The significant role of post-pairing male behavior on the evolution of male preferences and female traits

Existing sexual selection theory postulates that a sufficiently large variation in female fecundity or other direct benefits are fundamental for generating male mate choice. In this study, we suggest that, in addition to pre-pairing preferences, choosy males can also have different post-pairing behaviors, a factor which has been comparatively overlooked by previous studies. We found that both male preferences and female traits could evolve much more easily than previously expected when the choosy males that paired with unpreferred females would allocate more efforts to seeking additional post-pairing mating opportunities. Furthermore, a costly female trait could evolve when there was a trade-off between seeking additional mating and paternal care investment within social pair for choosy males. Finally, a costly male preference and a costly female trait might still evolve and reach a stable polymorphic state in the population, which might give rise to a high variability in male choice and female traits in nature. We suggest that male mate choice may be even more common than expected, which needs to be verified empirically.

Prolactin action is necessary for parental behavior in male mice

Parental care is critical for successful reproduction in mammals. In comparison to maternal care, the neuroendocrine mechanisms supporting paternal care are less well-studied. Laboratory mice show a mating-induced suppression of infanticide (normally observed in virgins) and onset of paternal behavior. Using this model, we sought to investigate whether the hormone prolactin plays a role in paternal behavior, as it does for maternal behavior. First, using c-fos immunoreactivity in Prlr-IRES-Cre-tdtomato reporter mouse sires, we show that the circuitry activated during paternal interactions contains prolactin-responsive neurons, including the medial preoptic area, bed nucleus of the stria terminalis, and medial amygdala. To evaluate whether prolactin action is required for the establishment and display of paternal behavior, we conditionally deleted the prolactin receptor (Prlr) from 3 distinct cell types: glutamatergic, GABAergic, and CaMKIIα-expressing forebrain neurons. Prlr-deletion from CaMKIIα-expressing forebrain neurons, but not from glutamatergic or GABAergic cells, resulted in a profound effect on paternal behavior, as none of these males completed the pup retrieval task. Finally, although sires do not show an acute increase in circulating prolactin levels in response to pups, pharmacological blockade of prolactin-release at the time of pup exposure resulted in failure to retrieve pups, similar to when the Prlr was deleted from CaMKIIα neurons, with prolactin administration rescuing this behavior. Taken together, our data show that paternal behavior in sires is dependent on basal levels of circulating prolactin acting at the Prlr on CaMKIIα-expressing neurons. These new data in male mice demonstrate that prolactin has a similar action in both sexes to promote parental care.

THE ROLE OF MONOAMINERGIC SYSTEM GENE POLYMORPHISMS IN AGGRESSION LEVEL IN HEALTHY INDIVIDUALS

Aggressive behavior is an integral part of the human psyche. However, environmental risk factors, mental illness and somatic diseases can cause increased aggression, which represents the biological basis of antisocial behavior in a human society. An important role in the development of aggressive behavior belongs to the hereditary factors, that are probably related to abnormal functioning of neurotransmitter systems in the brain. However, the underlying genetic mechanisms remain unclear. The present study aimed to assess the main effects of monoaminergic systems gene polymorphisms (serotonergic - SLC6A4 , HTR2A , HTR1B, dopaminergic - DRD4 , MAOB ) together with haplotypic and gene-environmental effects on individual differences in aggression level in 642 mentally healthy individuals with sex and ethnicity inclusion as covariates. Aggression level was assessed using the Russian version of the Buss-Perry Aggression Questionnaire. The genotyping of the SLC6A4 ( 5-HTTLPR and rs1042173 ), HTR2A ( rs7322347 ), HTR1B ( rs13212041 ), DRD4 ( rs1800955 ), MAOB ( rs6651806 ) gene polymorphisms was conducted via polymerase chain reaction (real time and restriction fragment length polymorphism analysis). Statistical analysis included multiple linear/logistic regression (PLINK v. 1.9). The correction for multiple testing was conducted by the FDR procedure (False Discovery Rate). Statistical analysis revealed the association of SLC6A4 5-HTTLPR S -allele with an increased aggression level in men (pFDR = 0.022) and in Udmurts (pFDR = 0.009). In addition, we revealed that paternal care significantly affected association of SLC6A4 rs1042173 and aggression level (p = 0.001). The study demonstrated environmental, genderand ethnicity-specific role of the SLC6A4 gene in individual differences in aggression level in mentally healthy individuals.

Internet Addiction: The Role of Parental Care and Mental Health in Adolescence

Internet addiction in adolescence is a social issue which is being increasingly discussed worldwide. Hence, deepening the knowledge of its development is necessary to prevent short- and long-term negative outcomes. This study involving 266 adolescents (mean age = 16.1 years, SD = 1.4) aimed at analyzing the relationship between quality of parental care, Internet addiction and adolescents’ mental health, by means of the following self-report tools: the Parental Bonding Instrument, the Internet Addiction Test, and the Strengths and Difficulties Questionnaire. The findings, collected through structural equation model analyses, showed that perceived care from both father and mother had significant indirect effects on Internet addiction problems through adolescents’ mental health problems. Furthermore, Internet addiction problems were demonstrated to be negatively associated with maternal care but not with paternal care. The study provides empirical support to the need of family-based prevention and intervention programs to take care of Internet addiction.

