Mate Guarding Research Papers - Academia.edu (original) (raw)

The following article reviews literature regarding female mate guarding, male mate guarding, and female aversion to mate guarding in the context of the “Good Genes Sexual Selection” theory, “Sperm Retention” hypothesis, and “Mate... more

The following article reviews literature regarding female mate guarding, male mate guarding, and female aversion to mate guarding in the context of the “Good Genes Sexual Selection” theory, “Sperm Retention” hypothesis, and “Mate Switching” hypothesis. Mate guarding by both sexes is preceded by jealousy and serves to protect relationships and the propagation of genes from mate poachers. While male mate guarding is heightened when partners are fertile and more attractive, females may mate guard valued partners due to mate value discrepancies.

Extra-pair paternity is widely documented in birds, but the behaviors that lead to extra-pair copulations (EPCs) have been less well studied, particularly in territorial songbirds. We studied the behaviors associated with... more

Extra-pair paternity is widely documented in birds, but the behaviors that lead to extra-pair copulations (EPCs) have been less well studied, particularly in territorial songbirds. We studied the behaviors associated with extra-territorial forays (ETFs) and male mate guarding in a socially monogamous, but genetically promiscuous, neotropical migrant passerine, the yellow-breasted chat (Icteria virens). Focal observations and radiotelemetry revealed that both males and females engaged in ETFs. 65% of the females in our study engaged in at least one foray onto a neighboring territory. 50% of males also were observed engaging in ETFs, but males were much more conspicuous during these intrusions compared to females. Females preferred to remain close to the ground in areas where vegetation was the densest. Female behavior was difficult to observe during ETFs but females sometimes interacted with neighboring extra-pair males. Males attempted to guard their mates by remaining close to them and following them during extra-territorial intrusions. We observed instances in which a male attacked his mate and appeared to herd her back to his territory. However a male's ability to maintain close proximity to his mate was significantly and negatively correlated with vegetation density. Our results suggest that the behaviors which lead to extra-pair encounters are influenced by the behavior of all participants and are modified by the characteristics of the habitat.

A combination of laboratory and field investigations of birds has shown that expression of behavior such as territorial aggression can occur throughout the year in many species and in different life history stages. Although it is well... more

A combination of laboratory and field investigations of birds has shown that expression of behavior such as territorial aggression can occur throughout the year in many species and in different life history stages. Although it is well known that testosterone regulates territorial aggression in males during the breeding season, the correlation of plasma testosterone and aggression appears to be limited to periods of social instability when a male is challenged for his territory by another male, or when mate-guarding a sexually receptive female. How essentially identical aggression is modulated in nonbreeding life history stages is not fully resolved, but despite low circulating levels of testosterone outside the breeding season, expression of territorial aggression does appear to be dependent upon aromatization of testosterone and an estrogen receptor-mediated mechanism. There is accumulating evidence that prolonged high levels of circulating testosterone may incur costs that may potentially reduce lifetime fitness. These include interference with paternal care, exposure to predators, increased risk of injury, loss of fat stores and possibly impaired immune system function and oncogenic effects. We propose six hypotheses to explain how these costs of high testosterone levels in blood may be avoided. These hypotheses are testable and may reveal many mechanisms resulting from selection to avoid the costs of testosterone. It should also be noted that the hypotheses are applicable to vertebrates in general, and may also be relevant for other hormones that have a highly specialized suite of actions in one life history stage (such as breeding), but also have a limited action in other life history stages when the full spectrum of effects would be inappropriate.

The population dynamics of a monogamous coral-reef fish were examined to test hypotheses of recruitment limitation, predation, and postrecruitment processes, and to determine their affects on the mating system. Valenciennea strigata are... more

The population dynamics of a monogamous coral-reef fish were examined to test hypotheses of recruitment limitation, predation, and postrecruitment processes, and to determine their affects on the mating system. Valenciennea strigata are monogamous gobies that live in sand and rubble zones throughout the Indo-Pacific. Seasonal abundance was recorded in the summer and winter over 2.5 years. A subset of this population was tagged (n = 256) and followed to determine mortality and mobility. Valenciennea strigata were more abundant in summer than in winter, suggesting that a pulse of recruitment in the spring set the maximum population density. Growth rates derived from tagged fish support the hypothesis that recruitment peaked in the spring. Tagged fish experienced 88% mortality within six months; the annual mortality rate approached 100%. Evidence of predation, antipredatory behavior and strong site fidelity implicate predation as the primary source of mortality. Competition for space was not observed between adults, but may affect settlement and recruitment. Despite the lack of adult competition for space, both sexes guarded their mates and courted individuals of the opposite sex. Thus, although population size appears to be determined by nonequilibrium processes, the mating system is affected by competition for mates. Successful mate guarding by both sexes enforced monogamy.

Aspidoscelis costata energetic cost male cost adjustment male lizard mate guarding whiptail lizard Simultaneous effects of mate guarding on a male's energy intake and expenditure have not been measured. We tested whether guarding males of... more

Aspidoscelis costata energetic cost male cost adjustment male lizard mate guarding whiptail lizard Simultaneous effects of mate guarding on a male's energy intake and expenditure have not been measured. We tested whether guarding males of the western Mexican whiptail lizard, Aspidoscelis costata, reduce energy intake and increase expenditure of energy on male-male aggression. Also, we tested whether guarding males calibrate their aggressive behaviour and feeding to aggression from male rivals (a proxy of their female's probability of extrapair copulation) and body size of the guarded female (positively correlated with fecundity in this species). Observation during and after guarding showed that guarding males (1) ate 77% fewer prey/h and 54% smaller prey, (2) initiated 87% more agonistic interactions/h and (3) participated in 120% more escalated agonistic interactions/h than when alone. Also, guarding males initiated more aggressions when aggression from other males and female size were greater. These results indicate that mate guarding is costly for males because of simultaneous reduction in energy intake and increased expenditure on aggression, and that males incur higher guarding costs when competition with other males and female reproductive value are greater. These costs of mate guarding probably result in negative energy balances that could reduce male fitness through diminished survival. The evolutionary persistence of mate guarding by males can be explained if the net gain in fitness derived from guarding more than offsets its survival costs. Ó

We examined the dynamics and avoidance of mate guarding, by males and females, in the blue-footed booby, in which the two social mates are usually simultaneously present on the territory but each of them is unmonitored by the other for... more

