Histological Observation of Germ Cell Development and Discovery of Spermatophores in Ovoviviparous Black Rockfish(Sebastes schlegeli Hilgendorf) in Reproductive Season

Black rockfish(Sebastes schlegeli) is an important species for culture; however, its reproductive characteristics have not been fully documented. In this study, we investigated the morphology and developmental process of germ cells in this ovoviviparous rockfish in reproductive season(October 2011–November 2012) with histological methods. We found that the gonad of mature fish showed notable seasonal changes in developmental characteristics and morphological structure. The sperm cells matured during a period lasting from October to December, significantly earlier than the oocytes did. A large number of spermatozoa and other cells occurred in testis at different developmental stages. Vitellogenesis in oocytes began in October, and gestation appeared in April next year. Spermatophores were discovered for the first time in Sebastes, which assembled in testis, main sperm duct, oviduct and genital tract, as well as ovarian cavity in October and April. These organs may serve either as production or hiding places for spermatophores and spermatozoa which were stored and transported in form of spermatophores. Testicular degeneration started from the distal part of testis in April, with spermatophores assembled in degenerating testis and waiting for transportation. The copulation probably lasted for a long period, during which the spermatozoa were discharged in batches as spermatophores. These spermatophores were coated with sticky materials secreted from the interstitial areas of testis and the main sperm duct, then transported into ovary.

Relationship Between Behavioral Frequency and Reproductive Potential of Female Alpine Musk Deer in Captivity

Between June 2005 and February 2006, focal sampling and all occurrence behavior recording were used to quantify the behavioral patterns of captive female alpine musk deer （Moschus sifanicus） at Xinglongshan Musk Deer Farm, Gansu Province, China. Copulation success was used to differentiate individuals into two groups （successful and unsuccessful） and to provide a basis for behavioral comparisons, throughout both mating （rut） and non mating seasons. The results indicated significant differences between the behavior patterns of successful and unsuccessful females; however, the reproductive season played an important environmental factor. Pooling results across reproductive seasons, successfully copulating females showed significantly higher frequencies of vigilance and lower frequency of feeding behavior as compared with unsuccessfully copulating females. In the non-mating season, unsuccessfully copulating females had higher frequency of self-directed behavior, environment sniffing, and were less aggressive than successful copulating females. Furthermore, females who were successful at copulating also demonstrated tail-pasting behavior; however, this only occurred during the rut season. The results of this study can improve management practices for musk deer farms through increasing mating success and reducing maintenance costs. Furthermore, variation in behavior may also be used as a predictor of copulation success and reproductive potential, whereby females can be grouped and separated according to their reproductive history and past reproduction success.

Synthesis of (R)(E)-3,7-Dimethyl-2-octene-1,8-dioic Acid, a Copulation Released Pheromone Component of Azuki Bean Weevil

Started from 5-hydroxy-2-pentanone, (R)(E)-3,7-dimethyl-2-octene-1,8-dioic acid, callosobruchusic acid, was synthesized via five steps with D-(-)-camphor sultam as the chiral auxiliary. It was of good optical purity and yield.

Basolateral Amygdala Inactivation Reduces Sexual Motivation in Male Rats during Performance of a T-Maze Task with a Sexual Reward

This study was aimed to determine the effect of amygdaline inactivation on the sexual motivation of male rats during a T-maze task with a sexual reward. Subjects were chronically implanted with two stainless-steel cannulae that enabled the infusion of tetrodotoxin, a sodium channel blocker, into the left and right basolateral amygdala (BLA). Animals were divided into 3 groups: saline (SS);TTX1 (tetrodotoxin at 2.5 ng);and TTX2 (tetrodotoxin at 5.0 ng). To induce a sexually-motivated state, all male rats were allowed to have an intromission with a receptive female before performing the T-maze task, after which their sexual motivation was evaluated during seven trials in which a receptive female was placed in one goal-box of the T-maze, and a non-receptive one in the other. Subjects were allowed an intromission as a sexual reward whenever they reached the goal-box containing the receptive female, but were returned to the start-box if they did not. At the end of the experiment, copulation until ejaculation was permitted. Both doses of TTX increased the time rats required to cross the maze stem during the final trials. In terms of sexual interaction, the high dose of TTX increased more markedly mount, intromission and ejaculation latencies and the number of mounts and intromissions. Overall, these results indicate that the BLA may play an important role in modulating sexual behavior, particularly in maintaining sexual motivation in successive trials in a T-maze task and during sexual interaction per se.

