – wildlife conflict. Residence can have an effect, as well, since conditions between living in urban or rural areas often differ. Hypothesis for this study are 1) attitudes towards large carnivores get worse while getting closer to protected areas, 2) attitudes towards large carnivores differ between eastern and western study areas, and 3) a higher education level increases positive attitudes towards large carnivores. The effect of ecological knowledge, prior experiences with large carnivores, age, sex and position in conflict was also explored. Study was conducted as a questionnaire, with face-to-face interviews and web survey distribution targeting two areas in Finland with large carnivore occupancy, one in the West and one in the East. A link between negatively perceived personal experiences and negative opinions towards large carnivores and their management was found. Living in the western area, where large carnivores have resided for a shorter time, predicted attitudes towards stricter management of the species. Third level education influenced attitudes positively. By understanding local attitudes towards large carnivores, it is possible to better understand the conflict between humans and predators, and so, find more likely solutions. Conservation actions where locals have been included, have been documented as successes. Regional differences in attitudes should be further studied and included in future decision making.
  • Schwenk, Cindy Emilia (2022)
    Breeding-dispersal and philopatry are important life-history traits when it comes to the ecology of animals. A number of factors such as sex, age, habitat stability, population density, predation and various environmental factors influence the movement patterns of species. Philopatry, in general, can be used by organisms as a predator avoidance strategy and to improve feeding efficiency. Dispersal on the other hand has been shown to help avoid inbreeding and competition within groups or between kin. Among the different types of dispersal and philopatry, breeding dispersal and site fidelity to breeding sites have been studied in many vertebrates. Many birds and some ungulate species have been the focus of these studies and have shown that breeding success influences site fidelity. Among ungulates, the reindeer genus (Rangifer tarandus spp.) however, has received little attention for this topic. A species of special conservational value is the wild forest reindeer (Rangifer tarandus fennicus), which is a rare, and near-threatened subspecies of reindeer living in Finland. Knowledge of factors influencing the dispersal and site fidelity for this species is lacking but has important implications for the conservation and management of this and other vulnerable species. In my thesis I investigated the philopatry of wild forest reindeer females from eastern Finland and tested if the calving site fidelity was influenced by breeding success, predator pressure and the female’s age. Given the high densities of predators in the study area (Kainuu) and thus high predator pressure on reindeer, I expected (i) the philopatry of the wild forest reindeer female’s to be stronger in areas with higher predator pressure but (ii) higher dispersal movement when wild forest reindeer females had no breeding success the previous year. Additionally, I expected (iii) the dispersal distances of wild forest reindeer females to be negatively correlated with their age. For this study I used long-term GPS monitoring data of 53 collared wild forest reindeer females, which were followed for varying periods (2-6 years) between 2010-2021 from Eastern Finland. I found that the inter-year distances between calving sites per female had a median distance of 2.84 km, confirming that female wild forest reindeer show philopatry to calving sites, as do other reindeer subspecies. Even though the movement ranged from 4.8 m to 36.99 km, showing substantially longer dispersal for some individuals. The model outcomes indicate some association between predation pressure and site fidelity, and reduced philopatry following calf mortality, although none of these associations were significant. The age of the mother did also not show any significant influence on a female’s site fidelity. Nonetheless, these results would suggest that a mother's choice to leave or return to the same calving site might be influenced by the previous year's calf mortality but more complex variables like anthropogenic disturbances, environmental factors, as well as intrinsic factors and the physical condition of the mother most likely also play a role in this.