We examined the dynamics and avoidance of mate guarding, by males and females, in the blue-footed booby, in which the two social mates are usually simultaneously present on the territory but each of them is unmonitored by the other for one-quarter of its time. Both sexes were promiscuous and liable to switch mates. Cuckolded individuals did not increase their overall presence on the territory, but in response to the extra-pair (EP) courtships of their mates, both sexes doubled their rate of intra-pair (IP) courtship and sometimes showed aggression. The male or female's presence depressed the social mate's EP activity, but intra-pair courtship had no such effect, tending even to propitiate that EP activity. Similarly, when females responded to their social mates' EP courtship with approach or aggression, disruption of EP activity was short-lived. Promiscuous females modified their diurnal pattern of attendance, as if attempting to sidestep monitoring by their mates, but cuckolded males matched the modification. Both sexes tended to perform their EP activities at a distance when their mates were present, possibly to evade monitoring or disruption by their mates. Male and female boobies cannot monitor their mates continuously, they do little to facultatively adjust their presence on territory to the risk of infidelity, and their immediate responses to overt infidelity have only the briefest impact; but the information they acquire while monitoring their mates may be critical Communicated by R. M. Gibson

Thirty-eight normally cycling women provided daily reports of sexual interests and feelings for 35 days. Near ovulation, both pair-bonded and single women reported feeling more physically attractive and having greater interest in... more

Thirty-eight normally cycling women provided daily reports of sexual interests and feelings for 35 days. Near ovulation, both pair-bonded and single women reported feeling more physically attractive and having greater interest in attending social gatherings where they might meet men. Pair-bonded women who were near ovulation reported greater extra-pair flirtation and greater mate guarding by their primary partner. As predicted, however, these effects were exhibited primarily by women who perceived their partners to be low on hypothesized good genes indicators (low in sexual attractiveness relative to investment attractiveness). Ovulation-contingent increases in partner mate guarding were also moderated by female physical attractiveness; midcycle increases in mate guarding were experienced primarily by less attractive women, whereas more attractive women experienced relatively high levels of mate guarding throughout their cycle. These findings demonstrate ovulationcontingent shifts in desires and behaviors that are sensitive to varying fitness payoffs, and they provide support for the good genes hypothesis of human female extra-pair mating. The daily assessment method provides an important supplement to existing studies using scheduled laboratory visits as the purpose of the study (examining cycle-related variation) is not known by participants.

Recent research suggests that men may possess adaptations that evolved to counter strategic variation in women's preferences for masculine men. For example, women's preferences for masculine, dominant men are stronger during the fertile... more

Recent research suggests that men may possess adaptations that evolved to counter strategic variation in women's preferences for masculine men. For example, women's preferences for masculine, dominant men are stronger during the fertile phase of the menstrual cycle than at other times and men demonstrate increased sensitivity to facial cues of male dominance when their partners are ovulating. Such variation in men's dominance perceptions may promote efficient allocation of men's mate guarding effort (i.e., allocate more mate guarding effort in response to masculine, dominant men in situations where women show particularly strong preferences for such men). Here, we tested for further evidence of adaptations that may have evolved to counter strategic variation in women's masculinity preferences. Men who reported having particularly feminine romantic partners demonstrated a greater tendency to attribute dominance to masculinized male faces than did men who reported having relatively masculine romantic partners. This relationship between partner femininity and men's sensitivity to facial cues of male dominance remained significant when we controlled for potential confounds (men's age, self-rated masculinity, reported commitment to their relationship, and the length of the relationship) and may be adaptive given that feminine women demonstrate particularly strong preferences for masculine, dominant men. While previous research has emphasized variation in women's masculinity preferences, our findings add to a growing body of research suggesting that sexual selection may also have shaped adaptations that evolved to counter such systematic variation in women's preferences for masculine, dominant men.

Paternal investment has long been considered responsible for the evolution of predominantly monogamous marriage in humans. However, male-male competition resulting in mate-guarding and male coercion could be equally important. In this... more

Paternal investment has long been considered responsible for the evolution of predominantly monogamous marriage in humans. However, male-male competition resulting in mate-guarding and male coercion could be equally important. In this review, I use a comparative approach to examine the effect of variation in human paternal investment on our mating system. I conclude paternal investment is important but so too is mate-guarding. I propose a model of our mating system incorporating both factors. Variation in the mating system is explained by variation in male resource control and contribution, resulting in ecologically imposed monogamy or polygyny, as predicted by the polygyny threshold model, as well as variation in male -male competition for status, resulting in socially imposed monogamy or polygyny.

Two spermatogenetic cycles, vernal and aestival, have been described in temperate colubrid snakes. In both cycles, mating occurs in the spring, although vernal species produce spermatozoa in spring, just before mating, while aestival... more

Two spermatogenetic cycles, vernal and aestival, have been described in temperate colubrid snakes. In both cycles, mating occurs in the spring, although vernal species produce spermatozoa in spring, just before mating, while aestival species use spermatozoa produced the previous summer. In this study, we describe the reproductive cycles of male and female Malpolon monspessulanus (Colubridae), and compare them to previously published cycles of five other snake species, four vernal and one aestival, inhabiting the same area. We also examine the consequences of both spermatogenesis cycles over the entire reproductive processes of male and female snakes in the south-eastern Iberian Peninsula. Vernal species mate later than do aestival species, as males must produce spermatozoa just prior to mating. However, vernal species are able to condense spermatogenesis and vitellogenesis processes, hence undertaking oviposition at the same time as aestival species. Here we discuss advantages of accomplishing the entire reproductive cycle in one (vernal species) or two (aestival species) calendar years. We also found that mature male M. monspessulanus exhibit decreased testes volume relative to body size. Large testes are expected in scenarios of sperm competition. The mating system of M. monspessulanus (territoriality, mate guarding, male-male combat) does not suggest sperm competition, hence it may be more advantageous for males of this species to invest in body size than in testes size.

The timing of breeding may not only affect breeding patterns such as the overlap of chick rearing period with the peak in food availability but also the opportunity for extra-pair mating. A negative relationship has been predicted between... more

The timing of breeding may not only affect breeding patterns such as the overlap of chick rearing period with the peak in food availability but also the opportunity for extra-pair mating. A negative relationship has been predicted between extra-pair paternity and breeding synchrony, assuming that male extra-pair activity is traded against mate guarding and parenting duties. In contrast, if female ability to assess male quality is temporally constrained, sperm competition might be a positive function of breeding synchrony. Here we manipulated the progress of nesting by nest material exchange within nesting aggregations to see whether the timing of breeding affects extra-pair paternity in house sparrows. We found that late broods within nesting clusters contained extra-pair young more often than early broods, but breeding synchrony did not turn out to be a significant predictor of extra-pair paternity. Our study indicates that temporal constraints of male extra-pair activity may account for extra-pair paternity levels, but it is also possible that late-breeding females may accept extra-pair copulations to ensure egg fertilization.

