Mating Research Articles

Het Atlantis van de Middelnederlandse ridderepiek : Een schatting van het tekstverlies met methodes uit de ecodiversiteit

It is well known that the study of historical literature is impeded by the incom- plete transmission of sources: due to a century-long loss of sources, inevitably, a large number of texts is no longer known to us. As such, our current perspective on the literary diversity of the past is probably underestimating the actual wealth of texts that once existed. Statistical methods from eco-diversity can assist us in adjusting this esti- mate in a quantitative and precise manner. Applied to Middle Dutch chivalric epics, these methods suggest that prior estimates of text loss may be too conservative: the methods estimate that up to half of the original texts have been lost (and possibly many more).

Observations of the mating behavior of Portunus trituberculatus and the role of shelters in its mating process

In this study, the mating behavior of Portunus trituberculatus under indoor conditions and the role of shelters in its mating process were systematically studied by using behavioral observation methods. The results showed that the mating behavior of P. trituberculatus was divided into four stages: courtship and pre-copulatory guarding, reproductive moulting, copulation, and post-copulatory guarding. P. trituberculatus in the no shelter group (NSG) usually preferred to gather at the edges or corners of the cement tank, while P. trituberculatus in the shelter group (SG) preferred to hide in the shelters. During the whole experiment, the shelter occupancy rate of P. trituberculatus during the day (57.40%) was significantly higher than that at night (38.08%) (P < 0.05). In terms of hiding rate, the hiding rate was as high as 63.32% during the day, which was significantly higher than that at night (37.70%) (P < 0.05). The copulation time of the SG was similar to that of the NSG. However, the durations of the pre-copulatory guarding period and post-copulatory guarding period of the SG were shorter than those of the NSG, indicating that the presence of shelters could shorten the total mating duration of P. trituberculatus. P. trituberculatus provided with shelter did not hinder its mating behavior, and there was little difference in mating rate between NSG and SG, which were 100% and 97.22%, respectively. In addition, we found that there was certain cannibalism during the reproductive moulting of female crabs, which could lead to the death or injury of some individuals. However, the survival rate of the SG (89.58%) was significantly higher than that of the NSG (72.92%) (P < 0.05). Moreover, the injury rate in the SG was only 14.13%, which was significantly lower than that in the NSG (31.31%) (P < 0.05). In general, shelters have the capability of appealing to P. trituberculatus during mating and can effectively reduce the incidence of intraspecific cannibalism during mating and improve the survival rate of P. trituberculatus.

Efecto de la duración de cópula en la respuesta ovulatoria y tasa de preñez en alpacas

An experiment was carried out at the Experimental Center La Raya-Universidad Nacional del Altiplano Puno, to determine the effect of copulation duration on ovulation and pregnancy in alpacas. 47 adult females were used (postpartum time ≥ 20 days and presence of a follicle ≥ 7 mm) distributed in three groups, according to copulation time: 20, 35 and 50 min, for G1 (n = 15), G2 (n = 16) and G3 (n = 16), respectively. For the mating, 6 reproducers of proven fertility were used, interrupting the copulation at the established time. Ovulation and pregnancy rates were evaluated on days 7 and 30 post service respectively (by ultrasound and receptivity of the female), the data were analyzed using X2 and simple correspondence. Both the ovulation rate (G1: 73.33%, G2: 81.25% and G3: 81.25%); and pregnancy (G1: 53.33%, G2: 81.25% and G3: 75%) were not different (P&gt; 0.05). Pregnancy rates between G1 and G2 tended to be different (P &lt;0.10), consistent with the simple correspondence analysis. Despite there being no differences in ovulation and pregnancy rates, there was a higher percentage trend in G2 and G3, suggesting that the longer duration of mating would have some positive effect on them, according to the simple correspondence analysis, and the trend of low significance (P &lt;0.10) in favor of pregnancy in G2 compared to G1. In conclusion, there were no significant differences in the effect of copulation duration on ovulation; however, there was a 90% trend for the difference between mating duration of 35 minutes versus 20 minutes (in pregnancy).