Heart and ventilatory measures in crayfish during copulation

Monitoring heart rate (HR) and ventilatory rate (VR) during defined sensory stimuli and during aggressive and submissive social interactions has provided additional information of a crayfish's physiological state which is not achieved by behavioral observations. In this study, the HR and VR of crayfish were monitored before, during and after the act of copulation in both heterosexual partners. The female crayfish abruptly reduces HR and VR during copulation but the male maintains HR and VR. After separation from copulation the female HR and VR are elevated, potentially paying back the O2 debt. The tight relationship with HR and VR in direction of change indicates a potential neural coupling. These physiological changes in cardiac and respiratory systems suggest an autonomic-like regulation of HR and VR. How these neuronal functions are driven and regulated remains to be determined. Olfactory cues from the female to the male during copulation may be reduced by the reduction in VR in the female. These studies offer experimental paradigms for future neuronal and pharmacological investigations into autonomic regulation of HR and VR as well as the neural circuitry involved.

Increased serotonin concentration and tryptophan hydroxylase activity in reproductive organs of copulator males:a case of adaptive plasticity

Individual male rats may systematically display or not copulatory behavior when paired with receptive females. Although these phenotypes are associated with differences in brain organization and function, they might also do so at the level of the reproductive organs. We then used high performance liquid chromatography to quantify serotonin concentration and the activity of tryptophan hydroxylase in the reproductive organs of copulator and non-copulator males. Sexual behavior display was compared between groups and parameters of fertility and reproductive fitness were determined for copulator males. Copulator males had higher concentrations of serotonin in the epididymis, testicle and ventral prostate than their non-copulator counterparts, as it was found for epididymal and testicular tryptophan hydroxylase activity. However, preliminary data shows that serotonin elevation occurs in copulator males only until they have accumulated several sexual encounters, so it might be a response to genital gratification or sexual rewarding. Interestingly, only epididymal serotonin concentration correlated with reproductive fitness, offspring number, mating success and seminal plug volume in copulator males. Our results support that copulator and non-copulator male rats feature a phenotype-specific serotoninergic tone in the epididymis, testicle and ventral prostate gland. The observation documenting that epididymal serotonin concentration correlated with parameters that monitor male fertility and reproductive fitness in copulator males predicts that epididymal factors increase their chances of parenting offspring.

Sperm allocation strategies in a sperm heteromorphic insect

Theories predict that in polyandrous species,the focal male should increase sperm allocation per mate in the presence of rivals to gain greater share of paternity,but in the presence of additional mates,he should reduce sperm allocation per mate to save sperm for insemination of more mates.However,empirical findings are often inconsistent and reasons behind are unclear.Furthermore,many studies use copulation duration as an estimate of the number of sperm transferred.Yet,empirical evidence for such assumption is largely lacking.Here,we used a sperm heteromorphic insect Ephestia kuehniella whose males produce two types of sperm,eupyrenes(fertile)and apyrenes(nonfertile),to test these postulations.We allowed focal males to detect chemical and acoustic but no tactile cues from rivals or additional mates both before and during mating and measured copulation duration and sperm allocation in successive copulations.We demonstrate that males transfer significantly more eupyrenes per mate in the presence of rivals and that the sperm allocation pattern persists in successive copulations under this condition.However,males do not adjust apyrene allocation in response to rivals probably because apyrenes play a relatively minor role in male reproductive success.Contrary to a previous study,focal males do not respond to additional mates most likely due to the lack of tactile cues in the present study.We reveal that sperm allocation is not a function of copulation duration in this insect for spermatophore formation and delivery occupy most of copulation duration and sperm transfer is complete near the end of copulation.

