Successful Copulation Research Articles

Courtship in Two Morphotypes of the Anastrepha fraterculus (Diptera: Tephritidae) Cryptic Species Complex and their Implications for Understanding Mate Recognition

Ritualized courtship behaviors are used to recognize potential mates and behavioral patterns are inevitably different among populations that demonstrate reproductive incompatibility. We characterized and compared the courtship behaviors of two morphotypes of the cryptic species complex Anastrepha fraterculus: Brazil-1 morphotype and Brazil-3 morphotype. Courtship behaviors were filmed to analyze the behavioral sequences of these two morphotypes during homotypic crossings. The behavioral units Alignment (AL) and Abdominal movements (AB and AB-call) were newly recognized in the courtship ethogram of Anastrepha fraterculus males. The two morphotypes show distinct behavioral sequences leading up to copulation. Some behaviors were repeated frequently during the courtship process, while others were more restricted to the final moments of courtship. The three behavioral units that contributed most to copulation success were Contact, Alignment, and Arrowhead 1 in the Brazil-1 morphotype and Alignment, Arrowhead 1, and Fanning in the Brazil-3 morphotype. Some behavioral routines differed across the two morphotypes. Significant differences were also noted between the frequencies of the behavioral units displayed during courtship in the two morphotypes. The relationships between the pre-zygotic incompatibilities of the Brazil-1 and Brazil-3 morphotypes and the differences between the courtship behaviors of their males are discussed. Our results indicate that behavioral isolation is involved in the process of pre-zygotic reproductive isolation of Brazil-1 and Brazil-3 morphotypes.

Disentangling the mechanisms of mate choice in a captive koala population.

Successful captive breeding programs are crucial to the long-term survival of many threatened species. However, pair incompatibility (breeding failure) limits sustainability of many captive populations. Understanding whether the drivers of this incompatibility are behavioral, genetic, or a combination of both, is crucial to improving breeding programs. We used 28 years of pairing data from the San Diego Zoo koala colony, plus genetic analyses using both major histocompatibility complex (MHC)-linked and non-MHC-linked microsatellite markers, to show that both genetic and non-genetic factors can influence mating success. Male age was reconfirmed to be a contributing factor to the likelihood of a koala pair copulating. This trend could also be related to a pair’s age difference, which was highly correlated with male age in our dataset. Familiarity was reconfirmed to increase the probability of a successful copulation. Our data provided evidence that females select mates based on MHC and genome-wide similarity. Male heterozygosity at MHC class II loci was associated with both pre- and post-copulatory female choice. Genome-wide similarity, and similarity at the MHC class II DAB locus, were also associated with female choice at the post-copulatory level. Finally, certain MHC-linked alleles were associated with either increased or decreased mating success. We predict that utilizing a variety of behavioral and MHC-dependent mate choice mechanisms improves female fitness through increased reproductive success. This study highlights the complexity of mate choice mechanisms in a species, and the importance of ascertaining mate choice mechanisms to improve the success of captive breeding programs.

Close‐distance courtship of laboratory reared Bactrocera tryoni (Diptera: Tephritidae)

AbstractClose‐range courtship behaviours are a critical element of a species' biology but, if rapid, can often be overlooked. Beyond male chemical and audio calling, close‐range courtship interactions leading to copulation in the Queensland fruit fly Bactrocera tryoni are unknown; this may be due to a true absence or because they have been overlooked and not previously investigated. We sought to resolve the close‐range courtship sequence of B. tryoni and construct an ethogram of identified behaviours. Close‐range video recordings of B. tryoni courtship were taken during the dusk mating window and an ethogram constructed by combining all observed behaviours which led to successful copulation and unsuccessful copulation. While the previously well‐recognised male wing fanning behaviour was documented, a number of other behaviours were identified for the first time in B. tryoni courtship, including female ovipositor extension, and both male and female synchronous supination, face‐to‐face contact, and fore‐ and hind leg interactions. Analyses showed that the total duration of male synchronous supination, but not the number of occurrences, differed significantly between successful and unsuccessful males. Male foreleg interaction with the female abdomen was significantly different in both total duration and total number of occurrences between successful and unsuccessful males. The results reinforce data obtained from other Bactrocera species of simplified courtship sequences in these flies in comparison with other tephritid genera, but nevertheless courtship is more complex than previously recognised.

