Changes In Male Behavior Research Articles

The impact of COVID-19 on sexual risk behaviour for HIV acquisition in east Zimbabwe: An observational study.

The Covid-19 pandemic and associated restrictions have the potential to alter sexual risk behaviours for HIV acquisition with important implications for HIV prevention programmes in sub-Saharan Africa. To date, no large-scale data have been published to substantiate hypothesised changes in sexual risk behaviours. We used longitudinal survey data to assess the impact of Covid-19 on sexual risk behaviours in east Zimbabwe. Data on sexual behaviours in HIV-negative adults aged 15-54 years were collected in two rounds of a general population open-cohort survey conducted in Manicaland, Zimbabwe shortly before (July 2018 to December 2019; N = 7316) and several months into the Covid-19 epidemic (February to July 2021; N = 6356). Descriptive statistics and logistic regression models of serial cross-sectional and prospective cohort data were used to assess changes in sexual risk behaviours. The proportion of females aged 15-19 years reporting sexual debut declined from 29.7% before Covid-19 to 20.3% during Covid-19 (adjusted odds ratio (AOR) = 0.49, 95% confidence interval (95% CI), 0.38-0.63). Fewer sexually-active females reported multiple sexual partners during Covid-19 (3.35% versus 6.07%; AOR = 0.55, 95% CI, 0.43-0.72). No population-level changes in male behaviour between survey rounds were recorded but the cohort analysis revealed a complex pattern of behaviour change with HIV risk behaviours increasing for some individuals and decreasing for others. Overall HIV risk behaviours remained high in a sub-Saharan African population with a generalised HIV epidemic over a period of Covid-19 lockdowns when movements and social contacts were restricted.

Peripheral oxytocin injection modulates vomeronasal sensory activity and reduces pup-directed aggression in male mice

Behaviors are shaped by hormones, which may act either by changing brain circuits or by modifying sensory detection of relevant cues. Pup-directed behaviors have been previously shown to change via action of hormones at the brain level. Here, we investigated hormonal control of pup-induced activity in the vomeronasal organ, an olfactory sensory structure involved in the detection of non-volatile chemosignals. Vomeronasal activity decreases as males switch from a pup-aggressive state to a non-aggressive parenting state, after they socially contact a female. RNA sequencing, qPCR, and in situ hybridization were used to identify expression, in the vomeronasal sensory epithelium, of candidate GPCR hormone receptors chosen by in silico analyses and educated guesses. After identifying that oxytocin and vasopressin receptors are expressed in the vomeronasal organ, we injected the corresponding hormones in mice and showed that oxytocin administration reduced both pup-induced vomeronasal activity and aggressive behavior. Conversely, injection of an oxytocin receptor antagonist in female-primed male animals, which normally exhibit reduced vomeronasal activity, significantly increased the number of active vomeronasal neurons. These data link oxytocin to the modulation of olfactory sensory activity, providing a possible mechanism for changes in male behavior after social experience with females.

CONSUMER BEHAVIOR IN RELATION TO COSMETICS

Cosmetics are shown highlighted in trade not only in Brazil, but also worldwide. If previously there was little participation of the male audience in this segment, currently the scenario is different. The change in male behavior, the demands of modern society and the labor market for a better appearance, were the main factors that drove male demand for beauty products and services. The general objective is to understand and analyze male consumer behavior with cosmetics. The methodology used was a bibliographic, exploratory, quantitative research, with male consumers. The survey showed that 58% are concerned with appearance, 73% spend up to R $ 100.00, 55% are concerned with quality, 57% buy from specialized stores, vanity is related to well-being 61% and 48% buy products to take care of the whole body.

The genesis of giants: Behavioral, social, and vocal development of northern elephant seals

To identify the conditions that support the development of hierarchical relationships within networks of familiar competitive rivals, we consider the ontogeny of area use, social relationships, and communicative behavior among male northern elephant seals (Mirounga angustirostris). We cross-sectionally sampled the behavior of 207 males during reproductive development on the breeding colony at Ano Nuevo, CA to determine (1) whether space utilization changes as a function of age, (2) how social relationships vary across different age classes, and (3) the structural development of their ritualized acoustic displays. As males mature, space use within the breeding colony decreases, creating a more predictable social environment in which repeated interactions promote greater connectivity between individuals. Additionally, the vocalizations of sub-adult males transition from highly variable and unstructured to stable adult calls that reliably convey individual identity. The emergence of these acoustic signatures during a profound period of physical development—along with concurrent changes in movement patterns—coincides with the establishment of stable relationships between mature competitors. These findings indicate that ontogenetic changes in male behavior can be important determinants of adult position within structured hierarchies and provide insight into the role of behavioral development in species that exhibit intense competition for access to resources.To identify the conditions that support the development of hierarchical relationships within networks of familiar competitive rivals, we consider the ontogeny of area use, social relationships, and communicative behavior among male northern elephant seals (Mirounga angustirostris). We cross-sectionally sampled the behavior of 207 males during reproductive development on the breeding colony at Ano Nuevo, CA to determine (1) whether space utilization changes as a function of age, (2) how social relationships vary across different age classes, and (3) the structural development of their ritualized acoustic displays. As males mature, space use within the breeding colony decreases, creating a more predictable social environment in which repeated interactions promote greater connectivity between individuals. Additionally, the vocalizations of sub-adult males transition from highly variable and unstructured to stable adult calls that reliably convey individual identity. The emergence of these acoustic signatures...

