Cumulative Effect of Male's Displays in the Sexual Behaviour of the Smooth Newt Triturus vulgaris (Urodela,Salamandridae)1

The relevance of the temporal spacing of signals to the timing and nature of the receiver's response during a communicative process was studied in the sexual behaviour of the smooth newt Triturus vulgaris. The possibility that a high rate of stimulation allows an accumulation of the effects of successive signals was investigated by comparing sexual interactions leading and not leading to spermatophore deposition. Results showed that the difference between the two types of interactions lay only in temporal features of the stimulation provided by the male to the female. Females, although in a comparable initial state of receptivity and exposed to comparable amounts of stimulation, performed the act triggering spermatophore deposition by the male only in some interactions. Display bouts, in which the male displayed at short intervals (less than 4 s), were longer in interactions where spermatophore deposition took place than in the others. This suggests that courtship was effective if accumulation of the effects of male displays could occur. This proposition was supported by the observation of a progressive change in the immediate female response to a given male display in the group where courtship bouts were longer. Our results indicate the existence of a system of tonic communication (see Schleidt 1973) during the sexual behaviour of the smooth newt, in which the effects of the male displays accumulate over time until some critical threshold is reached in the female.     

Sexual Interference and Sexual Defense in the Smooth Newt,Triturus vulgaris (Amphibia,Urodela, Salamandridae)

• 1 When a male smooth newt encounters a ♀ who is already engaged in courtship, he may mimic her behaviour during the spermatophore deposition and transfer stages of the courtship. He thereby usurps the courting ♂ and may inseminate the ♀ himself. Such sexual interference depresses the short-term, and perhaps long-term, mating success of the courting ♂.
• 2 In the presence of a potential rival, the courting ♂ alters certain aspects of his sexual behaviour. He displays more intensely to the ♀ and attempts to draw her away from the rival by increasing the duration of his display. He may also “check” that it is the ♀, and not the rival, who will elicit the deposition of a spermatophore from him. These changes in the behaviour of the courting ♂ are interpreted as defense against sexual interference.
• 3 Female smooth newts may be multiply inseminated as a consequence of sexual interference; this may result in sperm competition. However, ♀♀ seem to find competitive interactions between ♂ ♂ “aversive”.
• 4 Sexual interference by ♀-mimicry and associated defensive behaviour patterns are common in the urodele amphibians. Interference can be thought of as a “side-payment” conditional mating strategy.

     

人工饲养下金丝猴繁殖的观察研究 Ⅰ.交配行为

金丝猴(Rhinopithecus roxellanae)是我国稀有的珍贵特产动物,笔者在多年观察金丝猴的繁殖行为的基础上,又于1986年8-9月在北京动物园,对金丝猴的交配、爬跨行为进行了专门观察,发现金丝猴发动性活动的一些特点,并在交配爬跨时,雄性金丝猴有卷尾现象。其交配行为与叶猴和猕猴有差异。     

Sexual Interference in the Sword-tailed Newt,Cynops ensicauda popei (Amphibia: Salamandridae)

This paper describes competitive interaction between males of the salamandrid Cynops ensicauda popei. The sexual behaviour of the male is influenced by the presence of a second, rival, male. Competition for access to the female and other male interactions continuously interrupt ongoing courtships. Spermatophore pick-up success is lower than in encounters involving single pairs. During triad encounters, fewer spermatophores were deposited than in dyad encounters, due to interference during the creep stage of courtship. Two basic forms of male sexual interference were distinguished: ‘lure away’ during the creeping stage, from a position that is different from the direction of creep; and ‘female mimicry’, during which the male presses his snout alternately against the courting male's tail and the female's snout. In both forms, a rival male may shove one of the courting individuals away. The repertoire of sexual behaviour patterns of Cynops ensicauda popei appears to be less complex and varied than that of most Triturus species. The courtship of Cynops places less emphasis on display behaviour with tail and body, and a stronger emphasis on the creeping stage, where the male carefully leads the responsive female over a series of spermatophores, but during which rival males may interfere in a variety of ways.     