Inter- and Intrasexual Interactions in Anoplophora glabripennis (Coleoptera: Cerambycidae) and the Impact of Different Sex Ratios.

The behaviors of Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) during inter- and intrasexual interactions between both solitary and paired individuals at different sex ratios were observed on Acer platanoides L. (Sapindales: Sapindaceae) branches in the laboratory. Intrasexual contact was generally ignored by females, but between males resulted in battles from which one male ultimately retreated. When male size differed, larger males won battles, whereas equally sized males split the wins and battled longer. When males initiated intersexual contact, they quickly found and mounted the female. The female apparently determined if and how long the male could copulate with her by controlling access to her genital opening and males would eventually dismount if the female remained unreceptive. After successful copulation, males ignored female intruders and fought off male challengers, generally without dismounting. Some males dismounted females without attempting to copulate. Individual age and size were not predictive of either female or male choice in a mate. Mating duration was affected by both female receptivity and sex ratios present. Male interruptions of the pair shortened time in copula. Male-skewed sex ratios (1F:2M) significantly shortened the time a male would stay with an unreceptive female. Female-skewed sex ratios (2F:1M) did not impact mating duration. Probability of dispersal both from and within the branch was greater for smaller individuals of both sexes and for males when sex ratios were male-skewed. This information demonstrates how reproductive activity might be impacted as population densities decline during efforts at eradication of this species in North America.

Male age is associated with extra-pair paternity, but not with extra-pair mating behaviour

Extra-pair paternity is the result of copulation between a female and a male other than her social partner. In socially monogamous birds, old males are most likely to sire extra-pair offspring. The male manipulation and female choice hypotheses predict that age-specific male mating behaviour could explain this old-over-young male advantage. These hypotheses have been difficult to test because copulations and the individuals involved are hard to observe. Here, we studied the mating behaviour and pairing contexts of captive house sparrows, Passer domesticus. Our set-up mimicked the complex social environment experienced by wild house sparrows. We found that middle-aged males, which would be considered old in natural populations, gained most extra-pair paternity. However, both, female solicitation behaviour and subsequent extra-pair matings were not associated with male age. Further, copulations were more likely when solicited by females than when initiated by males (i.e. unsolicited copulations). Male initiated within-pair copulations were more common than male initiated extra-pair copulations. To conclude, our results did not support either hypothesis regarding age-specific male mating behaviour. Instead, female choice, independent of male age, governed copulation success, especially in an extra-pair context. Post-copulatory mechanisms might determine why older males sire more extra-pair offspring.

Full-term pregnancy with vaginal birth following dystocia and caesarean section in two cheetahs (Acinonyx jubatus)

The cheetah (Acinonyx jubatus) population in North American zoos remains unsustainable despite extensive management within the Species Survival Plan. Successful copulation, pregnancy and birth are essential to achieving population sustainability...

Does the winner-loser effect determine male mating success?

Winning or losing a fight can have lasting effects on competitors. Controlling for inherent fighting ability and other factors, a history of winning often makes individuals more likely to win future contests, while the opposite is true for losers (the 'winner-loser effect'). But does the winner-loser effect also influence a male's mating success? We experimentally staged contests between male mosquitofish (Gambusia holbrooki) such that focal males either won or lost three successive encounters with stimulus males. We then placed a size-matched (to control for inherent fighting ability) winner and loser with a female and monitored their behaviour (n = 63 trios). Winners spent significantly more time associating with the female. Winners did not make more copulation attempts, nor have a greater number of successful attempts. There was, however, a significant effect of male size on the number of successful copulation attempts: success decreased with male size for losers, but size had no effect on the success rate of winners.