  • Loponen, Laura (2020)
    The Miocene epoch (c. 23-5 million years ago) was a noteworthy geological time period in which significant changes took place both in the climate regimes as well as in vegetation characteristics, bringing about novel adaptations in many herbivorous lineages. These adaptations constituted morphological, dietary, and ecological factors in a relatively short period of evolutionary time. Among these herbivores were the proboscideans, the living and extinct elephants, which were among the most dominant and largest herbivores at the time. Despite that proboscideans were diverse and large group of hundreds of species, yet the understanding of dietary and ecological patterns of majority of Miocene sympatric species is still limited. The aim of this study was to analyse the molar surfaces of Miocene proboscideans (e.g. Deinotherium and Gomphotherium) from Eurasia to provide a reconstruction of the feeding preferences of the study species based on observed dental wear. The dental wear indicates the abrasiveness of the diet, thus allowing broad categorization to either browser (<10% grass in the diet), mixed-feeder (10-90% grass in the diet) or grazer (>90% grass in the diet). Secondly, this study aimed for providing estimation of the environmental characteristic and vegetation patterns of the study localities by comparing to the previous studies and to hypsodonty value (proxy of general openness and aridity of the environment). Proboscidean dietary signals from the key localities of Maragheh (Iran) and Pannonian basin (Austria) were compared with the paleobotanical studies. Thus, the general estimation of spatial and temporal variation of the environment characteristics in the study localities were based on these parameters. The materials of fossilized molars were analysed by mesowear angle method, in which the measured angles show the diet abrasiveness due the nutritional targets’ differences. The results allowed the reconstruction of the feeding preferences which suggested that majority of Miocene proboscideans were browsers and browse-dominated mixed feeders or pure mixed-feeders. Instead, Choerolophodon pentelici was found grass-dominant mixed-feeder. The wide spectrum of feeding preferences allowed diet flexibility according available vegetation and also these sympatric species to co-exist by niche partitioning. Thus, demonstrating clearly the connection between diets and environments thought the diet. As a conclusion, in the diet of the paleocommunities of proboscideans had, on average, more grass-dominant components in open and dry environment likely due the presence of grass-dominant vegetation. Instead, in the wet conditions the closed-canopy forest environments enhanced browsing. Further, the results indicated shift in feeding preferences of proboscideans prior to Miocene climate and environment changes. These results are in line with the findings of the previous studies of modern elephants’ diet- environment relationships. The further studies would provide insight to the relative amounts of the grass in the diet of Miocene proboscideans.
  • Milosavljevic, Silvija (2021)
    Post-transcriptional modifications (PTMs) in RNA are present in all known RNA species and conserved in all kingdoms of life. Transfer RNA (tRNA) has been shown to have numerous conserved modifications, which exemplifies the importance of modifications having impact on the structure of the tRNA and its function as carrier of the amino acids. Ribosomal RNAs (rRNA) are universally modified as well, and modifications are situated at functionally important spots of the ribosome. Given the fact that types and sites of modifications are conserved, it is likely that these modifications have been selected for and that they optimize the ribosomal structure and functions. Stress, such as temperature or infection by a pathogen, is known to change the presence or abundance of modifications in RNA molecules and thereby affect translation efficacy. In line with that, this master’s thesis project sought to gain insight into the dynamics of PTMs in tRNA and rRNA upon oxidative stress, with the goal of utilizing recently optimized UPLC/MS method for identifying modified ribonucleosides. As the specific aim of the thesis was to estimate the change in PTMs in tRNA and rRNA in response to oxidative stress with 0.5 mM and 2 mM hydrogen peroxide H2O2, 3 immediate goals were: (i) to isolate total tRNA from yeast grown in stress conditions, (ii) to isolate rRNA from yeast 80S ribosomes, and (iii) to identify present modifications using mass spectrometry. Yeast was cultured in presence of H2O2 as a stressor in mentioned concentrations, and both treatments considered showed a difference in survival when compared to the control. Rough cell concentration estimates (OD600) did not show the effect of the stressor on cell survival clearly, but when number of viable cells per mL was estimated, it was clear that growth of the stressed yeast cultures was hindered 2 hours after exposure to H2O2 but recovered during the 24 hours. Firstly, using UPLC/MS analysis, 29 modifications were identified in tRNA from control and H2O2 treated yeast. Most identified modifications showed no change in abundance in treatments, which is to be verified with additional replicates. However, distinct dynamics of stress-related change was found for several modifications, revealing additional modifications that may play a role in stress related modificome reprogramming to the previously known signature modifications of oxidative stress. It was expected that recovery of culture growth after 24 hours may be accompanied with modification level recovery. However, that was not demonstrated here as downregulation at 2 hours followed by upregulation at 24 hours was seen for 2-methylthio-N6-methyladenosine, N4-acetylcytidine and 5-methoxycarbonylmethyl-2-thiouridine, and the reverse was shown for N4-methylcytidine. Upregulation in both time points was also shown here for some modifications. Taken together, these results confirm a complex and dynamic control of tRNA modifications in cellular survival responses. Modifications found to be affected by oxidative stress are most frequently located on the wobble position 34 and anticodon loop position 37, so it is expected that changes in their modification levels could directly affect the tRNA function in translation, making them a specific target for future research. Secondly, modifications in rRNA from control yeast cultures were identified, such as expected methylations of all 4 canonical nucleosides. However, further analysis will be needed to confirm the other identified modifications, due to the potential mRNA and tRNA contamination. Optimizing the method for rRNA modifications identifications by acquiring more modified nucleosides specific for the rRNA to use as standards in the analysis, analyzing rRNA types separately and using tandem mass spectrometry would enable getting a deeper understanding of which modifications are present and where they are positioned. Finally, it would enable reliable identification of the signals of novel modifications present in rRNA, such as the tRNA modification 5-carbamoylmethyluridine signal found here. In conclusion, this thesis work lays the foundation to study the evolutionary conserved function of PTM changes during stress as modulators of translation, using the methodological approaches discussed in-depth within the thesis, primarily to confirm the intriguing results found here.
