Male Pairs Research Articles

O7.7. NEUROBIOLOGICAL ROOTS OF SCHIZOPHRENIA

The estimated heritability of schizophrenia is 80–85%, and if one of monozygotic twins has the illness, the risk for the other twin is about 50%. It has remained unclear which factors are associated just with the increased risk, and which neurobiological mechanisms are related to the cascade leading to actual onset of illness. It has also remained a mystery why this neurodevelopmental disorder manifests itself after adolescence. We used iPSC-derived neurons from 5 monozygotic twin pairs discordant for schizophrenia (3 female and 2 male pairs; all 5 affected individuals were chronically symptomatic and treated with antipsychotics, 3 with clozapine) and 6 healthy controls matched by age and sex to enhance signal by minimizing genetic heterogeneity. Diagnoses were assigned using DSM-IV criteria and SCID-I interviews, and severity of symptoms was assessed with PANSS. Skin biopsy-derived fibroblasts were reprogrammed into integration-free induced pluripotent stem cell (iPSCs) lines by Sendai virus technology. The cells were further differentiated into cortical-like neurons expressing markers of GABAergic and glutamatergic neurons. The top genes from RNAseq analysis were validated by quantitative polymerase chain reaction (qPCR). In the proteomic analysis, the 16 samples were processed through the SysQuant workflow using Tandem Mass Tag (TMT) reagents within two TMT 10plexes. A reference pool containing all samples was also included. To identify statistically significant regulated features (peptide, phosphopeptides or proteins), a LIMMA-based modified t-test was performed at the peptide, phosphopeptide and protein levels in pairwise comparisons using distribution-dependent fold change (FC) and p-value (p) thresholds. Transcriptomic and proteomic analyses showed very large effect sizes (differences up to 7.3-fold in gene expression and 2.7-fold in protein levels in the comparison between affected twin versus healthy twin). Among the most robust findings related to disease status were down-regulation of COL6A3, SSTR2, and LHX1 genes, and altered glycosaminoglycan, CAMK2G-related AMPA/NMDA/glutamate, GABAergic synapse, and purine metabolism pathways. While only 12% of genes were differentially expressed between healthy males and females, up to 61% of the illness-related genes were sex-specific (p-values down to 2.3 x 10E-295 for the difference). Most of the genes with the largest effect sizes were different between males and females. At gestational age of 90 days, neurons of affected twins showed altered calcium responses for NMDA-specific glutamate (p < 0.001) and for GABA exposure compared with their healthy twins, and these alterations were normalized when the neurons were treated with clozapine. Results imply that somatostatin 2 receptor defect may contribute to dysfunction of NMDA receptors in somatostatin/calreticulin GABAergic interneurons, and that clozapine might have a beneficial effect on this cascade. Consistent findings on down-regulation of N-glygan and calnexin/calreticulin pathways, affecting protein folding in endoplastic reticulum, indicate also their major role in schizophrenia. Our results imply that although both sexes share many of the final common pathways involving the same proteins, the underlying primary pathophysiology of schizophrenia may differ between males and females. This may explain why the disease typically manifests after adolescence, when the expression levels of many sex-specific genes change.

Territory quality differs between paired and unpaired male Common Redstarts Phoenicurus phoenicurus

ABSTRACTWe compared habitat characteristics between territories of paired and unpaired males of the long-distance migratory Common Redstart Phoenicurus phoenicurus. Nesting possibilities and reachable sparse vegetation were more abundant in territories of paired males, clearly highlighting the importance of both parameters when implementing habitat enhancements for the species.

Landscape heterogeneity in landform and land use provides functional resistance to gene flow in continuous Asian black bear populations.