Reproductive behaviour, testis size and faecal androgen metabolite concentrations in the African lesser bushbaby

AbstractPeriods of reproduction are linked to changes in male behaviour, physiology and physical parameters. Although high androgen concentrations hold numerous advantages, especially during reproductive periods, chronically elevated androgen concentrations over long periods may be costly and thus need to be regulated. As such seasonal breeders will display temporary elevated androgen concentrations, increased testis levels and mating behaviour only during important reproductive periods. We studied a captive as well as a free‐ranging population of the polygamous strepsirrhine primate, the African lesser bushbaby Galago moholi, to clarify the link between androgen concentration, reproductive behaviour and testis size and the importance of the two mating periods observed in the species. To monitor androgen patterns, we used faecal sampling and quantification of faecal androgen metabolites (fAM). We additionally collected testicular measurements and behavioural data. G. moholi displayed a strong degree of reproductive seasonality, with maximum fAM concentration, testicular volume (TV) and behavioural activity focused on the mating periods. In contrast to other studies, TV increased prior to fAM, with reproductive activity being initiated only when fAM concentrations reached high levels. Changes in TV and fAM concentrations were not significantly different between both mating periods. Based on the absence of a significant difference between mating seasons, it is likely that male G. moholi attempt to maximize their reproductive success by utilizing both mating periods equally. This study is the first to describe the reproductive endocrine pattern linked to physical changes and mating behaviour in any galago species, increasing our understanding of the reproductive biology of nocturnal, polygamous primates.

Male Sexual Behavior and Pheromone Emission Is Enhanced by Exposure to Guava Fruit Volatiles in Anastrepha fraterculus.

BackgroundPlant chemicals can affect reproductive strategies of tephritid fruit flies by influencing sex pheromone communication and increasing male mating competitiveness.Objective and MethodologyWe explored whether exposure of Anastrepha fraterculus males to guava fruit volatiles and to a synthetic blend of volatile compounds released by this fruit affects the sexual performance of wild and laboratory flies. By means of bioassays and pheromone collection we investigated the mechanism underlying this phenomenon.ResultsGuava volatile exposure enhanced male mating success and positively affected male calling behavior and pheromone release in laboratory and wild males. Changes in male behavior appear to be particularly important during the initial phase of the sexual activity period, when most of the mating pairs are formed. Exposure of laboratory males to a subset of guava fruit volatiles enhanced mating success, showing that the response to the fruit might be mimicked artificially.ConclusionsVolatiles of guava seem to influence male mating success through an enhancement of chemical and physical signals related to the communication between sexes. This finding has important implications for the management of this pest species through the Sterile Insect Technique. We discuss the possibility of using artificial blends to improve the sexual competitiveness of sterile males.

Age-dependent male mating investment in Drosophila pseudoobscura.

Male mating investment can strongly influence fitness gained from a mating. Yet, male mating investment often changes with age. Life history theory predicts that mating investment should increase with age, and males should become less discriminatory about their mate as they age. Understanding age-dependent changes in male behavior and their effects on fitness is important for understanding how selection acts in age-structured populations. Although the independent effects of male or female age have been studied in many species, how these interact to influence male mating investment and fitness is less well understood. We mated Drosophila pseudoobscura males of five different age classes (4-, 8-, 11-, 15-, 19-day old) to either young (4-day) or old (11-day) females, and measured copulation duration and early post-mating fecundity. Along with their independent effects, we found a strong interaction between the effects of male and female ages on male mating investment and fitness from individual matings. Male mating investment increased with male age, but this increase was more prominent in matings with young females. Male D. pseudoobscura made smaller investments when mating with old females. The level of such discrimination based on female age, however, also changed with male age. Intermediate aged males were most discriminatory, while the youngest and the oldest males did not discriminate between females of different ages. We also found that larger male mating investments resulted in higher fitness payoffs. Our results show that male and female ages interact to form a complex pattern of age-specific male mating investment and fitness.