Courtship and mating in the whip spider Phrynichus orientalis Weygoldt, 1998 (Chelicerata: Amblypygi)

Mating behaviour and spermatophore morphology of the south-east Asian whip spider Phrynichus orientalis is described. During courtship there is less bodily contact between mates than in other studied species of the same genus. However, a peculiarity for the species is that the pair often pauses for minutes, sitting front to front without any movement. For spermatophore formation, the male shifts his body under that of the female like in many other species. However, after spermatophore formation, the male lures the female to the spermatophore instead of pulling her as in most other species studied. The spermatophore differs from those of most other species of the genus by the fact that the cushions in front of the sperm masses are replaced by a hard, transparent mass which has the same function as the cushions. Mating behaviour and spermatophore morphology of P. orientalis thus show peculiarities that so far have not been described for other species of the genus. It is not clear whether these characters should be considered plesiomorphic or apomorphic. But it does clearly show that there is more diversity within this genus than expected.     

Mating behavior ofPhytoecia rufiventris Gautier (Coleoptera: Cerambycidae)

Sexual behavior between males and females, as well as between males, is described and discussed for the cerambycid beetlePhytoecia rufiventris. The beetles' taxis toward plants taller than average height brings the sexes together from a distance. A male may mount another individual (male or female) and attempt copulation without sex discrimination. The male can discern the sex of another individual only when the terminal part of his abdomen touches the ventral surface of the fifth visible sternite of the latter. No evidence of a sex pheromone is found in this species. Within 1.5–5.5 cm the substrateborne vibrations produced by a moving individual may be the important factor which elicits males to approach a moving individual and attempt copulation. If a female is receptive when a male touches her, he can copulate with her without any courtship display. However, if the female runs away and appears unreceptive, the male will perform courtship displays. Copulation is usually terminated by males. Homosexual behavior between males is discussed.     

Increase in song frequency decreases spermatophore size: correlative evidence of a macroevolutionary trade-off in katydids (Orthoptera: Tettigoniidae)

In many katydids, the male feeds his mate with a large gelatinous spermatophore. Males of most species also produce elaborate calling songs. We predicted a negative relationship between spermatophore size and call frequency because of trade-offs between these two costly traits. Our comparative analysis controlling phylogeny and body size supported this prediction. Although call frequency is expected to decrease with increasing body size, after controlling for phylogeny, both variables were not related. Finally, given that song frequency and spermatophore size are likely targets of sexual selection, we examined the relationship between these variables and sexual size dimorphism (SSD) which can be influenced by sexual selection on body size. We found that only female body size was positively related to SSD, suggesting that natural and/or sexual selection on female body size may be stronger than sexual selection on male and spermatophore size.     

Heritable variation in the timing of spermatophore removal, a mechanism of post-copulatory female choice in crickets

Female crickets can exert post-copulatory mating preferences by prematurely removing a male's spermatophore after copulation, which terminates sperm transfer. Although most models of sexual selection assume that female mating preferences are heritable, there has been little work addressing genetic variation underlying post-copulatory mate choice. We used a paternal half-sib design, in which different males were randomly assigned as mates to several females to create half-sib families, to determine the heritability of spermatophore retention time in female house crickets, Acheta domesticus. There was significant additive genetic variance in the timing of spermatophore removal by females [h(2) = 0.50 +/- 0.19 (+/- SE)], suggesting that the timing of spermatophore removal is determined, in part, by the female's own genotype independent of the quality of her mate. The relatively high heritability of spermatophore retention time may be reflective of the absence of strong selection on this trait, consistent with previous work showing no difference in the fitness of females permitted to freely remove the spermatophore of their mates and those forced to accept complete ejaculates.     

