Though numerous experimental manipulations have induced sex ratio bias in mice, none have assessed the fitness of the offspring from these litters relative to controls. Here, we retrospectively analyze experimentally derived fitness data gathered for the purpose of toxicological assessment in light of 2 leading hypothesis Trivers—Willard hypothesis [TWH] and cost of reproduction hypothesis [CRH] , seeking to test if this facultative sex ratio adjustment fits into an adaptive framework. Control F 1 males were heavier than F 1 females, but no differences in mass were detected between exposed F 1 males and females, suggesting that exposed dams did not save energy by producing fewer males, despite producing F 1 offspring of both treatments were released into seminatural enclosures where fitness was quantified. Thus, exposed dams increased their fitness by adjusting litters toward females who were less negatively affected by the exposure than males. Collectively, these data provide less support that the observed sex ratio bias results in energetic savings CRH , and more support for the TWH because fitness was increased by biasing litters toward female offspring. These mammalian data are unique in their ability to support the TWH through the use of relevant fitness data. In , Trivers and Willard proposed that if parents are capable of facultative sex ratio adjustment of their offspring toward the sex that is likely to have higher reproductive success, then these parents can increase their inclusive fitness.
Introduction
INTRODUCTION
Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. Breeding and welfare problems confront many conservation breeding programs. Stereotypies—repetitive, unvarying, functionless behaviours —are common abnormal behaviours that often arise in suboptimal conditions. While the role of stereotypies in welfare assessment is well studied, few investigations address the relationship between stereotypic behaviour and reproduction.
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Local residents near Irvine Beach Park in Irvine, North Ayrshire, Scotland, have been shocked to discover discarded clothes, condom wrappers and lube at a beauty spot notorious for dogging meetings. Sex-crazed strangers are breaking lockdown to fulfil their desires by visiting sites known for dogging despite the health risks posed by the coronavirus outbreak. A trail of evidence has been uncovered at a notorious coastal beauty spot in Scotland — with condoms, lubes, and discarded clothes found along the shore. Sand at a beach in the area has been cleared in order for doggers to park illegally before participating in the liaisons in the West of Scotland town.
