Diestrus Research Articles

Effect of two chamber type with different depths on stallion sperm kinematic parameters

Thirteen dromedaries were used to study the relationship between the size of the dominant follicle, vaginal electrical resistance (VER), sexual receptivity, and serum concentrations of oestradiol-17β (E2) and progesterone (P4) throughout the follicular phase. On a daily basis, the animals experienced teasing with a vasectomised camel, trans-rectal ultrasound examination of the ovaries, and measurement of VER and blood collection for serum E2 and P4. Results revealed no significant differences between the mean VER in the animals that had a follicle of 5–10 mm (group I, n = 11), 11–15 mm (group II, n = 12) and 16–20 mm (group III, n = 13). The VER did not correlate with the follicular size. The E2 concentrations in the animals in groups II (60.14 pg/ml) and III (66.52 pg/ml) were significantly (P < 0.05) higher than those of animals in group I (48.31 pg/ml). E2 was positively correlated (r = 0.50; P < 0.05) with the overall size of the follicles. The P4 concentration was significantly (P < 0.05) lower in the animals of group II than in those in groups I and III. Serum P4 concentrations were inversely correlated (r = −0.40; P < 0.05) with the overall size of the follicles. Complete sexual receptivity was reported in 63.64%, 16.67% and 76.92% of the animals in groups I, II and III, respectively. In group III, significant (P < 0.05) complete sexual receptivity was confirmed. However, 23.08% of the animals were incompletely receptive. In conclusion, impedometric characteristics of the vaginal mucosa were not a reliable method for predicting the dominant follicular size during the follicular phase in dromedary camels.

Estrogen and progesterone priming induces lordosis in female rats by reversing the inhibitory influence of the infralimbic cortex on neuronal activity of the lateral septal nucleus

The lateral septal nucleus (LSN) exerts inhibitory control over lordosis in female rats, but the influence of forebrain structures, such as prelimbic (PL) and infralimbic (IL) regions of the medial prefrontal cortex (mPFC), on LSN activity during sexual receptivity is unknown. We hypothesized that the neural responsivity of these connections may differ depending on sexual receptivity. Gonadally intact female Wistar rats received sequential priming injections of estradiol and progesterone (E2-P4). The presence of lordosis was then confirmed by exposing the female rats to a sexually experienced male rat. Intromission was not allowed. Vaginal smear analyses verified that the rats were in proestrus-estrus of the estrous cycle. The results were compared with a diestrus group, which was verified by vaginal smears and the absence of lordosis. Under ethyl-carbamate anesthesia, single-unit extracellular recordings of the LSN were performed during electrical stimulation of the PL and IL to evaluate possible changes in the responsivity of neural connections. Stimulation of the PL or IL produced a short-latency, brief-duration (paucisynaptic) excitatory response in the LSN, followed by a period of afterhyperpolarization. Responsivity of the PL-LSN pathway was unaffected by E2-P4 priming. The paucisynaptic response of the IL-LSN pathway was significantly greater in the E2-P4-primed group than in the diestrus group, and the afterhyperpolarization response decreased to nearly zero. These findings indicate that the IL exerts inhibitory control over the LSN during diestrus in rats, but this inhibitory control decreases under the action of gonadal steroids, seemingly favoring sexual receptivity.

Sexual experience with a known male modulates c-Fos expression in response to mating and male pheromone exposure in female mice