  • Päiviö, Elisa (2020)
    Behaviour is a key component in ecological interactions and studying its role in adaptation is central in our understanding of natural selection and phenotypic variation in the wild. Predation is an important driver shaping animal behaviour in the wild, since predators have been shown to select against particular behavioural phenotypes. However, it is not easy to demonstrate that specific behaviours are adaptive to certain levels of predation, since behaviours are often correlated with each other forming multivariate phenotypes and display notable phenotypic plasticity. I studied how predation shapes genetically determined behaviour of the nine-spined stickleback (Pungitius pungitius) through variation in historical predation pressures and by inducing phenotypic plasticity. This was achieved through rearing 65 full-sib families of nine-spined sticklebacks derived from four coastal marine (predator-sympatric) and four pond (predator-naïve) populations in a common garden experiment and quantifying their behaviour in the laboratory in the presence and absence of natural predators. Since the fish used were F1-generation offspring from artificial crosses, I was also able to estimate the heritability and genetic correlations of the studied behaviours. Pond sticklebacks tended to be more explorative and took more risks during foraging than marine sticklebacks regardless of predation risk. In all fish, predator presence decreased the propensity to take risks during foraging, but not exploration tendency. Since the fish were reared in a common garden setting, there is a genetic basis for these population differences. Both behaviours were heritable in all populations. In this study, I observed genetically based and heritable behavioural differences between pond and marine stickleback populations. Despite showing similar levels of behavioural plasticity as marine sticklebacks, pond sticklebacks were still inappropriately active in the presence of predators and would have a low survival probability in a predator-sympatric environment. In risk-taking during foraging, the behavioural trend caused by acute predation risk was directionally the same as that caused by evolutionary history of predation risk, implying that the behavioural differentiation between marine and pond populations in this behaviour is due to predation. These results provide evidence of local adaptation in behaviour to differing levels of predation in these populations, and that this adaptation comes about as differences in the overall level of behaviour rather than in phenotypic plasticity.