Ejaculation Induced by the Activation of Crz Neurons Is Rewarding to Drosophila Males

The reward system is a collection of circuits that reinforce behaviors necessary for survival [1, 2]. Given the importance of reproduction for survival, actions that promote successful mating induce pleasurable feeling and are positively reinforced [3, 4]. This principle is conserved in Drosophila, where successful copulation is naturally rewarding to male flies, induces long-term appetitive memories [5], increases brain levels of neuropeptide F (NPF, the fly homolog of neuropeptide Y), and prevents ethanol, known otherwise as rewarding to flies [6, 7], from being rewarding [5]. It is not clear which of the multiple sensory and motor responses performed during mating induces perception of reward. Sexual interactions with female flies that do not reach copulation are not sufficient to reduce ethanol consumption [5], suggesting that only successful mating encounters are rewarding. Here, we uncoupled the initial steps of mating from its final steps and tested the ability of ejaculation to mimic the rewarding value of full copulation. We induced ejaculation by activating neurons that express the neuropeptide corazonin (CRZ) [8] and subsequently measured different aspects of reward. We show that activating Crz-expressing neurons is rewarding to male flies, as they choose to reside in a zone that triggers optogenetic stimulation of Crz neurons and display conditioned preference for an odor paired with the activation. Reminiscent of successful mating, repeated activation of Crz neurons increases npf levels and reduces ethanol consumption. Our results demonstrate that ejaculation stimulated by Crz/Crz-receptor signaling serves as an essential part of the mating reward mechanism in Drosophila. VIDEO ABSTRACT.

Dynamic changes in display architecture and function across environments revealed by a systems approach to animal communication.

Animal communication is often structurally complex and dynamic, with signaler and receiver behavior varying in response to multiple environmental factors. To date, studies assessing signal dynamics have mostly focused on the relationships between select signaling traits and receiver responses in a single environment. We use the wolf spider Schizocosa floridana to explore the relationships between courtship display form and function across two social contexts (female presence vs absence) and two light environments (light vs dark). We use traditional analytical methods to determine predictors of copulation success (i.e., signal function) and examine these predictors in a structural context by overlaying them on signal phenotype networks (Wilkins etal. 2015). This allows us to explore system design principles (degeneracy, redundancy, pluripotentiality), providing insight into hypotheses regarding complex signal evolution. We found that both social context and light environment affect courtship structure, although the predictors of mating success remain similar across light environments, suggesting system degeneracy. Contrastingly, the same display traits may serve different functions across social environments, suggesting pluripotentiality. Ultimately, our network approach uncovers a complexity in display structure and function that is missed by functional analyses alone, highlighting the importance of systems-based methodologies for understanding the dynamic nature of complex signals.

Courtship and copulation in Glaucous-winged Gulls,Larus glaucescens, and the influence of environmental variables

ABSTRACT Courtship and copulation constitute crucial elements of avian reproduction and fitness. Despite the potential impact of environmental perturbations and long-term climate change on avian reproduction, few studies provide quantitative information on courtship and copulation behaviors and their responses to proximate environmental factors. We provide the first quantitative description of courtship and copulation behavior in Glaucous-winged Gulls (Larus glaucescens), an important indicator species of marine environmental quality in North America's Pacific Northwest. Male and female Glaucous-winged Gulls exhibited similar frequencies of most pre- and post-mount behaviors, which closely resemble those used by other larids. Mounts were more frequent than expected during the pre-egg-laying and egg-laying stages of the breeding season and less frequent than expected during the incubation stage. In 2008, numbers of successful copulations vs. unsuccessful copulations, numbers of cloacal contacts per success...

Courtship activity, copulation & insemination success in a mosquito vector fed a herbal aphrodisiac: Implications for sterile insect technology.