Manipulating mate-choice for a quantitative augmentation of a biological control agent, Coccinella transversalis Fabricius

For food security and sustainable crop protection, it is a necessity to optimize the massrearing and augmentation of biocontrol agents of numerous aphid pests. Coccinellids, commonly known as ladybird beetles, are potential predators on several sucking pests and promising biocontrol agents. In the present investigation, laboratory experiments were performed to find out whether manipulation of mate choice in aphidophagous ladybird Coccinella transversalis Fabricius (Coleoptera: Coccinellidae) under varying mating status could influence reproductive output in terms of high fecundity. It was found that the mating status under the mate choice highly affects mating duration and fecundity. The mating commenced earlier under the presence of different males than the females in an arena. The mating lasted for a longer duration between virgin females and multi-mated males than vice-versa. The bouts in copula increased with an increase in the mating status in both sexes. Females of multi-mated status were more fecund than the unmated females. Thus, the present study will be useful for the manipulation of quantitative mass-rearing of C. transversalis for the biocontrol of aphids and thereby enhancing crop productivity and sustainable crop protection.

Mate-guarding duration is mainly influenced by the risk of sperm competition and not by female quality in a golden orb-weaver spider.

Males are expected to mate with as many females as possible, but can maximize their reproductive success through strategic mating decisions. For instance, males can increase their own fitness by mating with high quality females that produce more offspring. Additionally, males can adjust mating effort based on the relative distribution of females and male competitors. To test factors that influence male mate choice, we assessed male mating decisions in the golden silk orb-weaver spider, Trichonephila clavipes (Nephilidae), a species in which females are polyandrous, males guard females before and after copulation occurs and large males are the most successful at guarding mates. We tested the hypothesis that males spend more time guarding high quality females that are spatially isolated, and when the risk of sperm competition is higher. We also hypothesized that this effect increases with male body size. We assessed solitary and aggregated female webs in the field and quantified female quality (i.e., female body condition), male size (i.e., male body size), the risk of sperm competition (i.e., number of males in each female web), and mate-guarding duration (i.e., number of days each male spent in each web). We found that mate-guarding behaviour is largely influenced by the presence of male competitors. In addition, male body size seems to moderately influence male guarding decisions, with larger males guarding for a longer time. Finally, female body condition and type of web (i.e., solitary or aggregated) seem to play small roles in mate-guarding behaviour. As mate-guarding duration increased by 0.718 day per each additional male competitor in the web, and guarding behaviour prevents males from seeking additional mates, it seems that guarding females can be considerably costly. We conclude that failing to guard a sexual partner promotes high costs derived from sperm competition, and a male cannot recover his relative loss in fertilization success by seeking and fertilizing more females. In addition, the search for more sexual partners can be constrained by possible high costs imposed by weight loss and fights against other males, which may explain why the type of web only moderately influenced male mate choice. Following the same rationale, if high-quality females are not easy to find and/or mating with a high-quality female demands much effort, males may search females and guard them regardless of female quality. In conclusion, the factor that most influences male mate-guarding behaviour among T. clavipes in the field is the risk of sperm competition.

Roles of P300 and Late Positive Potential in Initial Romantic Attraction.

Initial romantic attraction (IRA) refers to a series of positive reactions to potential romantic partners at the initial encounter; it evolved to promote mate selection, allowing individuals to focus their mating efforts on their preferred potential mates. After decades of effort, we now have a deeper understanding of the evolutionary value and dominant factors of IRA; however, little is known regarding the brain mechanisms related to its generation and evaluation. In this study, we combined classic event-related potential analysis with dipole-source analysis to examine electroencephalogram (EEG) signals generated while participants assessed their romantic interest in potential partners. The EEG signals were categorized into IRA-engendered and unengendered conditions based on behavioral indicators. We found that the faces elicited multiple late positivities, including P300 over the occipital–parietal regions and late positive potentials (LPPs) over the anterior regions. When compared to faces that did not engender IRA, faces that did engender IRA elicited (1) enhanced P300 over the parietal regions and heightened neural activity in the insula and cingulate cortex and (2) larger LPPs over the anterior regions and heightened neural activity in the orbitofrontal cortex, dorsolateral prefrontal cortex, cingulate cortex, frontal eye field, visual cortex, and insula. These results suggest IRA is generated and evaluated by an extensive brain network involved in emotion processing, attention control, and social evaluations. Furthermore, these findings indicate that P300 and LPP may represent different cognitive processes during IRA.