Female distribution exerts a major impact on male mating tactics. Giraffe cows have a reproductive cycle, and a social system, that should favor a male roaming reproductive tactic. We conducted a 2-year study of female Rothschild's... more

Female distribution exerts a major impact on male mating tactics. Giraffe cows have a reproductive cycle, and a social system, that should favor a male roaming reproductive tactic. We conducted a 2-year study of female Rothschild's giraffe (G. c. rothschildi) reproductive endocrinology in order to characterize attributes of the reproductive cycle and investigate how female endocrine and behavioral cues influence mating activity. We used non-invasive fecal steroid methods to determine reproductive state among females residing in a herd in a large outdoor enclosure. We found that females had an estrous cycle of 14.7 days and that they regularly had multiple ovarian cycles prior to conception. Adult males were more likely to associate with, and sexually investigate, females when they were cycling than when they were either pregnant or acyclic. During the estrous cycle, male-female proximity and sociosexual behavior were more pronounced during the probable fertile phase than the rest of the cycle. Sexual activity between giraffe coincided with the periovulatory period, with male interest in females peaking during the fertile window in the absence of proceptive behavior by females. We conclude that males detect reliable cues revealing female reproductive status and partition their reproductive effort in response to such cues. We propose that male giraffe adopt a roaming reproductive strategy with their large size, enabling them to search for and mate guard fertile females while minimizing metabolic costs.

This article explores the connection between sexual selection and religion, locating the origins of religious behavior in mate guarding after the transition to terrestrial life in Homo erectus 1.8 million years ago. An important... more

This article explores the connection between sexual selection and religion, locating the origins of religious behavior in mate guarding after the transition to terrestrial life in Homo erectus 1.8 million years ago. An important consequence of the transition was the emergence of a polygynous, multiple-family social structure, which gave rise to mate guarding as a successful strategy. Further, as a result of sleeping on the ground, REM (rapid-eye-movement) phases were substantially extended. This produced novel dream experiences in Homo erectus, which is identified as the origin of proto-religious traits. The article argues that proto-religious dream experiences and related behavioral expressions gave males psychological and strategic advantages in keeping competitors away from their females. Given the strong selective pressure of male competition in polygynous mating systems, biological traits underlying proto-religion were successful in natural selection. Finally, it is suggested how subsequent evolutionary leaps in human cognition shaped religious thought and behavior and their role in sexual selection. The article is concluded by outlining how elements of the mate-guarding hypothesis could be tested and improved using empirical methods.

Mercury (Hg) is a ubiquitous contaminant with deleterious effects on many wildlife species. Most studies to date have focused on fish-eating birds and mammals because much historical Hg pollution is aquatic. Recently, however, comparable... more

Mercury (Hg) is a ubiquitous contaminant with deleterious effects on many wildlife species. Most studies to date have focused on fish-eating birds and mammals because much historical Hg pollution is aquatic. Recently, however, comparable blood-Hg levels have been found in terrestrial insectivorous songbirds. As a result, research is needed to clarify the effects of Hg exposure on songbirds. One fundamental end point that is still poorly understood is the effect of Hg on the songbird immune system. If Hg affects the functioning of the immune system, exposed songbirds may be less able to mount an appropriate immune response against invading pathogens. To gain insight into how Hg affects songbird immune function on a cellular level, a flow cytometric assay was developed to measure lipopolysaccharide-induced B-lymphocyte proliferation in zebra finches (Taeniopygia guttata). This is the first experimental (dosing) study of the potential effect of Hg on songbird immune system functioning. Decreased B cell proliferation was observed after lipopolysaccharide exposure in individuals with greater concentrations of Hg in their blood and tissues. In addition, these individuals had decreased ratios of proliferating-to-resting B cells. This decrease in lymphocyte proliferation in response to an effective mitogen suggests that environmental exposure to sublethal levels of Hg may inhibit or delay B cell proliferation in songbirds, potentially increasing susceptibility to disease and decreasing survivorship.

The origins and evolution of sperm storage in Brachyura are enigmatic: sperm is either stored in seminal receptacles, accessible via the vulvae on the sixth thoracic sternite, or in spermathecae at the border between the seventh and... more

The origins and evolution of sperm storage in Brachyura are enigmatic: sperm is either stored in seminal receptacles, accessible via the vulvae on the sixth thoracic sternite, or in spermathecae at the border between the seventh and eighth sternites. Crabs with spermathecae are collectively referred to as "podotremes" while crabs with seminal receptacles belong to the Eubrachyura. The position of gonopores is the primary basis for subdividing the Eurachyura into the Heterotremata (female vulvae + males with coxal gonopores) and Thoracotremata (female vulvae + males with sternal gonopores). We present a hypothesis about the evolution of seminal receptacles in eubrachyuran female crabs and argue that the sternal gonopore has been internalized into chitin-lined seminal receptacles and the vulva is in fact a secondary aperture. The loss of some or all of the ancestral chitinous seminal receptacle lining was linked to ventral migration of the oviduct connection. Male and female strategies are to maximize gamete fertilization. The most important variable for females is sperm supply, enhanced by long-term storage made possible by the seminal receptacle. To maximize their fertilization rates males must adapt to the structure of the seminal receptacle to ensure that their sperm are close to the oviduct entrance. The major evolutionary impetus for female mating strategies was derived from the consequences of better sperm conservation and the structure of the seminal receptacle. The advantages were all to the females because their promiscuity and sperm storage allowed them to produce more genetically variable offspring, thereby enhancing variation upon which natural selection could act. We extend our arguments to Brachyura as a whole and offer a unifying explanation of the evolution of seminal receptacles, comparing them with the spermathecae found in "Podotremata": they were independent solutions to the same problem: maintaining sperm supply during evolutionary carcinization. Explanation of eubrachyuran mating strategies requires analysis of the mating-moulting link, indeterminate vs. determinate growth format and seminal receptacle structure. Two alternatives for each of these characters means that there are eight possible outcomes. Six of these outcomes have been realized, which we term Portunoid, Majoid, Eriphoid, Xanthoid, Cancroid, and Grapsoid-Ocypodoid strategies, respectively. Mapping these characters on to a workable phylogeny (wherein some changes to the seminal receptacle + moulting-mating links are assumed to have occurred more than once) produces the following relationships: Portunoids + Majoids are a sister group to the rest of the Eubrachyura, which fall into two sister groups, Eriphoids + Xanthoids and Cancroids + Grapsoid-Ocypodoids and the "Podotremata" is sister group to all the Eubrachyura.

