Male Behavior Research Articles

Examination of empathy-like behaviour in nicotine-preferring rat lines

Aim Addiction is an important global health issue, impacting also addicts environment and society. Empathy plays crucial role in establishing successful social relationships and is a fundamental component of social life. The aim of this study is to investigate how nicotine preferring (NP) strain and oral forced nicotine administration affects empathy-like behaviour in rats, with gender differences. Materials and Methods Sprague-Dawley NP rats (10 males/10 females) and wild-type control rats (10 males/10 females) were used. Behavioural tests were administered to all rats before and after oral forced nicotine administration. The behavioural tests were completed in the fourth week of nicotine administration. Anxiety levels that could affect empathy-like behaviour were evaluated with open field, elevated plus maze tests and with blood cortisol levels. Oxytocin receptor and arginine vasopressin (AVP) levels, which have been shown to be related to empathy-like behaviour, were examined in the prefrontal cortex and amygdala regions using the enzyme-linked immunoassay method. Results It was observed that males from the NP strain showed less empathy-like behaviour than all other groups, and nicotine administration did not cause a significant change in the results. Higher levels of locomotor activity (LA) were found in control females than in all other groups. Blood nicotine and corticosterone levels were higher in NP rats. No significant differences were found in AVP and oxytocin receptor levels in the prefrontal cortex and amygdala. Conclusions It was found that coming from an addicted strain particularly reduces empathy-like behaviour in males.

Long-Term Impact of Early-Life Stress on Serotonin Connectivity

BackgroundChronic childhood stress is a prominent risk factor for developing affective disorders, yet mechanisms underlying this association remain unclear. Maintenance of optimal serotonin (5-HT) levels during early postnatal development is critical for the maturation of brain circuits. Understanding the long-lasting effects of early-life stress (ELS) on serotonin-modulated brain connectivity is crucial to develop treatments for affective disorders arising from childhood stress. MethodsUsing a mouse model of chronic developmental stress, we determined the long-lasting consequences of ELS on 5-HT circuits and behavior in females and males. Using FosTRAP mice, we cross-correlated regional c-Fos density to determine brain-wide functional connectivity of the raphe nucleus. We next performed in vivo fiber photometry to establish ELS-induced deficits in 5-HT dynamics and optogenetics to stimulate 5-HT release to improve behavior. ResultsAdult female and male mice exposed to ELS showed heightened anxiety-like behavior. ELS further enhanced susceptibility to acute stress by disrupting the brain-wide functional connectivity of the raphe nucleus and the activity of 5-HT neuron population, in conjunction with increased orbitofrontal cortex (OFC) activity and disrupted 5-HT release in medial OFC. Optogenetic stimulation of 5-HT terminals in the medial OFC elicited an anxiolytic effect in ELS mice in a sex-dependent manner. ConclusionsThese findings suggest a significant disruption in 5-HT–modulated brain connectivity in response to ELS, with implications for sex-dependent vulnerability. The anxiolytic effect of the raphe–medial OFC circuit stimulation has potential implications for developing targeted stimulation-based treatments for affective disorders that arise from early life adversities.

NMDA- and 6-OHDA-induced lesions in the nucleus accumbens differently affect maternal and infanticidal behavior in pup-naïve female and male mice

Virgin and pups-naïve female and male adult mice display two opposite responses when they are exposed to pups for the first time. While females generally take care of the pups, males attack them. Since the nucleus accumbens (NA), and its dopaminergic modulation, is critical in integrating information and processing reward and aversion, we investigated if NMDA- and 6-OHDA-induced lesions, damaging mostly NA output and dopaminergic inputs respectively, affected female maternal behavior (MB) or male infanticidal behavior (IB) in mice. Our results revealed minor or no effects of both smaller and larger NMDA-induced lesions in MB and IB. On the other hand, while 6-OHDA-induced lesions in females reduced the incidence of full MB (12.5% 6-OHDA vs. 85.7% SHAM) increasing the latency to retrieve the pups, those lesions did not affect IB in males. There were no differences in locomotor and exploratory activity between the lesioned- and SHAM- females. Despite those lesions did not induce any major effect on IB, NMDA-lesioned males spent less time in the central area of an open field, while dopaminergic-lesioned males showed reduced number of rearing and peripheral crosses. The current study shows that an intact NA is not necessary for the expression of MB and IB. However, dopaminergic inputs to NA play different role in MB and IB. While damaging dopaminergic terminals into the NA did not affect IB, it clearly delayed the more flexible and rewarding expression of parental behavior.