ContextGenetic diversity is one of the most important facets of biological diversity, and changes in the spatial pattern of habitats, often modified by human activity, are believed to have affected the genetic diversity of resident natural populations.ObjectivesWe undertook a landscape genetic analysis in order to determine which landscape features influence gene flow within Asian black bear populations and to identify the underlying processes.MethodsIn our evaluation of gene flow, we estimated four parameters of resistance with regard to landscape elevation: the mean, the difference between the highest and lowest, the standard deviation, and the coefficient of variation of elevation among individuals. We then examined the resistance effect of different land use types.ResultsWith the exception of mean elevation, we found that all parameters showed a significant relationship with genetic distance, indicating that unevenness in elevation provides functional resistance to gene flow. Although we found no evidence of landscape barriers (isolation‐by‐barrier), there was an indication of landscape resistance (isolation‐by‐resistance). Urban area and farmland are suggested to be the strong factors contributing to the resistance to gene flow, even though isolation‐by‐distance was also detected. When we examined gene flow for pairs of males and pairs of females, both isolation‐by‐distance and isolation‐by‐resistance were stronger in order of female pairs, male pairs, all individual pairs.ConclusionsWe conclude that landscape resistance was detectable with a high contrast in landscape heterogeneity and they are more influential on females than males.OPEN PRACTICES This article has been awarded Open Data badge. All materials and data are publicly accessible via the Open Science Framework at https://doi.org/10.5061/dryad.gn0qf16. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.

Can live with ‘em, can live without ‘em: Pair housed male C57BL/6J mice show low aggression and increasing sociopositive interactions with age, but can adapt to single housing if separated

The basic question as to whether male laboratory mice should be singly or group housed represents a major animal welfare concern within current laboratory animal legislation and husbandry. To better understand the behavioural and physiological mechanisms underlying this issue, we conducted two longitudinal experiments using C57BL/6J mice. In the first experiment (N = 32), we explored social behaviour of pair housed males from weaning to adulthood. We took weekly measures of agonistic, socio-exploratory and affiliative behaviours within two different contexts, i.e. in the undisturbed home cage and immediately after cage cleaning. In the second experiment (N = 36), we investigated whether separation of male pairs into single housing at different ages (35, 56 or 77 days of age) affected welfare-related measures such as faecal corticosterone metabolites (FCMs) and anxiety-like behaviours. In the first experiment we found that levels of agonistic behaviour were higher after cage cleaning than in the undisturbed cage as expected, but did not significantly change with age in either context. Instead, affiliative behaviour increased with age in the undisturbed home cage. In the second experiment, social separation did not affect levels of FCMs or anxiety-like behaviours at any age point. Taken together, this study shows that pair housed male mice can maintain low levels of aggression across a long period of their life and perform increasing levels of sociopositive behaviours which may serve to promote stable social relations. At the same time, our results suggest that male mice can quickly adapt to separation into single housing at different ages, from adolescence to adulthood. These findings are in line with the behavioural ecology of wild male mice, which suggests that both solitary and group living represent two alternative strategies.

Affect of food provisioning on survival and reproductive success of the olive fruit fly parasitoid, Psyttalia lounsburyi, in the field

Conservation biological control offers approaches that can be integrated into classical biological control programs to enhance pest suppression. Food subsidies, such as nectar and honeydew, can increase a parasitoid’s fecundity either by extension of the reproductive lifespan, increasing the rate of egg maturation, or both. The olive fruit fly, Bactrocera oleae, is a major pest of olives in California, where a classical biological control program is currently underway using an exotic parasitoid, Psyttalia lounsburyi. We conducted a field study where female–male pairs of P. lounsburyi wasps were caged with B. oleae-infested olives, and provisioned either with or without food. Our study showed that adult feeding is crucial to P. lounsburyi survival and fecundity under field-cage conditions. Food provision increased P. lounsburyi survival and several components of the wasp’s reproductive success; nevertheless, parasitism rates and offspring production were relatively low. This was probably due, at least in part, to location of host larvae in enemy-free space ‘beyond the reach’ of the wasp’s ovipositor. Sex ratio of offspring was male-biased, perhaps due to inbreeding in the laboratory colony from which P. lounsburyi was sourced. Female wasps carried ca. 25–35 eggs at their time of death, suggesting that they were time limited rather than egg limited. Integration of conservation biological control (e.g., food provisioning) and classical biological control (release of an exotic natural enemy) have promise to suppress olive fruit fly populations. Evaluation of the effect of food provisioning on P. lounsburyi reproductive success under open field conditions is warranted.