We provide evidence for cooperative breeding in two endemic parrot species of New Caledonia, the New Caledonian Parakeet (Cyanoramphus saisseti) and the Horned Parakeet (Eunymphicus cornutus). We intensively monitored 11 breeding attempts... more

We provide evidence for cooperative breeding in two endemic parrot species of New Caledonia, the New Caledonian Parakeet (Cyanoramphus saisseti) and the Horned Parakeet (Eunymphicus cornutus). We intensively monitored 11 breeding attempts in two nests of New Caledonian Parakeets over 5 years, and noticed that two males of different size fed the female and the chicks in each nest. During one breeding attempt, the larger male guarded the female and the smaller male tried to copulate with her inside the nest. Genetic analyses showed that males shared paternity. During 17 breeding attempts in 11 Horned Parakeet nests, we observed two pairs sharing a nest on one occasion but we never saw feeding helpers.

Abstract: Religions are integral to cultures worldwide, their prevalence and persistence suggest that they fulfill human wants and needs. A foundational religious practice is the marriage ceremony, which contractually grants and obliges... more

Abstract: Religions are integral to cultures worldwide, their prevalence and persistence suggest that they fulfill human wants and needs. A foundational religious practice is the marriage ceremony, which contractually grants and obliges the betrothed access to each other while making their commitment known to the community. Throughout the animal kingdom the attempt to retain access to desirable conspecifics is termed mate guarding. If religions provide a means for humans to mate guard, religious behavior may have embedded adaptiveness. This study seeks to bring attention to the questions: does religion provide a socially sanctioned role for human mate guarding and if so, is there a positive correlation between self-reported religiosity and measures of mate retention?

The extent to which active female mating preferences influence male reproductive success in mammals is unclear, particularly for promiscuously breeding species like chimpanzees (Pan troglodytes). Previous studies from multiple long-term... more

The extent to which active female mating preferences influence male reproductive success in mammals is unclear, particularly for promiscuously breeding species like chimpanzees (Pan troglodytes). Previous studies from multiple long-term study sites have shown that female chimpanzees mate more restrictively around ovulation, and this has been taken as evidence for female choice. However, none of these studies rigorously evaluated the alternative hypothesis that restrictive mating results not from unconstrained choice, but in response to coercive mate guarding, in which males use punishment and intimidation to reduce female promiscuity and promote their own mating interests. Nor did they consider evidence for the potential genetic or phenotypic benefits that females might be choosing. Using 11 years of data from the Kanyawara community in Kibale National Park, Uganda, we previously demonstrated that males achieve elevated mating success with those females toward whom they direct high levels of aggression. Here we extend those findings to show that even female copulatory approaches, which have previously been attributed to female choice, are correlated with male aggression. Specifically, individual females at our site initiated periovulatory copulations most frequently with the males who were most aggressive toward them throughout their cycles. Those males showed high rates of aggression toward females throughout estrus, despite achieving high copulation rates, demonstrating a continuing conflict of interest over the exclusivity of mating access. Because sexual coercion is potentially widespread in primates and other mammals, our results stress the importance of considering the influence of male aggression in studies of female choice.

Predator-prey relationships are generally based on arm-race. Wasps and spiders are both predators, which could be potential prey for each other. The orb weaver spider Zygiella x-notata is sometimes a prey for the wasp Vespula germanica.... more

Predator-prey relationships are generally based on arm-race. Wasps and spiders are both predators, which could be potential prey for each other. The orb weaver spider Zygiella x-notata is sometimes a prey for the wasp Vespula germanica. We observed the wasp hunting behaviour under natural conditions, and we tested the influence of the spider's behaviour on the wasp attack success. Wasps were active predators during the reproductive period of the spider. Results showed that wasps located more easily male spiders than females particularly when they were engaged in mate guarding. Female location depended on the presence of a web, but also of prey or prey remains in the web. On the other hand, their location depend neither on the characteristics and the position of the retreat in the environment nor on the size of the web. After location, males were more often captured than females whatever their behaviour (mate guarding or not). Presence of prey remains or prey in the web did not increase the risk for the spider to be captured. There was also no influence of the retreat's characteristics or of its position in the habitat on the risk for the spider to be captured; but wasp successful attacks were less numerous when silk was present around the entrance of the retreat or when the spider was completely inside. As prey and prey remains favoured location of spiders by the wasps, we tested spider web cleaning behaviour as a response to wasp predatory pressure. By throwing small polystyrene pellets in the webs, we observed that more 80% of the spiders rejected the pellets in less than one minute. Our data indicated that wasps were significant predators of Z. x-notata and wasp attack could have been a selective pressure that had favoured spider defensive behaviours such as web cleaning.

Knowledge of a species' spatial behaviour is essential for understanding its behavioural ecology, as well as a prerequisite to planning of conservation strategies. The Little Owl (Athene noctua) has shown a substantial decline in... more

Knowledge of a species' spatial behaviour is essential for understanding its behavioural ecology, as well as a prerequisite to planning of conservation strategies. The Little Owl (Athene noctua) has shown a substantial decline in north-western Europe and is on the road of extinction in Denmark. To quantify relevant aspects of spatial behaviour in the last remaining Danish population, we followed 27 radio-tagged owls representing 14 territories during a period of 2 years. Mated owls were resident at nesting sites year-round with half of all nocturnal locations found within 125 m. Mean nightly distance from roosts peaked in January at 249 m (95% CI = 195-319) and dipped in May to 89 m (66-121). Distance from roosts varied non-linearly with temperature with the longest distances found at 6°C. Home range size varied with more than a tenfold difference between pairs, with pairs with neighbours maintaining 2-3 times larger ranges than isolated pairs independent of habitat composition. Mean home range size of 14 pairs was 41 (95% CI 27-64) and 2.6 ha (1.5-4.5) for 90 and 50% minimum convex polygons, respectively. Males and females behaved similarly, except in the breeding season where females foraged closer to the nest. Mates overlapped completely in activity distributions and were located closer to each other than expected by chance, suggesting a permanent pair-bond. Inter-mate distances were not shorter prior to egg laying compared to the rest of the year, indicating little male investment in mate guarding. No mates left their partner, but widowed birds left their territory within 6-12 months if unable to attract a new mate.

