Male-female Pairs Research Articles

Sexual selection in cane toads Rhinella marina: A male’s body size affects his success and his tactics

Abstract Male body size can play an important role in the mating systems of anuran amphibians. We conducted laboratory-based trials with cane toads Rhinella (Bufo) marina from an invasive population in the wet-dry tropics of northern Australia, to clarify the effects of a male’s body size on his reproductive success and behavior (mate choice). Males were stimulated with a synthetic hormone to induce reproductive readiness. Larger body size enhanced a male toad’s ability to displace a smaller rival from amplexus, apparently because of physical strength: more force was required to dislodge a larger than a smaller amplectant male. A male’s body size also affected his mate-choice criteria. Males of all body sizes were as likely to attempt amplexus with another male as with a female of the same size, and preferred larger rather than smaller sexual targets. However, this size preference was stronger in larger males and hence, amplexus was size-assortative. This pattern broke down when males were given access to already-amplectant male-female pairs: males of all body sizes readily attempted amplexus with the pair, with no size discrimination. An amplectant pair provides a larger visual stimulus, and prolonged amplexus provides a strong cue for sex identification (one of the individuals involved is almost certainly a female). Thus, a male cane toad’s body size affects both his ability to defeat rivals in physical struggles over females, and the criteria he uses when selecting potential mates, but the impacts of that selectivity depend upon the context in which mating occurs.

Disentangling Detoxification: Gene Expression Analysis of Feeding Mountain Pine Beetle Illuminates Molecular-Level Host Chemical Defense Detoxification Mechanisms

The mountain pine beetle, Dendroctonus ponderosae, is a native species of bark beetle (Coleoptera: Curculionidae) that caused unprecedented damage to the pine forests of British Columbia and other parts of western North America and is currently expanding its range into the boreal forests of central and eastern Canada and the USA. We conducted a large-scale gene expression analysis (RNA-seq) of mountain pine beetle male and female adults either starved or fed in male-female pairs for 24 hours on lodgepole pine host tree tissues. Our aim was to uncover transcripts involved in coniferophagous mountain pine beetle detoxification systems during early host colonization. Transcripts of members from several gene families significantly increased in insects fed on host tissue including: cytochromes P450, glucosyl transferases and glutathione S-transferases, esterases, and one ABC transporter. Other significantly increasing transcripts with potential roles in detoxification of host defenses included alcohol dehydrogenases and a group of unexpected transcripts whose products may play an, as yet, undiscovered role in host colonization by mountain pine beetle.

Sex differences in gray and white matter structure in age-matched unrelated males and females and opposite-sex siblings.

Apart from the general finding of larger global brain volumes in men, neuroimaging studies that compared brain structure between men and women have yielded some inconsistencies with regard to regional differences. One confound when comparing men and women may be differences in their genetic and or family background. A design that addresses such confounds compares brain structures between brothers and sisters, who share their genetic and family background.In the present study, we aimed to contribute to the existing literature on structural brain sex differences by comparing regional gray and white matter volume, using voxel based morphometry (VBM); and white matter microstructure, using tract-based spatial statistics (TBSS), between 40 unrelated males and females, and contrasting the results with those obtained in a group of 47 opposite-sex siblings, including 42 dizygotic opposite-sex (DOS) twin pairs.”Our results showed that men had larger global brain volumes as well as higher mean fractional anisotropy across the brain and showed regionally enlarged gray matter volume and higher fractional anisotropy in, or surrounding, subcortical structures (hypothalamus, thalamus, putamen and globus pallidus and rostral midbrain). Increased gray matter volume in women was restricted to areas of the cortex, including inferior temporal, insular, cingulate, precentral and frontal/prefrontal regions.These sex differences were generally consistent between the unrelated male-female pairs and the opposite-sex sibling pairs. Therefore, we conclude that these sex differences are not the result of confounding differences in genetic or family background and that the etiology of these sex differences merits further investigation.