Gender equity and male and female smoking behavior

AbstractWe document a positive relationship between culturally inherited beliefs about gender equity and female smoking, using data on first and second‐generation immigrants living in the United States. We find that a one standard deviation increase in our measure of gender equity is associated with an increase in the probability that a female immigrant smokes of approximately 1.4 and 1.8 percentage points or 23% and 20% for first and second‐generation immigrants respectively. As male smoking behavior is largely unaffected by gender equality, we find that gender equity tends to reduce the size of the gender gap in smoking.

Influence of kappa-agonist of opioid receptors compound RU-1205 on the generative function of male rats

The effect of a new kappa-opioid agonist benzimidazole derivative (compound RU-1205) on the generative function of outbred male rats was studied after oral administration for 2 months at doses of 5 mg/kg – experimentally proven therapeutic dose (TD) and 500 mg/kg (the highest dose is 100 TD). The absence of a damaging effect of the compound RU-1205 on the motivational sexual behavior of males and the processes of spermatogenesis was established.

Роль норм маскулинности в формировании школьного буллинга

<p><em>The article presents an analytical review of domestic and foreign publications highlighting the problem of school bullying in the context of adolescents’ adherence to the norms of traditional masculinity. It is necessary to consider school bullying through the prism of how gender stereotypes become dangerous for those boys who do not feel a sense of belonging to this large social group due to the fact that they do not fully comply with normative male behavior. Such children will be subject to ridicule and attempts to adjust their behavior to the appropriate norm both from the peers and, probably, from the teachers. Recent studies in several countries show that school bullying affects up to 35% of children. Most often, boys are involved in bullying and practices of physical abuse. Traditional norms of masculinity prescribe them and encourage aggressive, active behavior, competition and the avoidance of weakness and passivity. These standards prohibit boys from being tender, crying, and provoking aggression in response to an attack. Those boys who cannot fight back are bullied by other boys.</em></p>

Neural control of reproduction in reptiles.

Reptiles display considerable diversity in reproductive behavior, making them great models to study the neuroendocrine control of reproductive behavior. Many reptile species are seasonally breeding, such that they become reproductively active during their breeding season and regress to a nonreproductive state during their nonbreeding season, with this transition often prompted by environmental cues. In this review, we will focus on summarizing the neural and neuroendocrine mechanisms controlling reproductive behavior. Three major areas of the brain are involved in reproductive behavior: the preoptic area (POA), amygdala, and ventromedial hypothalamus (VMH). The POA and VMH are sexually dimorphic areas, regulating behaviors in males and females respectively, and all three areas display seasonal plasticity. Lesions to these areas disrupt the onset and maintenance of reproductive behaviors, but the exact roles of these regions vary between sexes and species. Different hormones influence these regions to elicit seasonal transitions. Circulating testosterone (T) and estradiol (E2) peak during the breeding season and their influence on reproduction is well-documented across vertebrates. The conversion of T into E2 and 5α-dihydrotestosterone can also affect behavior. Melatonin and corticosterone have generally inhibitory effects on reproductive behavior, while serotonin and other neurohormones seem to stimulate it. In general, there is relatively little information on the neuroendocrine control of reproduction in reptiles compared to other vertebrate groups. This review highlights areas that should be considered for future areas of research.

Divergent warning patterns influence male and female mating behaviours in a tropical butterfly.

Traits under divergent ecological selection that also function during mating can be important in maintaining species boundaries. Few studies have considered mutual mate choice, where both males and females base mating decisions on the same trait. Wing colouration in Heliconius butterflies evolved as a warning signal but also functions as a mating cue. We investigated the contribution of visual preference to assortative mating in an aposematic butterfly Heliconius cydno in the context of reproductive isolation with its sympatric, visually distinct relative Heliconius melpomene. Heliconius cydno have conspicuous white bands on their forewings, whereas those of H. melpomene are red in colour. We predicted that both sexes of H. cydno contributed to assortative mating by exhibiting visual preference towards conspecific wing colouration. We analysed published and new data from preference experiments, in which males were presented with conspecific and H. melpomene females. We also recorded female responses and mating outcomes in choice experiments, involving conspecific males with either the original white or artificially painted red forewing bands. Both sexes of H. cydno responded more positively towards the conspecific colouration, and males strongly preferred females of its own colours. In contrast, male colouration did not predict mating outcomes in female choice experiments. As courtships are initiated by males in butterflies, our findings suggest that female visual preference might be of secondary importance in H. cydno. Our data also suggest that the contribution of visual preference to reproductive isolation might be unequal between H. cydno and its sympatric relative H. melpomene.