Sexually naïve female mice are not sexually receptive in their first mating opportunity. Four to five sexual encounters are needed to display high sexual receptivity as assessed by the lordosis reflex. The neuronal changes induced by sexual experience are not well understood. In this study, we evaluated if repeated sexual stimulation with the same male was associated with an increase in the neuronal activity evaluated by c-Fos expression in brain structures associated with the control of sexual behavior such as the accessory olfactory bulb (AOB), ventromedial hypothalamus (VMH), and the medial preoptic area (MPOA). Ovariectomized female mice were randomly distributed into three groups: sexually naïve (SN), with no prior sexual stimulation; sexually inexperienced (SI), with one prior mating session; and sexually experienced (SE), with six prior mating sessions. Females were primed with estradiol benzoate and progesterone once a week for 7 weeks. Neuronal activation in response to mating or soiled bedding was evaluated in the 7th week. Each group was subdivided into three subgroups: clean (exposure to clean bedding), male bedding (exposure to sawdust soiled with secretions from a male), or mating. Each female mated with her assigned male; in the exposure subgroup, soiled bedding was obtained from the male with whom she mated.Neuronal activity data showed that SE females had a higher c-Fos response in the VMH when they mated in comparison to females exposed to clean bedding. SI females that mated had a decrease c-Fos expression in the glomerular cell layer of the AOB, compared to females exposed to male bedding. The mitral cell layer showed a higher c-Fos response in SI females that mated in comparison to those exposed to male bedding. Comparisons between groups presented with the same stimulus indicate that SI females exposed to male bedding showed a decrease in c-Fos response in the mitral cell layer in comparison to SE and SN females. Correlation analysis demonstrated that the lordosis quotient from the last mating test correlated positively with the number of c-Fos-positive cells in the mitral cell layer in SE and SI groups. A similar correlation was found in the MPOA in SI females. Prior mating in female mice is required to increase sexual receptivity. Changes in the neuronal activity in the AOB and VMH may be involved in the neuronal plasticity induced by repeated sexual stimulation.

Rethinking traditional husbandry practices – changing the lengths to which lambs’ tails are docked

Animals have tails for many reasons, such as helping with balance, providing shade, for use in defence, for dealing with skin irritations, as a means of locomotion and to aid...

The non-aromatizable androgen dihydrotestosterone (DHT) facilitates sexual behavior in ovariectomized female rats primed with estradiol

It is still unclear whether Testosterone (T) increases sexual desire through a stimulation of the androgen receptor in relevant brain regions or through its conversion to estrogens. The aim of this study was to clarify the mechanisms of T facilitation of female sexual desire by assessing the effect of a non-aromatizable androgen (Dihydrotestosterone, DHT) in a validated animal model.Ovariectomized (OVX) Long-Evans rats were treated with oil (O) + O, 10 mcg Estradiol Benzoate (EB) + O, 10 mcg EB + 500 mcg Progesterone (P), O + 500 mcg DHT or 10 mcg EB + 500 mcg DHT (n = 12 per group). EB was administered 48 h, while P and DHT 4 h, prior to 4 sexual behavioral testing sessions in bisected unilevel pacing chambers. Appetitive behaviors (the frequencies of hops/darts and solicitations) were considered as the main outcome measure. Sexual receptivity indexes [lordosis magnitude, expressed as lordosis rating (LR), and lordosis quotient (LQ)], rejection responses, as well as mounts, intromissions and ejaculations received from the male were also coded. The probability of transition among sexual behaviors was evaluated by Transition Matrices; T-Pattern analysis was performed to detect hidden repeated temporal behavioral sequences.Preliminary analyses found no statistically significant differences between the O + O and EB + O groups, therefore we excluded the EB + O group from further analyses. Rats treated with EB + DHT displayed significantly more appetitive behaviors compared to negative controls (O + O and O + DHT), whereas no difference was observed between EB + DHT rats and positive controls (EB + P); noteworthy, a higher number of appetitive behaviors was observed in the O + DHT group compared to the O + O group. Furthermore, rats treated with EB + DHT showed significantly higher receptivity measures (LR and LQ) and received more mounts, intromissions and ejaculations compared to negative controls (O + O and O + DHT), to levels equivalent to EB + P. No differences were detected in female-male mounts or rejection responses among the 4 groups. Under a qualitative perspective, full solicitation was found exclusively in T-patterns of the EB + DHT group, which was also the only one to display T-patterns of higher order encompassing appetitive behaviors-only events.In conclusion, the administration of DHT in EB-primed OVX Long-Evans rats enhances sexual behavior measures. Specifically, DHT seems to stimulate sequences of appetitive behaviors separated from copulative/reproductive measures. Our data support an independent role of androgens in the facilitation of female sexual desire.