Spatial Ecology of the Critically Endangered Fijian Crested Iguana, Brachylophus vitiensis, in an Extremely Dense Population: Implications for Conservation

The Critically Endangered Fijian crested iguana, Brachylophus vitiensis, occurs at extreme density at only one location, with estimates of >10,000 iguanas living on the 70 hectare island of Yadua Taba in Fiji. We conducted a mark and recapture study over two wet seasons, investigating the spatial ecology and intraspecific interactions of the strictly arboreal Fijian crested iguana. This species exhibits moderate male-biased sexual size dimorphism, which has been linked in other lizard species to territoriality, aggression and larger male home ranges. We found that male Fijian crested iguanas exhibit high injury levels, indicative of frequent aggressive interactions. We did not find support for larger home range size in adult males relative to adult females, however male and female residents were larger than roaming individuals. Males with established home ranges also had larger femoral pores relative to body size than roaming males. Home range areas were small in comparison to those of other iguana species, and we speculate that the extreme population density impacts considerably on the spatial ecology of this population. There was extensive home range overlap within and between sexes. Intersexual overlap was greater than intrasexual overlap for both sexes, and continuing male-female pairings were observed among residents. Our results suggest that the extreme population density necessitates extensive home range overlap even though the underlying predictors of territoriality, such as male biased sexual size dimorphism and high aggression levels, remain. Our findings should be factored in to conservation management efforts for this species, particularly in captive breeding and translocation programs.

Vertebral size, bone density, and strength in men and women matched for age and areal spine BMD.

To explore the possible mechanisms underlying sex-specific differences in skeletal fragility that may be obscured by two-dimensional areal bone mineral density (aBMD) measures, we compared quantitative computed tomography (QCT)-based vertebral bone measures among pairs of men and women from the Framingham Heart Study Multidetector Computed Tomography Study who were matched for age and spine aBMD. Measurements included vertebral body cross-sectional area (CSA, cm(2) ), trabecular volumetric BMD (Tb.vBMD, g/cm(3) ), integral volumetric BMD (Int.vBMD, g/cm(3) ), estimated vertebral compressive loading and strength (Newtons) at L3 , the factor-of-risk (load-to-strength ratio), and vertebral fracture prevalence. We identified 981 male-female pairs (1:1 matching) matched on age (± 1 year) and QCT-derived aBMD of L3 (± 1%), with an average age of 51 years (range 34 to 81 years). Matched for aBMD and age, men had 20% larger vertebral CSA, lower Int.vBMD (-8%) and Tb.vBMD (-9%), 10% greater vertebral compressive strength, 24% greater vertebral compressive loading, and 12% greater factor-of-risk than women (p < 0.0001 for all), as well as higher prevalence of vertebral fracture. After adjusting for height and weight, the differences in CSA and volumetric bone mineral density (vBMD) between men and women were attenuated but remained significant, whereas compressive strength was no longer different. In conclusion, vertebral size, morphology, and density differ significantly between men and women matched for age and spine aBMD, suggesting that men and women attain the same aBMD by different mechanisms. These results provide novel information regarding sex-specific differences in mechanisms that underlie vertebral fragility.

Using multiple joystick systems in computerised enrichment for captive orangutans

AbstractIt has been suggested that providing multiple computers with automatic reward dispensers as enrichment to captive orangutans (Pongospp) (as opposed to a single computer, with a care-staff person delivering reinforcers) might help improve behavioural outcomes. The purpose of the current study was to test this hypothesis by providing two computers with automatic reward dispensers to eight orangutans housed in four male-female pairs at Zoo Atlanta, USA. Subjects were observed for ten days during each of three phases: a baseline phase (during which, no computer was provided); immediately followed by Phase 1 (during which, one computer system was provided to each pair of subjects); immediately followed by Phase 2 (during which, two computer systems were provided to each pair). Data were collected in 1-h sessions using instantaneous scan sampling. There was no habituation to the computer system, nor were there any significant increases in aggression, rough scratching, and abnormal behaviours in either computer phase, which indicates that computer-joystick systems are effective as enrichment for captive orangutans. However, a high level of interest in the computer was shown by only a few individuals, which highlights a need to take into consideration individual differences when providing computerised enrichment to captive non-human primates. It would also be advisable to provide other forms of enrichment to increase activity levels for individuals which are not interested in interacting with a computer, as well as to help increase the diversity of behaviours being stimulated by the enrichment.