Neuronal Excitability in the Medial Habenula and Ventral Tegmental Area Is Differentially Modulated by Nicotine Dosage and Menthol in a Sex-Specific Manner.

The medial habenula (MHb) has been identified as the limiting factor for nicotine intake and facilitating nicotine withdrawal. However, few studies have assessed MHb neuronal excitability in response to nicotine, and, currently, a gap in knowledge is present for finding behavioral correlates to neuronal excitability in the region. Moreover, no study to date has evaluated sex or nicotine dosage as factors of excitability in the MHb. Here, we utilized an e-vape self-administration (EVSA) model to determine differences between sexes with different nicotine dosages ± menthol. Following this paradigm, we employed patch-clamp electrophysiology to assess key metrics of MHb neuronal excitability in relation to behavioral endpoints. We observed female mice self-administered significantly more than males, regardless of dosage. We also observed a direct correlation between self-administration behavior and MHb excitability with low-dose nicotine + menthol in males. Conversely, a high dose of nicotine ± menthol yields an inverse correlation between excitability and self-administration behavior in males only. In addition, intrinsic excitability in the ventral tegmental area (VTA) does not track with the amount of nicotine self-administered. Rather, they correlate to the active/inactive discrimination of mice. Using fast-scan cyclic voltammetry, we also observed that dopamine release dynamics are linked to reinforcement-related behavior in males and motivation-related behaviors in females. These results point to a sex-specific difference in the activity of the MHb and VTA leading to distinct differences in self-administration behavior. His could lend evidence to clinical observations of smoking and nicotine-use behavior differing between males and females.

Using artificial intelligence to explore sound symbolic expressions of gender in American English.

This study investigates the extent to which gender can be inferred from the phonemes that make up given names and words in American English. Two extreme gradient boosted algorithms were constructed to classify words according to gender, one using a list of the most common given names (N∼1,000) in North America and the other using the Glasgow Norms (N∼5,500), a corpus consisting of nouns, verbs, adjectives, and adverbs which have each been assigned a psycholinguistic score of how they are associated with male or female behaviour. Both models report significant findings, but the model constructed using given names achieves a greater accuracy despite being trained on a smaller dataset suggesting that gender is expressed more robustly in given names than in other word classes. Feature importance was examined to determine which features were contributing to the decision-making process. Feature importance scores revealed a general pattern across both models, but also show that not all word classes express gender the same way. Finally, the models were reconstructed and tested on the opposite dataset to determine whether they were useful in classifying opposite samples. The results showed that the models were not as accurate when classifying opposite samples, suggesting that they are more suited to classifying words of the same class.

Male guarding behavior and brood predators of invasive Bluegill in a Japanese lake

AbstractObjectiveThe Bluegill Lepomis macrochirus, which utilizes colony spawning, has been introduced globally, and in Japan it is considered one of the worst invasive species. However, a detailed examination of the factors driving male guarding behavior and brood predation in the invaded habitat is lacking. The removal of guarding males, a common management technique in Japan, is thought to be effective in controlling Bluegill. However, the colony spawning strategy may influence the effectiveness of selective male removal through brood protection from neighbor males.MethodsBluegill spawning was studied in Lake Nojiri, Nagano, Japan, using underwater video recording and experimental removal of guarding males.ResultBluegill were found spawning in shallow habitat during June–July, and nests were constructed in loosely aggregated colonies, with many solitary nests. Males utilized a variety of guarding behaviors, such as rim circling and predator chases, as well as paternal investment behaviors, such as tail fanning. Males that preyed upon their own eggs defended their nests less aggressively and invested less time in nourishing behaviors. Removal of guarding males revealed that brood predators were primarily conspecific Bluegill, but other fishes, such as invasive Smallmouth Bass Micropterus dolomieu and Largemouth Bass M. nigricans as well as native Japanese Dace Pseudaspius hakonensis, preyed on broods.ConclusionIn concurrence with the colony spawning theory, nests that were located closer to other nests with active guarding males experienced decreased brood predation and increased predator arrival time after male removal. In addition, nests where males had been guarding more aggressively prior to removal experienced reduced brood predation after male removal. These results provide insights into the factors driving male guarding behavior and brood predation of colony‐spawning Bluegill in an invasive habitat and indicate that the removal of guarding males—a common management strategy in Japan—may have reduced effectiveness due to colony spawning.

