Search results for "lisääntymiskäyttäytyminen"

Mating behaviour of the black grouse : genetic characteristics and physiological consequences

2008

Christophe Lebigre tutki väitöskirjassaan teeren soidinkäyttäytymistä sekä koiraiden pariutumismenestystä, ja näiden seurauksia teeripopulaatioiden geneettiseen rakenteeseen ja koirasyksilöiden kuntoon. Soidin on pariutumissysteemi, jossa koiraat kerääntyvät avoimille alueille eli soitimille päämääränään pariutua naaraiden kanssa. Koska koiraat eivät osallistu jälkeläishuoltoon, naaraat voivat hyötyä koiraasta ainoastaan sen geenien avulla. Aikaisemmat tutkimukset ovat osoittaneet huimia eroja koiraiden parittelumenestyksessä ja naaraiden valinnan voimakkuutta. Jos naaraat valikoivat jatkuvasti tietyntyyppisiä koiraita, saattaa perimä yksipuolistua.Lebigre havaitsi tutkimuksessaan, että tee…

The evolutionary dynamics of adaptive virginity, sex-allocation and altruistic helping in haplodiploid animals

2018

In haplodiploids, females can produce sons from unfertilized eggs without mating. However, virgin reproduction is usually considered to be a result of a failure to mate, rather than an adaptation. Here, we build an analytical model for evolution of virgin reproduction, sex-allocation, and altruistic female helping in haplodiploid taxa. We show that when mating is costly (e.g., when mating increases predation risk), virginity can evolve as an adaptive female reproductive strategy. Furthermore, adaptive virginity results in strongly divergent sex-ratios in mated and virgin queen nests ("split sex ratios"), which promotes the evolution of altruistic helping by daughters in mated queen nests. H…

Maintenance costs of male dominance and sexually antagonistic selection in the wild

2018

Variation in dominance status determines male mating and reproductive success, but natural selection for male dominance can be detrimental or antagonistic for female performance, and ultimately their fitness. Attaining and maintaining a high dominance status in a population of competing individuals is physiologically costly for males. But how male dominance status is mediated by maintenance energetics is currently not well understood, nor are the corresponding effects of male energetics on his sisters recognized. We conducted laboratory and field experiments on rodent populations to test whether selective breeding for male dominance status (dominant vs. subordinate breeding lines) antagonis…

Individual- and group-level sex ratios under local mate competition : consequences of infanticide and reproductive dominance

2023

Extremely female-biased sex ratios of parasitoid wasps in multiple-foundress groups challenges evolutionary theory which predicts diminishing bias as foundress numbers increase. Recent theory based on foundress cooperation has achieved qualitative rather than quantitative success in explaining bias among parasitoids in the genus Sclerodermus. Here, we develop an explanation, expanding the theory of local mate competition, based on the observation that male production seems dominated by some foundresses within groups. Two sex ratio effects arise from such reproductive dominance: an immediate effect via suppression of male production, and a long-term evolutionary response to reproductive skew…

Overwintering strategies of a boreal small mammal in a changing climate

2015

New insights on the role of ecology and life-history in social evolution

2017

Biological altruism, defined as a behaviour that benefits others at an apparent cost to the focal individual, is found abundantly across different levels of biological organization. While kin selection has been useful for explaining both cooperation and conflict in specialized cooperative societies, more theoretical work has to be done to develop models for realistic ecological and life-history contexts. This thesis aims to fill this gap by providing several new insights on the role of ecology and life-history in various social systems. Firstly, I propose a model that incorporates realistic ecological mechanisms of population regulation and study how different population regulation mechanisms affe…

Habitat selection by riverine grayling, Thymallus thymallus L

2004

Harjus vaihtaa olinpaikkaa vuodenajan mukaan. Tämä käy ilmi Mari Nykäsen väitöstutkimuksesta, jossa hän selvitti suomalaisen harjuksen liikkeitä ja elinympäristön- eli habitaatinvalintaa eri vuodenaikoina, kutupesien ominaisuuksia sekä vastakuoriutuneiden poikasten olinpaikkojen ominaisuuksia.

The extent and causes of interspecific reproductive interactions in damselflies

2015

Breeding near heterospecifics as a defence against brood parasites: can redstarts lower probability of cuckoo parasitism using neighbours?

2022

Breeding habitat choice based on the attraction to other species can provide valuable social information and protection benefits. In birds, species with overlapping resources can be a cue of good quality habitats; species with shared predators and/or brood parasites can increase joint vigilance or cooperative mobbing, while raptors may provide a protective umbrella against these threats. We tested whether the migratory common redstart (Phoenicurus phoenicurus) is attracted to breed near active nests of the great tit (Parus major), a keystone-information source for migrant passerine birds, or a top predator, the northern goshawk (Accipiter gentilis). This system is unique to test these quest…

Multiple-batch spawning: a risk-spreading strategy disarmed by highly intensive size-selective fishing rate

2022

Can the advantage of risk-managing life-history strategies become a disadvantage under human-induced evolution? Organisms have adapted to the variability and uncertainty of environmental conditions with a vast diversity of life-history strategies. One such evolved strategy is multiple-batch spawning, a spawning strategy common to long-lived fishes that ‘hedge their bets' by distributing the risk to their offspring on a temporal and spatial scale. The fitness benefits of this spawning strategy increase with female body size, the very trait that size-selective fishing targets. By applying an empirically and theoretically motivated eco-evolutionary mechanistic model that was parameterized for …