Size-Assortative Pairing and Social Monogamy in a Neotropical Lizard, Anolis limifrons (Squamata: Polychrotidae)

Social monogamy, the formation of stable male-female pairs, is uncommon among reptiles and is particularly rare among squamates, in which only a handful of cases has been reported. Only one case of persistent pair formation has ever been reported in anoles, for Anolis limifrons, at a single site in Costa Rica. Detailed studies of A. limifrons at other sites, however, have not shown evidence of pair formation. I revisited the site where pairing was originally reported to observe pair behavior in this species and to measure morphological traits of paired and unpaired animals. I confirmed that male-female pairs are commonly encountered in the wild, although a smaller proportion of the animals observed in this study were found in pairs than previously reported. I also found evidence for size-assortative pairing; larger males tended to be found with larger females and smaller males were found with smaller females. I did not find any differences in the morphology of paired and unpaired animals. Although social monogamy has not been widely reported in squamates, I suggest that more examples of this phenomenon will be described as the social behaviors of poorly known species are increasingly subject to study.

Non‐Monogamous Copulations and Potential Within‐Group Mating Competition in White‐Faced Saki Monkeys (Pithecia pithecia)

Many primates display within-species variation in social organization and mating system. Individuals of these species may be confronted with both the challenges of between-group competition to exclude same-sex competitors as well as within-group competition for mating opportunities. Free-ranging white-faced saki monkeys (Pithecia pithecia) live in both male-female pairs and small multi-male, multi-female groups. Despite commonly held views that this species is monogamous, there are currently no published accounts of mating patterns in the genus Pithecia. I recorded copulations and sexual behavior from three free-ranging groups of white-faced sakis at Brownsberg Naturepark, Suriname over a period of 17 months. Groups displayed both monogamous and polygynandrous mating. Individuals in polygynandrous groups were not observed to mate more frequently with certain partners. Copulation harassment occurred in 8.6% of copulations (total N = 81) and was performed by both sexes. This harassment successfully prevented ejaculation in six out of seven instances and harassment by males resulted in male-male aggression on four occasions. Two cases of female-directed sexual aggression by males were also observed, which may indicate that males use sexual coercion to influence female mating behavior. Although based on a small number of groups, these data show that white-faced sakis display variability in mating system and that this variability is not directly dictated by social organization. Furthermore, groups with promiscuous copulations exhibit behaviors indicative of within-group mating competition.

Ophiodaphne scripta (Ophiuroidea: Amphiuridae), a brittle star exhibiting sexual dimorphism and epibiosis: first record from India, with notes on adaptations, systematics and distribution

Ophiodaphne scripta (Koehler, 1904) is an amphiurid brittle star exhibiting an unusual form of conspicuous sexual dimorphism and epibiosis. The males are much smaller and exist as epibionts on the larger female. These male–female pairs, attached mouth-to-mouth, are in turn epibionts on cake urchins such as Echinodiscus auritus Leske, 1778, attaching themselves via the aboral side of the female. In this paper, Ophiodaphne scripta (Koehler, 1904) is reported from off the southern Indian peninsula for the first time, extending the range of this species eastwards. The distribution of this species is discussed in conjunction with that of the only other species in this genus, Ophiodaphne formata (Koehler, 1905), which also exhibits similar sexual dimorphism and epibiotic behavior. A detailed description of the specimens from India is provided, along with adaptations to their peculiar lifestyle. In addition, a brief historical review of the systematics of the genus Ophiodaphne Koehler, 1930 is presented, pointing out some discrepancies which persist, despite numerous revisions.