Simultaneous choice bioassays accompanied by physiological changes identify civetone and decanoic acid as pheromone candidates for giant pandas.

Chemicals present in urine are thought to play an important role in mate identification in the solitary giant panda (Ailuropoda melanoleuca). During the breeding season, females will deposit chemical signals to advertise sexual receptivity to potential mates. The goal of this study was to determine if specific volatile compounds found in female urine could be considered as pheromones that elicit behavioral and physiological responses in males. Experimental simultaneous choice trials were conducted with captive male giant pandas (n = 3) housed at Memphis Zoo, San Diego Zoo, and Zoo Atlanta. Octanoic acid, 1H-pyrrole-2-carboxaldehyde, decanoic acid, and civetone were selected as stimuli because previous studies reported their elevation in urine during the breeding season. Male interest was determined by a behavioral preference toward these volatile compounds diluted in synthetic urine compared with nontreated synthetic urine. Male urine samples were collected 1 week prior, during, and 1 week after the experimental period to assess changes in urinary semiochemical composition and urinary androgen concentrations. No significant differences in investigation response (p = .395) or flehmen response (p = .600) were found when stimuli were compared; however, decanoic acid and civetone elicited a behavioral preference over the control (response ratio > 0.5). The relative abundance of 16 compounds identified in male urine was significantly elevated (p < .05) above baseline values after the males were exposed to the stimuli. Androgen levels were significantly elevated (p < .05) in one male after exposure to 1H-pyrrole-2-carboxaldehyde, decanoic acid, and civetone. These data suggested that civetone and decanoic acid in female urine may motivate sexual responses in males.

A Feedforward Circuit Regulates Action Selection of Pre-mating Courtship Behavior in Female Drosophila.

In the early phase of courtship, female fruit flies exhibit an acute rejection response to avoid unfavorable mating. This pre-mating rejection response is evolutionarily paralleled across species, but the molecular and neuronal basis of that behavior is unclear. Here, we show that a putative incoherent feedforward circuit comprising ellipsoid body neurons, cholinergic R4d, and its repressor GABAergic R2/R4m neurons regulates the pre-mating rejection response in the virgin female Drosophila melanogaster. Both R4d and R2/R4m are positively regulated, via specific dopamine receptors, by a subset ofneurons in the dopaminergic PPM3 cluster. Genetic deprivation of GABAergic signal via GABAA receptor RNA interference in this circuit induces a massive rejection response, whereas activation of GABAergic R2/R4m or suppression of cholinergic R4d increases receptivity. Moreover, glutamatergic signaling via N-methyl-d-aspartate receptors induces NO-mediated retrograde regulation potentially from R4d to R2/R4m, likely providing flexible control of the behavioral switching from rejection to acceptance. Our study elucidates the molecular and neural mechanisms regulating the behavioral selection process of the pre-mating female.

Optogenetic Activation of β-Endorphin Terminals in the Medial Preoptic Nucleus Regulates Female Sexual Receptivity.