  • Nivalainen, Pinja (2022)
    Eläinten tunnemaailma on meille melko vieras. Sen takia on tärkeää tutkia, millaiset asiat vaikuttavat siihen, miten tulkitsemme niiden tunteita. Tunteiden tulkintaan voivat vaikuttaa tulkitsijan omat kokemukset. Tämän tutkielman tarkoituksena on tutkia sitä, mitkä asiat vaikuttavat siihen, kuinka hyvin eläintarhakävijät tunnistavat villieläinten tunteita. Erityisesti keskityn siihen, miten vastaajan sukupuoli, ikä, kasvuympäristö ja lapsuuden ja aikuisuuden aikaiset eläinkokemukset vaikuttavat eläintarhakävijöiden kykyyn tunnistaa eläinten tunteita. Tutkimus tehtiin kyselytutkimuksena Korkeasaaren eläintarhassa kesällä 2021. Osallistujille näytettiin videolta eläin ja heidän tuli kertoa, onko eläimen tunnetila neutraali, myönteinen vai kielteinen ja onko se rauhallinen vai kiihtynyt. Tutkimuksessa tutkittiin tiikereiden, berberiapinoiden ja markhorvuohien tunnetilan tunnistamista. Osallistujista kerättiin taustatietoja, kuten ikä ja sukupuoli. Tulosteni perusteella eläinlajilla on vaikutusta tunnetilan tunnistamiseen. Tiikerin myönteisyys tai kielteisyys osattiin arvioida huonommin kuin berberiapinan. Myös vastaajan ikä vaikuttaa tunteiden tunnistukseen. Vanhemmat tunnistivat myönteisyyden tai kielteisyyden nuorempia ihmisiä heikommin. Sukupuoli vaikuttaa yhdessä iän kanssa kiihtyneisyyden tunnistamiseen. Kiihtyneisyyden tunnistivat paremmin 18–30-vuotiaat naiset kuin 61–75-vuotiaat naiset, mutta muiden ryhmien välillä ei havaittu merkitseviä eroja. Kiihtyneisyys tunnistettiin myös paremmin, jos eläimet ovat olleet osana vastaajan elämää vain lapsuudessa sen sijaan, että ne olisivat olleet aina osana elämää. Tulosten perusteella voidaan päätellä, että ihmiset tunnistavat eri eläinten tunteet eri tavalla ja ihmismäisempien eläinten tunteet ovat muita helpommin tunnistettavissa. Iällä ja sukupuolella voi olla vaikutusta ihmisten kykyyn tunnistaa eläinten tunteita. Myös eläinkokemus vaikuttaa ihmisten kykyyn tunnistaa tunteita ja kokemus ei ole sama kuin tiedon omaksuminen. Tuloksiani voidaan hyödyntää esimerkiksi ympäristökasvatuksessa.
  • Bergman, Nora (2021)
    Rapid environmental changes over the last 100 years have led to substantial range shifts across taxonomic groups. Understanding what facilitates successful shifts is important for predicting ecological consequences and planning efficient conservation actions. Interestingly, the very process of range expansion can affect the success of the shift by causing genetic changes in the expanding populations. Theory predicts that without sufficient gene flow, repeated founder events and strong genetic drift can result in allele frequency gradients and loss of genetic diversity along the expansion axis. Empirical studies testing these expectations in environment-driven range shifts are still relatively scarce, and how range expansions affect genetics in highly mobile species remains unclear. In this study, I investigated the genetic consequences of a recent range expansion in a long-distance migratory passerine, the reed warbler (Acrocephalus scirpaceus). Utilizing genome-wide data from restriction site-associated DNA sequencing (RAD-seq), I studied whether the expansion was reflected in either population structure or genetic diversity of the recently established Finnish range edge population. Despite philopatry and genetic differentiation to the range core populations, principal component analysis (PCA) and a model-based Bayesian clustering approach (fineRADstructure) revealed a lack of spatial population structure along a putative colonization route. Levels of genetic diversity, based on expected heterozygosity, nucleotide diversity, and private allele count, were found to be very similar between range edge (Finland) and range core (Central Europe). The results likely indicate high levels of gene flow both within the new population and across greater spatial distances during or after the range expansion. Due to a detected sequencing batch effect, however, the exact diversity estimates must be considered preliminary. These findings suggest that species with high enough dispersal propensity may escape the predicted genetic costs of range expansions, retaining high levels of genetic variation at range margins. This study provides valuable insights for understanding range shifts in mobile taxa, and highlights the need to investigate further the traits of species that enable the preservation of evolutionary potential during range shifts.
