Mating Research Articles

The Mating Game: How Gender Still Shapes How We Date

The Mating Game: How Gender Still Shapes How We Date

Phenotypic Mimicry Distinguishes Cues of Mating Competition From Paternal Investment in Men's Conspicuous Consumption.

Evolutionary psychologists propose that men's conspicuous consumption facilitates mate attraction because it predicts resource investment in offspring. This article elaborates on the ultimate functions of men's luxury displays based on Life History Theory. Three studies provide evidence for phenotypic mimicry, in which consumer product features mimicking male secondary sex characteristics indicate investment in mating competition, at the expense of paternal investment. Men owning shirts with larger luxury brand logos were rated higher on mating effort, lower on parental investment, higher on interest in brief sexual affairs, lower on interest in long-term committed romantic relationships, higher in attractiveness to women for brief sexual affairs, lower in attractiveness to women for long-term committed relationships, and higher in developmental environment unpredictability compared with men owning shirts displaying a smaller logo. Participants recognized the strategic use of luxury display properties across social contexts but did not consistently associate product properties with owners' physiological characteristics.

Book Review: The Mating Game: How Gender Still Shapes How We Date by Ellen Lamont

Book Review: <i>The Mating Game: How Gender Still Shapes How We Date</i> by Ellen Lamont

Effects of seasonal variation on the biology and morphology of the dusky cotton bug, Oxcarenus laetus (Kirby).

The dusky cotton bug (Oxycarenus laetus, KIRBY) a pest of several crops. The effects of winter and summer on the biology and morphology was investigated. The sampled eggs of dusky cotton bug (DCB) were kept under controlled environment for biological and morphological investigations. In winter, the mating duration of DCB was observed longer significantly (74.2 days), egg development period (3.93 days), an egg laying period (3.6 days) and hatching period (6.66 days) noted longer in winter season. Interestingly, average number of hatched egg (16.8 days) observed significantly higher in summer and the percentage of the hatching of eggs (81.95%) were also observed higher in summer as compare to winter. Whereas, the longevity of all nymph stages in winter longer days as compare to summer nymph stages. Moreover, differences were also observed between male and female development days between winter and summer. In the winter, female DCB development was suggestively higher as compare to summer (24 days). Whereas, the developmental days were noted considerably more in winter for males as compare to summer (14.93 days). On other hand, for morphological parameters, no differences were observed between winter and summer population of DCB.

Oxidative stress and the differential expression of traits associated with mating effort in humans

Oxidative stress is a physiological condition in which reactive oxygen species created through cellular respiration can potentially damage DNA and tissue. Oxidative stress may partially mediate trade-offs between reproductive effort and survival efforts. On the one hand, traits associated with reproductive effort, particularly costly male-male competition, are expected to raise oxidative stress. On the other hand, behavioral strategies may be a critical mediating mechanism, such that those who can better resist the physiological costs of oxidative damage exhibit increased mating effort. In a sample of 248 college students (173 men), we examined the associations between traits linked to mating effort—including personality features, athleticism, and history of illness—with levels of 8-OHdG, a biomarker of oxidative stress. 8-OHdG was measured twice, one week apart, once during active hours and once at awakening. In men, surgency, social dominance, and athleticism were all negatively associated with 8-OHdG levels in awakening, but not lab samples collected during active hours. In women, these same traits were positively associated with 8-OHdG levels, particularly in morning samples. Differences in associations based on sex and time of collection introduce additional complexities to understanding links between oxidative stress and mating effort.