Estrogen and progesterone (P4) act in neural circuits to elicit lordosis, the stereotypical female sexual receptivity behavior. Estradiol acts through membrane receptors to rapidly activate a limbic-hypothalamic circuit consisting of the arcuate (ARH), medial preoptic (MPN), and ventromedial (VMH) nuclei of the hypothalamus. This initial activation results in a transient but necessary inhibition of lordosis, which appears to be a result of the release of β-endorphin (β-End) from proopiomelanocortin (POMC) terminals onto cells containing the µ-opioid receptor (MOR) in the MPN. To functionally examine the role of the MOR in the hypothalamic lordosis circuit, we transfected a channelrhodopsin (ChR2) adeno-associated virus into POMC cell bodies in the ARH and photostimulated POMC/β-End axon terminals in the MPN in sexually receptive female Pomc-cre mice. Following estrogen and P4 priming, sexual receptivity was assessed by measuring the lordosis quotient (LQ). Following an initial trial for sexual receptivity, mice were photostimulated during behavioral testing, and brains were processed for MOR immunohistochemistry (IHC). Photostimulation decreased the LQ only in ChR2-expressing Pomc-cre mice. Furthermore, photostimulation of ChR2 in POMC/β-End axon terminals in the MPN resulted in the internalization of MOR, indicating activation of the receptor. Our results suggest that the activation of the MOR in the MPN is sufficient to attenuate lordosis behavior in a hormone-primed, sexually receptive female mouse. These data support a central role of MOR in female sexual behavior, and provide further insight into the hypothalamus control of sexual receptivity.

Neuroscience: Plasticity Matters for Mating.

It remains unclear how hormonally mediated internal states affect specific brain circuits to modify behaviour. A new study reveals that a hypothalamic projection pathway critical for female sexual receptivity is extensively remodelled during the estrous cycle.

300 Efficacy of the measurements of the vaginal electrical resistance to determine the phase of the estrous cycle in lactating dairy cattle

Abstract Estrus detection in dairy cattle is an important factor that contributes to the reproductive efficiency. Lack and inaccuracy of heat detection are associated with increased days open, calving interval, economic loss and culling due to infertility. Efforts have been made to identify methods to assist in estrus detection. The objective of this study was to examine if vaginal electrical resistance (VER) measured by a commercial probe throughout the estrous cycle in lactating dairy cows aids to determine the onset of estrus. A total of 9 lactating Holstein cows were monitored for 2 – 3 estrous cycles, ultrasonography of the ovary, blood sample for progesterone and VER was assessed every other day during the luteal phase (LUT) and every day during the follicular phase (FOL). A total of 339 VER measurements were collected, 66 during the FOL phase and 273 corresponded to the LUT phase. Mean VER differed (P &amp;lt; 0.001) between FOL (294.5 ± 51.3) and LUT (316.4 ± 46.2), similarly the progesterone concentration was different between the LUT and FOL phases (0.38 ± 0.24 ng/mL vs. 3.41 ± 2.08 ng/mL, respectively) (P &amp;lt; 0.001). No differences were observed between the vaginal temperature of cows in LUT (38.2 ± 0.4 C°) or FOL phase (38.3 ± 0.3 C°). Cervix diameter differed (P &amp;lt; 0.01) between FOL (35.9 ± 3.8 mm) and LUT (34.5 ± 3.4mm), VER has a significant relation (P &amp;lt; 0.001) with the diameter of the Corpus luteum (279.8 + 1.54 x Cervix diameter). Similarly, VER had a significant relationship (P = 0.03) with diameter of the dominant follicle at estrus (355.2 + -3.9 x follicle diameter). These findings suggest that VER changes according to the phase of the estrous cycle, VER decreased during sexual receptivity and increased during the luteal phase. VER may improve the accuracy to diagnose heat in dairy cows.

