Sexual Receptivity Signal of Lordosis Posture and Intra-Sexual Competition in Women

Previous research has shown that women may use self-enhancement strategies to compete with one other. Lumbar curvature in women is considered to enhance a woman′s attractiveness, potentially due to its role in bipedal fetal load and sexual receptiveness. The current study investigated the role of lumbar curvature on women’s perceptions of sexual receptiveness as well as its role in women’s intrasexual competitiveness. Study 1 (N = 138) tested and confirmed that women’s intrasexual competition influences their perception of sexual receptivity of women as a function of lordosis posture depicted in a standing posture. Study 2 (N = 69) replicated these results and extended them to other postures, namely, the quadruped and supine positions. Study 3 (N = 106), using a two-alternative forced-choice task, revealed that other women perceive relatively larger arched-back postures as more threatening to their relationship and frequently as being more attractive. Collectively, this work suggests that women consider a lordotic posture in other women as a signal of sexual receptivity and perceive it as a threat to their relationship. This research provides robust support for the sexually receptivity hypothesis of lumbar curvature, questioning the alternative morphological vertebral wedging hypothesis.

An intergenerational androgenic mechanism of female intrasexual competition in the cooperatively breeding meerkat

Female intrasexual competition can be intense in cooperatively breeding species, with some dominant breeders (matriarchs) limiting reproduction in subordinates via aggression, eviction or infanticide. In males, such tendencies bidirectionally link to testosterone, but in females, there has been little systematic investigation of androgen-mediated behaviour within and across generations. In 22 clans of wild meerkats (Suricata suricatta), we show that matriarchs 1) express peak androgen concentrations during late gestation, 2) when displaying peak feeding competition, dominance behaviour, and evictions, and 3) relative to subordinates, produce offspring that are more aggressive in early development. Late-gestation antiandrogen treatment of matriarchs 4) specifically reduces dominance behaviour, is associated with infrequent evictions, decreases social centrality within the clan, 5) increases aggression in cohabiting subordinate dams, and 6) reduces offspring aggression. These effects implicate androgen-mediated aggression in the operation of female sexual selection, and intergenerational transmission of masculinised phenotypes in the evolution of meerkat cooperative breeding.

Female Scarcity and Natal Dispersal Differences Between Sexes Among Bellbirds (Anthornis melanura)

<p>Sex ratio imbalances in wild bird populations have been a challenge for wildlife managers for decades. Differences between sexes during natal dispersal has long been thought to promote sex ratio imbalances. Natal dispersal distances may differ between sexes because of competition for food and space, or intrasexual competition and aggression. I investigated natal dispersal and intrasexual competition as mechanisms for a sex ratio imbalance in a small, translocated population of a New Zealand honeyeater, the bellbird (Anthornis melanura) in the Karori Wildlife Sanctuary- Zealandia, Wellington, New Zealand. I analysed long term records of population size and structure to document annual variation in sex ratios since the reintroduction of bellbirds to Zealandia. Radio telemetry was used to track the 2008/2009 cohort of bellbirds for five months after fledging to observe movements and distances travelled from their hatching location. Observations at a supplemental food source that was used by both adults and fledglings, were used to study intrasexual competition and aggression. Dispersal distances did not differ between the sexes for any of the measurement types used. Males did however significantly dominate the use of a supplemental food source and were significantly more aggressive around this food source, which is most likely responsible for the lower feeding rate among females. Therefore, I conclude that the sex ratio imbalance in the bellbird population in Zealandia may not result from a difference in natal dispersal, but from males dominating a supplemental food source, raising their population and fitness over that of females.</p>

Female Scarcity and Natal Dispersal Differences Between Sexes Among Bellbirds (Anthornis melanura)

<p>Sex ratio imbalances in wild bird populations have been a challenge for wildlife managers for decades. Differences between sexes during natal dispersal has long been thought to promote sex ratio imbalances. Natal dispersal distances may differ between sexes because of competition for food and space, or intrasexual competition and aggression. I investigated natal dispersal and intrasexual competition as mechanisms for a sex ratio imbalance in a small, translocated population of a New Zealand honeyeater, the bellbird (Anthornis melanura) in the Karori Wildlife Sanctuary- Zealandia, Wellington, New Zealand. I analysed long term records of population size and structure to document annual variation in sex ratios since the reintroduction of bellbirds to Zealandia. Radio telemetry was used to track the 2008/2009 cohort of bellbirds for five months after fledging to observe movements and distances travelled from their hatching location. Observations at a supplemental food source that was used by both adults and fledglings, were used to study intrasexual competition and aggression. Dispersal distances did not differ between the sexes for any of the measurement types used. Males did however significantly dominate the use of a supplemental food source and were significantly more aggressive around this food source, which is most likely responsible for the lower feeding rate among females. Therefore, I conclude that the sex ratio imbalance in the bellbird population in Zealandia may not result from a difference in natal dispersal, but from males dominating a supplemental food source, raising their population and fitness over that of females.</p>

KEKERASAN DALAM ‘PERSAHABATAN BERACUN’ ANTARPEREMPUAN PADA NOVEL ANTÉCHRISTA KARYA AMÉLIE NOTHOMB

(Title: Violence in Toxic Friendship Between Women in Amélie Nothomb's “Antéchrista” Novel). Violence is often identified with masculine expressions inherent in men. However, in reality, it is not gender-exclusive because women are also enabled to do so, including against those closest to them such as friends, as revealed in the novel Antéchrista by Amélie Nothomb, a Belgian francophone writer. This study aims to examine how the theme of violence in the 'toxic friendship' between women is displayed in the novel. The method used is descriptive qualitative with a feminist literary criticism approach. The data were collected from the novel using the note-taking technique and analyzed using the content analysis technique. The data consisting of words, phrases, and sentences in French were then translated by the researchers to be classified, interpreted, and studied. The result of the research shows that the novel Antéchrista presents women as victims who are also perpetrators of violence through oppression against each other, motivated by jealousy and intrasexual competition. The form of violence is in the form of psychological and verbal which is manifested in the form of intimidation, humiliation, and ostracism. Keywords: opression, toxic friendship, resistensi, women, feminist literature criticism