Burying beetles

Burying beetles

Does the Presence of Women Really Matter? Towards Combating Male Sexual Violence in Peacekeeping Operations

Women are being encouraged to join peacekeeping operations as sexual violence problem-solving forces while simultaneously undertaking a complex role as ‘protectors’ of local women from local men and male peacekeepers. Since the adoption of Security Council resolution 1325 in 2000, the UN has urged states to deploy more women. Among the implicit assumptions underlying these calls are that an increase in the representation of women in peacekeeping operations (PKOs) will lead to a decrease in the cases of HIV/AIDS, a decline in the number of brothels around peacekeeping bases, and a reduction in the number of babies fathered and abandoned by peacekeepers after their mission comes to an end. Evidence suggests that the presence of women peacekeepers can and does foster a change in male behaviour when women are deployed in PKOs. This article argues, however, that countering abuse should not be a substitute for the more encompassing goal of improving gender balance and equality in PKOs. While there is a need to combat sexual violence in PKOs, the responsibility for prevention should be on troop-contributing countries, which need to exercise accountability and prosecute sexual violence committed by their peacekeepers. Diverting responsibility to women does not address the problem of sexual violence in PKOs, or help eradicate its causes.

Are parental care trade‐offs in shorebirds driven by parental investment or sexual selection?

Sexual selection, mating systems and parental behaviour are closely linked, although the exact nature of their relationship is controversial. The parental investment hypothesis (PIH) states that parental care disparity drives sexual selection intensity, because the sex providing less care competes for the sex that provides more. In contrast, the sexual selection hypothesis (SSH) asserts that more intense sexual selection on males leads to reduced male parental investment. We tested these hypotheses using directional phylogenetic comparative methods in shorebirds, which have an unusually diverse array of breeding systems. Changes in parental care and sexual selection intensity were tightly correlated, and we carried out three sets of analyses focusing on changes in male behaviour, female behaviour and in either sex. The results from the analyses were consistent with both PIH and SSH, although the patterns in male transition were sensitive to model values. We propose two explanations for these results. First, phylogenetic transitions may be idiosyncratic so that they depend on the ecological circumstances of individual species. Second, transitions in social traits, such as breeding systems, may be rapid and take place in ecological time, so directional phylogenetic methods that work through longer time scales may not infer accurately the timing and direction of all changes.

MALE COURTSHIP BEHAVIOR IN CERATITIS CAPITATA (DIPTERA: TEPHRITIDAE) THAT HAVE RECEIVED AROMATHERAPY WITH GINGER ROOT OIL

The results of previous studies that showed that exposing mass-reared male Mediterranean fruit flies Ceratitis capitata (Wiedemann) to ginger root oil (aromatherapy) increases the likelihood of mating with wild females were confirmed. The increased male success could be due to female responses to changes in male behavior or male pheromones. There were no significant differences in the types of courtship movements executed by males with and without aromatherapy. The durations of movements also did not differ when mass-reared males were paired with mass-reared females; however, when they were paired with wild females, there were a few, small differences. Previous studies indicated that the effectiveness of the male long-distance attractant pheromone is not affected by aromatherapy, but these studies did not consider pheromones released at close range during courtship, which behavioral analyses suggest may be different. We propose the following possible explanation for the different effects of aromatherapy with different females. Selection on males under mass rearing may have altered their close-range pheromones in ways that can be remedied by aromatherapy; and only wild females respond because the pheromonal responsiveness of mass-reared females has also changed. We propose observations that could test these ideas.

Complicity or Conflict over Sexual Cannibalism? Male Risk Taking in the Praying Mantis Tenodera aridifolia sinensis

Male complicity versus conflict over sexual cannibalism in mantids remains extremely controversial, yet few studies have attempted to establish a causal relationship between risk of cannibalism and male reproductive behavior. We studied male risk-taking behavior in the praying mantid Tenodera aridifolia sinensis by altering the risk imposed by females and measuring changes in male behavior. We show that males were less likely to approach hungrier, more rapacious females, and when they did approach, they moved more slowly, courted with greater intensity, and mounted from a greater distance. Similarly, when forced to approach females head-on, within better view and better reach of females, males also approached more slowly and courted with greater intensity. Thus, males behaved in a manner clearly indicative of risk avoidance, and we support the hypothesis of sexual conflict over sexual cannibalism.