7 Pregnancy from a vitrified-warmed alpaca pre-implantation embryo

The alpaca (Vicugna pacos) is a ruminant livestock species in the South American camelid family. There are more than 9 million South American camelids globally that make important contributions to the livelihoods of rural farmers through conversion of low quality roughages to high quality food and fibre. Reproductive biotechnologies for alpacas are not well developed compared with those for other ruminant livestock species. In particular, embryo cryopreservation technologies are lacking. The objective of this study was to evaluate under field conditions a vitrification protocol originally developed for old world camels that we adapted for use in alpacas. Potential donors were evaluated for follicular development using a 7.5-MHz ultrasound probe. Hembras (sexually mature female alpacas) with ovarian follicles 7-10mm in diameter were behaviour tested to determine sexual receptivity, and receptive females were naturally mated to a proven herd sire. At the time of breeding, non-superovulated donors (n=4) received 30μg gonadorelin. Embryos were nonsurgically collected 7 days after breeding and handled at 20°C. Diameter of harvested embryos (n=4 quality grade 1 hatched expanded blastocysts) was measured using an eyepiece reticle. All recovered embryos were placed individually into 0.5-mL drops of vitrification solution (VS1: 1.4M glycerol) for 5min, 0.5-mL drops of VS2 (1.4 M glycerol + 3.6M ethylene glycol) for 5min, 0.05-mL drops of VS3 (3.4 M glycerol + 4.6M ethylene glycol) for 20s, and 0.05-mL drops of VS3 for 20s while loading into open-pulled straws (OPS). Each OPS was plunged directly into liquid nitrogen for storage for 29 days. At warming, each OPS was submerged into a 1-mL drop of warming solution 1 (WS1: 0.5M galactose) for 1min followed by 1min in WS2 (0.25 M galactose) for 5min before being incubated at 37°C in 5% CO2 in humidified air for 21h in 1mL of Syngro holding medium supplemented with 10% (vol/vol) alpaca serum. Embryos that grew during culture (n=2) were transferred individually into synchronous recipients, and embryos that did not appear to grow (n=2) were transferred together as a pair. Prior to embryo transfer, potential recipients were evaluated ultrasonographically as described previously. Hembras with ovarian follicles 7-10mm in diameter were behaviour tested, and sexually receptive females received 30μg gonadorelin 6 days before embryo transfer. Final selection of recipients (n=3) was based on presence of a corpus luteum and nonreceptive behaviour to a herd sire 24h before transfer. Pregnancy was detected ultrasonographically, and fetal heartbeat was detected 29 days post-transfer in one of the three recipients. Ultrasound at 177 days post-transfer revealed that the pregnancy, generated from a 400μm×375μm vitrified-warmed embryo that had grown in culture, was still ongoing. If this pregnancy results in the birth of a live cria (newborn alpaca), it would represent-to the best of our knowledge-the world's first cria born from a cryopreserved alpaca pre-implantation embryo. It would also demonstrate the potential utility of this protocol under field conditions.

Ovarian Hormones Mediate Changes in Adaptive Choice and Motivation in Female Rats.

In female rodents, sexual receptivity is coordinated with cyclic changes in the release of gonadal hormones. Increases in estradiol (E) and progesterone (P) during proestrus and estrus not only induce ovulation but also modulate behaviors that increase the likelihood that the female will find a mate and reproduce. This includes changes in receptive behaviors, such as lordosis, as well as changes in appetitive or proceptive behaviors, including motivation. Interestingly, the direction of these changes in motivation is dependent on the type of reward that is being pursued. While induction of sexual receptivity by E and P increases motivation for access to a male, motivation for a palatable food reward is decreased. These concurrent changes may facilitate adaptive choice across the estrous cycle; females bias their choice for sex when fertilization is most likely to occur, but for food when copulation is unlikely to result in impregnation. In order to test this hypothesis, we developed a novel paradigm to measure the motivated choice between a palatable food reward and access to a male conspecific. Ovariectomized, hormone primed females were trained to operantly respond for both food and sex on a fixed interval (FI) schedule. After training, unprimed and primed females were tested in a chamber that allows them to choose between food and sex while still requiring responding on the FI schedule for reach reward. From this we can not only determine the impact of hormone priming on female choice for food or sex, but also how this is reflected by changes in motivation for each specific reward, as measured by the average number of responses made during each fixed interval. Induction of sexual receptivity by hormone priming biases choice toward sex over food and this change is accompanied by an increase in motivation for sex but a decrease in motivation for food. This work provides evidence in support of a novel framework for understanding how the release of ovarian hormones over the course of the estrous cycle modulates adaptive behavioral choice in females by directly assessing motivation via operant responding when multiple rewards are available.