Copulation behaviour of Glossina pallidipes (Diptera: Muscidae) outside and inside the female, with a discussion of genitalic evolution

If species-specific male genitalia are courtship devices under sexual selection by cryptic female choice, then species-specific aspects of the morphology and behaviour of male genitalia should often function to stimulate the female during copulation. The morphology and behaviour of the complex, species-specific male genitalia of the tsetse fly, Glossina pallidipes Austen, were determined from both direct observations and dissections of flash-frozen copulating pairs; we found that some male genitalic traits probably function to stimulate the female, while others function to restrain her. The male clamps the ventral surface of the female's abdomen tightly with his powerful cerci. Clamping does not always result in intromission. Clamping bends the female's body wall and her internal reproductive tract sharply, posteriorly and dorsally, and pinches them tightly. The male performed sustained, complex, stereotyped, rhythmic squeezing movements with his cerci that were not necessary to mechanically restrain the female and appeared instead to have a stimulatory function. Six different groups of modified setae on and near the male's genitalia rub directly against particular sites on the female during squeezing. The designs of these setae correlate with the force with which they press on the female and the probable sensitivity of the female surfaces that they contact. As expected under the hypothesis that these structures are under sexual selection by female choice, several traits suspected to have stimulatory functions have diverged in G. pallidipes and its close relative, G. longipalpis. Additional male non-genitalic behaviour during copulation, redescribed more precisely than in previous publications, is also likely to have a courtship function. The elaborate copulatory courtship behaviour and male genitalia may provide the stimuli that previous studies showed to induce female ovulation and resistance to remating.     

Repeated copulations as a strategy to maximize fertilization in the fly, Dryomyza anilis (Dryomyzidae)

In the fly, Dryomyza anilis, males copulate repeatedly withthe same female during oviposition. Each copulation bout consistsof intromission followed by several tapping sequences duringwhich the male touches the external genitalia of the femalewith his claspers. The relative fertilization success of thelast male to mate with the female increases with the numberof tapping sequences. In this study, male benefits of repeatedcopulation bouts were examined by comparing matings with thesame number of tapping sequences in one and several copulationbouts. The relative fertilization success for the last maleincreased with successive copulation bouts. Simulated ovipositionpatterns showed that fertilization success in matings with manycopulation bouts was higher than in matings with one bout onlyif eggs were distributed between bouts in a certain way. Thesepredicted oviposition patterns were compared with natural ones.Although males may benefit from repeated copulation, femalesare likely to prefer matings with quick oviposition. This intersexualconflict may also affect natural oviposition patterns. It issuggested that repeated copulation in D. anilis may have evolvedin connection with males trying to secure their paternity becausefemales can discharge sperm at any moment during mating.     

Experimental evolution reveals divergence in female genital teeth morphology in response to sexual conflict intensity in a moth

The rapid evolutionary divergence of male genital structures under sexual selection is well documented. However, variation in female genital traits and the potential for sexual conflict to drive the coevolution between male and female traits has only recently received attention. In many lepidopterans, females possess genital teeth (collectively, signa). Comparative studies suggest these teeth, involved in the deflation of spermatophores, may have coevolved with male spermatophore thickness via sexually antagonistic coevolution in a contest over the rate of deflation of spermatophores within the reproductive tract. We tested the hypothesis that sexual conflict should generate coevolution between genital teeth and spermatophore morphology by examining these traits under experimental manipulation of sexual conflict intensity. Using micro‐CT scanning, we examined spermatophore and teeth morphology in populations of the Indian moth, Plodia interpunctella, which had been evolving for 110 generations under different adult sex‐ratio biases. We found divergence in female signa morphology in response to sexual conflict: females from female‐biased populations (reduced sexual conflict) developed wider signa. However, we found no evidence of coevolution between signa traits and spermatophore thickness as reported from comparative studies.     

The sexual behaviour of the red-spotted newt, Notophthalmus viridescens (Amphibia: Urodela: Salamandridae)

The sexual behaviour of the red-spotted newt, Notophthalmus viridescens is described. The male can adopt one of two types of behaviour depending on the initial responsiveness of the female. If she is responsive, the male performs a brief lateral (or hula) display, at the end of which one or more spermatophores may be deposited. If she is unresponsive, the male captures the female and a lengthy period of amplexus ensues, followed by spermatophore transfer behaviour. Spermatophore transfer is most successful after amplexus, and a preliminary cost-benefit analysis of the two types of courtship is given. The behaviour is discussed in the context of other urodele amphibians, and in the wider context of male reproductive strategies.     