Attention during Visual Preference Tasks: Relation to Caregiving and Face Recognition

This research examined how caregiver experience (female primary caregiver or distributed caregiving with mom and dad) influenced 10-, 14-, and 16-month-olds' visual preferences and attention toward internal facial features of female-male face pairs, and how these behaviors related to novelty preferences in a face recognition task and speed and accuracy on a visual search task. In the visual preference task, infants visually preferred male faces, regardless of caregiver experience. Despite similarities in visual preferences, infants' attention toward females and males' internal facial features was related for infants with distributed caregiving only. Infants' performance across face processing tasks most often correlated for those with female primary caregivers. Results further our understanding of how infants with female primary caregivers display specialized processing of female faces, and how infants with distributed caregiving show similarities in their attention to female and male facial features.

Towards development of a parasitoid cottage industry of the parasitoid wasp Habrobracon hebetor (say): optimum rearing and releases conditions for successful biological control of the millet head miner Heliocheilus albipunctella (De Joannis) in the Sahel

Augmentative biological control by the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is the most promising strategy to control millet head miner, Heliocheilus albipunctella (De Joannis) a major insect pest of pearl millet in the Sahel. As H. hebetor survival is somehow challenging during the nine month long off-season when the host, H. albipunctella is in diapause, there needs to be a sufficient supply of parasitoids for fresh release each year. Therefore, the aim of this study was to establish a small-scale parasitoid rearing process adjusted to the Sahel conditions that can be scaled-up as necessary. We conducted experiments to fine-tune and standardize the rearing technique of H. hebetor for cottage industrial use. The results showed that parasitoids fed with 30% honey solution and supplied daily with one late-larval-stage Corcyra cephalonica Stainton (Lepidotera, Pyralidae) produced highest number of progeny. The optimal times for mating and egg fertilization, was achieved when a male and female pair was confined for 24 h in a 30-cc vial. Our findings indicated that, compared with the conventional rearing method -2 females supplied once with 25 C. cephalonica larvae-, this new method resulted in 14-times greater parasitoid production. Furthermore parasitoid female can be stored for up to three weeks at fluctuating 23–32°C temperature and 25%–80% relative humidity for numbers accumulations prior to on-farm augmentative releases without altering its fitness.

Inclusive fitness benefits mitigate costs of cuckoldry to socially paired males

BackgroundIn socially monogamous species, reproduction is not always confined to paired males and females. Extra-pair males commonly also reproduce with paired females, which is traditionally thought to be costly to the females’ social partners. However, we suggest that when the relatedness between reproducing individuals is considered, cuckolded males can suffer lower fitness losses than otherwise expected, especially when the rate of cuckoldry is high. We combine theoretical modeling with a detailed genetic study on a socially monogamous wild fish, Variabilichromis moorii, which displays biparental care despite exceptionally high rates of extra-pair paternity.ResultsWe measured the relatedness between all parties involved in V. moorii spawning events (i.e. between males and females in social pairs, females and their extra-pair partners, and paired males and their cuckolders), and we reveal that males are on average more related to their cuckolders than expected by chance. Queller–Goodnight estimates of relatedness between males and their cuckolders are on average r = 0.038 but can range up to r = 0.64. This also increases the relatedness between males and the extra-pair offspring under their care. These intriguing results are consistent with the predictions of our mathematical model, which shows that elevated relatedness between paired males and their cuckolders can be adaptive for both parties when competition for fertilizations is strong.ConclusionsOur results show how cuckoldry by relatives can offset males’ direct fitness losses with inclusive fitness gains, which can be substantial in systems where males face almost certain paternity losses.