Multistressor Impacts of Warming and Acidification of the Ocean on Marine Invertebrates' Life Histories

Benthic marine invertebrates live in a multistressor world where stressor levels are, and will continue to be, exacerbated by global warming and increased atmospheric carbon dioxide. These changes are causing the oceans to warm, decrease in pH, become hypercapnic, and to become less saturated in carbonate minerals. These stressors have strong impacts on biological processes, but little is known about their combined effects on the development of marine invertebrates. Increasing temperature has a stimulatory effect on development, whereas hypercapnia can depress developmental processes. The pH, pCO2, and CaCO3 of seawater change simultaneously with temperature, challenging our ability to predict future outcomes for marine biota. The need to consider both warming and acidification is reflected in the recent increase in cross-factorial studies of the effects of these stressors on development of marine invertebrates. The outcomes and trends in these studies are synthesized here. Based on this compilation, significant additive or antagonistic effects of warming and acidification of the ocean are common (16 of 20 species studied), and synergistic negative effects also are reported. Fertilization can be robust to near-future warming and acidification, depending on the male-female mating pair. Although larvae and juveniles of some species tolerate near-future levels of warming and acidification (+2°C/pH 7.8), projected far-future conditions (ca. ≥4°C/ ≤pH 7.6) are widely deleterious, with a reduction in the size and survival of larvae. It appears that larvae that calcify are sensitive both to warming and acidification, whereas those that do not calcify are more sensitive to warming. Different sensitivities of life-history stages and species have implications for persistence and community function in a changing ocean. Some species are more resilient than others and may be potential "winners" in the climate-change stakes. As the ocean will change more gradually over coming decades than in "future shock" perturbation investigations, it is likely that some species, particularly those with short generation times, may be able to tolerate near-future oceanic change through acclimatization and/or adaption.

Reconciliation in Hamadryas Baboons (Papio hamadryas): Testing the Relationship Quality Hypothesis

Post-conflict interactions between former opponents were investigated in a troop of hamadryas baboons, Papio hamadryas. This species is known for it's multilevel structure with evidently expressed hierarchy between males and females. Due to this fact hamadryas baboons represent an ideal object for testing the "relationship quality" hypothesis. The analyses were done on 436 PC-MC pairs of animals, which represented different social classes (harem male-female pairs, harem females, relatives, females from different harems. Male-male pairs, and female-subadult pairs). Reconciliation was practiced in different social classes of individuals: harem male-female pairs, harem female-female pairs, kin-kin pairs, male-male pairs, female-subadult pairs. Significant differences in the rate of reconciliatory tendency for different categories of interacting animals were found. Interactions between former opponents were highly selective. These may be interpreted as an indicator of the influence of the relation quality on the probability of reconciliation in hamadryas baboons.

Female mate choice for multimodal courtship and the importance of the signaling background for selection on male ornamentation

Abstract Conspicuous visual ornaments are frequently incorporated into complex courtship displays that integrate signal components from multiple sensory modalities. Mature male Schizocosa crassipes (Walckenaer, 1837) wolf spiders wave, arch, and tap their ornamented forelegs in a visual courtship display that simultaneously incorporates seismic components. To determine the importance of modality-specific signal components in female mate choice, we used a signal ablation design and compared the mating frequency of female-male pairs across signaling environments with manipulated modality-specific transmission properties. We found that the successful transmission of isolated visual or seismic signaling was sufficient for mating success; neither signaling modality was necessary. Additionally, the environment enabling the successful transmission of composite, multimodal displays yielded the highest mating frequencies. Our results indicate the presence of selection from S. crassipes females for multimodal courtship and suggest that multimodal signaling may facilitate mating across variable signaling environments. We next explored the influence of ornamentation per se on female choice by phenotypically manipulating males into two groups: (i) intact (brushes present) and (ii) shaved (brushes absent). We compared the mating frequencies of intact versus shaved males in the presence versus absence of seismic signaling. Males with brushes intact had higher mating frequencies than shaved males, but only under specific signaling conditions – in the presence of seismic signaling. Female choice for male brushes then appears dependent on the signaling background, making brushes themselves an unlikely target of direct selection. Our results emphasize the complex nature of female choice, highlighting the potential for both trait interactions and environment-dependent selection.