Background & objectives:In sterile insect technology (SIT), mating competitiveness is a pre-condition for the reduction of target pest populations and a crucial parameter for judging efficacy. Still, current SIT trials are being hindered by decreased effectiveness due to reduced sexual performance of released males. Here, we explored the possible role of a herbal aphrodisiac in boosting the mating activity of Aedes aegypti.Methods:Males were fed one of two diets in this study: experimental extract of Eurycoma longifolia (MSAs) and sugar only (MSOs). Differences in life span, courtship latency, copulation activity and mating success were examined between the two groups.Results:No deaths occurred among MSA and MSO males. Life span of MSOs was similar to that of MSAs. The courtship latency of MSAs was shorter than that of MSOs (P<0.01). MSAs had greater copulation success than MSOs (P<0.001). In all female treatments, MSAs mated more than MSOs, but the differences in rate were significant only in the highest female density (P<0.05). In MSAs, mating success varied significantly with female density (P<0.01), with the 20-female group (P<0.01) having the lowest rate. Single MSA had better mating success at the two lowest female densities. In MSOs, there were no significant differences in mating success rate between the different female densities.Interpretation & conclusions:Our results suggested that the herbal aphrodisiac, E. longifolia, stimulated the sexual activity of Ae. aegypti and may be useful for improving the mating competitiveness of sterile males, thus improving SIT programmes.

The Effect of Larval Diet on Adult Survival, Swarming Activity and Copulation Success in Male Aedes aegypti (Diptera: Culicidae)

Control of Aedes aegypti (L.) (Diptera: Culicidae) populations is vital for reducing the transmission of several pervasive human diseases. The success of new vector control technologies will be influenced by the fitness of laboratory-reared transgenic males. However, there has been relatively little published data on how rearing practices influence male fitness in Aedes mosquitoes. In the laboratory, the effect of larval food availability on adult male fitness was tested, using a range of different fitness measures. Larval food availability was demonstrated to be positively correlated with adult body size. Larger males survived longer and exhibited greater swarming activity. As a consequence, larger males may have more mating opportunities in the wild. However, we also found that within a swarm larger males did not have an increased likelihood of copulating with a female. The outcome of the mating competition experiments depended on the methodology used to mark the males. These results show that fitness assessment can vary depending on the measure analyzed, and the methodology used to determine it. Continued investigation into these fitness measures and methodologies, and critically, their utility for predicting male performance in the field, will increase the efficiency of vector control programs.

Triggers of the Postural Display of Courtship in Drosophila persimilis Flies

D. persimilis courtship shows some flexibility and courting males sometimes perform an elaborate postural display in addition to the standard courtship behaviours shared by most Drosophila species. This postural display includes the acrobatic contortion and tremulation of their abdomen, accompanied by the generation of substrate-borne vibrations, and they proffer a nutritional droplet to the female. Here, we use courtship and choice assays to ask what triggers this display and what advantages males may gain from it during courtship. In pair assays, we found no differences in the courtship duration and copulation success between displaying and non-displaying males. In trio assays, however, the female always mated with the male who performed the display. To investigate what promotes the male display, we varied the level of receptivity of the female and studied the impact of a second male. We found that rejection by the female does not induce the male to display, contrary to what was previously suggested. We present evidence that the male display is in fact promoted by the presence of an attentive and sexually receptive female and the absence of male competition, with the greatest exhibition rate obtained if the courted female is starved. These findings provide valuable information about the social ecology of flies, and how internal and external cues influence sexual behaviours and mate choice.

Generalized structural equations improve sexual-selection analyses.

Sexual selection is an intense evolutionary force, which operates through competition for the access to breeding resources. There are many cases where male copulatory success is highly asymmetric, and few males are able to sire most females. Two main hypotheses were proposed to explain this asymmetry: “female choice” and “male dominance”. The literature reports contrasting results. This variability may reflect actual differences among studied populations, but it may also be generated by methodological differences and statistical shortcomings in data analysis. A review of the statistical methods used so far in lek studies, shows a prevalence of Linear Models (LM) and Generalized Linear Models (GLM) which may be affected by problems in inferring cause-effect relationships; multi-collinearity among explanatory variables and erroneous handling of non-normal and non-continuous distributions of the response variable. In lek breeding, selective pressure is maximal, because large numbers of males and females congregate in small arenas. We used a dataset on lekking fallow deer (Dama dama), to contrast the methods and procedures employed so far, and we propose a novel approach based on Generalized Structural Equations Models (GSEMs). GSEMs combine the power and flexibility of both SEM and GLM in a unified modeling framework. We showed that LMs fail to identify several important predictors of male copulatory success and yields very imprecise parameter estimates. Minor variations in data transformation yield wide changes in results and the method appears unreliable. GLMs improved the analysis, but GSEMs provided better results, because the use of latent variables decreases the impact of measurement errors. Using GSEMs, we were able to test contrasting hypotheses and calculate both direct and indirect effects, and we reached a high precision of the estimates, which implies a high predictive ability. In synthesis, we recommend the use of GSEMs in studies on lekking behaviour, and we provide guidelines to implement these models.