Mate guarding in primates arises due to partner scarcity, even if the father provides no paternal care at all

Paternal care is unusual among primates; in most species males compete with one another for the acquisition of mates and leave the raising of offspring to the mothers. Callitrichids defy this trend with both fathers and older siblings contributing to the care of offspring. We extend a two-strategy population model (paternal care versus male–male competition) to account for various mechanisms that could possibly explain why male callitrichids invest in paternal care over male–male competition, and compare results from callitrichid, chimpanzee and hunter-gatherer life history parameters. The survival benefit to offspring due to care is an insufficient explanation of callitrichid paternal care, and the additional inclusion of differences in lactation-related biology similarly do not change that picture. Instead, paternal care may arise in parallel with, or even as a result of, mate guarding, which in turn is only beneficial when partners are scarce as modelled by the birth sex ratio in callitrichids and menopause in hunter-gatherers. In that situation, care need not even provide any benefit to the young (in the form of a survival bonus) for guarding to out-compete multiple mating competition.

Males from multiple colonies improve queen mating success in the bumblebee Bombus lantschouensis (Hymenoptera: Apidae)

Mating is an important process in bumblebees that could affect queen diapause survival and offspring reproduction. Both queens and males could influence mating failure. Here, we used the indigenous bumblebee Bombus lantschouensis to evaluate the mating interactions of males and gynes. The effects of kin recognition and males and gynes from multiple colonies on mating latency, mating duration, and the mating success rate were investigated. The results showed that gynes mated with related males had a longer mating latency than those mated with unrelated males (42.88 ± 3.8 min and 24.15 ± 2.5 min, respectively, P < 0.05) and that the mating success rate was significantly higher in unrelated groups than in related groups (49.29 ± 4.1% and 36.74 ± 2.6%, respectively, P < 0.05). However, no preference for related or unrelated males was observed in the mixed mating groups (mating success rate 30.63 ± 3.1% and 30.73 ± 2.4%, respectively, P > 0.05). Interestingly, the occurrence of males from multiple sources significantly increased the mating success rate (one colony 39.1 ± 4.2% to four colonies 60.05 ± 5.7%, P < 0.05). Nonetheless, an increase in the number of gyne sources had no effect on the mating success rate (one colony 39.50 ± 4.9% to four colonies 43.52 ± 5.7%, P > 0.05). Mating latency was significantly more influenced by males and gynes from multiple colonies than by kin relationship, male number, and gyne number (P < 0.05). In conclusion, there is no evidence that the bumblebee B. lantschouensis can recognize kin relationships before mating. The presence of males and gynes from multiple colonies can influence mating latency. Moreover, males from multiple colonies can significantly enhance mating success, which has implications for bumblebee ecological conservation and artificial mass rearing.

Genomic evidence consistent with antagonistic pleiotropy may help explain the evolutionary maintenance of same-sex sexual behaviour in humans.

Human same-sex sexual behaviour (SSB) is heritable, confers no immediately obvious direct reproductive or survival benefit and can divert mating effort from reproductive opportunities. This presents a Darwinian paradox: why has SSB been maintained despite apparent selection against it? We show that genetic effects associated with SSB may, in individuals who only engage in opposite-sex sexual behaviour (OSB individuals), confer a mating advantage. Using results from a recent genome-wide association study of SSB and a new genome-wide association study on number of opposite-sex sexual partners in 358,426 individuals, we show that, among OSB individuals, genetic effects associated with SSB are associated with having more opposite-sex sexual partners. Computer simulations suggest that such a mating advantage for alleles associated with SSB could help explain how it has been evolutionarily maintained. Caveats include the cultural specificity of our UK and US samples, the societal regulation of sexual behaviour in these populations, the difficulty of measuring mating success and the fact that measured variants capture a minority of the total genetic variation in the traits.