Den attendance patterns in swift foxes during pup rearing: varying degrees of parental investment within the breeding pair

Parental investment varies in mammalian species, with male care of young being more common in social and monogamous species. Monogamy is commonly observed in canid species, with both males and females, and often ''helper'' individuals, providing some degree of care for the young. Social units of the swift fox (Vulpes velox), a small North American canid species, usually consist of a male- female pair and occasionally helpers. The role of parental investment and behavior in swift fox society is currently poorly understood. We observed swift fox dens during the pup-rearing season in each of 2 years to evaluate attendance and frequency of visits to natal dens by adult males and females. Female foxes remained at dens longer and visited them more frequently than did male foxes. Female attendance and visitation decreased throughout the pup-rearing season as pups became older and more independent. Environmental factors, including climate and its effect on prey, appeared to contribute to differences in fox behavior between the 2 years. We observed only one fox outside of the breeding pair attending a den in each of the 2 years, both of which were males. We concluded that each of these two foxes were living within the social unit of the male-female pair as a trio, but not serving as a helper and contributing to the care of the pups. Our results increased knowledge of the ecology and behavior of the swift fox, a species of conservation concern in the Great Plains of North America.

Differences in sexual behavior of two distant populations of the funnel-web wolf spider Aglaoctenus lagotis

Generally, sexual repertoire within a species is conserved, but frequencies of occurrence of sexual behavioral acts often vary, and wide geographic distributions may favor these variations. Aglaoctenus lagotis is distributed along South America and belongs to Sosippinae, a subfamily of wolf spiders that builds funnel webs. Previous reports, based on different populations, suggested variations in sexual behavior and life cycle. Our objective was to describe and compare the sexual behavior of two populations of A. lagotis: ‘Southern Uruguay’ (SU) and ‘Central Argentina’ (CA). We carried out intrapopulation trials, in the laboratory, with 15 female–male pair matings. The most representative courtship acts in SU were web-stretching, striding-forward and forelegs-elevating, whereas in CA they were alternate-waving, web-stretching and leg-tapping. Juddering, forelegs-elevating and striding-forward were exclusive for SU, while alternate-waving and simultaneous-waving were exclusive for CA. We also found differences in copulatory characteristics such as frequencies of insertions and ejaculations. We documented body-shaking during copulation for the first time. Some sexual acts were exclusive of each population, while the shared ones differed in pattern and frequencies of occurrence. In addition to variations in sexual periods, these differences may favor divergence processes or an exceptional high level of flexibility in the sexual behavior of A. lagotis.

Social dynamics and dispersal in free-living prairie voles (Microtus ochrogaster)

Following dispersal from 1 group, individuals may join other established social groups. Such intergroup transfer may increase access to potential mates and decrease mate competition. We used data from 402 individuals to examine patterns of intergroup transfer in prairie voles (Microtus ochrogaster). Nearly 32% of established social groups (single female units, male–female pairs, or communal groups of at least 2 adults of the same sex) were joined by 1 or more individuals. Most individuals (76%) that joined social groups were wanderers that were either unmarked, recently marked during grid trapping, or marked transients; 70% were males. Joining a group was not contingent upon recent disappearance of residents. Total number of residents positively affected the probability of a female joining a social group, whereas number of adult female residents and population density negatively affected it. Some individuals (24%) moved directly from one group to another without an intervening wandering stage; we refer to these instances of intergroup transfer as direct transfers. Most direct transferers moved into nearby groups, but not the closest group. Males were more likely than females to directly transfer into groups with potential mates and without potential competitors. Thus, males directly transferred in a manner consistent with maximizing reproductive opportunities. In contrast, 25% of females directly transferred into groups without potential mates and 96% into groups with at least 1 adult female. Females may be less constrained by group composition with respect to potential mates because wandering males, with which females can mate, are prevalent. All-male groups almost never occur in our population, so females probably cannot avoid joining groups with competitors.

