Contested dominance modifies the anovulatory consequences of social subordination in female marmosets

Dominance status among female marmosets is reflected in agonistic behavior and ovarian function. Socially dominant females receive submissive behavior from subordinates, while exhibiting normal ovulatory function. Subordinate females, however, receive agonistic behavior from dominants, while exhibiting reduced or absent ovulatory function. Such disparity in female fertility is not absolute, and groups with two breeding females have been described. The data reported here were obtained from 8 female-female pairs of captive female marmosets, each housed with a single unrelated male. Pairs were classified into two groups: “uncontested” dominance (UD) and “contested” dominance (CD), with 4 pairs each. Dominant females in UD pairs showed significantly higher frequencies (4.1) of agonism (piloerection, attack and chasing) than their subordinates (0.36), and agonistic behaviors were overall more frequently displayed by CD than by UD pairs. Subordinates in CD pairs exhibited more agonistic behavior (2.9) than subordinates in UD pairs (0.36), which displayed significantly more submissive (6.97) behaviors than their dominants (0.35). The data suggest that there is more than one kind of dominance relationship between female common marmosets. Assessment of progesterone levels showed that while subordinates in UD pairs appeared to be anovulatory, the degree of ovulatory disruption in subordinates of CD pairs was more varied and less complete. We suggest that such variation in female-female social dominance relationships and the associated variation in the degree and reliability of fertility suppression may explain variations of the reproductive condition of free-living groups of common marmosets

Abordando o sono no ensino médio: proposta de unidade didática contextualizada com o tema saúde

Biological rhythms are part of the life from the simplest to the most complex living beings. In humans, one of the most important biological rhythms is the sleep-wake cycle (SWC), which represents an indispensable behavior for health, since sleep deprivation can lead to deficits in attention and memory, mood and daytime sleepiness which may affect school performance. Nevertheless, the SWC is a content rarely discussed in schools. Thus, the aim of this research was to address contents of the sleep-wake cycle, related to the content of Health to encourage healthy sleep habits. This study was conducted in a public school with 33 students of the 3rd year of high school and is divided into four stages: 1st) Study and analysis of the content of the textbook adopted by the school to subsidize the activities covered in the teaching unit (TU) and approximation with the biology teacher from the class to evaluated the feasibility of schedules for the development of TU; 2nd) Survey of students' prior knowledge, through a questionnaire, to guide the development of the TU; 3rd) Development and implementation of a TU based on meaningful learning and characterization of the students sleep habits, 4th) Evaluation of the TU as a viable proposal to teach biological rhythms concepts. Previous knowledge of students about the SWC are scarce and this content is not covered in the books adopted by the school. Alternative conceptions were observed, particularly with regard to individual differences in sleep, which may contribute to the occurrence of inadequate sleep habits, as reported by the adolescents in this study. The activities developed during UD were well received by the students who showed participative, motivated and evaluated positively the procedures used by the researcher. After the TU, students' knowledge about the concept of biological rhythms has been increased and they started to identify that the SWC changes throughout life and occur due biological and socio-cultural factors. Thus, the UD elaborated in this study represents a viable proposal to teach the concepts of biological rhythms contextualized to the content of Health, in high school

Contested dominance modifies the anovulatory consequences of social subordination in female marmosets

Dominance status among female marmosets is reflected in agonistic behavior and ovarian function. Socially dominant females receive submissive behavior from subordinates, while exhibiting normal ovulatory function. Subordinate females, however, receive agonistic behavior from dominants, while exhibiting reduced or absent ovulatory function. Such disparity in female fertility is not absolute, and groups with two breeding females have been described. The data reported here were obtained from 8 female-female pairs of captive female marmosets, each housed with a single unrelated male. Pairs were classified into two groups: “uncontested” dominance (UD) and “contested” dominance (CD), with 4 pairs each. Dominant females in UD pairs showed significantly higher frequencies (4.1) of agonism (piloerection, attack and chasing) than their subordinates (0.36), and agonistic behaviors were overall more frequently displayed by CD than by UD pairs. Subordinates in CD pairs exhibited more agonistic behavior (2.9) than subordinates in UD pairs (0.36), which displayed significantly more submissive (6.97) behaviors than their dominants (0.35). The data suggest that there is more than one kind of dominance relationship between female common marmosets. Assessment of progesterone levels showed that while subordinates in UD pairs appeared to be anovulatory, the degree of ovulatory disruption in subordinates of CD pairs was more varied and less complete. We suggest that such variation in female-female social dominance relationships and the associated variation in the degree and reliability of fertility suppression may explain variations of the reproductive condition of free-living groups of common marmosets