Effects of mating status on copulation investment by male bushcricket Gampsocleis gratiosa (Tettigoniidae, Orthoptera)

Male’s copulation investment, including spermatophore; sperm investment were very high in the Chinese bushcricket Gampsocleis gratiosa. The effects of mating status of both males; females on male’s copulation investment were examined in this study. The fresh weight of spermatophylax increased positively with the weight of males’ body. This indicated that the nutritional investment during copulation depended on male’s quality. Spermatophore investment showed insignificant differences in every copulation protocols. This finding supported the paternal investment hypothesis, that is, males contributed to their offspring with little attention to their partners. Sperm releasing per ejaculation varied significantly among the trials. Males decreased 54.19% sperm in second mating than in its first mating, demonsrated that males regarded the first mating highly,; were more prudent in subsequent mating. These males’ strategies may contribute to the viability of the offspring.

The evolution of copulation frequency and the mechanisms of reproduction in male Anolis lizards

The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships among the integrated suite of structures associated with male reproduction. In this study, we examined nine species of lizards in the genus Anolis to determine whether larger copulatory morphologies and higher potential for copulatory muscle performance evolved in association with higher copulation rates. In 10--12 adult males of each species, we measured the size of the hemipenes and related muscles, the seminiferous tubules in the testes, and the renal sex segments in the kidneys, and we assessed the fiber type composition of the muscles associated with copulation. In a series of pbylogenetically-informed analyses, we used field behavioral data to determine whether observed rates of copulation were associated with these morphologies.We found that species with larger hemipenes had larger fibers in the RPM （the retractor penis magnus, a muscle that controls hemipenis movement）, and that the evolution of larg- er hemipenes and RPM fibers is associated with the evolution of higher rates of copulatory behavior. However, the sizes of the seminiferous tubules and renal sex segments, and the muscle fiber composition of the RPM, were not associated with copulation rates. Further, body size was not associated with the size of any of the reproductive structures investigated. The results of this study suggest that peripheral morphologies involved in the transfer of ejaculate may be more evolutionarily labile than internal structures involved in ejaculate production.

Mobility affects copulation and oviposition dynamics in Pieris brassicae in seminatural cages

When, how often and for how long organisms mate can have strong consequences for individual fitness and are crucial aspects of evolutionary ecology. Such determinants are likely to be of even greater importance in monandrous species and species with short adult life stages. Previous work suggests that mobility, a key dispersal? related trait, may affect the dynamics of copulations, but few studies have investigated the impact of individual mobility on mating latency, copulation duration and oviposition latency simultaneously. In this paper, we monitored the copulation dynamics of 40 males and 40 females, as well as the oviposition dynamics of the females of the Large White butterfly Pieris brassicae, a facultative long-distance disperser butterfly. Individuals from a breeding were selected to create a uniform distribution of mobility and we recorded the timing, number and duration of all copulations in a semiexperimental system. We showed that mobility, measured as the time spent in flight under stressful conditions (a proxy of dispersal tendency), correlates with all aspects of copulation dynamics: mobile males and females mated earlier and for shorter periods than less mobile individuals. In turn, late mating females increased the time between copulation and oviposition. These results feed the previously described mobility syndrome of R brassicae, involving morphological and physiological characters, with life-history traits. We suggest that the reduction of mating latency and copulation duration has an adaptive value in dispersing individuals, as their life expectancy might be shorter than that of sedentary individuals.