Long-term mating positively predicts both reproductive fitness and parental investment

Empirical data on the relations between mating and reproductive success are rare for humans, especially for industrial and post-industrial populations. Existing data show that mating (and especially long-term mating) can be beneficial for fitness, especially that of males. This finding is in line with the hypothesis of sexual selection operating in human populations. The present research expands on previous studies by: 1) analysing additional fitness indicators, including having children with different partners; 2) including parental investment in the analysis as another important marker of sexual selection; 3) analysing several mediators between mating, reproductive fitness and parental investment, i.e. age of first and last reproduction and desired number of children. The data were obtained in 2019 from a sample of parents living in Serbia (N=497). The findings showed that long-term mating (duration of longest partner relationship) was positively related to parental investment and number of offspring and grand-offspring. Furthermore, the link between long-term mating and reproductive success was completely mediated by the age of first reproduction and desired number of children. Short-term mating (number of sexual partners) was marginally positively related to the number of children participants had with different partners and negatively related to parental investment. No sex differences in the link between mating, fitness and parental investment were detected. In general, the signatures of sexual selection were weak in the present data, but those that were detected were in line with sexual selection theory. The present findings provide a deeper insight into the adaptive function of mating and also the mechanism of how mating is beneficial for fitness.

Quantifying the costs of pre- and postcopulatory traits for males: Evidence that costs of ejaculation are minor relative to mating effort.

Although it is widely stated that both mating behavior and sperm traits are energetically costly for males, we currently lack empirical estimates of the relative costs to males of pre‐ versus postcopulatory investments. Such estimates require the experimental separation of the act of mating from that of ejaculation, which is a nontrivial logistical challenge. Here, we overcome this challenge using a novel morphological manipulation (gonopodium tip ablation) in the eastern mosquitofish (Gambusia holbrooki) to tease apart investment in mating effort from that in sperm replenishment following ejaculation. We quantified the relative cumulative costs of investing in mating effort and ejaculation by comparing somatic traits and reproductive performance among three types of males: ablated males that could attempt to mate but not ejaculate; unablated males that could both mate and ejaculate; and control males that had no access to females. We show that, after eight weeks, mating investment significantly reduces both body growth and immunocompetence and results in a significant decline in mating effort. In contrast, cumulative investment into sperm replenishment following ejaculation has few detectable effects that are only apparent in smaller males. These minor costs occur despite the fact that G. holbrooki has very high levels of sperm competition and multiple mating by both sexes, which is usually associated with elevated levels of sperm production. Crucially, our study is the first, to our knowledge, to experimentally compare the relative costs of pre‐ and postcopulatory investment on components of male fitness in a vertebrate.

Sensitivity and resolution improvement for in vivo magnetic resonance current‐density imaging of the human brain

Magnetic resonance current-density imaging (MRCDI) combines MRI with low-intensity transcranial electrical stimulation (TES; 1-2 mA) to map current flow in the brain. However, usage of MRCDI is still hampered by low measurement sensitivity and image quality. Recently, a multigradient-echo-based MRCDI approach has been introduced that presently has the best-documented efficiency. This MRCDI approach has now been advanced in three directions and has been validated by phantom and in vivo experiments. First, the importance of optimum spoiling for brain imaging was verified. Second, the sensitivity and spatial resolution were improved by using acquisition weighting. Third, navigators were added as a quality control measure for tracking physiological noise. Combining these advancements, the optimized MRCDI method was tested by using 1 mA TES for two different injection profiles. For a session duration of 4:20 min, the new MRCDI method was able to detect TES-induced magnetic fields at a sensitivity level of 84 picotesla, representing a twofold efficiency increase against our original method. A comparison between measurements and simulations based on personalized head models showed a consistent increase in the coefficient of determination of ΔR2 = 0.12 for the current-induced magnetic fields and ΔR2 = 0.22 for the current flow reconstructions. Interestingly, some of the simulations still clearly deviated from the measurements despite the strongly improved measurement quality. This highlights the utility of MRCDI to improve head models for TES simulations. The achieved sensitivity improvement is an important step from proof-of-concept studies toward a broader application of MRCDI in clinical and basic neuroscience research.

Male age alone predicts paternity success under sperm competition when effects of age and past mating effort are experimentally separated.