For women, forming close, cooperative relationships with other women at once poses important opportunities and possible threats-including to mate retention. To maximize the benefits and minimize the costs of same-sex social relationships,... more

For women, forming close, cooperative relationships with other women at once poses important opportunities and possible threats-including to mate retention. To maximize the benefits and minimize the costs of same-sex social relationships, we propose that women's mate guarding is functionally flexible and that women are sensitive to both interpersonal and contextual cues indicating whether other women might be likely and effective mate poachers. Here, we assess one such cue: other women's fertility. Because ovulating (i.e., high-fertility) women are both more attractive to men and also more attracted to (desirable) men, ovulating women may be perceived to pose heightened threats to other women's romantic relationships. Across 4 experiments, partnered women were exposed to photographs of other women taken during either their ovulatory or nonovulatory menstrual-cycle phases, and consistently reported intentions to socially avoid ovulating (but not nonovulating) women-but on...

Brood desertion involves a series of interactions between the members of a pair. This process is likely to be based on either member's perception of the other's propensity to desert. We manipulated this perception in males by... more

Brood desertion involves a series of interactions between the members of a pair. This process is likely to be based on either member's perception of the other's propensity to desert. We manipulated this perception in males by experimentally increasing female body mass in the rock sparrow (Petronia petronia), a species in which females can desert their first brood before the nestlings from the first brood leave the nest. We predicted that the male would either desert the brood first or stay even if this implied the risk of caring for the brood alone. We found that males mated to loaded females did not leave but stayed and significantly increased their courtship rate and mate guarding. Unexpectedly, they also increased their food provisioning to the nestlings, even though loaded females did not reduce their nestling-feeding rate. The increase in male feeding rate may be explained as a way for the male to reduce the female's propensity to switch mate and desert or to increase her propensity to copulate with the male to obtain paternity in her next brood. Altogether, our results demonstrate that the perception of the risk of being deserted by the female does not necessarily induce males to desert first, contrary to what is generally assumed by theoretical models.

Background: The evolution of primate sexual swellings and their influence on mating strategies have captivated the interest of biologists for over a century. Across the primate order, variability in the timing of ovulation with respect to... more

Background: The evolution of primate sexual swellings and their influence on mating strategies have captivated the interest of biologists for over a century. Across the primate order, variability in the timing of ovulation with respect to females' sexual swelling patterns differs greatly. Since sexual swellings typically function as signals of female fecundity, the temporal relation between ovulation and sexual swellings can impact the ability of males to pinpoint ovulation and thereby affect male mating strategies. Here, we used endocrine parameters to detect ovulation and examined the temporal relation between the maximum swelling phase (MSP) and ovulation in wild female bonobos (Pan paniscus). Data were collected at the Luikotale field site, Democratic Republic of Congo, spanning 36 months. Observational data from 13 females were used to characterise female swelling cycles (N = 70). Furthermore, we measured urinary oestrone and pregnanediol using liquid chromatography–tandem mass spectrometry, and used pregnanediol to determine the timing of ovulation in 34 cycles (N = 9 females).
Results: We found that the duration of females’ MSP was highly variable, ranging from 1 to 31 days. Timing of ovulation varied considerably in relation to the onset of the MSP, resulting in a very low day-specific probability of ovulation and fecundity across female cycles. Ovulation occurred during the MSP in only 52.9 % of the analysed swelling cycles, and females showed regular sexual swelling patterns in N = 8 swelling cycles where ovulation did not occur. These findings reveal that sexual swellings of bonobos are less reliable indicators of ovulation compared to other species of primates.
Conclusions: Female bonobos show unusual variability in the duration of the MSP and in the timing of ovulation relative to the sexual swelling signal. These data are important for understanding the evolution of sexual signals, how they influence male and female mating strategies, and how decoupling visual signals of fecundity from the periovulatory period may affect intersexual conflict. By prolonging the period during which males would need to mate guard females to ascertain paternity, the temporal variability of this signal may constrain mate-guarding efforts by male bonobos.

Because ancestral women faced trade-offs in choosing mates, they may have evolved to pursue a dual-mating strategy in which they secured investment through one partner and obtained good genes through others. The dual-mating theory... more

Because ancestral women faced trade-offs in choosing mates, they may have evolved to pursue a dual-mating strategy in which they secured investment through one partner and obtained good genes through others. The dual-mating theory predicts that women will display greater interest in extra-pair sex near ovulation, especially if they are mated to a primary male partner who is low in sexual attractiveness. Forty-three normally ovulating women rated their partner's sexual attractiveness and separately reported their own desires and their partner's mate retention behaviors at high and low fertility (confirmed using luteinizing hormone tests). In the high-fertility session relative to the low, women who assessed their partners as being lower in sexual attractiveness reported greater extra-pair desires and more expressed love and attention from their male partners. Women's desire for their own partners did not differ significantly between high and low-fertility sessions. D

It has been proposed that mate guarding is the primary paternity insurance in birds, and only those species in which the male is compelled to leave his mate unattended during the fertile period resort to frequent copulation as a means of... more

It has been proposed that mate guarding is the primary paternity insurance in birds, and only those species in which the male is compelled to leave his mate unattended during the fertile period resort to frequent copulation as a means of assuring paternity. A higher frequency of both extra-pair copulation (EPC) and extra-pair paternity (EPP) has been predicted in non-guarding species. These predictions were examined in Eurasian kestrels, Falco tinnunculus, breeding in western Finland. During the course of a 3-year vole cycle, the mean within-pair copulation frequency was 0.72 per h and the mean number of extra-pair intrusions 0.07 per h. The proportion of EPCs was only 1% of copulations. The within-pair copulation frequency was higher in a year of increasing food abundance (1991) than in the years of decreasing (1992) and low food abundance (1990), although the kestrel breeding density was lower in 1990 than in 1991-1992. Males spent more time mate guarding in 1991-1992 than in 1990 (overall mean 40%). Single-locus DNA profiling revealed EPP in 7% of 27 broods and 5% of 112 offspring in 1991 but none in 1990 or 1992 (19 and 29 broods, respectively). Kestrel males successfully used both frequent pair copulation and mate guarding as complementary paternity guards. The low frequency of EPP may reflect the importance of male parental care in determining the reproductive success of raptors. Females may jeopardize future aid from their mates by soliciting EPCs from intruders. This strategy might markedly reduce female fitness, because the male is the main provider for female and young from before egg laying until the late nestling period.

