Sentences with phrase «biased sex ratio»

The female - biased sex ratio of some western gull colonies may have been the result of pollution by pesticides that acted like estrogen and made some male embryos develop as females.

The strongly male - biased sex ratio of captures at the barrier fence suggested high levels of reinvasion from beyond the harvested area of the pastoral lease and this made effective control in this open system difficult.

According to their findings, frogs reared in oak leaf litter in the absence of salt exhibited a female - biased sex ratio (63 percent).

Plentiful food sources are consistently linked with a male - biased sex ratio in nonhuman mammals, and a 2008 study found that British women with the best nutrition during conception were significantly more likely to give birth to boys than women with the poorest diet.

«In both cases, the offspring of the mice had a heavily male - biased sex ratio,» she says.

With the increase of global temperatures and climate change, sea turtle nests tend to produce more female - biased sex ratios further increasing their risk of extinction.

Professor Suckling added: «The sex differences in the limbic system include areas often implicated in psychiatric conditions with biased sex ratios such as autism, schizophrenia, and depression.

RNA - guided gene drives could also cause a population crash due to the buildup of recessive mutations causing infertility or inviability or by biasing the sex ratio.

Finnish women living in regions with male - biased sex ratios had earlier and higher fertility, but were no more likely to cohabit with a partner than women living in female - biased regions [62].

In Japan, female - biased sex ratios were associated with poorer union stability, shorter life expectancy, lower total fertility rates, and higher rates of spontaneous and artificial abortion [106].

Not exact matches

Giving the spiders antibiotics restored a normal sex ratio, proving that the previous female bias really was Wolbachia «s work (BMC Evolutionary Biology, DOI: 10.1186 / 1471-2148-11-15).

Sex - ratio - biasing constructs for the control of invasive lower vertebrates.

For example, by biasing inheritance toward the production of one sex over another, altered sex ratios might eventually cause a population to peter out.

Because sex ratio is biased toward males, the figure is expressed by dividing male births by total births.

Evolutionary biologists say male mortality, which is overall higher than that of females, explains the male bias in sex ratio: A slightly skewed sex ratio at birth that favors males ensures that there are roughly an equal number of males and females of reproductive age.

Analysis of the images provided data on sex - ratio bias, site fidelity and aggregation, hotspot sites, size and migration patterns of the animal — details that improve scientists» understanding of the species and help conservation efforts to protect them and their environment.

In fact, sample sex ratios collected for loggerhead turtles for more than 10 years in Palm Beach County, Fla. show significant variability, with highly female - biased ratios being produced over a wider range of temperatures than are found in many well - controlled laboratory studies.

Disproportionate mortality of males, presumably an important cause of the change in sex ratio of the snow leopard population in Tost, is reported in several carnivores as resulting from human - induced factors such as poaching and retaliatory killing, including Amur tigers in southeast Russia [32], leopards in South Africa [34], and cougars in the Pacific Northwest [33], although there are exceptions (e.g. tiger population in Panna, Central India, that had turned male - biased prior to extinction due to poaching; [36], [37]-RRB-.

Although seemingly stable, vigorous underlying dynamics were evident in this population, with the adult sex ratio shifting from being male - biased to female - biased (1.67 to 0.38 males per female) during the study.

This male bias in the SSR deviates from the 1 ∶ 1 sex ratio predicted by natural selection [2] and has prompted a large body of research investigating the causal mechanisms underpinning this anomaly.

Political unrest, natural disasters and maternal stress are among a long list of traits suggested to lower the male bias in human sex ratios [4], [5], whereas during the First and Second World Wars in Europe, a more male - biased SSR has been documented [6].

«There is great concern that a lack of males could lead to inbreeding in small populations of marine turtles, potentially causing a population crash,» explained Lucy Wright, a PhD candidate at the University of Exeter who led the study, «however our research suggests that there are more males out there than expected considering the female - biased hatchling sex ratios and that their mating patterns will buffer the population against any potential feminising effects of climate change.»

UK women's responses to female - biased operational sex ratios varied by women's current and childhood socio - economic status and reproductive strategy: high socio - economic status women with slow life - history strategies moved further towards the slow end of the life - history continuum and delayed reproduction, while low socio - economic status women with fast life - history strategies favoured earlier reproduction [61].

Women having low power within their relationships may be associated with female - biased population sex ratios [62,106].

Chipman & Morrison [61] discuss the importance of the operational sex ratio: male - biased populations favour female mate choice and female - biased populations favour male mate choice, affecting union formation, stability and reproduction.