The white gene controls copulation success in Drosophila melanogaster

Characteristics of male courtship behavior in Drosophila melanogaster have been well-described, but the genetic basis of male-female copulation is largely unknown. Here we show that the white (w) gene, a classical gene for eye color, is associated with copulation success. 82.5% of wild-type Canton-S flies copulated within 60 minutes in circular arenas, whereas few white-eyed mutants mated successfully. The w+ allele exchanged to the X chromosome or duplicated to the Y chromosome in the white-eyed genetic background rescued the defect of copulation success. The w+-associated copulation success was independent of eye color phenotype. Addition of the mini-white (mw+) gene to the white-eyed mutant rescued the defect of copulation success in a manner that was mw+ copy number-dependent. Lastly, male-female sexual experience mimicked the effects of w+/mw+ in improving successful copulation. These data suggest that the w+ gene controls copulation success in Drosophila melanogaster.

Effect of the age of ganders on reproductive behavior and fertility in a competitive mating structure

Abstract This paper presents the study on determination of gander-goose mating activity in relation to age and the position of gander in social hierarchic rank. Moreover, levels of fertility (F) and testosterone (T) in different gander age groups were analyzed. The study was carried out on one-year-old geese (N = 64) and one- or two-year-old ganders (N = 16; 1♂: 4♀). Observations of mating activity (MA) were conducted during the 3-h period of the daylight (10 h), 2-3 times per week (102 h/ group/34 days). The recording was done with a digital recorder connected to cameras. Agonistic behavioral interactions between ganders were noted to determine a social hierarchic rank. The MA was described by frequency of courtship displays, copulation attempts, successful copulation (SCop), and interaction disrupted (DMI) with agonistic behavior. Fertility was evaluated after the artificial incubation (1×/week) in a commercial hatchery. The frequency of SCop, DMI, and T concentration were higher (P&lt;0.05) for two- than one-year-old ganders. Moreover, F was higher by 11.2% for group of geese kept with two-year-old ganders. There was an effect of the gander’s rank in social hierarchy on the frequency of MA. For dominant ganders, frequency of courtship displays (1.0/times/3 h) and copulation attempts (0.8/times/3 h) were lower (P&lt;0.05), but SCop (1.5/times/3 h) was higher (P&lt;0.05) than for subordinate ones. Thus, in domestic goose flocks reproductive success was associated with age of ganders used in competitive mating system. This is probably a multifactor effect of interaction between sexual/social experience, T-dependent mating motivation, and efficiency of MA. It is recommended to keep one-year-old geese with older ganders (after sexual reactivation) for optimal fertility results with sex ratio adjusted to gander-gander antagonistic interaction dynamic.

Highly variable male courtship behavioral sequences in a crambid moth

Research on male courtship behavior of moths has focused on documenting stereotyped sequences for successful copulation. We characterized successful male courtship behavior among 126 virgin mating pairs of Ostrinia nubilalis. Using Markov analysis, stereotypy indices, and a novel application of ecological network analysis, we found high variability in these sequences. Fifteen courtship behaviors were described and 96 behavioral transitions were observed, 39 of which occurred only once. The number of courtship bouts ranged from one to ten, the number of behavioral transitions ranged from four to 41, and the number of copulation attempts ranged from one to 29. Only 23% of males used a common, simple behavioral sequence. Females exhibited acceptance or rejection behaviors in 40% of the sequences, but these did not explain the high variability in male courtship sequences. About half of the transitions occurred non-randomly, and stereotypy was low. Network analysis revealed that the courtship sequences started and ended with stereotyped behaviors and the high variability occurred in the middle of the sequences. Whole system analysis showed that the courtship sequences were more variable than for optimal transfer of information. Overall, these results suggest that the sequence of behaviors may be less important than the occurrence of certain behavioral elements for successful mating.

