Search results for "seksuaalivalinta"

Males influence maternal effects that promote sexual selection: a quantitative genetic experiment with dung beetles Onthophagus taurus

2003

J.S.K. was funded by the Academy of Finland, L.W.S. by the Australian Research Council, J.H. by an Australian Postgraduate Award, and J.L.T. by a postdoctoral research fellowship from the University of Western Australia. Recently, doubt has been cast on studies supporting good genes sexual selection by the suggestion that observed genetic benefits for offspring may be confounded by differential maternal allocation. In traditional analyses, observed genetic sire effects on offspring phenotype may result from females allocating more resources to the offspring of attractive males. However, maternal effects such as differential allocation may represent a mechanism promoting genetic sire effects…

Maintenance of genetic variation in sexual ornamentation : role of precopulatory and postcopulatory sexual selection

2010

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 …

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

2013

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…

Color Signals in the Black Grouse (Tetrao tetrix): Signal Properties and Their Condition Dependency

2007

Recent progress in techniques of quantifying betweenindividual differences of color-based ornaments has revealed undiscovered possibilities for research in sexual selection. We present how the color spectra data can be comprehensively used for studying the importance of sexual ornaments in the black grouse and how these ornaments are related to a male condition. For this, we used both correlative field and experimental data. Field data indicated that older males had more chromatic coloration than yearlings. Blue chroma of males was correlated with male mating success. We experimentally manipulated yearling birds with testosterone implants and found that testosterone-implanted males had impa…

Musiikista puhuminen internet-treffipalsta-kontekstissa : evoluutiopsykologinen näkökulma

2014

Tässä tutkimuksessa tutkittiin sitä, miten ihmiset puhuvat musiikista treffipalstoilla. Tarkastelukulma oli evoluutiopsykologinen, ja tarkoituksena oli selvittää voidaanko musiikista puhumista treffipalstoilla selittää seksuaalivalintateorian valossa. Aineistona tutkimuksessa toimi 250 naisen ja 250 miehen treffipalstailmoitusta. Tutkimusongelmaa lähestyttiin tutkimalla tilastollisesti sukupuolieroja ja ikäjakaumia siinä, miten moni ihminen mainitsee tuottavansa musiikkia profiilissaan. Tarkastelun kohteena oli myös profiilin omaavan henkilön toive mahdollisen kumppanin motivaatiosta suhteeseen, mitä verrattiin siihen, mainitseeko henkilö tuottavansa musiikkia vai ei. Tilastollisista testei…