Mating Behavior, Sexual Selection, and Copulatory Courtship in a Promiscuous Beetle

The function of male movements during copulation is unclear. These movements may be a result of the necessary mechanics of insemination, or they may also have further function, for instance, stimulating or courting a female during mating, perhaps influencing female mate choice. We present data from three experiments exploring the mating behavior and copulatory movements of the highly promiscuous beetle Psilothrix viridicoeruleus. Male mating success in the struggle over mating was not related to male or female size (measured by weight) but successful males were more vigorous in terms of copulatory movements. These males took longer to mount females but copulated longer and remained mounted longer. We discuss these results in terms of the mating system of Psilothrix and also in terms of observations of the timing of insemination during copulation. We suggest that copulatory movements in this species are best understood as copulatory courtship.     

Copulatory Plug Displacement Evidences Sperm Competition in Lemur catta

Male displacement of copulatory (sperm) plugs from female vaginas provides further evidence for sperm competition in ring-tailed lemurs (Lemur catta), a gregarious prosimian species with a multimale, multifemale mating system. During two mating seasons, I studied two groups of free-ranging ring-tailed lemurs on St. Catherines Island, GA, USA. I observed 22 mating pairs in which males achieved penile intromission. Copulatory plug displacement by males occurred in 9 cases. Plugs were displaced during copulation by male penes upon withdrawl following deep vaginal thrusting. In every case of copulatory plug displacement, the male displacing a plug mated to ejaculation with the estrous female. In a mating system in which females typically mate with more than one male during estrous, often in succession, copulatory plug displacement may function to disrupt or preclude other males' successful insemination of estrous females. The effects of sperm plug displacement on paternity in Lemur catta are unknown, as no study had heretofore documented copulatory plug displacement in this species. The first-male mating advantage suggested for Lemur catta should be re-evaluated where mating order is known, and copulatory plug displacement during mating, or lack thereof, is identified. Because there is a tendency for first-mating males to mate-guard for longer periods of time in Lemur catta, the latency period between the first mate's ejaculation and that of subsequent mates may be an important determinant of male fertilization success.     

Reproductive Strategies of <Emphasis Type="Italic">Trachypithecus pileatus</Emphasis> in Arunachal Pradesh,India

We studied reproductive behavior of free-ranging capped langurs (Trachypithecus pileatus) in the Pakhui Wildlife Sanctuary, Arunachal Pradesh, India. Four species of primates —Trachypithecus pileatus, Macaca mulatta, M. assamensis, and Nycticebus bengalensis— live there. We studied the mating seasons, mating frequency, copulatory attempts, time spent in copulation, and interval between 2 successive copulations, gestation length, and interbirth interval of 4 groups of capped langurs during 2001–2003. We observed 2 mating seasons in a year. The first was larger, comprising 5 months (September–January), and the second was short, April and May. Mating was intensive in the morning session (0600–1000 h); 57% of total mating events occurred then. The average gestation period was 200 d. November was the most favorable month for breeding. In a year, 107 mating events occurred involving 5 adult females. Average time per mounting attempt is 12 s. Duration of mounting was the maximum in November. Interbirth interval was 23 months and 10 d. The birth season was 129 days, December–April; 53% of births occurred in February and March. Average birth rate is 0.386 birth/female/yr.     

Mating duration and sperm precedence in the spider <Emphasis Type="Italic">Linyphia triangularis</Emphasis>