Effect of predation risk on grouping pattern and whistling behaviour in a wild mouflonOvis aries population

We studied the effect of predation risk on grouping pattern and whistling behaviour in a free-ranging mouflonOvis aries Linnaeus, 1758 population in Sardinia. Direct observations were carried out from July 2005 to June 2007 (n _groups=881,n _mouflon=3477). In our study site, the rut occurred in October and November, when social sexual segregation disappeared, while lambing peaked in April. Groups with lambs (mean ± SE: female groups with lambs 4.98 ± 0.23, mixed groups 6.49 ± 0.29) were larger than male groups (2.01 ± 0.10) and female groups without lambs (2.77 ± 0.11), especially during the lambing season. This reflected the anti-predator tactics adopted by mothers so as to benefit from the dilution effect. Also male aggregations increased in size during the lambing season, as a consequence of the gradual decrease of rutting activities and consequently of male-male aggressiveness. Among the anti-predator tactics adopted by mouflon, whistling behaviour seemed to be a warning signal directed to predators and not to conspecifics. This was because whistling was shown by smaller aggregations only, regardless of group type, presence of lamb and habitat occupied. Smaller groups cannot profit from the dilution effect and therefore may be more motivated to signal the predator that it has been spotted.     

Social Behaviour and Cooperative Breeding in Arctic Foxes,Alopex lagopus (L.), in a Semi-natural Environment

Most canid species show cooperative breeding at least occasionally. The helper-at-the-den system, when extra adults serve as helpers by feeding and guarding the cubs of an alpha pair, has been observed but not studied in any detail in wild Arctic foxes (Alopex lagopus). During a 3-months study of arctic foxes in two enclosures of 4 ha each, we measured the social behaviour during the reproductive season. Older foxes dominated younger ones and males dominated females of the same age. A litter with one surviving cub was born in one enclosure. The alpha male increased his rate of urine marking and barking and fed the alpha female both before and after the birth of the litter. However, about 10 days after the birth, the alpha female died. The cub was fed by his putative father, his sister and his brother (both one year old). The one year old female increased her rate of territorial defence, measured as urine marking and barking, when the mother died. The subordinate females were probably suppressed from breeding by the high aggression levels and territorial defence of the dominant females in each enclosure. The dominant female in the second enclosure came into heat after the death of the alpha female (her mother) in the first enclosure. These changes in behaviour can probably be explained by sexual inhibition by the alpha female while she was present. The significance of territorial defence and dominance, inbreeding avoidance, sexual suppression and evolution of helping behaviour are discussed.     

Competitive PCR reveals the complexity of postcopulatory sexual selection in Teleogryllus commodus

The outcome of mate choice depends on complex interactions between males and females both before and after copulation. Although the competition between males for access to mates and premating choice by females are relatively well understood, the nature of interactions between cryptic female choice and male sperm competition within the female reproductive tract is less clear. Understanding the complexity of postcopulatory sexual selection requires an understanding of how anatomy, physiology and behaviour mediate sperm transfer and storage within multiply mated females. Here we use a newly developed molecular technique to directly quantify mixed sperm stores in multiple mating females of the black field cricket, Teleogryllus commodus. In this species, female postcopulatory choice is easily observed and manipulated as females delay the removal of the spermatophore in favour of preferred males. Using twice‐mated females, we find that the proportion of sperm in the spermatheca attributed to the second male to mate with a female (S₂) increases linearly with the time of spermatophore attachment. Moreover, we show that the insemination success of a male increases with its attractiveness and decreases with the size of the female. The effect of male attractiveness in this context suggests a previously unknown episode of mate choice in this species that reinforces the sexual selection imposed by premating choice and conflicts with the outcome of postmating male harassment. Our results provide some of the clearest evidence yet for how sperm transfer and displacement in multiply mated females can lead directly to cryptic female choice, and that three distinct periods of sexual selection operate in black field crickets.     