Early Female Transgender Identity after Prenatal Exposure to Diethylstilbestrol: Report from a French National Diethylstilbestrol (DES) Cohort.

Diagnostic of transsexualism and gender incongruence are terms to describe individuals whose self-identity does not match their sex assignment at birth. A transgender woman is an individual assigned male at birth (AMAB) on the basis of the external or internal genitalia who identifies and lives as a woman. In recent decades, a significant increase in the number of transgender people has been reported. Although, its etiology is unknown, biological, anatomical, genetic, environmental and cultural factors have been suggested to contribute to gender variation. In XY animals, it has been shown that environmental endocrine disruptors, through their anti-androgenic activity, induce a female identity. In this work, we described four XY individuals who were exposed in utero to the xenoestrogen diethylstilbesterol (DES) and were part of the French HHORAGES cohort. They all reported a female transgender identity starting from childhood and adolescence. This high prevalence of male to female transgenderism (1.58%) in our cohort of 253 DES sons suggests that exposure to chemicals with xenoestrogen activity during fetal life may affect the male sex identity and behavior.

Neural mechanisms involved in female mate choice in invertebrates.

Mate choice is a critical decision with direct implications for fitness. Although it has been recognized for over 150 years, our understanding of its underlying mechanisms is still limited. Most studies on mate choice focus on the evolutionary causes of behavior, with less attention given to the physiological and molecular mechanisms involved. This is especially true for invertebrates, where research on mate choice has largely focused on male behavior. This review summarizes the current state of knowledge on the neural, molecular and neurohormonal mechanisms of female choice in invertebrates, including behaviors before, during, and after copulation. We identify areas of research that have not been extensively explored in invertebrates, suggesting potential directions for future investigation. We hope that this review will stimulate further research in this area.

Validation of cyber security behaviour among adolescents at Malaysia university: Revisiting gender as a role

Cyber-attacks and crimes are still a problem in Malaysia. COVID-19 has pushed Malaysians into the digital world more quickly. These cyberattacks may rise and affect more people. Thus, the aim of this study is to find out if there is a significant difference in the level of cyber security behaviour between males and females in the aspects of malware, password usage, phishing, social engineering and online scamming in Malaysia. An online questionnaire survey was used to gather data from Malaysia and received 207 total responses. Cronbach's alpha is used to measure questionnaire items' reliability. A t-test is used to determine the differences between male and female cyber security behaviour. The results show that there is no significant difference between males and females in four aspects out of five, which are malware, password usage, phishing and social engineering. There is a significant difference between males and females in the aspect of online scams. This research helps those who formulate education policies by determining that there is no noticeable gender difference. Men should get the same level of education and training as women. The findings also demonstrate that women's awareness of technology is increasing.

Genetic variants underlying human bisexual behavior are reproductively advantageous.

Because human same-sex sexual behavior (SSB) is heritable and leads to fewer offspring, how SSB-associated alleles have persisted and whether they will remain in human populations are of interest. Using the UK Biobank, we address these questions separately for bisexual behavior (BSB) and exclusive SSB (eSSB) after confirming their genetic distinction. We discover that male BSB is genetically positively correlated with the number of offspring. This unexpected phenomenon is attributable to the horizontal pleiotropy of male risk-taking behavior-associated alleles because male risk-taking behavior is genetically positively correlated with both BSB and the number of offspring and because genetically controlling male risk-taking behavior abolishes the genetic correlation between male BSB and the number of offspring. By contrast, eSSB is genetically negatively correlated with the number of offspring. Our results suggest that male BSB-associated alleles are likely reproductively advantageous, which may explain their past persistence and predict their future maintenance, and that eSSB-associated alleles are likely being selected against at present.