The European badger Meles meles is thought to mate throughout the year, with two mating peaks occurring in late winter/spring and summer/autumn. After mating, fertilized ova enter embryonic diapause (delayed implantation) at the... more

The European badger Meles meles is thought to mate throughout the year, with two mating peaks occurring in late winter/spring and summer/autumn. After mating, fertilized ova enter embryonic diapause (delayed implantation) at the blastocyst stage, which lasts up to eleven months. Even if mating is successful, however, the estrous cycle may continue during embryonic diapause, which suggests that female badgers are capable of superfetation (conception during pregnancy). This may increase female fitness by facilitating polyandry, and reduce the risk of infanticide by resident males through paternity confusion. Detailed understanding of female receptivity, specifically the association of superfetation with embryonic diapause, may explain field observations of seemingly inconsistent reproductive tactics of male badgers with regard to, for instance, whether or not they guard mates or defend territories. The combination of embryonic diapause and superfetation may occur in other mustelids; if so, the sociobiology of mustelids will need re‐evaluating, and the Mustelidae may prove to be a good model taxon for studies of sexual conflict in the reproduction of eutherian mammals.

For women, forming close, cooperative relationships with other women at once poses important opportunities and possible threats-including to mate retention. To maximize the benefits and minimize the costs of same-sex social relationships,... more

For women, forming close, cooperative relationships with other women at once poses important opportunities and possible threats-including to mate retention. To maximize the benefits and minimize the costs of same-sex social relationships, we propose that women's mate guarding is functionally flexible and that women are sensitive to both interpersonal and contextual cues indicating whether other women might be likely and effective mate poachers. Here, we assess one such cue: other women's fertility. Because ovulating (i.e., high-fertility) women are both more attractive to men and also more attracted to (desirable) men, ovulating women may be perceived to pose heightened threats to other women's romantic relationships. Across 4 experiments, partnered women were exposed to photographs of other women taken during either their ovulatory or nonovulatory menstrual-cycle phases, and consistently reported intentions to socially avoid ovulating (but not nonovulating) women-but on...

It has been demonstrated that in libellulid dragonflies the distribution of eggs during oviposition and the offspring size vary with the type of mate guarding during oviposition (non-contact guarding and contact guarding). In this study,... more

It has been demonstrated that in libellulid dragonflies the distribution of eggs during oviposition and the offspring size vary with the type of mate guarding during oviposition (non-contact guarding and contact guarding). In this study, we investigated the hypothesis that oviposition behaviour and life-history traits also differ between these two guarding types. Therefore, we studied oviposition behaviour and life-history traits in six species of a dragonfly assemblage of the Namib Desert. Among the oviposition behaviours, oviposition duration and number of pond changes differed significantly between the guarding types. Clutch size did not differ between the guarding types, whereas some offspring characters, namely egg width, temperature sum to hatch, and larval head width, differed between the guarding types. Eggs of tandem species (those performing contact guarding) were larger, which might explain differences in all other offspring characters studied; bigger eggs need a lower temperature sum for egg development, result in bigger larvae, and have a faster growth rate, all traits that might be seen as an adapation to temporary waters, which are major habitats of the tandem species. This observation is discussed in the light of different dispersal strategies between the species performing different guarding types.

Male Columbian ground squirrels, Spermophilus columbianus, give a repetitive vocalization after copulation. This 'mating call' sounds similar to certain alarm calls that are given during attacks by terrestrial predators. During 2005e2006,... more

Male Columbian ground squirrels, Spermophilus columbianus, give a repetitive vocalization after copulation. This 'mating call' sounds similar to certain alarm calls that are given during attacks by terrestrial predators. During 2005e2006, we investigated (1) the acoustic structure and similarity of mating calls and alarm calls; (2) the environmental context when mating calls occur; (3) whether males that are likely to benefit from mate guarding (viz., males that have sperm precedence because they are the first to copulate in a female's series of matings) give mating calls to guard oestrous females; and (4) whether mating calls advertise the caller to females that have not yet mated. Our approach was to observe mating behaviour in the field and quantify reactions of squirrels to mating calls and alarm calls, both in and out of their normal context, with playback experiments. Males that were the first to copulate with an oestrous female called during mate guarding, and guarded females experienced delays before subsequent copulations. Although sound characteristics of mating calls and alarm calls did not differ, squirrels became vigilant and sought protection upon hearing alarm calls, but continued feeding during mating calls. However, when we played recorded mating calls to squirrels after breeding season, they usually reacted as if an alarm call had been given. We conclude that (1) the male mating call is an intrasexual or intersexual signal that announces postcopulatory mate guarding, and (2) contextual information is important for assessing the message of mating calls.

This research tested the hypothesis that marital satisfaction is a psychological state regulated by evolved mechanisms that monitor spousal cost-in¯iction and bene®ts. Three separate data sources were used to study a sample of married... more

This research tested the hypothesis that marital satisfaction is a psychological state regulated by evolved mechanisms that monitor spousal cost-in¯iction and bene®ts. Three separate data sources were used to study a sample of married couples. First, 214 participants provided information on their personality and marital satisfaction. Second, participants provided information on their spouse's personality, mate guarding and susceptibility to in®delity. Third, couples were interviewed by two interviewers, who subsequently provided independent ratings of each participant's personality. Results indicate that costs associated with spouse's personality, mate guarding and susceptibility to in®delity negatively correlate with participants' marital satisfaction. Discussion evaluates the utility of an evolutionary perspective on marital satisfaction and spousal cost-in¯iction. #

We studied the association between extrapair paternity (EPP) rate and male mating status in the rock sparrow, Petronia petronia, a facultative polygynous species. Overall, 32.0% (58/181) of the chicks were not sired by the social father... more

We studied the association between extrapair paternity (EPP) rate and male mating status in the rock sparrow, Petronia petronia, a facultative polygynous species. Overall, 32.0% (58/181) of the chicks were not sired by the social father and 57.1% (24/42) of the broods contained at least one extrapair young. Polygynous males allocated less time to guarding their mate during her fertile period than monogamous males but did not differ in the time spent guarding their nest. Polygynous males were cuckolded more frequently than monogamous males (50.5 and 6.6% of the young, respectively) and their paternity loss was positively correlated with the degree of overlap between the fertile periods of their primary and secondary females. Paternity loss did not differ between primary and secondary broods of polygynous males and acquiring a second mate was possible only at the expense of paternity in both broods. Late broods contained fewer extrapair young, despite no significant seasonal trend in the time allocated by the male to guarding his mate. Male yellow badge size was not associated with paternity. Old males were cuckolded less frequently than first-year males, but male age had a minor effect on paternity compared with male mating status. Reproductive success (number of young fledged/year) did not differ between monogamous and polygynous males once paternity was accounted for. Together, these results suggest that mate guarding can be efficient in preventing cuckoldry, and that there is a trade-off between attracting an additional mate and protecting paternity in the rock sparrow, whereas male age and phenotype were, at best, fair predictors of paternity.