  • Rissanen, Jason (2020)
    Ants are among the most successful organisms in the world. They can be found almost anywhere on the planet and due to their high degree of sociality and complex societies they have become some of the most abundant creatures in most terrestrial ecosystems. Although sociality has benefits in the form of more efficient foraging, brood care, reproduction and protection from predators, it has costs too. Ants live in high densities in their nests and have frequent contact between them which can facilitate an efficient transmission of pathogens within the nest. Ants have become highly successful in spite of their potentially high susceptibility to pathogens. They share the same innate immune responses of other arthropods and have unique adaptations for coping with pathogens. In extension to physiological strategies for coping with pathogens, ants engage in behavioural strategies as well. Ants and other eusocial insects can also harness the structure and behaviour of the colony to prevent and cope with pathogen infections through social immunity. Ants can also engage in self-medication behaviour to combat disease. Self-medication is a behavioural strategy where individuals respond to pathogen infections by seeking out and using biologically active compounds to alleviate the effects of pathogens in a way that would be detrimental for uninfected individuals. The behaviour can be either therapeutic of prophylactic depending on when the compounds are used in relation to encountering the pathogen, and it can be extended beyond the self to other kin. While ants have been proven to medicate themselves with reactive oxygen species (ROS) in laboratory conditions, it remains unknown how they do it in the wild. In my thesis, I studied how the ant Lasius platythorax self-medicate in a natural setting by developing a multi-trophic system of ant – pathogen – aphid – plant interactions. In this system, the ants infected with a fungal pathogen (Beauveria bassiana) had the opportunity to forage on the nectar produced by the extrafloral nectaries (EFNs) of a broad bean plant (Vicia faba) infested by vetch aphids (Megoura viciae). Plants that are stressed by aphids react with a systemic production of ROS, which ants are known to use for self-medication, and ROS could therefore be present in the EFN nectar as well, along with other potentially medicinal compounds. The aphids themselves could present the ants with both ROS, if it accumulates in the aphids due to the immune responses of the plant, and protein if eaten. In my thesis I found out that infected ants increase their foraging on EFN nectar during the first three days after infection compared to healthy ants. This immediate response to a pathogen infection shown by the infected ants fits in a self-medication context as well as the infection cycle of the pathogen, making this a strong case for self-medication. The change in foraging by the infected ants did not reflect on the changes in ROS content in the ants, possibly due to a lack of ROS in the nectar, but instead were likely to be caused by self-generation of ROS in the infected ants. The aphids feeding on the plant contained a higher ROS content compared to the ants, but I found no evidence of ants preying on the aphids, possibly due to the M. viciae being unpalatable for the ants or the ants finding medicinal compounds in the EFN nectar. The result of my thesis is a first step in to identifying natural ways for ants to obtain and use medicinal compounds from their environments and opens up new avenues of research in the topic of self-medication. The result also highlights the importance of biodiversity for the conservation efforts for ants and other insects. Insects are facing a drastic decline in both abundance and diversity due to human impact on their environments, including the prevalence in pathogens. By understanding the full extent of the immune strategies that insects use, including self-medication, we can develop more efficient methods of conservation to help them.
  • Retez, Gabriele (2021)
    After drastic declines in large carnivores’ populations globally, conservation efforts have been successful, and predators’ populations are in recovery. However, their comeback has led to new interactions with locals, generating different conflicts. Two main approaches have been considered to mitigate these conflicts, those being the land sparing and land sharing models, however, the land sparing model requires great extents of protected areas, areas that in Europe are missing, therefore forcing a call for the land sharing model. In Finland, this approach has generated debates among different stakeholders, the outcomes of this debate shaping the fate for the four species: brown bear (Ursus arctos), grey wolf (Canis lupus), Eurasian lynx (Lynx lynx) and wolverine (Gulo gulo). Attitudes towards those species can be used to explore the drivers of the conflicts, however, only few studies have explored this context, considering the ecological and social dimension separately. In addition, the ecotourism industry has been recently recognized as a new stakeholder in the Finnish large carnivore’s context, but the effects of its activities were assessed only ecologically. Therefore, with this study I aimed to explore the attitudes of locals from a specific region of Finland towards the four large carnivores’ species, and to assess the different drivers of those species, through a combination of field questionnaires, social variables and large carnivores’ population data. I explored potential correlates of the differences in attitudes, adding also the spatial effect of ecotourism over the socio-ecological factors. I predicted attitudes to vary among species, having on one side the brown bear with positive attitudes, in contrast the wolf with negative attitudes, while neutral attitudes towards the lynx and wolverine. I also expected to find more negative attitudes in smaller localities rather than in localities with a greater human population density. Also, I explored whether the ecotourism activities have a positive or negative effect over the locals’ attitude towards carnivores, expecting the ecotourism industry to bring positive attitudes in nearby localities. As result, attitudes towards the four different species varied significantly, the attitudes towards each different species having different drivers, with the human population size being important for wolverines and wolves, while the status for bear and lynx populations. The ecotourism had an effect only on bear attitudes, being positively correlated (closer the ecotourism activities were, more positive the attitudes are). To mitigate the large carnivores-human conflict in Finland, a community approach is not the solution, since the different origins of the attitudes ‘drivers. However, the attitudes among species are positively correlated, consequently, by ameliorate the attitudes towards one species, also the others will benefit. Finally, by inducing a proper management within the ecotourism industry and promoting more the respective activity on a national level, the ecotourism can have a positive impact and get a positive role in the Finnish conflict.