In many animal species, mating behaviour is highly ritualised, which may allow us to relate some of its consequences, e.g. male paternity and female receptivity, to the progression of phases in the mating sequence; at the same time, ritualisation raises the question of to what extent the partners, especially the males, are able to influence the outcome of mating for their own benefit. We studied the linyphiid spider Linyphia triangularis in which mating follows a strict sequence during which the male inducts two droplets of sperm and transfers them to the female. We performed sperm competition experiments (sterile-male technique) including four treatments, in which the copulation of the first male was interrupted at prescribed phases of the mating sequence, while the second male was allowed a complete mating. Second males spent a shorter time than first males on the behaviours prior to sperm transfer, but the amount of sperm (2 droplets) and the time spent in sperm transfer were independent of the females’ mating status. The proportion of females accepting the second male depended on the mating duration of the first male, i.e. whether the first male had transferred one or two sperm droplets. After a complete first mating, most females accepted no further males. A last-male sperm precedence was apparent if only half of the first sperm droplet had been transferred by the first male, but this switched to a first male precedence if one full sperm droplet had been transferred. Thus, even in the face of sperm competition, it is sufficient for the first male to transfer one sperm droplet. The second sperm droplet and the extended copulatory courtship associated with its transfer may serve to induce a lack of receptivity in the female, but the males seem unable to enhance their reproductive success through variable copulatory tactics.     

Observations on the mating behavior of the alfalfa blotch leafminer,Agromyza frontella (Rondani) (Diptera: Agromyzidae), and evidence of a female sex pheromone

The mating behavior of Agromyza frontella was studied under laboratory conditions. Adults were able to mate on the day of emergence, with no evident periodicity throughout the photophase. The host plant was essential for mating to occur, its presence affecting female receptivity rather than male copulatory behavior. Males generally entered a stationary phase once in the proximity of a female, before undertaking a final approach. This stationary behavior frequently resulted in male aggregations around a female, and under such conditions males exhibited a characteristic wing vibrating behavior. As male wing vibration was not an essential behavior for successful mating, and rarely occurred during male encounters in the absence of females or when only one male was near a female, it was considered as being primarily a male-male signal. The majority of females that mated exhibited an ovipositor pumping behavior that stimulated the male approach. However, such behavior was not essential to attract mates, as dead females elicited the entire sequence of male mating behavior. This suggested the presence of a cuticular sex pheromone, as reported for other species of higher Diptera. Whole virgin female (<24- h or 3- day-old) hexane extracts applied to male cadavers increased the time males spent on the plant, the number of contacts with the treated cadavers, the incidence of attempted copulations, and the wing vibrating behavior between males compared with controls using untreated cadavers. The results obtained indicate that females control copulation in A. frontella and that both semiochemical and visual cues are important in eliciting male mating behavior.     

Post-copulatory Mounting Behavior of the West Indian Sweetpotato Weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae)

Post‐copulatory associations between males and females have been found in a variety of insects and are often described as mate guarding. Males of the West Indian sweetpotato weevil Euscepes postfasciatus (Fairmaire) mount the female's back after copulation. Two hypotheses have been advanced to explain this behavior: mate guarding to prevent future copulations by rivals (hypothesis 1), and mate guarding to gain additional copulations (hypothesis 2). We conducted three experiments to test predictions from these hypotheses. Our results disproved hypothesis 1 because the duration of the post‐copulatory association was very brief in comparison with the length of the refractory phase all females showed after copulation. When we prevented females from resisting copulations during the post‐copulatory mounted phase males copulated again, while under normal conditions, a second copulation was never observed. This result may indicate the presence of a sexual conflict over mating. However, we propose an alternative interpretation of the result, namely that after mating, males test whether the copulation has successfully reduced female receptivity by attempting to remate. If females resist the mating, males leave.     

Sexual coercion does not exclude luring behavior in the climbing camel-spider <Emphasis Type="Italic">Oltacola chacoensis</Emphasis> (Arachnida,Solifugae, Ammotrechidae)

Sexual coercion in the form of forced copulation has been used as a typical example to illustrate the conflict of interests between females and males. Among arthropods, forced copulation has been reported for some groups of insects and crustaceans, but not for arachnids. In the present work, we analyse and describe the behavioral patterns of mating behavior of the climbing camel-spider, Oltacola chacoensis, relating it to relevant morphological features, In this species, the male forcefully clasps the female’s genital region with his chelicerae and locks her fourth pair of legs with his pedipalps. In some cases, the cuticle of the female’s abdomen was damaged by this cheliceral clasping. In contrast to other camel-spiders, the female O. chacoensis never remained motionless during mating, but continuously shook her body, opening her chelicerae notably towards the male. Despite this coercive context, males performed copulatory courtship (tapping with pedipalps) and females showed an apparent cooperative behavior (they remained still during a short period of the sperm transfer phase). These results strengthen the idea that sexual coercion (in the form of forced copulation) and luring behavior (in the form of copulatory courtship) are not two mutually-exclusive male’s strategies during a single copulation.     