Automatic detection and identification of brown stink bug, Euschistus servus, and southern green stink bug, Nezara viridula, (Heteroptera: Pentatomidae) using intraspecific substrate-borne vibrational signals

Stink bugs cost the southeastern US cotton industry millions of dollars each year in crop losses and control costs. These losses are reduced by strategic pesticide applications; however, current methods of monitoring these pests for making management decisions are time-consuming and costly. Therefore, improved methods to identify and monitor these bugs must be investigated in order to optimize pesticide applications. One such method would be to exploit the substrate-borne vibrational signals (SBVSs) of these insects. Recordings of SBVS for two prevalent regional pests, the brown stink bug, Euschistus servus, and southern green stink bug, Nezara viridula, were segmented into separate pulses of variable duration based on signal energy. For each pulse, the linear frequency cepstral coefficients, dominant frequency, and duration were calculated and used as features. These features were classified using a Gaussian mixture model (GMM) and a probabilistic neural network (PNN) to discriminate these SBVS from incidental sounds and SBVS of different species from each other. Detection of SBVS generated by brown stink bugs was performed with over 92% accuracy for single male–female pairs with both PNN and GMM and with over 86% accuracy for 30 individuals with both PNN and GMM. Detection of SBVS generated by southern green stink bugs was performed with up to 82.5% accuracy with PNN and 68.0% accuracy with GMM for 30 individuals. Also, both PNN and GMM were over 90% accurate in identifying SBVS of brown and southern green stink bugs. Concurrent detection of SBVS from noise and identification of SBVS of brown and southern green stink bugs was 83.3% accurate using PNN and 71.5% accurate using GMM. These results indicated the capability of detecting and identifying stink bug species using their SBVS.

Face Space: Facial dominance aftereffects exist and they are not sex-tuned.

Event Abstract Back to Event Face Space: Facial dominance aftereffects exist and they are not sex-tuned. Rick Van Der Zwan1*, Elise Morris1 and Anna Brooks1 1 Southern Cross University, Psychology, Australia Background Interpreted for a long time as evidence for opponent processing, explanations of the mechanisms giving rise to aftereffects have matured to incorporate the observation that neurons seldom (if ever) are tuned for a single dimension: The array of neurons active in response to any stimulus captures a perceptual “space” describing the stimulus in the context of the observer’s experience. The dimensions of the space are reflected by the tuning properties of the neurons within it. In that context, prolonged adaptation to a stimulus alters the space such that subsequently presented stimuli are not "misperceived" as such, but perceived differently. With that in mind, aftereffects can again be deployed to investigate perceptual spaces. In the experiments described here face-dominance aftereffects were used to explore the multi-dimensional “face space” described by Todorov et al. (2008). In that space Todorov suggests there are independent dimensions for social qualities like facial dominance and trustworthiness. To better understand the dimension of dominance Experiment 1 was designed to discover if facial dominance cues give rise to “facial dominance” aftereffects: Can adaptation to a face at one point on the dominance dimension shift perceptions of subsequently viewed faces along the dimension? Experiment 2 was designed to explore the parameters of those effects. Specifically, Experiment 2 investigated whether or not facial dominance aftereffects are sex-tuned. Methods 10 female and 10 male observers were used. Observers adapted to female or male faces that had features consistent with being "dominant", "neutral", or "non-dominant". They then judged neutral faces as "non-domiant" or "dominant" in a classic 2AFC paradigm. In every case (each adaptation/test pairing) different facial identities were used to reduce identity confounds. In Experiment 1 adapting and test stimuli were always the same sex. In Experiment 2 same and opposite sex pairs were used as adapting and test stimuli. Results Experiment 1: Facial Dominance Aftereffects were observed. Adapting to a dominant face made a neutral face look less dominant. Adapting to a non-dominant face made a neutral face look more dominant. Experiment 2: The magnitudes of Facial Dominance Aftereffects were not affected by the sex of the adaptation/test pairs. That is, the magnitudes of effects elicited by female-female or male-male pairs was equal the the magnitudes of effects elicited by female-male and male-female pairs. Discussion Facial dominance aftereffects can be elicited independent of identity. That is, facial dominance is explicitly encoded within the cortex and is not tied to specific facial configurations. Similarly, it is not tied to the sex of the face. These data suggest that facial dominance cues and facial sex cues may map independent dimensions in face space. Theoretical implications will be described. References Todorov, A., Said, C.P., Engell, A.D., Oosterhof, N.N. (2008) Understanding evaluation of faces on social dimensions. Trends In Cognitive Sciences, 12, 455 - 460. Keywords: facial dominance, Aftereffects, Social cues, face space, social neuroscience Conference: ACNS-2013 Australasian Cognitive Neuroscience Society Conference, Clayton, Melbourne, Australia, 28 Nov - 1 Dec, 2013. Presentation Type: Oral Topic: Sensation and Perception Citation: Van Der Zwan R, Morris E and Brooks A (2013). Face Space: Facial dominance aftereffects exist and they are not sex-tuned.. Conference Abstract: ACNS-2013 Australasian Cognitive Neuroscience Society Conference. doi: 10.3389/conf.fnhum.2013.212.00168 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 15 Oct 2013; Published Online: 25 Nov 2013. * Correspondence: Prof. Rick Van Der Zwan, Southern Cross University, Psychology, Coffs Harbour, NSW, 2450, Australia, rick.vanderzwan@scu.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Rick Van Der Zwan Elise Morris Anna Brooks Google Rick Van Der Zwan Elise Morris Anna Brooks Google Scholar Rick Van Der Zwan Elise Morris Anna Brooks PubMed Rick Van Der Zwan Elise Morris Anna Brooks Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Does Experience Affect the Outcome of Male-Male Contests in the Burying Beetle,Nicrophorus quadripunctatus?

