نتایج جستجو برای: mating sex ratios

تعداد نتایج: 342926  

Journal: :Journal of personality and social psychology 2010
Phillip S Kavanagh Sarah C Robins Bruce J Ellis

Two studies (Ns = 80 and 108) tested hypotheses derived from Kirkpatrick and Ellis's (2001) extension and application of sociometer theory to mating aspirations. Experiences of social rejection-acceptance by attractive opposite-sex confederates were experimentally manipulated, and the impact of these manipulations on self-esteem, mating aspirations, and friendship aspirations was assessed. Resu...

Journal: :Genetics and molecular research : GMR 2002
Arundhati Som Bashisth N Singh

Minority male mating advantage was tested in wild type strains of Drosophila ananassae through multiple-choice experiments. Mating success of two types of flies present in five different ratios was scored by direct observation in an Elens-Wattiaux mating chamber. We found no evidence for minority male mating advantage in wild type strains of D. ananassae. The relative mating success of two type...

Journal: :The American naturalist 2003
Michael J Wade Stephen M Shuster Jeffery P Demuth

In a verbal model, Trivers and Willard proposed that, whenever there is sexual selection among males, natural selection should favor mothers that produce sons when in good condition but daughters when in poor condition. The predictions of this model have been the subject of recent debate. We present an explicit population genetic model for the evolution of a maternal-effect gene that biases off...

2014
Songdou Zhang Xiaoming Liu Bin Zhu Xinming Yin Mengfang Du Qisheng Song Shiheng An Olle Terenius

BACKGROUND Mating decreases female receptivity and terminates sex pheromone production in moths. Although significant progress has been made in elucidating the mating-regulated inactivation of pheromone biosynthesis-activating neuropeptide (PBAN) secretion, little is known about the mating induced gene expression profiles in pheromone glands (PGs). In this study, the associated genes involved i...

Journal: :Annual Review of Ecology and Systematics 1998

Journal: :Nature 1999
K R Willison

D uring sperm production in mammals, the process of meiosis generates sper-matozoa that are genetically different but functionally equivalent. So, with respect to the sex chromosomes, for example, equal numbers of sperm are produced carrying either an X or a Y chromosome. Because X and Y sperm are equally capable of fertilizing an egg, equal numbers of male and female embryos are produced, and ...

ژورنال: علوم آب و خاک 2008
جوهری, سید علی , کلباسی, محمد رضا ,

In order to reduce the adverse effects of sexual maturation on growth and survival of rainbow trout, production possibility of all-female triploid was investigated by means of early heat shock on eggs fertilized by masculinized male’s sperm. Fish ploidy level was determined by erythrocyte size measurement and confirmed by gill nucleolus (NORs) counting as well as chromosome number. Sexual ratio...

2012
Stefanie M. Zimmer Klaas W. Welke Jutta M. Schneider

Monogynous mating systems (low male mating rates) occur in various taxa and have evolved several times independently in spiders. Monogyny is associated with remarkable male mating strategies and predicted to evolve under a male-biased sex ratio. While male reproductive strategies are well documented and male mating rates are easy to quantify, especially in sexually cannibalistic species, female...

Journal: :Integrative and comparative biology 2006
Janet L Leonard

Over the last 130 years, research has established that (a) sexual selection exists and is widespread in the plant and animal kingdoms; (b) it does not necessarily entail sexual dimorphism; even hermaphrodites have it; (c) it does not require intelligence or a sophisticated sense of esthetics; even tapeworms and plants choose mates; and (d) it does not require brawn or even mobility for competit...

Journal: :Genetics 2003
J B Haldane C H Waddington

Self-fertilization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 8 Brother-sister mating. Sex-linked genes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 Brother-sister mating. Autosomal genes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

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