Mating Behavior in the Alpine Tiger Moth, <Emphasis Type="Italic">Metacrias huttoni</Emphasis>

The alpine Tiger moth, Metacrias huttoni, of South Island, New Zealand, has adapted to female microptery through unusual courting behavior and behavioral plasticity with regard to copulation position. Courting revolves around male manipulation (‘fluffing’) of the female’s highly derived covering of flocculent setae. This was found to be not only necessary to cue female receptivity, but was also shown to stimulate oviposition. Both freshly pupated (24 h after eclosion) and mature (1 wk after eclosion) virgin females showed significantly greater oviposition after artificial grooming. The standard back-to-back copulatory position of winged moths was replaced in 86% of matings with alternative positions. The structure and functional significance of female setae is examined. A preliminary hypothesis for the origin of the moths’ mating behavior is outlined.     

How the length of genital parts affects copulation performance in a carabid beetle: implications for correlated genital evolution between the sexes

To identify factors leading to the correlated evolution of exaggerated male and female genitalia, we studied the effects of the variable dimensions of corresponding functional genital parts (male copulatory piece and female vaginal appendix) on copulatory performance in the polygamous carabid beetle Carabus (Ohomopterus) maiyasanus. We used mating pairs of individuals from two populations to increase the variances in genital dimensions and determined the copulation performance (insemination and spermatophore replacement, and copulation time) in single‐ and double‐mating situations. In single mating, insemination success was not affected by genital dimensions, although the copulation time was significantly shorter when the male aedeagus was longer. In the double‐mating experiment, insemination and replacement of spermatophores by the second male succeeded more frequently when the copulatory piece was shorter and the vaginal appendix was longer, and when the difference between the length of the copulatory piece and the vaginal appendix was smaller. Thus, a matching of the corresponding genital parts between the sexes increases the male's reproductive success in sperm competition, but elongation of the copulatory piece cannot be explained simply by the improvement in male reproductive success. We discuss possible factors for the elongation of genital parts in terms of sexual conflict and reproductive interference through interspecific copulation.     

Sexual selection,genital morphology,and copulatory behavior in male Galagos

Variations in penile morphology among galago species are pronounced and complex. Comparative studies of galagos and other primate species show that elongation of the baculum (os penis)is associated with copulatory patterns involving a prolonged period of intromission. The enlarged penile “spines” of male galagos may be important in maintaining a genital “lock” during copulation. In primate species where females mate with a number of partners, sexual selection may have favored the rapid evolution of such features of penile morphology and masculine copulatory behavior. It is suggested that evolution of complex penile morphologies in galagos has been influenced by sexual selection and that such morphological variations are extremely useful in taxonomic studies.     

Analysis of the mating behavior and some possible causes of male copulatory success in Dryas iulia alcionea (Lepidoptera, Nymphalidae, Heliconiinae)

In this study we examined the mating behavior of Dryas iulia and the acceptance and rejection mechanisms of females during courtship activity. An ethogram of mating behavior was organized on the basis of 100 h of observation in an insectarium. Several different behaviors were catalogued and separated into two behavioral repertoires (pre-coupling, post-coupling). The behavioral sequence of mating behavior was also analyzed using a total of 53 pairs of D. iulia. The courtship activities involved interactions between the sexes in three sequential phases—the aerial, air-ground, and ground phases. In 49% of observations the courtship activities led to copulation. The mean time to the occurrence of the first interaction between males and females did not differ between interactions with and without copulation. The behavior of females and males in the two groups were analyzed and differences were found between behavioral activities of both sexes. The results indicate that males’ insistence on courtship does not affect their copulatory success, and that females play a decisive role in copulation occurrence. Analysis of behavioral transitions showed there are many alternative behavioral routines in interactions with and without copulation. The number of behavioral transitions recorded was smaller in the group in which copulation occurred, indicating that males with copulatory success modified their behavior less frequently. Successful males recorded more transitions with a probability of occurrence greater than 0.4, and their behavioral activity was also less reticulated. Analysis using the stereotyping index showed that situations in which copulations occurred were more stereotyped than those in which it did not.     