Behavioral verification and risk factors of HIV cross-population transmission in China: analysis of national surveillance data 1989–2022

IntroductionThe dynamic HIV/AIDS epidemic significantly impacts China, particularly affecting injection drug users (IDUs), former plasma donors (FPDs), men who have sex with men (MSM), and those engaging in high-risk heterosexual behavior (HRHB). This study specifically focuses on identifying the risk factors and influences that drive the spread of HIV among these population groups by performing a comprehensive analysis of contact histories of individuals diagnosed with HIV.MethodsData for this research were gathered from China’s HIV/AIDS Comprehensive Response Information Management System (CRIMS). Contact histories were described using bar and venn diagram. Trend in engaging in HBRB among MSM were identify potential change using the Cochran-Armitage test. Logistic regression was employed to analyze the factors influencing HBRB in MSM.ResultsFrom 1989 through to 2022, a total of 1,457,218 individuals aged 15 years or older in China, who reported being infected with HIV, indicated they had one or more types of contact histories including injecting drug use, male homosexual behavior, commercial plasma donation, and high-risk heterosexual behavior. Among these, 97.0% reported a single type of contact history, while 3.0% reported having multiple contact histories. Of those with multiple contact histories, 98.0% (42,258 individuals) had engaged in HRHB. Among all HIV-infected IDUs, MSM, and FPDs, their respective proportions of engagement in HRHB were 11.8%, 5.7% and 6.2%. Prior to 2012, most were reported to be IDUs; however, subsequent to this, most reported being MSM. Factors that heightened the risk of engaging in HRHB among HIV-infected MSM included being of age between 25–34 years [adjusted odds ratio (AOR) = 1.29] or 35–44 years (AOR = 1.22), marital status such as being married (AOR = 1.23) or being divorced/widowed (AOR = 1.17), belonging to an ethnic minority (AOR = 1.29), receiving diagnosis in hospitals (AOR = 1.81), residing in rural areas (AOR = 1.12), among others. However, the risk of HRHB decreased when age ≥ 55 years (55–64 years: AOR = 0.82; ≥ 65 years: AOR = 0.64).ConclusionThe potential for HIV transmission among diverse populations is substantial. As such, it is imperative that strategies are implemented to mitigate the propagation of HIV to the general populace via heterosexual intercourse.

Sex differences in nicotine intake and relapse behavior in nicotine-dependent adult wistar rats.

Tobacco use is highly addictive and the leading cause of premature mortality in the world. Long-access nicotine self-administration procedures in rats closely model human smoking behavior. However, significant gaps remain in our understanding of sex differences in the development of dependence and relapse in adult rats. In the present study, we investigated operant responding for both nicotine and saline and the development of dependence in adult rats of both sexes. The rats had daily access to nicotine or saline for 6h per day, 7days per week. Dependence was assessed by evaluating precipitated and spontaneous somatic withdrawal signs, measuring locomotor activity in the small open field test, and assessing anxiety-like behavior in the large open field and elevated plus maze test. The sucrose preference test was used to determine if cessation of nicotine intake leads to anhedonia. It was also investigated if a period of forced abstinence affects nicotine-seeking behavior. This study showed that nicotine intake is higher in females than in males when given daily long access to nicotine. Daily nicotine self-administration led to more precipitated and spontaneous somatic withdrawal signs compared to saline self-administration, with no sex differences observed. In addition, cessation of nicotine intake led to a similar increase in activity in both males and females in the small open field test. However, cessation of nicotine intake did not increase anxiety-like behavior or cause anhedonia in either males or females. A time course analysis revealed that the nicotinic acetylcholine receptor antagonist mecamylamine affected nicotine intake differently in males and females, increasing intake in males and decreasing intake in females. Three weeks of forced abstinence led to an increase in nicotine and saline-seeking behavior. The rats exhibited more nicotine than saline seeking, and the females displayed more nicotine seeking than the males. The present findings demonstrate that females self-administer more nicotine and display more nicotine-seeking behavior than males. Furthermore, there were no sex differences in somatic withdrawal signs or activity during abstinence from nicotine. This work underscores the importance of considering sex differences across various aspects of addiction, including intake and relapse, when developing novel treatments for tobacco use disorder.