  • Gawriyski, Lisa (2018)
    Life historyresearch seeks to explain how natural selection and ecological challenges shape organisms to optimize their fitness. A strong immune defense is energetically demanding to upkeep and there may be trade-offs among other life history traits. Investing a lot of energy to upkeep a strong immune defense in conditions where there are less pathogens and parasites might have negative fitness effects. Heliconius eratois a neotropical species of butterfly found widely in South America. The immune defense, ecologicalfactors affecting its immune defense, and possible life history trade-offs of the butterfly are currently not well known. Environmental moisture conditions have been shown to affect the diversity, quality and amount of microorganisms and parasites. The aim of this thesis was to use real-time quantitative PCR (RT-qPCR) to quantify immune gene expression of individuals of the butterfly species Heliconius eratocollected from different environmental moisture conditions. Additionally, individual variation in encapsulation rates, a physiological measure of immunity, was compared across the moisture gradient. Results indicate reduced expression of the gene encoding the antimicrobial peptide attacin in dry conditions, but no difference in encapsulation rates across the moisture gradient. Additionally, differential expression of the prophenoloxidase encoding gene was found between male and female butterflies. These results indicate a possibility of differential immune threats in different environmental moisture conditions in H. erato, but requires further study.
  • Fagerholm, Freja (2021)
    In the process of decomposition soil carbon is transformed into CO2 by microbial respiration, which makes decomposition a key process for understanding carbon cycling an releases of CO2. Since the northern permafrost regions contain half of all belowground carbon and the tundra regions are expected to be markedly affected by climate warming, it is of particular interest to understand how warming will affect decomposition in the tundra. Decomposition is however influenced by many factors, from climatic factors such as temperature and precipitation to the belowground organisms inhabiting the soils and the aboveground system dictating the litter that falls to the ground and is decomposed. Further, grazing has been shown to oppose some of the effects of warming on tundra. In this thesis I analyzed data collected from two long-term field experiments, one in Kilpisjärvi (NW Finland) and the other close to Kangerlussuaq Fjord (SW Greenland), both using fencing for manipulation of grazing regime and open-top chambers for artificial warming. My aim was to not only investigate how warming and grazing affect decomposition, but also to understand whether the magnitude of changes in decomposition can be explained by changes in plant community traits and soil characteristics. I found that in contrast to my hypothesis, warming decreased decomposition in Kangerlussuaq, where the soil was drier and contained less carbon than in Kilpisjärvi. I found no effects of grazing on decomposition, plant community traits nor soil characteristics in neither of the study locations. Neither did I find any consistent associations between changes in decomposition and changes in plant community traits, indicating that the effect of litter quality on decomposition is minor in these areas likely rather limited by climate. I found an association for increased decomposition when plant community C:N ratio and C:P ratio increased as a response to warming, but only in Kilpisjärvi, and since increased plant community C:N and C:P ratios are linked to resistant litter this positive effect is unlikely driven by enhanced litter quality. However, I did find a positive relationship between increased root biomass and increased decomposition as a response to warming that was consistent across areas and grazing regimes, indicating that warming can boost decomposition in different tundra habitats by promoting root growth.