In a recent review, compiled evidence that extra-pair paternity results from a three-player interaction in which sexual conflict is a potent force. Sequentially polyandrous species of birds appear to fit this idea well. Earlier breeding... more

In a recent review, compiled evidence that extra-pair paternity results from a three-player interaction in which sexual conflict is a potent force. Sequentially polyandrous species of birds appear to fit this idea well. Earlier breeding males may attempt to use sperm storage by females to obtain paternity in their mate's subsequent clutches. Later-breeding males may consequently attempt to avoid sperm competition by preferring to pair with previously unmated females. Females may bias events one way or the other. We examined the applicability of these hypotheses by studying mating behavior and paternity in red-necked phalaropes (Phalaropus lobatus), a sex-role reversed, socially polyandrous shorebird. Male red-necked phalaropes guarded mates more strongly than other shorebirds. Males increased within-pair copulation attempts during their mate's fertile period, and maintained or further increased attempts towards the end of laying, suggesting an attempt to fertilize the female's next clutch; these at-tempts were usually thwarted by the female. Paired males sought extra-pair copulations with females about to reenter the breeding pool. Multilocus DNA fingerprinting showed that 6% of clutches (4/63) each contained one chick sired by a male other than the incubator, producing a population rate of these events of 1.7% (n=226 chicks). Male mates had full paternity in all first clutches (n=25) and 15 of 16 monogamous replacement clutches. In contrast, 3 of 6 clutches of second males contained extra-pair young likely fathered by the female's previous mate. Previously mated female phalaropes may employ counterstrategies that prevent later mating males from discriminating against them. The stability of this polyandrous system, in which males provide all parental care, ultimately may depend on females providing males with eggs containing primarily genes of the incubating male, and not a previous mate.

Several factors can influence the risk of cuckoldry through extra-pair paternity for male birds. The number of neighbouring males is thought to affect the chance of females engaging in extra-pair copulations, and species which breed both... more

Several factors can influence the risk of cuckoldry through extra-pair paternity for male birds. The number of neighbouring males is thought to affect the chance of females engaging in extra-pair copulations, and species which breed both socially (colonially) and solitarily provide an ideal opportunity to test the effect of close proximity on extra-pair behaviour and paternity guards. In this study, the extent to which male house sparrows, Passer domesticus, used two alternative strategies, namely frequent copulation and mate-guarding, to ensure paternity was investigated. We also examined how males vary the two paternity guards according to their breeding sociality. Pairs at the dense colony started to copulate at a higher rate at the beginning of the fertile period than those of the medium-sized colony and solitary breeding pairs. Male house sparrows appear to fine-tune their strategies according to the breeding density. Both strategies are alternatively used in the weak fertile period but are simultaneously used in the peak fertile period. Our results suggest that males modify their strategy according to their individual abilities: mate-guarding intensity was positively correlated with the black breast badge size.

We studied how egg size, larval size and egg development time are related to oviposition site selection and mate guarding in a dragonfly assemblage of the Namib desert. Species that oviposited mainly in tandem flight (Pantala flavescens... more

We studied how egg size, larval size and egg development time are related to oviposition site selection and mate guarding in a dragonfly assemblage of the Namib desert. Species that oviposited mainly in tandem flight (Pantala flavescens and Sympetrum fonscolombii) spread their eggs over several ponds, which we interpreted as spatial risk spreading. Other species (Orthetrum chrysostigma, Trithemis kirbyi, T. annulata and Crocothemis erythraea) performed noncontact guarding and localized their eggs, usually in a single pond, which we interpreted as distinct habitat selection. Because long oviposition durations increase the risk of disruption by rival males, we predicted that in species that localize their eggs to a distinct oviposition habitat the first-laid eggs of a clutch should be the largest, indicating high quality. Species that perform risk spreading should distribute large eggs randomly over all oviposition sites. We tested our hypothesis at artificial ponds using experimental manipulations of oviposition. In O. chrysostigma and T. kirbyi, egg size and larval size decreased significantly with order of laying, and the time to hatch was randomly distributed. As predicted, within the clutches of P. flavescens and S. fonscolombii, egg size was randomly distributed over a clutch and we found no trend of decrease in larval size or increase in the time to hatch in relation to order of laying.

One male strategy to prevent female re-mating is post-copulatory mate guarding. In the pholcid spider Holocnemus pluchei last male's fertilization success is around 74% and females remain receptive after copulation. It is, thus,... more

One male strategy to prevent female re-mating is post-copulatory mate guarding. In the pholcid spider Holocnemus pluchei last male's fertilization success is around 74% and females remain receptive after copulation. It is, thus, reasonable to suppose that males should engage in post-copulatory mate guarding. Chronologically, the present study focused on the following aspects: (1) to determine if male permanence near females corresponds to mate guarding. For this, a second male (intruder) was introduced. Time of permanence, distance and behaviour of residents did not change whether or not an intruder was present; (2) to investigate the duration of mate guarding and male distance to the female in a time series intervals after copulation. Males remained close to females during 14 h keeping a distance of less than 15 cm; (3) to evaluate whether guarding duration is influenced by female sexual receptivity. We found that 24 h after the first copulation, when the resident was placed again next to the female, he tried to re-mate; and (4) to examine differences in paternity in relation to whether or not the resident exerted guarding. P2 was higher when second males copulated again within the first 6 h compared to 24 h after the first copulation.

Males of many species adjust their reproductive behaviour according to the perceived risk of sperm competition. Although this phenomenon is widespread in insects and other animals, the mechanisms that allow mates to assess sperm... more

Males of many species adjust their reproductive behaviour according to the perceived risk of sperm competition. Although this phenomenon is widespread in insects and other animals, the mechanisms that allow mates to assess sperm competition levels remain largely unexplored. In this study, we analysed the mating behaviour of pairs of Tenebrio molitor beetles under three odour treatments representing increasing levels of sperm competition risk (SCR) and sperm competition intensity (SCI). Copula duration and male and female post-copulatory behaviour varied significantly with odour treatment. Both copula duration and post-copulatory associations (PCAs) increased significantly in odour treatments reflecting high male density. To our knowledge, this is the first study to report that insects may assess the actual density of potential competitors at the time of mating, a cue to SCR and SCI, on the basis of chemical cues. In T. molitor, males inhibit sperm release from the spermatophore of a rival male when remating takes place at short intervals. We show that, when sperm competition levels are high, PCAs increase female remating interval just above that necessary to prevent spermatophore inhibition by rival males. This finding strongly suggests that strategic male behaviour plays a 'spermatophore guarding' role in this species. Although common in insects with external spermatophore transfer, spermatophore guarding is not expected in species with rapid ejaculate transfer and internal spermatophore delivery. Our results reveal that spermatophore guarding may evolve, even under these circumstances, as an evolutionary response to short-term spermatophore inhibition or displacement mechanisms.