The bigger individual in a fight usually wins unless the smaller individual is a resident or has recently won a fight. I conducted three experiments on the effects of body size, residency, and fight history on the outcome of male-male fights in a burying beetle. Fights were staged between an intruding male and the male of a male-female pair. When males differed in size, the larger male usually won regardless of residency or individual fight histories. Residents and winners of previous fights won only when competing males were similar in size. Hence, male body size largely determines the outcomes of fights in this beetle.

Similarity of relationship standards, couple communication patterns, and marital satisfaction among Chinese couples.

Prior research has indicated that partners' standards for their couple relationships are associated with their levels of marital satisfaction, both in terms of similarity between standards and the degree to which partners are able to resolve differences in their standards constructively. However, little is known about processes through which couples effectively cope with conflicting relationship standards. Furthermore, most research on relationship standards has been conducted in Western countries, and there is a need for more information about the role of this form of cognition in Asian and other cultures. In the present study, relationship standards and communication patterns were examined in relation to marital satisfaction among 297 community couples in a northern city in mainland China. Results indicated that the similarity of relationship standards of members of real couples was significantly higher than randomly matched male-female pairs. A hypothesized conceptual model predicting marital satisfaction from partners' similarity of relationship standards and communication patterns was tested using structural equation modeling. Similarity of relationship standards can affect couple's marital satisfaction indirectly, through perceived communication patterns. The interdependence between husbands' and wives' aspects of relationship functioning also are examined and discussed.

A Novel Report of Hatching Plasticity in the Phylum Echinodermata

Hatching plasticity occurs in response to a wide range of stimuli across many animal taxa, including annelids, arthropods, mollusks, and chordates. Despite the prominence of echinoderms in developmental biology and more than 100 years of detailed examination of their development under a variety of conditions, environmentally cued hatching plasticity has never been reported in the phylum Echinodermata. Here we report plasticity in the timing and stage of hatching of embryos of the sand dollar Echinarachnius parma in response to reductions in salinity. Embryos of E. parma increased their time to hatching more than twofold in response to ecologically relevant salinity reductions, while maintaining an otherwise normal developmental schedule. Embryos that experienced the greatest delay in hatching time emerged from the fertilization envelope as four-arm pluteus larvae rather than hatching as blastulae or early gastrulae. Salinity manipulations across multiple male-female pairs indicated high variability in hatching time both within and among clutches, suggesting significant intraspecific variation in developmental responses to salinity.