Older males often perform poorly under post-copulatory sexual selection. It is unclear, however, whether reproductive senescence is because of male age itself or the accumulated costs of the higher lifetime mating effort that is usually associated with male age. To date, very few studies have accounted for mating history and sperm storage when testing the effect of male age on sperm traits, and none test how age and past mating history influence paternity success under sperm competition. Here, we experimentally manipulate male mating history to tease apart its effects from that of age on ejaculate traits and paternity in the mosquitofish, Gambusia holbrooki. We found that old, naive males had more sperm than old, experienced males, while the reverse was true for young males. By contrast, neither male age nor mating history affected sperm velocity. Finally, using artificial insemination to experimentally control the number of sperm per male, we found that old males sired significantly more offspring than young males independently of their mating history. Our results highlight that the general pattern of male reproductive senescence described in many taxa may often be affected by two naturally confounding factors, male mating history and sperm age, rather than male age itself.

Mating preference is mating system and relatedness dependent in the ladybird beetle, Menochilus sexmaculatus

AbstractMate choice results from the sensory or behavioural properties that cause individuals to mate with some phenotypes and not others. It can result in direct or indirect (genetic) benefits. Mate choice can also be influenced by various abiotic and biotic factors including the mating system. Here, we investigated how the mating system of the ladybird, Menochilus sexmaculatus, influences mate choice and also affects the time of commencement of mating, copulation duration, fecundity and percent egg viability. We also tested whether mate choice is dynamically affected by relatedness. We found that monandrous and polyandrous females both preferred polyandrous rather than monandrous males. In contrast, males preferred monandrous females over polyandrous females. However, females preferred unrelated monogynous males which were earlier rejected over related polygynous and males preferred unrelated polyandrous females over related monandrous females. Mating system and relatedness also impacted time to commence mating and copulation duration, fecundity and percent egg viability. This will help us to understand precisely why these shifts occur, which will be the subject of future study.

Conservatism and religiousness participate in fast life history dynamics via elevated reproductive motivation

Social attitudes like religiousness and conservatism have been rarely examined in a life history framework. However, there are two competing hypotheses regarding the role of religiousness in human life history: in evolutionary psychological research it is thought to indicate slow life history while the behavioral ecological framework highlights its role in faster life history via elevated reproduction output and lower age of first reproduction. We tested these hypotheses for conservatism and religiousness by analyzing their relations with the variables that measure childhood environmental characteristics, mating effort, and reproductive motivation. The research was conducted via an online study on a sample of young adults in Serbia (N = 528). Bivariate correlations showed that religiousness and conservatism are positively related to reproductive motivation and a beneficial childhood environment, with negative correlations with mating effort. Furthermore, the Network Analysis showed that these two social attitudes are related only to enhanced reproductive motivation when analyzed in a multivariate fashion: conservatism was positively related with reasons favoring parenthood and desired number of children while religiousness was positively related to reasons for parenthood, and negatively for reasons against parenthood and pregnancy planning. Both attitudes had above average centrality indices in the life history network. The results are interpreted in a framework of life history theory and behavioral ecology of social attitudes in general.

Knockdown of a β-Adrenergic-Like Octopamine Receptor Affects Locomotion and Reproduction of Tribolium castaneum.

The neurohormone octopamine regulates many crucial physiological processes in insects and exerts its activity via typical G-protein coupled receptors. The roles of octopamine receptors in regulating behavior and physiology in Coleoptera (beetles) need better understanding. We used the red flour beetle, Tribolium castaneum, as a model species to study the contribution of the octopamine receptor to behavior and physiology. We cloned the cDNA of a β-adrenergic-like octopamine receptor (TcOctβ2R). This was heterologously expressed in human embryonic kidney (HEK) 293 cells and was demonstrated to be functional using an in vitro cyclic AMP assay. In an RNAi assay, injection of dsRNA demonstrated that TcOctβ2R modulates beetle locomotion, mating duration, and fertility. These data present some roles of the octopaminergic signaling system in T. castaneum. Our findings will also help to elucidate the potential functions of individual octopamine receptors in other insects.

Does male mate choice select for female coloration in a promiscuous primate species?

