Search results for "eläinten käyttäytyminen"
showing 10 items of 64 documents
Should dispersers be fast learners? Modeling the role of cognition in dispersal syndromes.
2021
Abstract Both cognitive abilities and dispersal tendencies can vary strongly between individuals. Since cognitive abilities may help dealing with unknown circumstances, it is conceivable that dispersers may rely more heavily on learning abilities than residents. However, cognitive abilities are costly and leaving a familiar place might result in losing the advantage of having learned to deal with local conditions. Thus, individuals which invested in learning to cope with local conditions may be better off staying at their natal place. In order to disentangle the complex relationship between dispersal and learning abilities, we implemented individual‐based simulations. By allowing for develo…
Condition-dependence of male sexual signalling in the drumming wolf spider Hygrolycosa rubrofasciata
2003
Jari Ahtiaisen väitöskirjatyön tutkimusten perusteella voidaan todeta, että H. rubrofasciata susihämähäkkinaaraat voivat käyttää koiraan seksuaalista kuntoa mittana arvioidessaan koiraan fenotyyppistä ja geneettistä laatua. Näyttäisi myös siltä, että seksuaalivalinnalla on merkittäviä populaatiotason vaikutuksia. Eläinten seksuaaliominaisuudet voivatkin tulevaisuudessa tarjota uusia keinoja populaatioiden sukupuuttouhan ja elinkyvyn arvioimiseen. The ´good genes´ or ´handicap´ model of sexual selection focuses on the evolution of female preferences for male sexual traits by using condition-dependence as the mediating mechanism. As the ´size´ of the preferred sexual trait increases, male fit…
From influencing to engaging : the role of communication in protecting endangered species
2018
Tämän tutkimuksen tarkoituksena on selvittää, mikä on viestinnän rooli uhanalaisten eläinlajien suojelussa. Kohdeorganisaationa on WWF Nepal. Nepal valikoitui kohteeksi, sillä maassa on saatu aikaan merkittäviä suojelusaavutuksia. Nepal on muun muassa saavuttanut jo neljä kertaa vuoden mittaisen jakson, jonka aikana ei ole salametsästetty yhtäkään sarvikuonoa. Lisäksi maan sarvikuono- ja tiikerikannat ovat kasvussa. Nepalin uhanalaisten eläinten suojelusta on siis selkeästi opittavaa, ja tämä tutkimus pyrkii etsimään viestinnällisten tekojen vaikutuksia prosessissa. Tämä tutkimus on abduktiivinen, eli teoreettisen viitekehyksen rakentaminen ja aineiston analyysi ovat edenneet limittäin. Ain…
Behavioural thresholds of blue tit colour vision and the effect of background chromatic complexity
2020
Vision is a vital attribute to foraging, navigation, mate selection and social signalling in animals, which often have a very different colour perception in comparison to humans. For understanding how animal colour perception works, vision models provide the smallest colour difference that animals of a given species are assumed to detect. To determine the just-noticeable-difference, or JND, vision models use Weber fractions that set discrimination thresholds of a stimulus compared to its background. However, although vision models are widely used, they rely on assumptions of Weber fractions since the exact fractions are unknown for most species. Here, we test; i) which Weber fractions in lo…
Is it interspecific information use or aggression between putative competitors that steers the selection of nest-site characteristics? A reply to Sla…
2018
A growing number of studies have demonstrated that heterospecific individuals with overlapping resource needs – putative competitors – can provide information to each other that improves the outcomes of decisions. Our studies using cavity nesting resident tits (information provider) and migratory flycatchers (Ficedula spp., information user) have shown that selective interspecific information use (SIIU) can result in flycatchers copying and rejecting the apparent nest-site feature preferences of tits, depending on a perceivable fitness correlate (clutch size) of the tits. ese, and other results on the interspecific information use, challenge the predictions of traditional theory of species coexi…
Balancing food, activity and the dangers of sunlit nights
2019
Living in northern latitudes poses challenges to the animals that live in those habitats. The harsh environment provides a short breeding season where the sunlit summer nights provide little reprieve from visibility to predators and increased risk. In this paper, we tested the activity and food choice patterns of bank voles Myodes glareolus in early spring season, categorized by 18 h of daylight and 6 h of dusk in every day cycle. We found that territorial females showed a less predictable pattern of activity than males that were most active during the hours of dusk. The voles also showed preference to forage on high carbohydrate foods at sunset, while switching over to a more protein and f…
Switching spatial scale reveals dominance-dependent social foraging tactics in a wild primate
2017
When foraging in a social group, individuals are faced with the choice of sampling their environment directly or exploiting the discoveries of others. The evolutionary dynamics of this trade-off have been explored mathematically through the producer-scrounger game, which has highlighted socially exploitative behaviours as a major potential cost of group living. However, our understanding of the tight interplay that can exist between social dominance and scrounging behaviour is limited. To date, only two theoretical studies have explored this relationship systematically, demonstrating that because scrounging requires joining a competitor at a resource, it should become exclusive to high-rank…
Importance of diet and prophylactic treatment on survival and immunity of polyphagous Arctia plantaginis (Arctiidae) larvae
2018
Diet is one of the major factors directly and indirectly influencing insect’s life history traits and risk of getting infected. Additionally the insect’s fitness is severely affected by the broad diversity of parasites they are exposed to. As a consequence insects have developed well-evolved defences. Behavioural responses include self-medication, the ability of insects to change dietary intake in response to an infection. When studying this ability it is of major importance to consider the insects natural diet range. In this thesis I investigated the effect of different host plants on fitness and immunocompetence of polyphagous Arctia plantaginis larvae and whether the larvae can therapeut…
Chimpanzees surviving in a fragmented high‐altitude forest landscape of the Congolese Albertine Rift
2021
This paper documents a community of eastern chimpanzees (Pan troglodytes schweinfurthii Giglioli, 1872) inhabiting three relict forest fragments situated on the Lake Albert escarpment, down the Ituri highlands, of eastern Democratic Republic of the Congo (DRC). The area explored had a combined forested surface of ±18.15 km2 in 2017, shrinking by 1.2% per year between 2010 and 2015. Between 2015 and 2017, we found 160 chimpanzee nests along 37.6 km of pilot walks, some up to 2,000 m altitude. Another 123 nests logged along 6.7 km transects led to an estimate of chimpanzee density of 4.62 weaned individuals per square kilometer of forest habitat. Camera‐trap images and direct observations rev…
Interspecific information on predation risk affects nest site choice in a passerine bird
2018
Abstract Background Breeding site choice constitutes an important part of the species niche. Nest predation affects breeding site choice, and has been suggested to drive niche segregation and local coexistence of species. Interspecific social information use may, in turn, result in copying or rejection of heterospecific niche characteristics and thus affect realized niche overlap between species. We tested experimentally whether a migratory bird, the pied flycatcher Ficedula hypoleuca, collects information about nest predation risk from indirect cues of predators visiting nests of heterospecific birds. Furthermore, we investigated whether the migratory birds can associate such information w…