A single GnRH challenge promotes paternal care, changing nestling growth for one day

Decades of comparative and experimental work suggest that testosterone (T) promotes mating effort at the expense of parental effort in many vertebrates. There is abundant evidence that T-mediated trade-offs span both evolutionary and seasonal timescales, as T is often higher in species or breeding stages with greater mating competition and lower in association with parental effort. However, it is less clear whether transient elevations in T within a male's own reactive scope can affect parental effort in the same way, with effects that are visible to natural selection. Here, we injected free-living male tree swallows (Tachycineta bicolor) with gonadotropin-releasing hormone (GnRH), thus temporarily maximizing T production within an individual's own limit. Passive loggers at each nest showed that GnRH-injected males provisioned more frequently than saline males for the subsequent day, and their offspring gained more mass during that time. The degree of offspring growth was positively correlated with the father's degree of T elevation, but provisioning was not proportional to changes in T, and GnRH- and saline-injected males did not differ in corticosterone secretion. These results suggest that prior knowledge of T-mediated trade-offs garnered from seasonal, evolutionary, and experimental research cannot necessarily be generalized to the timescale of transient fluctuations in T secretion within an individual. Instead, we propose that GnRH-induced T fluctuations may not result in visible trade-offs if selection has already sculpted an individual male's reactive scope based on his ability to handle the competing demands of mating and parental care.

Ineffective nuptial gifts suggest female emancipation from sensory exploitation

Male sensory exploitation of female gustatory pre-existing bias has been proposed for the origin of nuptial gifts in insects and spiders. This sexual trait may have been beneficial to both sexes, giving mating and survival advantages to males and providing nutritional resources for females. However, the evolution of deceptive worthless gifts is against females’ interests and may trigger a co-evolutionary change in females’ preferences. We evaluated females’ preferences for nuptial gifts and the adaptive function of the gift in the spider Trechaleoides keyserlingi. The genus belongs to the understudied Neotropical family Trechaleidae in which nuptial gifts are widespread. The family is composed of only two species, and the gift seems to be absent in the sister species, creating a relevant scenario for understanding co-evolutionary processes. In the laboratory, we found that although males invested more in nuptial gifts when encountering mated females compared to unmated, they had similar mating access and duration than males lacking a gift. We also found an absence of female choice between males offering nutritive and worthless gifts. Few females were aggressive and cannibalized males, and we did not find evidence that the gift protected males from cannibalism. In the field, 50% of the gifts were worthless items. This is congruent with the laboratory findings where males offering worthless gifts seem to better attract females, which we discuss in the context of exploitation of female gustatory bias. We therefore propose that females may have evolved indifference for the gift and that gift-giving in this species represents a currently non-functional remnant of a behaviour. Nutritive nuptial gifts can exploit female gustatory preferences, with mutual benefits for both sexes: males can increase mating success and survival, while females increase their fecundity. But males can offer worthless gifts leading females to suboptimal matings, and in turn females can evolve indifference for the trait. The spider genus Trechaleoides is ideal to examine this process because gift-giving behaviour is present in one species and absent in the other. We examined females’ preferences for nuptial gifts and its function for males in the gift-giving species T. keyserlingi. We found that males invest in a gift but gain no reproductive advantage, as females were equally likely to mate with them regardless of whether they offered a gift or whether the gift was nutritive or worthless. We propose that females may have changed their preferences and that the gift is a remnant non-functional trait.

C. elegans spermatozoa lacking spe-45 are incapable of fusing with the oocyte plasma membrane.

C. elegans spe-9 class genes encode sperm proteins with indispensable roles during fertilization. We have previously reported that spe-45 belongs to the spe-9 class, based on the finding that self-sperm of spe-45(tm3715) hermaphrodites were not consumed by fertilization. In this study, we directly observed live fertilization in the spermatheca of fem-1(hc17) females after mating with spe-45(tm3715) males. As expected, it was clearly shown that spe-45 mutant spermatozoa failed to fuse with the oocyte plasma membrane. Thus, our live imaging system for C. elegans fertilization seems to be useful for evaluation of the functions of male and female gametes.

Involuntary singlehood and its causes: The effects of flirting capacity, mating effort, choosiness and capacity to perceive signals of interest

A considerable proportion of the population is involuntarily single; that is, they want to be in an intimate relationship but they face difficulties in doing so. The current paper attempted to assess some possible predictors of this phenomenon. More specifically, in a sample of 1228 Greek-speaking women and men, we found that participants who scored low in flirting capacity, capacity to perceive signals of interest and mating effort, were more likely to be involuntarily single than in an intimate relationship, and experienced longer spells of singlehood. Mating effort had also a significant effect on voluntary singlehood, with low scorers being more likely to be in this category than high scorers. Choosiness had also a significant effect, but only on voluntary singlehood, with high scorers being more likely to prefer to be single than low scorers.