The traditional view of sex roles and sexual selection emphasizes the evolution of male ornaments as a result of female mate choice and male–male competition. Female ornaments are now receiving more attention, although their roles in mating decisions are still less well understood, especially considering cases in which colourful ornaments are expressed by both sexes. In this study, we analysed whether female skin coloration (luminance and redness of the face and hindquarters) influenced male mate choice and sexual behaviours in relation to intracycle (cycle phase), intercycle (number of consecutive cycles, conceptive nature of the cycle) and interindividual (age, social rank, weight and parity) variation in a captive social group of Japanese macaques, Macaca fuscata . Males did not preferentially choose darker/redder females. Moreover, males did not appear to use female skin coloration to apportion their mating efforts on the fertile phase of the menstrual cycle or during cycles that led to conception, or to discriminate between females. Collectively, our results suggest that female skin coloration may not have been sexually selected in this species and that males mated regardless of such variation across females. To our knowledge, our study is among the few to report a lack of male choice for female coloration in a species where both sexes display ornamentation. Our findings provide novel insights on the role and evolution of female coloration in sexual signalling and mating decisions. • Nonsex-specific colourful traits can potentially influence mate choice. • In most primate species, it is unclear if males attend to colourful female traits. • We tested the effect of female coloration on male mate choice in Japanese macaques. • Males did not discriminate between/within females or cycles based on coloration. • Female coloration is unlikely to be a sexually selected trait in Japanese macaques.

Is the link between endorsement and engagement in sexual coercion associated with life history strategy?

We assess whether traits associated with life history strategy moderate the association between endorsement and engagement of sexual coercion. In a sample of 155 men, we measured engagement in subtle sexually coercive behaviours using a novel measure, where participants reported their likely response when faced with several sexual/dating scenarios (e.g., a situation where the participant is sexually rejected). We also measured participants on mating effort, aggression, socioeconomic status (SES), the dark triad traits (psychopathy, narcissism, and Machiavellianism), and endorsement of sexual coercion through acceptance of rape myths. We found that men high in mating effort, SES, and Machiavellianism were more likely to engage in sexually coercion. As expected, greater endorsement was associated with greater engagement in sexual coercion, and this was significantly moderated by narcissism and Machiavellianism, but in opposite directions, with higher levels of Machiavellianism and lower levels of narcissism associated with a greater association between endorsement and engagement. Overall, there was no consistent pattern between traits associated with an accelerated life history strategy and sexually coercive behaviour.

Effects of Delayed Mating on Mating Performance and Reproductive Fitness of the Willow Leaf Beetle (Coleoptera: Chrysomelidae) under Laboratory Conditions.

Age at mating is one of the most important factors that affect mating selection, sexual performance, and fecundity. We studied the effects of mating age on the mating performance and reproductive fitness of Plagiodera versicolora Laicharting, a serious pest of poplar and willow, by measuring the time from pairing to successful mating, mating duration, fecundity, hatching probability, and female lifespan. Delayed mating of females and males significantly prolonged the time from pairing to successful mating and the mating duration, but had no effect on the duration of the egg-laying period. Delayed mating of females did not significantly affect fecundity or egg hatching, but significantly prolonged the female lifespan. Although delayed mating of males had a significant negative impact on egg hatching, it had no effect on the lifespan or fecundity of females. These results indicate that delayed mating affects the mating performance of P. versicolora, although it has a limited effect on reproductive fitness. This suggests that delayed mating is unlikely to contribute to the success of mating disruption, when applied to control P. versicolora.

Ēhara tāku toa i te toa takitahi, engari he toa takitini: the power of a collective

ABSTRACT Transmission of skills and knowledge is a core message in dominant discourses surrounding early verbal and non-verbal communication of babies. Narrow conceptualisations fail to place adequate emphasis on sociocultural elements of language and children’s sophisticated non-verbal communication. Utilising Kaupapa Māori research methods, this study describes a critical reflective narrative of a community-led parenting programme that makes space for whānau to re-centre Indigenous linguistic and cultural practices. ‘He Awa Whiria/The Braided Rivers’ metaphor is used to illustrate three themes derived from the analysis: Ma te kotahitanga e whai kaha ai mātau/In unity we have strength, reciprocity/whakaututu, whānau ki te whānau and manaakitanga/love and compassion for others. Data sources included focus groups; interviews; and reflective researcher memos. The evolution of the collective-agentive approach is illustrated within each theme with selected critical episodes. This study describes the parent-coaches-researchers journey to illustrate how a community’s rangatiratanga/sovereignty led to system transformation. The whānau collective journey represents an organic response of one ‘targeted’ community to lead the way in responding to deficit assumptions of parents and their children held by educators in the realm of early oral language. Indigeneous knowledge, ways of being and languaging are central and valid for the success of all tamariki/children.