Paternal care effects outweigh gamete-mediated and personal environment effects during the transgenerational estimation of risk in fathead minnows

Background Individuals can estimate risk by integrating prenatal with postnatal and personal information, but the relative importance of different information sources during the transgenerational response is unclear. The estimated level of risk can be tested using the cognitive rule of risk allocation, which postulates that under consistent high-risk, antipredator efforts should decrease so that individual metabolic requirements can be satisfied. Here we conduct a comprehensive study on transgenerational risk transmission by testing whether risk allocation occurs across 12 treatments that consist of different maternal, paternal, parental care (including cross-fostering) and offspring risk environment combinations in the fathead minnow Pimephales promelas, a small cyprinid fish with alloparental care. In each risk environment, we manipulated perceived risk by continuously exposing individuals from birth onwards to conspecific alarm cues or a control water treatment. Using 2810 1-month old individuals, we then estimated shoaling behaviour prior to and subsequent to a novel mechanical predator disturbance. Results Overall, shoals estimating risk to be high were denser during the prestimulus period, and, following the risk allocation hypothesis, resumed normal shoaling densities faster following the disturbance. Treatments involving parental care consistently induced densest shoals and greatest levels of risk allocation. Although prenatal risk environments did not relate to paternal care intensity, greater care intensity induced more risk allocation when parents provided care for their own offspring as opposed to those that cross-fostered fry. In the absence of care, parental effects on shoaling density were relatively weak and personal environments modulated risk allocation only when parental risk was low. Conclusions Our study highlights the high relative importance of parental care as opposed to other information sources, and its function as a mechanism underlying transgenerational risk transmission.

An Examination of Psychological Resilience and Remembered Parental Care among University Students

In this study, the aim was to examine the relationship between the psychological resilience and remembered parental care of college students in young adulthood and whether this relationship varies according to gender and perceived socio-economic level. A correlational model was used as a research model. For data collection purposes, ‘‘a personal information form,’’ the “Psychological Resilience Scale for Adults” and the “Parental Bonding Instrument” were used by the researchers. The age range of individuals involved in the study ranged from 18 to 26. The research results were tested with SPSS 21. A strong positive relationship was found between remembered mother and remembered father care, while a moderately positive relationship was found between psychological resilience and remembered mother and father care. One of the findings is that there was a significant difference between the care of mothers and of fathers as remembered by male and by female participants. In addition, the study found that there was a statistically significant difference in the level of remembered maternal care, remembered paternal care, and psychological resilience in terms of perceived socioeconomic level. Based on these results, it can be argued that perceived socioeconomic status, which refers to the perception of the presence of means one possesses, had an impact on the individual’s psychological resilience in a direct proportion. In line with the findings, the significant correlation between remembered mother’s care and remembered father’s care can be shown as a long-term contribution to the positive effect on children of the rapport between mother and father. Alongside the fact that the remembered mother’s and father’s care was an important variable in predicting the factors that affected the psychological resilience of undergraduates, it is noted that democratic, caring and warm paternal attitudes are important, rather than the traditional sex-oriented attitudes. Hence, one can argue that it is of importance that fathers and fathers-to-be have increased awareness of their roles in the long-term development of psychologically resilient youngsters, by means of taking on more responsibilities in childrearing.

Intranasal oxytocin reduces pre-courtship aggression and increases paternal response in California mice (Peromyscus californicus)

Oxytocin (OXT) is a neuropeptide that can facilitate prosocial behavior and decrease social stress and anxiety. We investigated whether acute pulses of intranasal (IN) OXT influenced social behavior during social challenges that are likely to occur throughout the lifespan of a wild mouse. To test this, we examined the acute effects of IN OXT in the male California mouse (Peromyscus californicus), a monogamous, biparental, and territorial rodent, using a within-subjects longitudinal design. Social challenges included a pre-courtship male-female encounter conducted during the initial aggressive and not the following affiliative phase of courtship, same-sex resident intruder test, and parental care test, with each test and dose separated by at least two weeks. Males were treated with intranasal infusions of 0.8 IU/kg OXT or saline controls 5-min before each behavioral test, receiving a total of three treatments of either IN OXT or saline control. We predicted that IN OXT would 1) decrease aggression and increase affiliation during the pre-courtship aggression phase, 2) increase aggression during resident intruder paradigms and 3) increase paternal care and vocalizations during a paternal care test. As predicted, during pre-courtship aggression with a novel female, IN OXT males displayed less contact aggression than control males, although with no change in affiliative behavior. However, post-pairing, during the resident intruder test, IN OXT males did not differ from control males in contact aggression. During the paternal care test, IN OXT males were quicker to approach their pups than control males but did not differ in vocalizations produced, unlike our previous research demonstrating an effect on vocalizations in females. In summary, during pre-courtship aggression and the paternal care test, IN OXT promoted prosocial approach; however, during the resident intruder test IN OXT did not alter social approach. These data suggest that IN OXT promotes prosocial approach specifically in social contexts that can lead to affiliation.