  • Finne, Hanna (2020)
    Boreal mires are natural sources of methane and contribute considerably to the global methane budget. Therefore, in order to comprehend the overall impact that these ecosystems have on climate change, it is essential to understand the factors that influence processes involved in methane production and consumption. Factors affecting methane flux vary between different mires, but there is also great spatial and temporal variation in flux within mires. In previous studies, temperature and water table position have been shown to influence methane flux, but vegetation could aid in explaining the small-scale variation. Vegetation can indicate spatial variation in water table position, but also affect methane flux directly by the transportation of methane through plant tissues, and by providing substrate for microorganisms through primary production. Furthermore, redox potential is a poorly studied factor that can reflect if chemical conditions in peat are suitable for methane production or consumption, making it a useful tool in predicting methane flux. In this thesis, I seek to identify if small-scale spatial variation in the methane flux occurs within the studied mire area. In addition, I strive to identify important controllers of the observed spatiotemporal variation in methane flux, with a specific focus on the effect of vegetation properties and redox potential. Methane and carbon dioxide fluxes were measured with the closed chamber technique at a boreal fen in Sodankylä (67°22'06.6"N 26°39'16.0"E) during the growing season in 2019. Flux measurements were carried out at nine measurement plots belonging to three different vegetation types: flark, lawn and string. Coverage and height of plant functional groups were followed during the summer and continuous redox potential was measured for each plot. CH4 fluxes of different plots and vegetation types were compared to study the spatial variation in methane flux. Generalized additive models (GAM) were used to determine which variables are best to explain spatiotemporal variation in methane flux over the growing season. Mean methane flux during the summer was 0.94 ug CH4 m-2 s-1 which is in the same magnitude as observed in a previous study at the fen. Some small-scale spatial variation in the methane fluxes was observed at the study site, with strings having lower flux than flaks and lawns. However, overall the spatial variation was small, while temporal variation in methane flux over the growing season was considerable. The best model, that was a combination of vegetation, redox potential and environmental variables, and it explained 72 % of the observed variation in methane flux. Vascular plant variables were the most important variables in the model, whereas moss functional groups were of lesser importance. Redox potential in deeper peat layers was also important in the model, but redox potential closer to the surface was not found to be significant. Vegetation is an important controller of methane flux, and this information could potentially be used when predicting methane flux over larger areas by using remote sensing to map vegetation characteristics. Redox potential, on the other hand, is relatively easy to measure, and the result suggests that it could provide a useful tool for improving the predictions of methane flux.
  • Aro, Niilo (2022)
    With the growth and concentration of urban areas, methods for minimizing the impacts of fragmentation and habitat loss on biodiversity are needed. Spatial Conservation Prioritization (SCP) methods, which holistically assess the connectivity of urban areas, provide an effective tool for prioritizing conservation efforts, but producing these analyses require large amounts of high-quality data on e.g., the spatial distribution of biodiversity features in the area. An index-based approach is a simpler way to evaluate the ecological quality of single corridors, and could be a cheaper alternative to SCP methods, especially in cases where prior environmental data is limited or there is a frequent need for new analyses. In this study, I created an index-based method to evaluate the ecological quality and functionality of wildlife corridors. The three-step approach included a literature review on factors affecting the functionality of wildlife corridors as well as the building and testing of the index. The main objective in creating the index was to provide a tool that is easy to use and interpret, and that could be used in decision-making to minimize human impact on nature. The index is based on scientific literature and provides information on the ecological functionality of wildlife corridors in facilitating the dispersal of organisms. From the literature review I identified certain key elements of functionality for wildlife corridors. These elements included sufficient width of the corridor to form an undisturbed core habitat, the absence of barriers and disturbance within the corridor and the connectivity of the corridor habitat itself. When tested on fictitious example corridors, the index was able to differentiate wildlife corridors according to their ecological quality. To further test the index, it was applied on a real-world wildlife corridor located in Uusimaa as a case study. The index was found to be effective on evaluating the ecological functionality of wildlife corridors, but further development needs were also discovered. The most important next steps are to fine-tune the parameter values given to factors hindering dispersal (resistance values) based on an extended literature review, and systematic testing on real-world corridors to spot irregularities and possible mistakes. At its current state the index can be used to identify features that impede or promote the ecological functionality of the corridor, even without extensive prior inventories on the areas’ biodiversity features.