Hormonal modulation of reproduction in Polistes fuscatus social wasps: Dual functions in both ovary development and sexual receptivity

Hormones are often major regulators of complex behaviors, such as mating and reproduction. In insects, juvenile hormone (JH) is integral to many components of reproductive physiology and behavior, but its role in female sexual receptivity is not well understood. To investigate the influence of JH on receptivity, we utilized the social wasp Polistes fuscatus. In Polistes, mating behavior is temporally separated from other components of reproduction, which allows for examination of the physiology and behavior of mating, disentangled from fertilization and egg-laying. We reared virgin gynes (reproductive females) in the lab and divided them into four groups, in which gynes received multiple topical treatments of either 20 μg, 10 μg, 5 μg, or 0 μg of the JH analog methoprene. Gynes were then placed in petri dishes with 2 unrelated males and we recorded attempted and successful mating. Additionally, we measured gyne ovarian development and survival in each group. We found that methoprene increased both sexual receptivity and ovarian development, but was associated with a decrease in long-term survival. Receptivity increased linearly as methoprene treatment increased, but the effect of methoprene on ovarian development was independent of dose. These results demonstrate the importance of JH in sexual receptivity and mating behavior. We argue that the relatively understudied Polistes gyne has potential as a model for mating and reproduction, and for the internal and external regulation of this complex behavior.

Vaporized Cannabis differentially modulates sexual behavior of female rats according to the dose

Studies exploring the effect of compounds that modulate the endocannabinoid system on sexual behavior have yielded contradictory results. However, the effect of smoked Cannabis in women has been consistently associated with an increase in sexual drive. Therefore, it can be speculated that vaporized Cannabis will augment sexually motivated components of the sexual behavior of female rats. To test this hypothesis, we compared the sexual behavior of late-proestrous female rats in a bilevel chamber after vaporizing 0, 200 or 400 mg of Cannabis flowers (containing 18% of delta-9-THC and undetectable levels of cannabidiol) during 10 min. We found that both doses of Cannabis increased the duration of the lordosis response, whereas the highest dose also reduced the lordosis quotient of females. The lowest dose of Cannabis augmented the display of hops and darts without altering the expression of sexual solicitations of females, while the highest one did not affect the expression of hops and darts but reduced sexual solicitations. These effects were not accompanied by alterations of females' ambulatory behavior. The increment of the duration of lordosis response produced by both doses of Cannabis could be associated to a general effect of this drug in sensory processing, as can be an enhancement of females' sensory reactivity to male's stimulation. However, the reduction in the display of solicitations and lordosis in response to mounting observed in females exposed to the highest dose when compared to control and 200 mg of Cannabis groups indicates a reduction of sexual receptivity and motivation. This differential effect of vaporized Cannabis according to the dose employed, suggests that it modulates sexual behavior in a complex way, impacting neural circuits that control different aspects of this social behavior.

Effects of Cannabinoids on Female Sexual Function.

With the legalization of both medical and recreational marijuana in some countries and a few US states, its use has become more widely prevalent. Both exogenous cannabinoids such as tetrahydrocannabinol (THC) and endogenous cannabinoids (endocannabinoids) have been shown to affect female gonadotropin pathways and female sexuality. Yet, our understanding of the mechanisms and effects on female sexual function is limited. To review the literature regarding the effects of both endogenous and exogenous cannabinoids on female sexual function in both animals and humans. We performed a PubMed search for English-language articles in peer-reviewed journals between 1970 and 2019. We used the following search terms: "cannabinoids," "endocannabinoids," "marijuana," "cannabis," and "female sexual function" or "sexual function." The main outcomes of the papers were reviewed. The main outcome measure was sexual function in females. A total of 12 human studies and 8 animal studies that evaluated the relationship between cannabinoids and female sexual function were included. Study types in animals were blinded, prospective, placebo-controlled trials. Human studies were based primarily on questionnaire data. The data indicate dose-dependent effects on female sexual desire and receptivity, such that low doses generally facilitate or have no effect but high doses inhibit. More research is needed to develop a better understanding of the effects of cannabinoids on female sexual function. There does appear to be an effect on both animals and humans, but whether the effect is positive or negative along dose and species lines requires more study. With the legalization of marijuana occurring in more countries and more US states, there needs to be more well-controlled studies evaluating the effects. Lynn B, Gee A, Zhang L, etal. Effects of Cannabinoids on Female Sexual Function. Sex Med Rev 2020;8:18-27.