The causal relationship between sexual selection and sexual size dimorphism in marine gastropods

Sexual size dimorphism is widespread among dioecious species, but its underlying driving forces are often complex. A review of sexual size dimorphism in marine gastropods revealed two common patterns: first, sexual size dimorphism, with females being larger than males, and, second, females being larger than males in mating pairs. Both patterns suggest sexual selection and sexual size dimorphism are causally related. To test this hypothesis, we investigated, first, mechanisms driving sexual selection on size in three congeneric marine gastropods with different degrees of sexual size dimorphism, and, second, the correlation between male/female sexual selection and sexual size dimorphism across several marine gastropod species. Male mate choice via mucus trail following (as evidence of sexual selection) was found during the mating process in all three congeneric species, even though not all species showed sexual size dimorphism. There was also a significant and strong negative correlation between female sexual selection and sexual size dimorphism across 16 cases from seven marine gastropod species. These results suggest that sexual selection does not drive sexual size dimorphism. There was, however, evidence of males utilizing a similar mechanism to choose mates (i.e. selecting a female slightly larger than their own size) which may be widespread among gastropods, and, in tandem with sexual size dimorphism varying between species, provides a plausible explanation of the mating patterns observed in marine gastropods.

The shape of personal space

The notion of a personal space surrounding one's ego-center is time-honored. However, few attempts have been made to measure the shape of this space. With increasing use of virtual environments, the question has arisen if real-world aspects, such as gender-effects or the shape of personal space, translate to virtual setups. We conducted two experiments, one with real people matched according to body height and level of acquaintance in a large laboratory setting, and one where subjects faced a virtual character, likewise matched to their body height. The first experiment also used a mannequin in place of the second human observer. The second experiment additionally manipulated the perspective of the subject to compare estimates of interpersonal distance between an egocentric and an allocentric perspective (in third-person view). Subjects approached (or were approached) from different angles until a comfortable distance for conversation with a stranger was reached (stop-distance task). Personal space turned out to be rather circular with a radius of about 1 m. Male pairs kept larger distances from one another than female or mixed-gender pairs. All subjects assumed larger distances to the mannequin compared to the real observer. Very comparable distances were preferred to the avatar in the virtual environment. Also, it did not matter whether the subject was engaged in active approach, was approached, or merely adjusted the distance between two avatars. Implications for theories of personal space are discussed.

Conserved transcriptomic profiles underpin monogamy across vertebrates

Social monogamy, typically characterized by the formation of a pair bond, increased territorial defense, and often biparental care, has independently evolved multiple times in animals. Despite the independent evolutionary origins of monogamous mating systems, several homologous brain regions and neuropeptides and their receptors have been shown to play a conserved role in regulating social affiliation and parental care, but little is known about the neuromolecular mechanisms underlying monogamy on a genomic scale. Here, we compare neural transcriptomes of reproductive males in monogamous and nonmonogamous species pairs of Peromyscus mice, Microtus voles, parid songbirds, dendrobatid frogs, and Xenotilapia species of cichlid fishes. We find that, while evolutionary divergence time between species or clades did not explain gene expression similarity, characteristics of the mating system correlated with neural gene expression patterns, and neural gene expression varied concordantly across vertebrates when species transition to monogamy. Our study provides evidence of a universal transcriptomic mechanism underlying the evolution of monogamy in vertebrates.

Mating pattern, female reproduction and sexual size dimorphism in a narrow-mouthed frog (Microhyla fissipes)

Abstract The difference in body size and/or shape between males and females, called sexual size dimorphism, is widely accepted as the evolutionary consequence of the difference between reproductive roles. To study the mating pattern, female reproduction and sexual size dimorphism in a population of Microhyla fissipes, amplexus pairs were collected, and the snout-vent length of males and females, female reproductive traits and fertilization rate were measured. If the body size of amplexed females is larger than that of amplectant males, this is referred to as a female-larger pair, a phenomenon that was often observed for M. fissipes in this study. Interestingly, snout-vent length of males in male-larger pairs was greater than that in female-larger pairs, however the post-spawning body mass, clutch size, egg dry mass and clutch dry mass did not differ between both types of pairs. Snout-vent length of males was positively related to that of females in each amplexus pair. After accounting for the snout-vent lengths of females, we showed that snout-vent lengths of males in male-larger pairs were greater than those of females in female-larger pairs. The snout-vent length ratio of males and females was not related to fertilization rate in each amplexus pair. The mean fertilization rate was not different between both amplexus pairs. These results suggest that (1) M. fissipes displays female-biased sexual size dimorphism and has two amplexus types with size-assortative mating; (2) the snout-vent length ratio of males and females in each amplexus type was consistent with the inverse of Rensch’s rule, and was driven by the combined effect of sexual selection and fecundity selection; (3) females with a larger body size were preferred by males due to their higher fecundity, while the body size of males was not important for fertilization success.