Gamma Ray Radiation Effects Emitted from Am-241 on Some Physiological Cases of Adult Rats

In this search we found the effect of 0.06.0.1 and 0.4 mGy / h gamma rays as radiation doses for 55 days at h /7 day irradiation in certain physiological cases as the sex ratio of adult rats. Major reductions in the total number of offspring were observed (p ˂0.05). female and male sex ratio when exposed to 0.06-0.4 mGy / h doses when compared to control group. Another argument, the effects of gamma radiation with the above dose levels and with the same mating showed substantial increases (p ˂0.05) in the number of female offspring and their sexual ratio. This rise is directly proportional to the increase in doses. This paper also revealed major differences in the sex ratio of male and female rats. The ratio of female offspring to gamma radiation was greater than the ratio of male offspring to control .The exposure of any source with frequency greater than GHz. and wave length in (10-10 meters) must therefore be avoided during gestations.

Male Sexual Preference for Female Swimming Activity in the Guppy (Poecilia reticulata).

Simple SummaryIn our first experiment, we found that male and female guppies differ consistently in their swimming activity, both when alone and when together in heterosexual pairs, and that males, regardless of their own activity, show more sexual behaviours to more active females in these pairs. In the second experiment, we gave males the choice between a slow and a fast-moving virtual female and found that males prefer to associate with the fast-moving female. Both experiments together provide evidence that guppy males prefer faster moving females as mating partners over slower moving ones. Higher activity patterns may indicate health, fitness and receptivity and a mating preference for more active females can help males increase their own reproductive success.Mate choice that is based on behavioural traits is a common feature in the animal kingdom. Using the Trinidadian guppy, a species with mutual mate choice, we investigated whether males use female swimming activity—a behavioural trait known to differ consistently among individuals in many species—as a trait relevant for their mate choice. In the first experiment, we assessed male and female activity in an open field test alone (two repeated measures) and afterwards in heterosexual pairs (two repeated measures). In these pairs, we simultaneously assessed males’ mating efforts by counting the number of sexual behaviours (courtship displays and copulations). Male and female guppies showed consistent individual differences in their swimming activity when tested both alone and in a pair, and these differences were maintained across both test situations. When controlling for male swimming behaviour and both male and female body size, males performed more courtship displays towards females with higher swimming activity. In a second experiment, we tested for a directional male preference for swimming activity by presenting males video animations of low- and high-active females in a dichotomous choice test. In congruence with experiment 1, we found males to spend significantly more time in association with the high-active female stimulus. Both experiments thus point towards a directional male preference for higher activity levels in females. We discuss the adaptive significance of this preference as activity patterns might indicate individual female quality, health or reproductive state while, mechanistically, females that are more active might be more detectable to males as well.

A Cinderella effect in the childcare assistance provided by European grandparents

Survey data from 36,771 European grandparents were analyzed with respect to childcare assistance that interviewees provided to their birth children versus stepchildren. Interviewees with current partners provided far more such assistance to adult children who were the progeny of both partners than to those who were stepchildren of either one's self or one's partner, but both husband and wife helped the wife's children from prior unions more than they helped the husband's children, supporting the interpretation of stepfathers' involvement as primarily an investment in the new partnership (“mating effort”) rather than in the grandchildren. Interviewees resided farther away from their adult stepchildren than from their birth children, on average, but discriminative care did not depend merely on residential proximity, being substantial regardless of whether proximity was statistically controlled. Grandmothers without current partners exhibited the greatest discrimination, with stepchild: birth child Odds Ratios of 0.10 or less in various analyses, whereas grandfathers without partners exhibited no significant discrimination. Interviewees of both sexes listed far more stepchildren, proportionately, if they had a current partner than if they were either widowed or divorced, however, which suggests that single respondents may have omitted former stepchildren with whom they had ceased to interact from their list of children, and hence that the degree to which single grandparents divest from them may be even larger than estimated.

