Can male white-faced saki monkeys (Pithecia pithecia) detect female reproductive state?

For mammalian males, copulating with females during ovulation is critical to reproductive success. However male knowledge of ovulation may not always be advantageous for females, as it could hinder mate choice or promote harassment. White-faced saki monkeys live in variably monogamous and polygamous social groups and hence females may have multiple motivations to conceal ovulatory timing. White-faced sakis further show no obvious physical or behavioral signs of ovulation, although they do use scent in a variety of contexts, including sexual behavior. We collected data on three wild groups of white-faced sakis at Brownsberg Naturepark, Suriname in order to assess whether male copulations are coordinated with female ovulatory timing. We recorded all occurrences of copulations and genital inspections, and collected fecal samples from females which were radioimmunoassayed to obtain estradiol and progesterone levels. We found that males copulated throughout the female reproductive cycle, although the association between copulation and reproductive state varied between dyads. Only one male–female dyad showed significantly more copulations than expected during ovulation. However four of five dyads copulated less than expected with pregnant females, suggesting that males may be able to differentiate cycling from non-cycling females. While genital inspections were distributed randomly with regard to female reproductive state, the decision to copulate was not: males were more likely to mate with both ovulating and cycling females than with non-cycling females after genital inspection. Regardless, males were not more likely to copulate with an ovulating vs. a cycling (non-ovulating) female. These data indicate that while males may receive olfactory information on female hormonal status, they do not make entirely accurate decisions with regard to copulation timing. This inaccuracy may be due to males' inability to detect ovulation, or alternately a lack of motivation to limit copulations solely to conceptive periods. Pair familiarity and sexual experience may also play a role in copulation accuracy.

Sex Differences in Interpreting Male-Female Dyad Interactions: Males' Predominance in Perceiving Sexual Intent

Astudy is reported investigating gender differences in judging the behaviour of males and females during mixed-dyad conversations and the impact of the endorsement of rape myths in explaining these gender differences. A total of 51 males and 40 females watched a videotape of a male actor and female actor verbally interacting in a social environment and were asked to give their impression about this interaction. They were also requested to fill in the Rape Myths Acceptance Scale (1980). Results revealed that compared to females, males had a stronger tendency to see the interaction in sexual terms. Also, male participants endorsed rape myths more strongly. Finally, gender differences in rape myth endorsements accounted for gender differences in perceiving male-female mixed-dyad interactions to alimited extent. Implications of the findings are discussed.

EFFECT OF GENDER DOMINANCE EXPECTANCIES FOR KNOWLEDGE ON SELF-TOUCHING DURING CONVERSATIONS

We investigated how expectancies about gender dominance for knowledge influence the frequency of self-touching enacted by conversing members of mixed-sex dyads. The study was a 2 (male vs. female dyad member) × 2 (normatively male vs. female knowledge dominance) design. Two alternative hypotheses about the effects of normative expectancies for gender-knowledge dominance on self-touching were evaluated. Normative expectation of knowledge deficiency could provoke greater performance concerns and self-touching than a normative expectation of knowledge dominance, or a normative expectation of knowledge dominance could provoke greater performance concerns and self-touching than a normative expectation of knowledge deficiency. Results supported the latter alternative.

Reproductive status influences odor preferences of the meadow vole, Microtus pennsylvanicus, in winter day lengths

Sporadic winter breeding is a common occurrence in populations of arvicoline rodents. To elaborate the olfactory basis of winter breeding, odor preferences of meadow voles that did or did not develop their reproductive systems in short day lengths were compared. Voles that did not respond to short days with reproductive inhibition were reproductively mature and are termed nonresponders, while voles that did respond to short days with reproductive inhibition were reproductively immature and are termed responders. Nonresponder females preferred odors of nonresponder males over those of nonresponder females and nonresponder female over responder female odors. Nonresponder males preferred nonresponder over responder female odors. The mutual attraction between male – female and female – female nonresponders may facilitate winter breeding and female – female dyad formation for communal rearing of young, respectively. Responder females preferred odors of female responders over those of male responders and responder over nonresponder male odors. Olfactory preferences of nonresponder short-day voles were not equivalent to those of reproductively competent long-day animals. Differences in odor communication between responder and nonresponder voles are attributable only in part to differences in gonadal hormone secretion.

Social Stigma of Pregnancy: Further Evidence

As expected fewer shoppers among 40 men and 40 women invaded the personal space of a female dyad when one member of the dyad appeared to be pregnant and when the members of the dyad were conversing.