Male Psyllids Differentially Learn in the Context of Copulation.

In the Asian citrus psyllid, Diaphorina citri Kuwayama, stimulatory cuticular hydrocarbons act as sex pheromone attractants. Male psyllids locate aggregations of females using those olfactory cues, as well as vibrational communication on the plant surface. Although previous research has indicated that learning plays a role in modulating female reproductive behaviors in psyllids, it is unknown whether males similarly use learning to increase the likelihood of copulatory success. We used an olfactometer-based bio-assay to study the effects of experience on male response to female odor. First, we compared male attraction to female odor in virgin and previously mated males. Second, we tested the effect of several modes of experience with a novel odor, vanillin, to determine whether mating, feeding, or general environmental exposure elicited a learned response. We found that male attraction to female odor significantly increased after mating experience. In addition, we found that males learn about odor specifically in the context of mating, rather than feeding or general exposure. Electrophysiological measurements of antennal response to odorants confirmed that mating status did not affect the sensitivity of the peripheral nervous system to volatile stimuli implicating learning at the level of the central nervous system. These results suggest that male response to female odor is not an entirely innate behavior. Males may require mating experience with female conspecifics to develop attraction to those olfactory cues produced by the female and in association with the female’s habitat. This adaptive plasticity may allow males to detect females in an ever-changing environment and promote diversification and further specialization on different host genotypes.

Caenorhabditis elegansMale Copulation Circuitry Incorporates Sex-Shared Defecation Components To Promote Intromission and Sperm Transfer

Sexual dimorphism can be achieved using a variety of mechanisms, including sex-specific circuits and sex-specific function of shared circuits, though how these work together to produce sexually dimorphic behaviors requires further investigation. Here, we explore how components of the sex-shared defecation circuitry are incorporated into the sex-specific male mating circuitry in Caenorhabditis elegans to produce successful copulation. Using behavioral studies, calcium imaging, and genetic manipulation, we show that aspects of the defecation system are coopted by the male copulatory circuitry to facilitate intromission and ejaculation. Similar to hermaphrodites, male defecation is initiated by an intestinal calcium wave, but circuit activity is coordinated differently during mating. In hermaphrodites, the tail neuron DVB promotes expulsion of gut contents through the release of the neurotransmitter GABA onto the anal depressor muscle. However, in the male, both neuron and muscle take on modified functions to promote successful copulation. Males require calcium-dependent activator protein for secretion (CAPS)/unc-31, a dense core vesicle exocytosis activator protein, in the DVB to regulate copulatory spicule insertion, while the anal depressor is remodeled to promote release of sperm into the hermaphrodite. This work shows how sex-shared circuitry is modified in multiple ways to contribute to sex-specific mating.

Male Mate Choice Among Captive Long-tailed Macaques (Macaca Fascicularis)

The purpose of this study was to investigate male preference and to define the aspects of females that affect male preference. We set experimental conditions that enabled us to measure successful mating by gathering sperm from female vaginal washings and observing sexual behavior. The animal subjects in our study were cynomolgus monkeys, all of whom were bred in our primate institute. During the study, one male would be grouped with two females, each of whom lived in a cage adjacent to the male’s cage. This enabled each of the females to be housed with the male in turn; 12 males and 24 females were included in the study. After a male was housed with a female, we observed through a microscope the existence of sperm in the female’s vaginal washing, thus confirming copulation success. In some of the groups, behavioral observation was conducted on both the male and female subjects. According to our findings, in the multiparous females, successful mating was observed on 29% of cohabitation days. Among nulliparous females, the presence of sperm was observed on only 6% of cohabitation periods. Some 66.7% of nulliparous females never mated with a male. Our observations also revealed that sexual behaviors were more frequently observed when a male lived with a multiparous female. “Male-grooming-of-female” activities were seen more frequently between a male and multiparous female; that is, the male approached a multiparous female for copulation by grooming her. Our study suggests that male cynomolgus monkeys prefer multiparous females, as it is important that a male choose a female who more easily and regularly becomes pregnant and gives birth to offspring with a higher survival rate. Thus, male choice is biologically significant with respect to leaving more offspring.