Search results for "valinta"

Strength of sexual and postmating prezygotic barriers varies between sympatric populations with different histories and species abundances

2019

The impact of different reproductive barriers on species or population isolation may vary in different stages of speciation depending on evolutionary forces acting within species and through species’ interactions. Genetic incompatibilities between interacting species are expected to reinforce prezygotic barriers in sympatric populations and lead to cascade reinforcement between conspecific populations living within and outside the areas of sympatry. We tested these predictions and studied whether and how the strength and target of reinforcement between Drosophila montana and Drosophila flavomontana vary between sympatric populations with different histories and species abundances. All barri…

Sex-biased dispersal and kin aggregation on leks in the black grouse (Tetrao tetrix)

2007

Selection on two behavioral genes : fitness effects of receptor genes for arginine vasopressin 1a and oxytocin in the bank vole Myodes glareolus

2017

Most variation in behavior is regulated by genes; nevertheless the mechanisms behind maintenance of genetic diversity at behavioral loci have remained mainly elusive in natural populations. I studied in my thesis selection mechanisms of two genes associated with socio-sexual behavior, arginine vasopressin receptor 1a (Avpr1) and oxytocin receptor (Oxtr) in bank vole (Myodes glareolus). Expression of Avpr1a and Oxtr in specific regions of the brain regulates diverse social and reproductive behaviors such as parental care, aggression, sexual behavior, social recognition as well as pair and parent- offspring bonding in mammals. In addition, there is a link between the length of a regulatory re…

Testing theories of sexual selection in decorated crickets (Gryllodes sigillatus)

2007

Question: Do females choose males according to their level of acoustic sexual activity, fluctuating asymmetry, size, condition or do they select for genetic compatibility according to relatedness? What are the relative strengths of selection on these traits and what might be the benefit of the choice – large nuptial gifts, heritable attractiveness or quality? Organism: Laboratory colony of decorated crickets (Gryllodes sigillatus). Methods: Behavioural trial of female preference on male traits, multivariate logistic regression of male traits on female preference, and heritability estimation of the traits with an animal model. Results: Female attraction strongly discriminated in favour of ce…

Mate choice or polyandry: reconciling genetic compatibility and good genes sexual selection

2002

Sexual selection for good genes is based on the assumption that ‘good genes’ are equally good for all females. In contrast, selection for genetic compatibility is based on the assumption that offspring viability will depend on the interaction between male and female genotypes, and hence one male may not be good for all females. Here we present a simple model to examine the relationship between the genetic compatibility hypothesis and good genes sexual selection. We examine the circumstances under which selection arising from genetic compatibility will favour an increase in the number of males a female mates with. Our model shows that if there is some cost of mating, then some form of sperm …

Sexual selection on song and cuticular hydrocarbons in two distinct populations of Drosophila montana

2011

Sexual selection has the potential to contribute to population divergence and speciation. Most studies of sexual selection in Drosophila have concentrated on a single signaling modality, usually either courtship song or cuticular hydrocarbons (CHCs), which can act as contact pheromones. We have examined the relationship between both signal types and reproductive success using F1–3 offspring of wild- collected flies, raised in the lab. We used two populations of the Holarctic species Drosophila montana that represent different phylogeographic clades that have been separate for ca. 0.5 million years (MY), and differ to some extent in both traits. Here, we characterize the nature and identify …

Fitness in male black grouse (Tetrao tetrix) : effects of life histories and sexual selection on male lifetime mating success

2013

Fitness and viability of small populations : the effects of genetic drift, inbreeding, and interpopulation hybridization

2012

The effects of inbreeding on mating success and offspring production of males and females in a Drosophila littoralis population

2011

Sisäsiitoksella, eli pariutumisella lähisukulaisten kesken, on monia negatiivisia vaikutuksia sekä populaation että yksilön kelpoisuudelle. Sisäsiitos lisää homotsygotiaa ja mahdollistaa siten väistyvien haitallisten mutaatioiden ilmentymisen fenotyypissä sekä estää heterotsygotiasta johtuvaa paremmuutta lokuksissa, joissa on ylidominanssia. On osoitettu, että sisäsiittoisuus voi vaikuttaa koiraisiin ja naaraisiin eri tavalla siten, että toinen sukupuolista kärsii sisäsiitoksesta toista enemmän. Jotkut tutkimukset ovat näyttäneet, että sisäsiittoisuudella on voimakkaampi negatiivinen vaikutus koiraiden kuin naaraiden lisääntymiskykyyn, kun taas toiset osoittavat että naaraat kärsivät enemmä…

Sukupuolelleen epätyypillisen soitinvalinnan tehneiden tie musiikkiharrastuksen alusta ammattilaisiksi

2015

Tutkimuksen tarkoituksena oli selvittää aiempien tutkimusten valossa sukupuolelleen epätyypillisen soitinvalinnan tehneiden henkilöiden instrumenttivalinnan ja soittamisen motivaation syitä. Aiemmissa tutkimuksissa on todettu instrumenttien olevan sukupuolittuneita ja onkin esitetty instrumenttiin liitettävän maskuliinisen tai feminiinisen mielikuvan vaikuttavan jopa soitinvalintaan. Tässä tutkimuksessa haastattelin sukupuolelleen epätyypillisen soitinvalinnan tehneitä instrumentalisteja, jotka olivat jatkaneet soittamista aina ammattiopintoihin asti. Selvitin heidän instrumenttivalintansa syitä, soittomotivaatiotaan sekä kartoitin, miten he kokevat oman soittimensa mahdollisen sukupuolittu…