Neuropeptide B mediates female sexual receptivity in medaka fish, acting in a female-specific but reversible manner

Male and female animals display innate sex-specific mating behaviors. In teleost fish, altering the adult sex steroid milieu can effectively reverse sex-typical mating behaviors, suggesting remarkable sexual lability of their brains as adults. In the teleost medaka, neuropeptide B (NPB) is expressed female-specifically in the brain nuclei implicated in mating behavior. Here, we demonstrate that NPB is a direct mediator of estrogen action on female mating behavior, acting in a female-specific but reversible manner. Analysis of regulatory mechanisms revealed that the female-specific expression of NPB is dependent on direct transcriptional activation by estrogen via an estrogen-responsive element and is reversed in response to changes in the adult sex steroid milieu. Behavioral studies of NPB knockouts revealed that female-specific NBP mediates female receptivity to male courtship. The female-specific NPB signaling identified herein is presumably a critical element of the neural circuitry underlying sexual dimorphism and lability of mating behaviors in teleosts.

Housing Rabbit Does in a Combi System with Removable Walls: Effect on Behaviour and Reproductive Performance

Simple SummaryThis study focuses on the welfare and reproductive performance of rabbit does housed in individual conventional cages (C) or in different colony cages: simple (does in the group for 100% of the reproductive cycle: C1) or combi (in both individual and group caging: C2). The results showed that C2 had some benefits compared to continuous grouphousing, but both colony systems achieved lower reproductive performance levels than the conventional system. Although C2 showed some improvement on the behaviour of does, the aggressiveness of group-housing the does to establish a rank order was responsible for injuries, higher disease risks, and higher kit mortality.We evaluated the effects of two types of colony cages, in which rabbit does were always in a group (C1), and where they were in combi cages furnished with removable internal walls to allow both individual and grouphousing (C2), in addition to the control group (C: conventional individual cage), on welfare, reproductive performance, and global efficiency. Forty-eight New Zealand White nulliparous rabbit does underwent artificially insemination (AI) and were divided into three groups, and reared in the different systems for about 1 year. The reproductive rhythm provides AIs at weaning (30d). In the C1 system, does were continuously grouped, while in C2, walls were inserted four days before kindling and removed 1week after it (60% of the timesheet in group). Reproductive traits and behaviour were evaluated during the entire year. The behavioural observations were performed around days 7, 36, and 44, corresponding to the inclusion of the does in the maternal cages, the insertion of walls four days before kindling, and the removal of the walls 1week after parturition in the C2 group, respectively. The percentages of does with severe skin injuries and the distribution of the injuries on different parts of body were also registered. Does reared in conventional cages showed the greatest presence of stereotype behaviours, while the C1 group showed the highest (p < 0.05) incidence of aggressiveness after regrouping (attack, dominance features, and lower allo-grooming) in comparison to the C2 group (17% and 22%, in C2 and C1 does, respectively).Individually caged does achieved the best productive performance (sexual receptivity, fertility, kindling rate, and number of kits born alive and at weaning). The C1 group showed the lowest performance (p < 0.05), whereas C2 showed an intermediate one. Does housed in the combi cage (C2) had higher (p < 0.05) receptivity and fertility rates and higher numbers of kits born alive and at weaning (79.2% and 76.2%; 7.95 and 7.20, respectively) than the C1 group, but lower values (p < 0.05) than does that were individually housed.