Life in a fishbowl: Space and environmental enrichment affect behaviour of Betta splendens.

The public has expressed growing concern for the well-being of fishes, including popular pet species such as the Siamese fighting fish (Betta splendens). In captivity, male Bettas behave aggressively, often causing injuries and death if housed together. As a result, they are typically isolated in small fishbowls, which has been widely criticised as cruel. To investigate the impact of keeping Bettas in these conditions, we recorded the behaviour of individual males in containers of different sizes that were either bare or enriched with gravel, large rocks, and live plants. When male Bettas were housed individually in small bowls (0.5 L) they spent less time swimming than they did when they were kept in larger aquaria (10, 38, and 208 L). Fish that were kept in enriched containers exhibited more instances of swimming. To determine if two male Bettas housed together might coexist peacefully if given enough space and cover from plants and large rocks, we quantified the behaviour of pairs of male Bettas in bare or enriched aquaria of different sizes (10, 38, 208, 378 L). Fish performed fewer approaches and aggressive displays, but not attacks, and more bouts of foraging, when in larger aquaria. This study shows that the small fishbowls typically used in pet stores suppress swimming behaviour in male Bettas and at least a 10-L aquarium is required to ensure full expression of swimming behaviour. Furthermore, even the use of very large aquaria cannot guarantee peaceful cohabitation between two males.

Phospholipid supplementation inhibits male and female odor discrimination in mice.

Dietary phospholipids (PLs) are promising supplements that are commonly found as natural food ingredients and emulsifier additives. The present study aimed to evaluate the effect of major PLs found in food supplements on social behavior in mice. In this study, the effect of short-term high dietary PL content was studied in terms of social odor discrimination and social interactions with male and female intruders in male mice. We used odor discrimination and habituation tests to demonstrate that PL-fed male mice tend to lose preference toward female odor and fail to discriminate against socially significant scents. At the same time, test animals recognize non-social odors. We also found that PL affected the social behavior of the test males, who tend to behave indiscriminately toward male and female intruders during direct contact. Brain metabolomic profiling revealed no major changes in the intermediary metabolism or neurotransmitter biosynthesis. At the same time, intranasal PL application resembled the effects of dietary supplementation. These data suggest that certain PL might suppress pheromone perception in the olfactory system and affect the sense of socially important odor cues.

Wing mechanics and acoustic communication of a new genus of sylvan katydid (Orthoptera: Tettigoniidae: Pseudophyllinae) from the Central Cordillera cloud forest of Colombia.

Stridulation is used by male katydids to produce sound via the rubbing together of their specialised forewings, either by sustained or interrupted sweeps of the file producing different tones and call structures. There are many species of Orthoptera that remain undescribed and their acoustic signals are unknown. This study aims to measure and quantify the mechanics of wing vibration, sound production and acoustic properties of the hearing system in a new genus of Pseudophyllinae with taxonomic descriptions of two new species. The calling behaviour and wing mechanics of males were measured using micro-scanning laser Doppler vibrometry, microscopy, and ultrasound sensitive equipment. The resonant properties of the acoustic pinnae of the ears were obtained via μ-CT scanning and 3D printed experimentation, and numerical modelling was used to validate the results. Analysis of sound recordings and wing vibrations revealed that the stridulatory areas of the right tegmen exhibit relatively narrow frequency responses and produce narrowband calls between 12 and 20 kHz. As in most Pseudophyllinae, only the right mirror is activated for sound production. The acoustic pinnae of all species were found to provide a broadband increased acoustic gain from ~40-120 kHz by up to 25 dB, peaking at almost 90 kHz which coincides with the echolocation frequency of sympatric bats. The new genus, named Satizabalus n. gen., is here derived as a new polytypic genus from the existing genus Gnathoclita, based on morphological and acoustic evidence from one described (S. sodalis n. comb.) and two new species (S. jorgevargasi n. sp. and S. hauca n. sp.). Unlike most Tettigoniidae, Satizabalus exhibits a particular form of sexual dimorphism whereby the heads and mandibles of the males are greatly enlarged compared to the females. We suggest that Satizabalus is related to the genus Trichotettix, also found in cloud forests in Colombia, and not to Gnathoclita.