Fitness consequences of divorce in the azure-winged magpie depends on the breeding experience of a new mate

Sexual conflict in producing and raising offspring is a critical issue in evolutionary ecology research.Individual experience affects their breeding performance,as measured by such traits of provisioning of offspring and engagement in extra-pair copulations,and may cause an imbalance in sexual conflict.Thus,divorce is hypothesized to occur within aged social pairs,irrespective of current reproductive success.This concept was explored in the azure-winged magpie Cyanopica cyanus by investigating the divorce of a social pair and its relationship to their changes in breeding performance with prior experience.Females engaging in extra-pair copulation may intensify sexual conflicts and may be the main reason for divorce.Once divorced,females repairing with an inexperienced male realized higher reproductive success than that repairing with an experienced male;males repairing with an experienced female realized higher reproductive success than that repairing with an inexperienced female.This finding indicates that the fitness consequence of divorce depends on the breeding experience of new mates.Divorced females can obtain more extra-pair copulations,whereas divorced males cannot,when they repair with inexperienced breeders.Divorced females provisioned a brood at lower rates than inexperienced females whereas divorced males had no such difference.It appears that divorced females can obtain an advantage in sexual conflicts with inexperienced mates in future reproduction.Consequently,females are probably more active than males in divorcing their aged mates so as to select an inexperienced male as a new mate.Azure-winged magpies thus provide novel insights into the implicaticns of sexual conflict in birds.

Testes extracts inhibit heart contractions in females of the blood-feeding insect, Rhodnius prolixus

Myogenic contractions of the heart of the female blood-feeding insect, Rhodnius prolixus （Stal）, are inhibited by crude extracts of testes applied directly to isolated dorsal vessels. Dorsal vessels were observed with a stereo microscope and heart beats timed with a stopwatch. In normal Rhodnius saline, hearts contract at 14.8 4- 7.1 beats per minute （n = 45）. Crude extracts of the testes and the two male reproductive accessory organs （the opaque and transparent accessory glands） were prepared from previously frozen tissue by homogenizing 5-20 glands in a small glass homogenizer containing Rhodnius saline, centrifuging for 5 rain at 2 000 g, and collecting the supernatant. Testes extract as low as 1.0 glands per mL inhibit contractions whereas crude extracts of the opaque or transparent accessory glands have no consistent effect. We refer to this cardiac inhibitor as rhodtestolin （Rhodnius testis inhibitory factor）, and discuss its possible effects on the female during copulation.

Copulatory pattern and behavior in a semi-captive population of Eld＇s deer

Male copulatory patterns, female multiple copulation and male post-copulatory guarding were studied in Eld＇s deer Cervus eldi in Datian National Nature Reserve, China. Mating behavior in 18 females and 11 males from a group of 61 semi-captive Eld＇s deer were observed. The majority （55.8%） of copulations occurred between 15：00-19：00 h. The ejaculatory mount was preceded by an average of 5.1 prior mounts. Successful copulation consisted of a single thrust with ejaculation during one intromission, with no lock. This copulatory pattern is classified as pattern No. 15 （no lock, no intravaginal thrusting, single intromission, and multiple ejaculation） and No. 16 （no lock, no intravaginal thrusting, single intromission, and single ejaculation） under Dewsbury＇s scheme （1972） and as No. 16 （no lock, no thrusting, single and brief intromission） under Dixson＇s classification （1998）. Copulation frequency was 1.5 ± 0.9 times for males/females with the same female/male per day. The duration of the final mount, which included ejaculation, was brief （3.4±1.3 s）, and ejaculation usually terminated copulation. Eleven females copulated more than once in this study： three of them copulated with several males （multi-male copulations） and the remainder copulated with a single male （repeated copulations）. Our results indicate that some female Eld＇s deer may seek multiple copulations to be a strategy to improve the genetic quality of their offspring or to avoid harassment. Post-copulatory guarding of females by males followed all copulations, with dominant males guarding for significantly longer than subordinate males. Dominant males appear to be more effective at post-copulatory guarding than subordinate males. Subordinate males engaged in a quicker pre-copulatory phase to improve their chances of finishing copulation before being forced to accede to dominant males [Current Zoology 57 （3）： 284-292, 2011].