Spiders, microbes and sex: Bacterial exposure on copulatory organs alters mating behaviour in funnel‐web spiders

AbstractEnvironmental microbes have the potential to be involved in nearly all behavioural processes. For example, mating systems where males use intromittent organs to transfer sperm to females represent a means by which environmental microbes collected by males can breach entry into females' body cavities during mating. However, the degree to which the acquisition of environmental microbes onto important sex structures alters courtship behaviours remains unknown. Here, we collected bacteria from the copulatory organs of Agelenopsis pennsylvanica funnel‐weaving spiders in situ to test whether exposure to bacteria on copulatory organs can alter hosts' courtship behaviour, reproductive success and survival. We used a standardized assay to repeatedly measure each spider's aggressiveness, a behavioural component of both male courtship and female sexual receptivity. Then, we experimentally altered the bacteria present on male and female spiders' copulatory organs with an application of either (a) a mixture of bacteria collected from conspecifics to increase bacterial presence, (b) an antibiotic to reduce bacterial presence or (c) a procedural control. Each spider was paired with a size‐matched spider of the opposite sex whose copulatory organs were unaltered, and we measured the latency until the onset and the duration of courtship. Spiders were then isolated, and we measured each individual's time until death and female fecundity over the next 40 days. We found that female exposure to bacteria had multiple effects on mating dynamics. Males took over four times longer to begin courting females that had been exposed to bacteria compared to unexposed and antibiotic‐treated females. Only when courting these bacteria‐exposed females, males began courtship sooner when females were more aggressive. Lastly, females whose mate had been exposed to bacteria experienced reduced survival. These data suggest that bacteria present on animals' copulatory organs can alter courtship behaviours, female survivorship, and may potentially play a role in mating dynamics.

Female secondary sexual traits in spiders: Adaptive interpretations of the sternum projection in the pholcid Holocnemus pluchei

Sexually dimorphic traits are the outcome of a network of selective pressures acting upon each sex. While male secondary sexual traits are frequently restricted to intrasexual competition, female ornaments or weapons are mostly associated to social interactions for the access to limited resources. Here we investigate a sexually dimorphic trait expressed within the female's sternum of the spider species Holocnemus pluchei (Pholcidae), and its adaptive maintenance under the three leading hypotheses: sexual receptivity signaling, mate choice and sexual conflict hypothesis. We provide fine-scaled behavioral descriptions of the copulatory behavior of Holocnemus pluchei, corroborating that mating interactions are mediated by the female's sternum projection. The single moment of contact between the female projection and male body occurs during sperm transfer, always followed by a reduction on the intensity of the male genital movement. Additionally, biometrical properties of the female sternum projection corroborate our functional interpretation for the trait as restricting the intensity of males' copulatory movements. We claim that female sternum projection is a sexually selected trait mediating sexual conflict, with several adaptive consequences upon the sexes.

Field air analysis of volatile compounds from free-ranging giant pandas

Giant pandas (Ailuropoda melanoleuca) use chemical cues to determine identity, gender, and sexual receptivity of conspecifics. We hypothesized that volatile chemical profiles of free-ranging giant pandas are detectable in air. Therefore, we aimed to identify volatile compounds produced by free-ranging giant pandas residing in the Wolong Nature Reserve (Sichuan, China) through field air analysis/solid phase microextraction/gas chromatography–mass spectrometry (FAA/SPME/GCMS). From 28 June to 12 July 2017, 3 SPME fibers were secured to trees that appeared to have previous marking activity. Trail cameras confirmed that a single giant panda performed scent-marking behavior at one sampling location. The abundance of 7 compounds were elevated in samples collected from the tree visited by the giant panda compared with controls. Three of these compounds (Ethane, 1,1-dinitro-; Octane, 4-ethyl-; 2(1H)-Pyridinethione, 3-ethoxy-6-methyl-) were unique to the giant panda visit. Novel methods to detect giant pandas would benefit conservation efforts. We suggest our method also may be used to study chemical communication in other bear species.