Male Performance and Body Size Affect Female Re-Mating Occurrence in the Orb-Web Spider Leucauge mariana (Araneae, Tetragnathidae)

Females can affect male probabilities of paternity success through behavioural, morphological and/or physiological processes occurring during or after copulation. These processes under female-control include the acceptance or rejection of mating attempts by subsequent males. Leucauge mariana is an orb weaving spider that shows male mate guarding of penultimate females, male–male competition on female webs and copulatory plugs, suggesting a polyandric mating system. The aim of the present study was to ascertain whether male behaviour during courtship and copulation in L. mariana relate with female re-mating decisions. Forty-three virgin females were exposed to up to three males until they mated. In 24 cases, the copulatory plug was absent after mating and females were exposed the next day to up to three other males. Eighteen females accepted a second mating. Relatively larger females were more receptive to second matings and were more likely to copulate if the second male was smaller. Longer duration of female tapping and abdominal bobbing during courtship, and first copulations with less short insertions and more flubs, were associated with increased female acceptance to second matings. The results indicate cryptic female choice on male courtship and copulatory performance and suggest female-control over the determination of male mating success in this spider species.     

A potential mechanism for cryptic female choice in a flour beetle

In polyandrous mating systems, events occurring during copulation can alter the fate of the mating male's sperm. These events may exert selective pressures resulting in the evolution of diverse reproductive behaviours, morphologies and physiologies. This study investigates the role of male and female copulatory behaviours on sperm fate in the red flour beetle, Tribolium castaneum. I describe and quantify copulatory behaviours for mating pairs, and examine sperm fate by quantifying sperm transfer, sperm storage and second male sperm precedence. Whereas female quiescence during copulation and male leg rubbing during copulation together account for significant variation (26%) in sperm precedence, female copulatory quiescence alone provides information about the timing and numbers of sperm transferred. These experiments show that a female copulatory behaviour predicts sperm fate, and emphasize the value of studying variation in both male and female copulatory behaviours for understanding factors affecting sperm use.     

高原鼠兔交配期及交配行为模式的研究

1985至1988年在青海湖黑马河地区,以耳标法对高原鼠兔(Ochotona curzoniae)的交配期及交配行为模式进行了研究。该鼠繁殖期一般是从3月底或4月初开始到7月上旬或8月上旬结束,时间长达3-4个月。在繁殖期中有3-5个交配期。配偶间雄鼠对雌鼠有跟随,接吻,嗅吻肛门区和爬跨抚摸一系列反复“求爱”行为。雌鼠呈现“脊椎前凸”和外生殖器反射行为。雄鼠交配时以前肢紧紧夹住雌鼠腰部,3-5次盆部抽动,一次较深的推进即为射精。每次交配时间约3-5秒,多次交配射精。还发现该鼠有临产交配行为。     

Copulatory wounds in the monandrous ant species <Emphasis Type="Italic">Formica japonica</Emphasis> (Hymenoptera,Formicidae)

Males of several insect species inflict wounds on female genitalia during copulation, but the significance of such copulatory wounds for males is not clear. I compared the genitalia of virgin and mated Formica japonica females and for the first time report the occurrence of copulatory wounds in this monandrous ant species. All inseminated females examined had two types of melanized patches, indicating wound repair, and the serrated penis valves and sharp-pointed volsellar digitus of male genitalia were the likely instruments of these wounds. Physically damaging mating in monandrous species supports the view that copulatory wounds do not necessarily contribute to postcopulatory fitness gains for males via advantages in sperm competition or cryptic female choice. Received 10 September 2007; revised 15 October 2007; accepted 16 October 2007.     