Activity budget of zoo-housed Dolichotis patagonum mates

Captive conditions differ widely from an animal’s natural environment and risk making them prone to reduced behavioural flexibility and sometimes impaired reproduction. The Patagonian mara Dolichotis patagonum, a near threatened species, is a large rodent endemic to Argentina with a singular social organisation that combines monogamy with communal breeding. The aim of this study was to learn more about the activity budget and behavioural synchrony between mates of zoo-housed D. patagonum and thus contribute to research and conservation programmes at modern zoos worldwide. The study implicated 28 animals housed at Cordoba Zoo (Argentina) under natural photoperiod and temperature conditions. Behaviour was recorded once a week every hour from 0800–1800 for a 28-day period and the total offspring at the end of the spring-summer season were counted. The recorded activity budget was: resting (43%), feeding (25%) and alert (13%), the remaining categories accounting for less than 10%. Resting, feeding and alert were the only categories associated with hourly changes. There was 48% behavioural synchrony between mates (both sexes engaging in the same behaviour at the same time) and a total of 23 offspring were counted, corresponding to one litter each reproducing female. The similarity between the behavioural response of these zoo-housed individuals and available data on the behaviour of D. patagonum in the wild indicates that zoo-housed D. patagonum behavioural activities can be considered positive responses, providing useful information for the future development of reintroduction programmes.

Do captive golden mantella frogs recognise wild conspecifics calls? Responses to the playback of captive and wild calls

With so many species being threatened with extinction, captive breeding programmes are becoming an important aspect of ex-situ conservation. Captive populations are important for species conservation and for reintroduction back into the wild. Some of the most important wild behaviours to maintain in captive animals are those associated with sexual reproduction, such as courtship and mating. Amphibian reproductive behaviour is associated with call patterns, with studies demonstrating that male advertisement calls elicit positive behavioural responses from females. This study evaluated the response of captive golden mantella frogs Mantella aurantiaca to playback calls from different wild and captive populations (one generation in captivity and more than five generations in captivity). During the experiment, three different calls were used as treatments: one from wild populations, and two from captive populations. Generalised linear mixed models were used to evaluate the effects of the playback treatments on the behaviour of captive frogs: replicates and enclosures were used as random factors. The model showed that vocalisations from wild individuals led to an increase in movement and social behaviours while calls from captive frogs did not. This was especially true of frogs bred for more than five generations in captivity. This could have negative consequences on the reproduction of captive frogs if released to the wild.

Trade-offs between fighting and breeding: a social network analysis of bison male interactions.

In most polygynous species, males compete for access to females using agonistic interactions to establish dominance hierarchies. Typically, larger and stronger males become more dominant and thus gain higher mating and reproductive success over subordinate males. However, there is an inherent trade-off between time and energy invested in dominance interactions versus courtship and mating activities. Individuals may overcome this trade-off by selectively engaging in more effective mating tactics. North American bison (Bison bison) are a species of conservation concern that exhibit female-defense polygyny with two predominant mating tactics: (1) tending individual females; or (2) challenging tending males as a satellite and then mating opportunistically. Here, we use social network analysis to examine the relationship between position in the agonistic interaction network of bison males and their mating, reproductive success, and reproductive tactics and effort. To assess the potential for social network analysis to generate new insights, we compare male (node) centrality in the interaction network with traditional David’s score and Elo-rating dominance rankings. Local and global node centrality and dominance rankings were positively associated with prime-aged, heavy males with the most mating success and offspring sired. These males invested more effort in the “tending” tactic versus the “satellite” tactic, and they tended more females for longer periods during peak rut, when most females were receptive. By engaging in the most effective mating tactic, dominant males may mitigate the trade-off between allocating time and energy to agonistic interactions that establish dominance, versus courtship and mating. While less dominant males participated more in the alternative mating tactic, network analysis demonstrated that they were still important to the interaction network on both a local and global scale.

Female ornaments: is red skin color attractive to males and related to condition in rhesus macaques?