Inter-sexual multimodal communication during mating in wild geladas:the leading role of females

Female primates can emit vocalizations associated with mating that can function as honest signals of fertility.Here,we investigated the role of mating calls and visual signals in female geladas(Theropithecus gelada).Because females have a central role in the gelada society and seem to solicit sexual interactions,we answered whether they emit vocalizations in conjunction with gazing to increase mating success probability.Before and during copulations,females can emit pre-copulation calls and copulation calls.For the first time,we identified a new female vocalization emitted at the final stage of copulations(end-copulation call),possibly marking the occurrence of ejaculation.We found that longer pre-copulation call sequences were followed by both prolonged copulations and the presence of end-copulation calls,thus suggesting that females use pre-copulation calls to ensure successful copula completion.Moreover,we found that different combinations of female vocal types and gazing had different effects on male vocal behavior and motivation to complete the copula.The analysis of the vocal and visual signals revealed a complex inter-sexual multimodal chattering with the leading role of females in the signal exchange.Such chattering,led by females,modulates male sexual arousal,thus increasing the probability of the copula success.

Observation of intra-group and extra-group copulation and reproductive characters in free ranging groups of western black crested gibbon(Nomascus concolor jingdongensis)

Black crested gibbons(Nomascus concolor)are 1 of only 3 gibbon species that have been observed in long-term polygynous groups,but their mating behavior and reproductive characters have never been reported.Based on population monitoring over 7 years and direct observation for 26 months of the study groups in Wuliang Mountain,central Yunnan,we describe for the first time the copulation behavior and breeding pattern of free-ranging western black crested gibbons.The gestation period of black crested gibbons is estimated to be between 6 and 7 months.The average breeding interval is 3.5 years,with infant independence at approximately 2.5 years.We observed 2 intra-group copulations and 5 extra-group copulations.Copulations were initiated when a female gave a‘solicitation’gesture.When a male made any mating attempt,the female might refuse it.These results demonstrate direct female mate choice.Both male and female gibbons dispersed from their natal groups and sometimes replaced paired adults in other groups.We observed no evidence of infanticide during inter-group conflicts or after replacement of adults.Together with extra-group copulations,these phenomena indicate a flexible social organization and complex mating system.We also observed a male-biased sex ratio among offspring.More genetic work is necessary to describe the effects of inter-group copulation and the genetic diversity of this population.

Female preferences for male golden snub-nosed monkeys vary with male age and social context

Age is a key factor affecting sexual selection,as many physical and social traits are age-related.Although studies of primate mate choice often consider particular age-related traits,few consider the collective effects of male age.We tested the hypothesis that female golden snub-nosed monkeys Rhinopithecus roxellana prefer prime aged males(10-15 years)over younger and older males.We examined a habituated,provisioned troop during a 3-year study in the Qinling Mountains,China.Prime age males were more likely to be resident males of 1-male units(OMUs)than males of other ages.Since females are free to transfer between OMUs,the number of females per OMU can be indicative of female preferences.We examined the number of females per OMU,and found that it increased with resident male age up to 7-8 years,and declined after 12 years,such that prime age resident males had more females than other resident males.Females also initiated extra-unit copulations with high-ranking prime age males at significantly higher rates than with other males.Nevertheless,females tended to transfer from OMUs with high-ranking,older resident males to those with low-ranking,younger resident males.Thus,females appear to use different strategies when choosing social mates and extra-unit mates(i.e.,different social contexts).We speculate that females may perceive early signs of aging in males and trade off the benefits and costs of high rank versus male senescence.This study lays the groundwork for future studies that examine possible direct and indirect benefits of such strategies.