Group mating among Norway rats I. Sex differences in the pattern and neuroendocrine consequences of copulation

The copulatory pattern of groups of rats (Rattus norvegicus) was studied in the laboratory in a seminatural environment. In a given mating session, every oestrous female copulated with each male; likewise, every male copulated with each oestrous female. While individual males and females experienced similar amounts of copulation, there were dramatic sex differences in sequence and temporal pattern. Males mated in a multiple intromission pattern and had more ejaculatory series when several females were in oestrus. In contrast, females received intromissions and ejaculations in a random order, not in the sequence of a male ejaculatory series. Males copulated at shorter intervals than females did, a temporal sex difference that was determined by the pattern of female solicitations and male approaches. These sex differences are used to discuss the different units of analysis that are appropriate for male and female sexual behaviour in this species. Furthermore, the sex differences in the temporal pattern of copulation which emerged during group mating parallel the known sex differences in the temporal parameters of the neuroendocrine reflexes which mediate successful reproduction in the domestic strain.     

Female walking during copulation reduces the likelihood of sperm transfer from males in the sweet potato weevil,Cylas formicarius

Behaviour during copulation can alter the fate of sperm of the mating males. This behaviour may exert selective pressure, resulting in the evolution of diverse reproductive behaviour, morphology, and physiology. This study examined the role of female copulatory behaviour on sperm fate in the sweet potato weevil, Cylas formicarius (Fabricius) (Coleoptera: Brentidae). In this species, males mount the female during copulation. The female frequently walks during copulation, carrying the male on her back. Here, we describe and quantify the copulatory behaviour of mating pairs and examine the sperm fate. Insemination success, as determined by the presence of sperm in the spermatheca, was lower when females walked for longer periods during copulation. This result emphasizes the value of studying variation in female copulatory behaviour in order to understand the factors that influence sperm fate. We discuss the implications of these results on sexual selection and utility in programs applying sterile insect techniques.     

Influence of mating experience on mating latency and copulation duration in <Emphasis Type="Italic">Drosophila melanogaste</Emphasis> females

Two important components of mating behavior, mating latency and duration of copulation, were examined during first and second mating in D. melanogaster females. Our results confirm the published findings of lower receptivity of previously mated D. melanogaster females, since fertilized females present significantly longer mating latencies. Duration of copulation also depends on female mating experience, as naive females copulated significantly longer than those previously mated. An important role of female D. melanogaster in the control of both examined components of mating behavior is displayed in the course of second mating, as part of behavioral and physiological changes induced by the first mating. The article is published in the original.     

Copulatory Courtship in Drosophila birchii and D. serrata,Species Recognition and Sexual Selection

Two endemic Australian Drosophila species, D. birchii and D. serrata, have a copulatory courtship, i.e., the males court the female mainly during copulation. In the present study we found the males of both species to mount their prospective mating partners selectively, exhibiting both sex and species recognition. The males began to sing after mounting the female, and they often exhibited also postcopulatory displays typical to copulatory courtship. D. birchii and D. serrata females discriminated against males which did not sing during mounting/copulation, which suggests that the females utilize cryptic female choice. Our findings raise the question of how widespread a phenomenon cryptic female choice is in Drosophila species.     

Copulatory Courtship in Drosophila: Behavior and Songs of D. birchii and D. serrata

D. birchii and D. serrata, two endemic Australian Drosophila species, have a copulatory courtship. The males of these species begin to court the female after mounting her and often go on with the courtship after the copulation is over. In the present paper we have described behavioral interactions between the male and the female and analyzed acoustic signals produced by the flies during courtship. Species differences were more pronounced in female than in male behavior. Variation within the species was obvious in the relative proportions of time the flies spent in different behaviors. Even though courtship took place nearly solely during copulation, some remains of precopulatory courtship were observed in both species. It is suggested that copulatory courtship exhibited by D. birchii and D. serrata flies is a derived rather than a primitive character.