Nephilid spiders are known for gigantic females and tiny males. Such extreme sexual dimorphism and male-biased sex ratios result in fierce male-male competition for mates. Intense sperm competition may be responsible for behaviors such as... more

Nephilid spiders are known for gigantic females and tiny males. Such extreme sexual dimorphism and male-biased sex ratios result in fierce male-male competition for mates. Intense sperm competition may be responsible for behaviors such as mate guarding, mate binding, opportunistic mating, genital mutilation, mating plugs and male castration (eunuchs). We studied the mating biology of two phylogenetically, behaviorally and morphologically distinct south-east Asian nephilid spider species (Herennia multipuncta, Nephila pilipes) in nature and in the laboratory. Specifically, we established the frequencies and effectiveness of plugging (a plug is part of the male copulatory organ), and tested for male and female copulatory organ reuse. Both in nature and in the laboratory, plug frequencies were higher in H. multipuncta (75-80% females plugged) compared with N. pilipes (45-47.4%), but the differences were not significant. Plugs were single and effective (no remating) in H. multipuncta but multiple and ineffective (remating possible) in N. pilipes. In Herennia, the males plugged when the female was aggressive and in Nephila plugging was more likely when mating with previously mated and larger females. Further differences in sexual biology are complete palpal removal and higher sexual aggressiveness in Herennia (sexual cannibalism recorded for the first time), and mate binding in Nephila. Thus, we propose the following evolutionary hypothesis: nephilid plugging was ancestrally successful and enabled males to monopolize females, but plugging became ineffective in the phylogenetically derived Nephila. If the evolution of nephilid sexual mechanisms is driven by sexual conflict, then the male mechanism to monopolize females prevailed in a part of the phylogeny, but the female resistance to evade monopolization ultimately won the arms race.

It has been proposed that mate guarding is the primary paternity insurance in birds, and only those species in which the male is compelled to leave his mate unattended during the fertile period resort to frequent copulation as a means of... more

It has been proposed that mate guarding is the primary paternity insurance in birds, and only those species in which the male is compelled to leave his mate unattended during the fertile period resort to frequent copulation as a means of assuring paternity. A higher frequency of both extra-pair copulation (EPC) and extra-pair paternity (EPP) has been predicted in non-guarding species. These predictions were examined in Eurasian kestrels, Falco tinnunculus, breeding in western Finland. During the course of a 3-year vole cycle, the mean within-pair copulation frequency was 0.72 per h and the mean number of extra-pair intrusions 0.07 per h. The proportion of EPCs was only 1% of copulations. The within-pair copulation frequency was higher in a year of increasing food abundance (1991) than in the years of decreasing (1992) and low food abundance (1990), although the kestrel breeding density was lower in 1990 than in 1991-1992. Males spent more time mate guarding in 1991-1992 than in 1990 (overall mean 40%). Single-locus DNA profiling revealed EPP in 7% of 27 broods and 5% of 112 offspring in 1991 but none in 1990 or 1992 (19 and 29 broods, respectively). Kestrel males successfully used both frequent pair copulation and mate guarding as complementary paternity guards. The low frequency of EPP may reflect the importance of male parental care in determining the reproductive success of raptors. Females may jeopardize future aid from their mates by soliciting EPCs from intruders. This strategy might markedly reduce female fitness, because the male is the main provider for female and young from before egg laying until the late nestling period.

Several studies have reported the ability of Gammarus pulex to successfully compete with and ultimately displace G. duebeni in freshwater. These studies have been unable, however, to provide adequate explanations for this displacement... more

Several studies have reported the ability of Gammarus pulex to successfully compete with and ultimately displace G. duebeni in freshwater. These studies have been unable, however, to provide adequate explanations for this displacement based on mechanisms of exploitative competition and/or differences in the environmental tolerances of the species. The present study investigates the role of predation as an extreme form of interference competition between G. pulex and G. duebeni. The data presented show that: (1) given the opportunity, males of both species prey on females of the other species, but only on females that have recently moulted; (2) mate guarding in both species significantly reduces the incidence of predation on moulted females; (3) mate guarding by male G. pulex is more successful in reducing predation on moulted females than is guarding by male G. duebeni. We propose that differential predation rate on moulted females may constitute the primary mechanism by which G. pulex displaces G. duebeni.

Three hypotheses for the function of postcopulatory mate guarding were tested in the field cricket Gryllus bimaculatus De Geer. The duration of spermatophore attachment was greater in the absence than in the presence of a guarding male.... more

Three hypotheses for the function of postcopulatory mate guarding were tested in the field cricket Gryllus bimaculatus De Geer. The duration of spermatophore attachment was greater in the absence than in the presence of a guarding male. The ejaculate protection hypothesis was, therefore, rejected. The duration of mate guarding was found to be equal to the interval between copulations, supporting

While post-copulatory mate guarding has been well documented in field crickets (Orthoptera: Gryllidae), the occurrence of pre-copulatory mate guarding in this family has been largely overlooked. We examined the relationship between the... more

While post-copulatory mate guarding has been well documented in field crickets (Orthoptera: Gryllidae), the occurrence of pre-copulatory mate guarding in this family has been largely overlooked. We examined the relationship between the intensity of two components of mate guarding (body judders and antennal whips) and the time before and after copulation. We found that when male Gryllus bimaculatus encounter a female but do not have a spermatophore ready to transfer, they engage in pre-copulatory mate guarding that is very similar to post-copulatory mate guarding. The intensity of pre-copulatory mate guarding increased up to the point at which the male was ready to transfer his spermatophore. Following copulation, the intensity of mate guarding initially remained high before declining, after which it began to increase again just before the male resumed courtship stridulation. We interpret this pattern of post-copulatory mate guarding as being consistent with both the ejaculate-protection and spermatophore-renewal hypotheses for the function of mate guarding. We found no significant relationship between mate guarding intensity and male body mass.