Vocalization can mediate male–male sexual interactions in Java sparrows

Abstract Same-sex sexual behaviors do not have direct fitness outcomes, but might be adaptive. This issue is often discussed in group-living animals, where social bonding is crucial. In our captive environment, around 33% of the Java-sparrow (Lonchura oryzivora) males kept in unisex cages have stable bonded partners. Those bonded males often perch side by side and show allopreening and joint-defensive behaviors towards others. In this study, we aimed to determine how males including such same-sex bonded individuals communicate with each other via vocalizations. We introduced same-sex pairs of Java sparrows, which were bonded or non-bonded, in sound-attenuated boxes and compared their recorded vocalizations with those from male–female pairs. For the male–male pairs, we identified two vocalizations that are usually exchanged between paired partners in intimate contexts: mating trills – which are usually emitted by females during successful copulation – and meowing calls – which are given when both members of the pair are in the nest at the same time. We found that males gave mating trills when their partner males were singing courtship songs, or performed trill duets, which sometimes also included meowing calls. Acoustic analyses revealed that there was no difference between male–male and male–female vocalizations. Meowing calls showed greater within-individual variation in duration and other acoustic parameters, but were similar in same-sex and mixed-sex contexts. Our results indicate that male–male pairs exchanged intimate vocal communications just like male–female couples.

Cytogenetic relationships, polyploid origin and taxonomic issues in Paspalum species: inter- and intraspecific hybrids between a sexual synthetic autotetraploid and five wild apomictic tetraploid species.

Paspalum is a noteworthy grass genus due to the forage quality of most species, with approximately 330 species, and the high proportion of those that reproduce via apomixis. Harnessing apomictic reproduction and widening knowledge about the cytogenetic relationships among species are essential tools for plant breeding. We conducted cytogenetic analyses of inter- and intraspecific hybridisations involving a sexual, colchicine-induced autotetraploid plant of P. plicatulum Michx. and five indigenous apomictic tetraploid (2n=40) species: P. compressifolium Swallen, P. lenticulare Kunth, two accessions of P. nicorae Parodi, P. rojasii Hack. and two accessions of P.plicatulum. Fertility of the hybrids was investigated and their reproductive system was analysed considering the relative embryo:endosperm DNA content from flow cytometry. Morphological, nomenclatural and taxonomic issues were also analysed. Cytogenetic analysis suggested that all indigenous tetraploid accessions of five apomictic species are autotetraploid or segmental allotetraploid. If segmental allotetraploids, they probably originated through autoploidy followed by diploidisation processes. Autosyndetic male chromosome pairing observed in all hybrid families supported this assertion. Allosyndetic chromosome associations were also observed in all hybrid families. In the hybrids, the proportion of male parent chromosomes involved in allosyndesis per pollen mother cell varied from 5.5% to 35.0% and the maximum was between 25% and 60%. The apomictic condition of the indigenous male parents segregated in the hybrids. These results confirm a strong association between autoploidy and apomixis in Paspalum, and the existence of cytogenetic relationships between different species of the Plicatula group. Allosyndetic chromosome pairing and seed fertility of the hybrids suggest the feasibility of gene transfer among species.

Kinship influences social bonds among male southern Australian bottlenose dolphins (Tursiops cf. australis)