Sexual selection produces extravagant male traits, such as colorful ornaments, via female mate choice. More rarely, in mating systems in which males allocate mating effort between multiple females, female ornaments may evolve via male mate choice. Females of many anthropoid primates exhibit ornaments that indicate intraindividual cyclical fertility, but which have also been proposed to function as interindividual quality signals. Rhesus macaque females are one such species, exhibiting cyclical facial color variation that indicates ovulatory status, but in which the function of interindividual variation is unknown. We collected digital images of the faces of 32 rhesus macaque adult females. We assessed mating rates, and consortship by males, according to female face coloration. We also assessed whether female coloration was linked to physical (skinfold fat, body mass index) or physiological (fecal glucocorticoid metabolite [fGCM], urinary C-peptide concentrations) condition. We found that redder-faced females were mated more frequently, and consorted for longer periods by top-ranked males. Redder females had higher fGCM concentrations, perhaps related to their increased mating activity and consequent energy mobilization, and blood flow. Prior analyses have shown that female facial redness is a heritable trait, and that redder-faced females have higher annual fecundity, while other evidence suggests that color expression is likely to be a signal rather than a cue. Collectively, the available evidence suggests that female coloration has evolved at least in part via male mate choice. Its evolution as a sexually selected ornament attractive to males is probably attributable to the high female reproductive synchrony found in this species.

Modest Exercise-Induced Increases in Testosterone Concentration Are Not Associated with Mating Strategy Change in Healthy Young Men

Research has demonstrated that increases in testosterone (T) concentration can affect the expression of behaviours and preferences that are typical of high mating effort. However, little research has considered whether such T increases affect mating strategy more generally and whether this is achievable using a physical intervention. In this pilot study, we examined whether exercise-induced changes in T covary with, or predict, changes in male mating strategy. Healthy young men (N = 94) completed a measure of short- and long-term relationship preference, before and after a series of short cycling sprints. Salivary T was measured pre- and post-exercise, along with salivary cortisol (C), which is known to moderate some behavioural effects of T. A significant group-level increase in T was observed, though this was smaller than anticipated (~ 10%, d = 0.27) with substantial intragroup variation. No group-level change in C or mating preferences emerged. Testosterone change did not significantly predict a change in short- or long-term mating preference from baseline, even with inclusion of C change as a moderator. The current findings suggest that modest exercise-induced increases in T concentration have little impact on male mating strategies. Pharmaceutical interventions, which produce larger and more consistent T increases, may be required to observe mating strategy change.

Does mate preference represent mate choice? A cross-cultural investigation.

Does mate preference represent mate choice? A cross-cultural investigation.

Reproductive success in Zygogramma bicolorata: A role of post-insemination association of male and female.

Reproductive success is attained by various mechanisms in insects. Prolonged post insemination association is one such mechanism to increase the reproductive success. The present study was conducted to assess the role of post insemination association of mating partners on reproductive performance in Chrysomelidae beetle, Zygogramma bicolorata Pallister. The matings were disrupted at different time intervals and fecundity and percent egg viability of the females were recorded. In addition, the mounting attempts, mating attempts, time to commencement of mating and latent period were also recorded. It was hypothesized that: (1) the mounting and mating attempts would not exist, (2) copulation duration, would not affect the reproductive performance, and (3) the beetle would not exhibit the mate guarding behaviour. Interestingly, results revealed that 6.00 ± 1.3 and 6.59 ± 0.93 mounting and mating attempts are needed to establish successful mating. The results revealed that males improved their percent egg viability with a mating duration ranging from nearly 30–50 min. While fecundity increased with a mating duration of above 30 min and up to a duration of 60 min. This result concluded that males of this beetle display post copulatory mate guarding behaviour after 60 min in which male rides on female’s back with his aedeagus inserted in the female genital tract.

In memoriam: Dr. Fernando Bonadeo Lassalle

On August 20, Fernando died at home surrounded by his wife and lifetime mate, his children, and his grandchildren. The ongoing pandemic prevented deeply shocked friends and colleagues from saying goodbye to him in the HI Chapel, as it should have been, and from accompanying his remains to his grave.