What Hanuman langur males know about female reproductive status

In species with a high risk of infanticide, a conflict of interest exists between the sexes over the amount of paternity information that is available to males. While females are expected to keep males unaware of their reproductive status in order to confuse paternity, selection should favor those male traits that enhance the males' assessment of female status and consequently of paternity probability. In Hanuman langurs (Semnopithecus entellus), a species that is extremely vulnerable to infanticide, females have been shown to successfully conceal the exact timing of ovulation from males--perhaps because they exhibit no sexual swelling and mate during all reproductive phases, including gestation. Nevertheless, it remains unclear whether males have hitherto unrecognized information about females' reproductive condition on a broader level that could still enhance male reproductive success. We investigated male assessment of female reproductive states in a population of wild Hanuman langurs as indicated by changes in male behavior, such as rates of copulations, anogenital inspections, and consortships, in relation to different female receptive periods (pregnant, fertile-nonconceptional, and conceptional). Our data indicate that males were able to discern qualitatively distinct reproductive states. Males were more interested in fertile than pregnant females, as indicated by higher copulation rates. Based on consortships, males distinguished fertile from nonfertile phases, as well as fertile, nonconceptional receptive periods from conceptional ones. Hanuman langur males are thus not as unaware of female reproductive condition as previously thought, supporting the idea of an ongoing battle of the sexes over paternity information. However, granting some knowledge while at the same time concealing the exact day of ovulation may also reflect a pure female strategy of balancing paternity concentration with paternity confusion, which is the most likely strategy in this system with high infanticide risk and male defense of infants.

Complicity or Conflict over Sexual Cannibalism? Male Risk Taking in the Praying Mantis Tenodera aridifolia sinensis

Male complicity versus conflict over sexual cannibalism in mantids remains extremely controversial, yet few studies have attempted to establish a causal relationship between risk of cannibalism and male reproductive behavior. We studied male risk‐taking behavior in the praying mantid Tenodera aridifolia sinensis by altering the risk imposed by females and measuring changes in male behavior. We show that males were less likely to approach hungrier, more rapacious females, and when they did approach, they moved more slowly, courted with greater intensity, and mounted from a greater distance. Similarly, when forced to approach females head‐on, within better view and better reach of females, males also approached more slowly and courted with greater intensity. Thus, males behaved in a manner clearly indicative of risk avoidance, and we support the hypothesis of sexual conflict over sexual cannibalism.

Do female zebra finches (Taeniopygia guttata) copy each other's mate preferences?

We investigated whether female zebra finches (Taeniopygia guttata) would alter their mate preferences after observing the choices of other females. Experimental trials consisted of four 30-min stages: (A) acclimation, (B) observer female chooses between two males, (C) observer female watches a model female interact with her nonpreferred male from stage B, and (D) observer female again chooses between the two males. Control trials were identical except that there was no model female in stage C. Females in both experimental and control trials spent significantly more time with the nonpreferred male in stage D than they had in stage B; thus, our experiment appeared to reveal no evidence of mate choice copying. There was, however, a significant positive relationship between the increase in the time that an observer female in experimental trials spent with her nonpreferred male in stage D and the number of interactions that she had previously observed between the model female and that male in stage C. A second experiment of similar design, where observer females were prevented from observing the model female and nonpreferred male interact in stage B, demonstrated that the behaviour of the observer female in the first experiment was not simply a response to changes in male behaviour in stage D. While our experiment does not support the hypothesis that female zebra finches copy each other's mate preferences, our findings suggest that public information may influence the behaviour of female zebra finches toward potential mates.

Operational sex ratio and resource defence as predictors of the mating system in European bitterling

Operational sex ratio (OSR), the ratio of sexually active males to fertilizable females in a population, plays a central role in the theory of mating systems by predicting that the intensity of male–male competition and the degree of sexual selection increases as the OSR becomes increasingly male biased. At high values of OSR, however, resource defence theory predicts the breakdown of territoriality and a shift towards scramble competition with a decrease in sexual selection. The direction that correlations between OSR and resource competition and variance in mating success will take depends on the biology of the species of interest. We investigated the effects of male population density and male‐biased operational sex ratio on male mating tactics shown by a freshwater fish, the European bitterling, Rhodeus sericeus. This species spawns inside living unioneid mussels. Large males defended territories, were aggressive towards conspecifics under equal sex ratios and monopolized pair spawnings with females. The mating tactic, however, changed at high male density where large males ceased to be territorial and instead competed with groups of smaller males to release sperm when females spawned. This change in male behaviour from pair to group spawning has two ramifications for sexual selection. The intensity of sexual selection and variance in male mating success decrease, and the form of sexual competition changes from resource‐ to sperm competition. Thus, the use of alternative mating tactics renders the OSR unable to predict the direction of resource competition and variance in male mating success at high densities.