Male mammals employ a wide variety of mating strategies in order to increase their reproductive success, which in turn influence their social behavior. In some populations of bottlenose dolphins (Tursiops spp.), males cooperate in small groups or alliances to gain access to females for mating. However, the occurrence of these male cooperative groups has been predicted to occur only under certain social and ecological conditions, driven by factors such as differences in population density, operational sex ratio, and sexual size dimorphism. Here, we used generalized affiliation indices, social network techniques, and maternally and bi-parentally inherited genetic markers to investigate the affiliation patterns and genetic relatedness among male southern Australian bottlenose dolphins (Tursiops cf. australis) in a small embayment in South Australia. Photo-identification data and biopsy samples were collected in Coffin Bay from 2013 to 2015 through systematic boat-based surveys. We found that highly sighted male dolphins formed 12 social clusters composed of two to five individuals. Genetic analyses revealed that general male affiliation patterns were significantly correlated with mtDNA haplotype sharing. In addition, preferred affiliates showed significantly higher levels of genetic relatedness compared to casual and avoided male pairs. Our results corroborate theoretical expectations for the formation of social bonds in small delphinids and suggest that a high density of dolphins, with an expected skewed operational sex ratio and no apparent sexual size dimorphism, is likely to have favored the formation of strong male affiliations. In addition, the availability of genetic relatives within the population may have favored male affiliations based on kinship relationships. Male bottlenose dolphins use different strategies to gain access to females, from single roving individuals, pairs or trios in alliances, to stable mixed-sex groups. Moreover, the role of kinship in the formation of male social bonds also varies within and among populations. This variability has been attributed to differences in ecological and intrinsic factors. Here, we studied the affiliation patterns and genetic relatedness in southern Australian bottlenose dolphins and demonstrated that kinship plays an important role in the formation of close male social ties. Furthermore, the results corroborate previous findings about the factors that contribute to the formation of male social bonds in these animals.

A Twin Study of Genetic Influences on Nephrolithiasis in Women and Men

BackgroundNephrolithiasis is a complex phenotype influenced by both genetic and environmental factors. Previously we found a genetic component to stone disease using a sample of male twin pairs. We now report on the genetic contribution to stones in a sample of female and male twin pairs.MethodsWe conducted a classic twin study of kidney stones using the Washington State Twin Registry. Data were collected by questionnaire to obtain self-reported history of kidney stones. Univariate structural equation modeling was used to determine the relative contributions of additive genetics, common environment, and unique environment.ResultsThere were 7053 same-sex pairs with kidney stone data. The mean age of the sample was 39 years, similar in women and men. The prevalence of stones was 4.9% of women and 6.2% of men. We found significant contributions from genetics and the unique environment (P < 0.05 for both) for the risk for stone disease in women and men. There was no significant contribution of the common environment for either sex. After adjusting for age, heritability was 46% (95% confidence interval 0.36–0.56) in women and 57% (0.46–0.68) in men, which was significantly different (P < 0.05).ConclusionsNephrolithiasis in women has a heritable component less than that we again demonstrate in men. This finding may in part explain why more stone formers are men than women. Women twins demonstrated a greater effect of the unique environment on stone prevalence. The specific environmental risk factors that account for this effect are not currently known.

Associations Between Features of Placental Morphology and Birth Weight in Dichorionic Twins.

Low birth weight is associated with perinatal and long-term morbidity and mortality, and may be a result of abnormal placental development and function. In studies of singletons, associations have been reported between features of placental morphology and birth weight. Evaluating similar associations within twin pairs offers a unique opportunity to control for key confounders shared within a twin pair, including gestational age, parental characteristics, and intrauterine environment. Data from 3 studies in the United States that were completed from 2012 to 2013, 2006 to 2008, and 1959 to 1966 were used in our analysis of 208 sets of dichorionic twins with unfused placentas. We used linear regression to model difference in birth weight within a twin pair as a function of differences in placental characteristics (i.e., thickness, 2-dimensional surface area, intraplacental difference in diameter). After controlling for sex discordance, a 75.3- cm2 difference in placental surface area, which reflects the interquartile range, was associated with a difference in birth weight of 142.1 g (95% confidence interval (CI): 62.9, 221.3). The magnitude of the association also may be larger for same-sex male pairs than same-sex female pairs (males: 265.8 g, 95% CI: 60.8, 470.8; females: 133.0 g, 95% CI: 15.7, 250.3). Strong associations between surface area and birth weight are consistent with reported results for singleton pregnancies.