Impact of male condition on his spermatophore and consequences for female reproductive performance in the Glanville fritillary butterfly

In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males’ contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia (Linnaeus, 1758) (Nymphalidae), in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food‐deprivation, and is not influenced by developmental food‐limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult‐resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior.     

Correlated evolution of female neoteny and flightlessness with male spermatophore production in fireflies (Coleoptera: Lampyridae)

The beetle family Lampyridae (fireflies) encompasses ～100 genera worldwide with considerable diversity in life histories and signaling modes. Some lampyrid males use reproductive accessory glands to produce spermatophores, which have been shown to increase female lifetime fecundity. Sexual dimorphism in the form of neotenic and flightless females is also common in this family. A major goal of this study was to test a hypothesized link between female flight ability and male spermatophore production. We examined macroevolutionary patterns to test for correlated evolution among different levels of female neoteny (and associated loss of flight ability), male accessory gland number (and associated spermatophore production), and sexual signaling mode. Trait reconstruction on a molecular phylogeny indicated that flying females and spermatophores were ancestral traits and that female neoteny increased monotonically and led to flightlessness within multiple lineages. In addition, male spermatophore production was lost multiple times. Our evolutionary trait analysis revealed significant correlations between increased female neoteny and male accessory gland number, as well as between flightlessness and spermatophore loss. In addition, female flightlessness was positively correlated with the use of glows as female sexual signal. Transition probability analysis supported an evolutionary sequence of female flightlessness evolving first, followed by loss of male spermatophores. These results contribute to understanding how spermatophores have evolved and how this important class of seminal nuptial gifts is linked to other traits, providing new insights into sexual selection and life-history evolution.     

SEXUAL SELECTION IS INVOLVED IN SPECIATION IN A LAND SNAIL RADIATION ON CRETE

We investigated the importance of sexual selection in facilitating speciation in a land snail radiation on Crete. We used differences in the genitalia of the Cretan Xerocrassa species as potential indices of sexual selection. First, we rejected the hypothesis that differences in the genitalia of the Xerocrassa species can be explained by genetic drift using coalescent simulations based on a mitochondrial gene tree. Second, we showed that there is no evidence for the hypothesis that the differences in the genitalia can be explained by natural selection against hybrids under the assumption that this is more likely in geographically overlapping species pairs and clades. Third, we showed that there is a positive scaling between male spermatophore-producing organs and female spermatophore-receiving organs indicating sexual coevolution. The spermatophore enables the sperm to escape from the female gametolytic organ. Thus, the coevolution might be a consequence of sexual conflict or cryptic female choice. Finally, we showed that the evolution of differences in the length of the flagellum that forms the tail of the spermatophore is concentrated toward the tips of the tree indicating that it is involved in speciation. If speciation is facilitated by sexual selection, niches may remain conserved and nonadaptive radiation may result.     

Sexual interactions in red-spotted newt populations

Two alternative reproductive tactics (amplexus and spermatophore transfer interference) and three sexual interference tactics (spermatophore transfer interference, pseudofemale behaviour, amplexus interference) are described for male red-spotted newts, Notophthalmus viridescens. The two reproductive tactics yield equal insemination rates for males displaying these behaviours. The three sexual interference tactics decrease the potential fitness of amplectic males either directly, by displacing them from receptive females and/or duping them into fruitless spermatophore depositions, or indirectly, by increasing the time spent in amplexus with no concomitant increase in probability of successful insemination.     

To breathe or not to breathe; the newt's problem

In a number of experiments designed to investigate the interaction between sexual behaviour and breathing, male newts were presented with females whose behaviour was controlled by the experimenter. In some experiments the male received sufficient positive feedback from the female to enable him to complete his sexual sequence; in others he did not. The results are interpreted in terms of McFarland's (1969) hypothesis that the transitions from one activity of another may occur either by competition or by disinhibition. It is suggested that in the absence of sufficient positive stimulation to enable the male to complete his sexual sequence, breathing occurs by competition with sexual behaviour. When the male has sufficient stimulation the temporal patterning of his behaviour becomes more under his control and breathing occurs by disinhibition.