Central Vasopressin Administration Regulates the Onset of Facultative Paternal Behavior in Microtus pennsylvanicus (Meadow Voles)

Pharmacological experiments have implicated a role for central arginine vasopressin (AVP) in regulating paternal behavior in monogamous prairie voles. Although nonmonogamous meadow voles exhibit appreciable paternal care when housed under winter, short day lengths (SD), no research has examined whether the same neurobiological systems are involved in regulating paternal behavior in a nonmonogamous species when it behaves paternally. The goal of these experiments was to determine whether central administration of AVP, but not cerebrospinal fluid (CSF), affected the suppression of pup-directed aggression and/or the onset of paternal behavior in meadow voles. Data from experiment 1 implicated a role for AVP in facilitating changes in male behavior: central administration of 1 ng of AVP (but not 3 ng or CSF) inhibited pup-directed aggression in previously pup-aggressive males, and 3 ng of AVP (but not 1 ng or CSF) induced paternal behavior in previously nonpaternal males. In contrast, AVP (1 and 3 ng) did not enhance paternal behavior in already paternal males. Experiment 2 tested the specificity of AVP. Previous research indicated that 24 h of unmated cohabitation with a female reliably induced paternal behavior in SD males. Hence, experiment 2 examined whether administration of a V1a AVP antagonist (AVPA), but not CSF, prior to 24 h of unmated cohabitation would block the onset of paternal behavior. Males that received CSF displayed paternal behavior faster and engaged in more investigatory and paternal behaviors than males that received AVPA. Thus, pharmacological experiments support the hypothesis that AVP likely regulates paternal behavior in both facultatively and consistently paternal vole species.

Male honour and the decline of public violence in eighteenth-century London

In explaining the long-term decline of violence in English society, historians have failed to recognize the importance of changing gender-based conceptions of honour. During the eighteenth century the per capita rate of homicide in London decreased dramatically, and because 93% of homicides were committed by men, this decline essentially involved a change in male behaviour. At the start of the period violence served to enhance or defend men's reputations, and thereby to reinforce their social and gender identities. In order to maintain their honour, most men felt the need to physically challenge anyone who insulted them or questioned their honesty or courage. Such disputes often took the form of duels and other ritualized staged fights and were conducted by men of all social classes. While the violence was limited by accepted rules (violence committed by women, though much rarer, more easily got out of hand), fatalities nonetheless occurred. Over the course of the century, however, these types of disputes became far less common as reputations came to be defined much less publicly in London, and men found new ways of establishing and defending their honour, and thus of asserting gender and social differences. However, private violence, notably wife beating, continued behind closed doors.

Male honour and the decline of public violence in eighteenth-century London

In explaining the long-term decline of violence in English society, historians have failed to recognize the importance of changing gender-based conceptions of honour. During the eighteenth century the per capita rate of homicide in London decreased dramatically, and because 93% of homicides were committed by men, this decline essentially involved a change in male behaviour. At the start of the period violence served to enhance or defend men's reputations, and thereby to reinforce their social and gender identities. In order to maintain their honour, most men felt the need to physically challenge anyone who insulted them or questioned their honesty or courage. Such disputes often took the form of duels and other ritualized staged fights and were conducted by men of all social classes. While the violence was limited by accepted rules (violence committed by women, though much rarer, more easily got out of hand), fatalities nonetheless occurred. Over the course of the century, however, these types of disputes became far less common as reputations came to be defined much less publicly in London, and men found new ways of establishing and defending their honour, and thus of asserting gender and social differences. However, private violence, notably wife beating, continued behind closed doors.

Sexually transmitted parasites and sexual selection in the milkweed leaf beetle, Labidomera clivicollis

Milkweed leaf beetles (MLBs; Labidomera clivicollis Chrysomelidae) are parasitized by a subelytral mite, Chrysomelobia labidomerae (Tarsonemina: Podapolipidae). We show that C. labidomerae is transmitted between MLBs when they copulate, and can reduce the survival of nutritionally stressed beetles. We investigated the effect of this sexually transmitted parasite on mate choice and male‐male competition in MLBs, and the consequences of variation in these behaviours for mite transmission. We found no evidence of parasite avoidance by MLBs, and evidence for high rates of parasitism in the MLB populations we surveyed. In the absence of females, parasitized males contacted unparasitized males more often and for longer than controls, and they tended to displace rival males from females more often than did unparasitized males, a result consistent with the interpretation that parasitized beetles compensate for loss of fitness by increasing reproductive effort. These changes can also benefit mites, because longer and possibly more contacts between beetles provide more opportunities for transmission, but there is no evidence that these changes in male behaviour result from parasite manipulation.