Semen collection by electro-stimulation in a variety of bird orders

It is unquestinable that artificial insemination (AI) offers many benefits to avian conservation programs, but a serious impediment towards implementing AI for wild species is the development of effective techniques to consistently collect good quality ejaculates. Thus, we aimed to examine the success rate of electro-stimulation (ES) in collecting semen from 49 unconditioned males from orders Piciformes, Strigiformes, Accipitriformes, Cathartiformes, Galiformes, Anseriformes and Psittaciformes at different times of the year. Sixty out of 299 ES attempts provided ejaculates with sperm, but collection success rates varied widely (0–50%) depending on the species. Except for swans whose greater results were registered during spring-summer, males from most orders responded better to ES during winter-spring, suggesting seasonal variations on semen collection success rates. Overall, ES enabled successful semen collection from males of unproven and proven fertility under mixed pairing conditions. However, the highest success rate occurred in paired males with fertile clutches (40.6%) followed by unpaired males (22.1%), paired males without clutches (13.9%), and paired males with infertile clutches (6.8%). Behavioral responses of male birds to electrical impulses were also recorded to assess any discomfort during semen collection. Furthermore, macroscopic and microscopic analysis provided ejaculate parameters from several species, even from orders that hitherto have never been assessed for semen collection, which may serve as a starting point in the future. Altogether, these findings demonstrate the feasibility of ES in collecting semen from unpaired, unconditioned and non-imprinted males from a variety of bird orders. In the medium to long term, the use of this technique in both captive and free-ranging populations offers new perspectives to ensure genetic diversity in avian conservation programs.

Effects of reproductive experience on paternal behavior, levels of testosterone, prolactin in serum and dendritic spines in medial prefrontal cortex of mandarin voles.

Maternal behaviors and brains change dramatically with pregnancy, parturition and other mothering experiences. However, whether paternal behavior, brain plasticity and levels of relevant hormones also change along with fathering experience and pups' age remains unclear. Using socially monogamous mandarin voles (Microtus mandarinus), we found that experienced fathers exhibited more active paternal behaviors, such as licking, retrievals and nest building, but less paternal care, such as huddling, than new fathers. The high levels of licking and nest building appeared in the earlier days of their mate's lactation. Experienced fathers retrieved 9-13-day-old pups more frequently. However, these paternal behaviors did not show significant changes with age of pups in new fathers. In addition, experienced fathers had dramatically higher prolactin levels than new fathers but had similar concentrations of testosterone to new fathers. New fathers had lower levels of testosterone but higher levels of prolactin than new paired males. The fathers had higher prolactin levels in the earlier days of their mate's lactation. The new and experienced fathers had similar dendritic length and spine density on pyramidal neurons in the medial prefrontal cortex but displayed higher levels than new paired males. Taken together, these results indicate that reduction of testosterone levels and increase of prolactin levels may be associated with initiation of paternal care. Fathering experience significantly affects levels of parental care and paternal behaviors toward different aged pups, and brain plasticity can also be enhanced by transition to fatherhood.

Bad tenants: female sheet-web spiders, Cambridgea foliata (Araneae: Desidae), lose feeding opportunities when cohabiting with males

In web-building spiders, females are often too widely distributed across the landscape for males to monopolize more than one mate. Consequently, males seek females one at a time and may cohabit with females in their webs. Pre-copulatory cohabitation is most common in araneomorphs, which suggests that the first male to mate with a female will have a greater share of paternity than any subsequent mates (first sperm precedence). However, pairs of adult New Zealand sheet-web spiders (Cambridgea foliata (L. Koch, 1872); Desidae) cohabit for longer than required to achieve copulation. This is counter-intuitive as it suggests that males defend females they have already copulated with, in lieu of seeking additional mating opportunities. To investigate the costs and benefits of extended cohabitation on male and female C. foliata, we conducted surveys of webs of solitary and paired males and females. We found that solitary spiders of both sexes consistently position themselves in the center of their webs but that when in pairs, females are displaced from the webs by males and will frequently leave the web altogether. Males in pairs would respond to vibrations simulating prey, while females would not respond. This strongly suggests that extended cohabitation should be costly for females. By contrast, for males, cohabitation is a valuable foraging strategy which, combined with the advantages of mate-guarding, may compensate for any lost mating opportunities due to foregoing searching for further mates.