  • Villani, Giovanna Marques (2020)
    Hypotheses to explain the emergence and maintenance of trichromacy in primates have long focused on the role of diet, often suggesting trichromats are better able to detect ripe fruits and nutritious leaves. However, many neotropical primate species also need to avoid eating conspicuous food items like insects that have evolved to warn potential predators of their unprofitability. This factor has largely been ignored in work on primate colour vision. We suggest here that dichromatic and trichromatic individuals vary in their ability to learn about conspicuous but unprofitable food and that trichromats could be more effective than dichromats at detecting conspicuous unprofitable prey. To test this hypothesis, three females and one male white-faced saki (Pithecia pithecia) participated in behavioral experiments at Korkeasaari zoo (Helsinki, Finland) where choice boxes were presented marked with two symbols against a green background. Only trichromats could discriminate orange symbols that provided an unprofitable food reward from the more profitable green symbols. Each saki made 80 choices over 10 trials. While we did not detect any evidence for learning about symbol profitability, we found two females significantly avoided the conspicuous prey meaning they received greater food rewards than the dichromat male and one putative dichromat female. Further analysis is needed of the opsin genes of the females in this study to confirm the role of unprofitable food in Saki colour vision.
  • Suutari, Miina (2021)
    Even though bats have no specialized predators in the temperate zone, they are still predated on. In fact, 11% of their annual mortality is caused by avian predators, especially owls. Bats are particularly vulnerable at emergence from their roost because this behaviour is very predictable. Because a successful predation event is mortal, it would be expected that bats need antipredatory responses to avoid it. The time and focus for these responses need to be shared with foraging in a way that maximizes survival. I studied antipredatory responses of bats in two settings: 1. during roost emergence and 2. during foraging at tawny owl territories and at places where there have been no tawny owl sightings. I collected acoustic data from 24 roosts and 11 foraging grounds for 10-13 nights. The roost emergence data was collected with the help of citizen science. Two controlled predation threats, recorded tawny owl calls and nestling sounds, were used. Nestling sounds were only played during roost emergence. In both tests music and silence were used as controls. Owl calls, music or tawny owl territory have no effect on bat presence when they are foraging. However, bats alter their emergence time and leave over 20 minutes later when tawny owl calls are played outside the roost. There is no difference in exit time when music or nestling sounds are played. These results show that bats have antipredatory responses. They also suggest that bats may be able to recognize high-risk situations and allocate their behaviour accordingly or that they place higher importance on foraging than avoiding predation.
  • Puikkonen, Laura (2020)
    Individuals of long-lived animal species can improve their reproductive success through experience. While individual’s resources available for survival and reproduction decrease toward the end of its lifespan through senescence, terminal investment hypothesis predicts the less likely old individuals reproduce again the more they invest in their current offspring. Experience gained through a long lifespan might have an important role in changing behavior to optimize the use of resources and compensate the effects of senescence. In addition, behavioral plasticity allows animals to respond changes in their habitat within much shorter timespan than on an evolutionary timescale. Svalbard reindeer (Rangifer tarandus platyrhynchus) is a wild subspecies of reindeer. It is only found in Svalbard, a remote archipelago in the Arctic with extreme weather conditions rapidly changing due to climate change. It has been isolated at least 5000 years and adapted to a barren habitat with nearly no hunting, predation or harassment of flying insects. The objective of this study is to investigate the effect of age and a calf at heel in Svalbard reindeer females’ maternal, vigilant, and social behavior and time budget in the light of life history theory and its senescence and terminal investment hypotheses. I carried out the field work for the study in two periods in summer in Semmeldalen valley and the south-western part of Reindalen valley on the island of Spitsbergen, Svalbard. I collected behavioral data on marked individuals by instant scan sampling and focal watch methods, wrote observations down manually and later fed them into computer. In addition, I have used birth year data collected by the long-term monitoring program by the Norwegian Polar Institute. I used generalized linear mixed models to analyze the effects of age and calf at heel to the behavior of females. The main results include that young dams maintained shorter distance to their calf in July than in August, and old females were less vigilant. Younger dams and older females without calves were in smaller groups than older dams and younger females without calves. In addition, females with calves spend proportionately less time lying down than females without calves. Dams maintained a longer distance to the nearest neighbor than females without calves. Older dams spend proportionately more time feeding and in groups in August than younger dams. These results show that the age and calf at heel do play a role in the behavior of Svalbard reindeer females and the effect varies over the course of the short Arctic summer. Experience may make older females more effective mothers by optimize the use of resources for example from vigilance to feeding in a predator-free environment. On the other hand, senescence may affect the amount of energy females can spend on their calves, potentially influencing their survival.