Reproductive behavior and mate fidelity in the monogamous goby,Valenciennea longipinnis

Reproductive behavior and mate fidelity of the gobiid fish,Valenciennea longipinnis, were studied on the coral reef at Sesoko Island, Okinawa, Japan. These fish usually live in pairs, not only foraging together for benthic animals in sandy areas, but also constructing several burrows within their home range. Before spawning, both fish, although mainly the male, constructed a mound, piling up dead-coral fragments, pebbles, shells, sand and algae onto one of the burrows. After spawning an egg mass on the ceiling of the burrow, the female stayed outside and continued the construction and maintenance of the mound for 3–5 days until hatching, while the male tended the eggs inside. Mate guarding of females seemed to prevent males from monopolizing several females. Although some pairs showed mate fidelity through several spawnings, more than half of the pairs broke up after only one spawning. The pair bond was broken by mate desertion and the disappearance of each sex. Both sexes preferred larger spawning partners; larger females spawned more eggs and larger males provided better egg care. Mate desertion occurred when larger potential mates, relative to the current partner, became available. The frequency of solitary individuals was higher in males than in females, resulting in females deserting their mates more often than males. Two factors seem to have facilitated mate desertion: (1) occurrence of size mis-matched pairing and (2) overlapping home ranges.     

The natural history of a monogamous coral-reef fish, Valenciennea strigata (Gobiidae): 1. abundance, growth, survival and predation

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.     

Division of labor in the monogamous goby,Valenciennea longipinnis, in relation to burrowing behavior

Feeding and burrowing behavior of the monogamous gobiid fish,Valenciennea longipinnis, were studied on the coral reef at Sesoko Island, Okinawa, Japan. These fish usually live in pairs, the male and female feeding in close proximity to one another upon benthic animals and constructing several burrows cooperatively for purposes of shelter or spawning. Paired females fed more and burrowed less frequently than their mates. Because burrow maintenance was mostly conducted by the latter, the paired females performed work much less frequently than solitary females. Thus, the paired females may be able to allocate more energy toward egg production. The division of labor related to burrowing behavior in this species may be an effective way to increase reproductive success for both sexes. Moreover, the fameles burrowed even less frequently when paired with larger males, probably because burrowing ability may be correlated with mouth size in males. This is a likely reason for the preference of females to mate with larger males.     

Social monogamy in the cleaning goby Elacatinus evelynae: ecological constraints or net benefit?

We tested predictions from four hypotheses to explain the occurrence of long-term socially monogamous pairs in the Caribbean cleaning goby Elacatinus (=Gobiosoma) evelynae, namely (1) resource limitation, (2) low population and/or low mate density, (3) territorial defence and (4) net benefit of single-mate sequestration. We found no evidence that resources, in terms of available cleaning stations or clients to clean, were limited (1) or that after experimental goby removals, single individuals could not maintain cleaning stations alone (2). Population density was low but this did not prevent artificially widowed fish from remating quickly with individuals as large as their initial partners (3). Social monogamy in E. evelynae appears to result from the benefits associated with sequestering a large, high-quality mate (4). Both males and females showed intrasexual aggression towards experimental intruders consistent with mate guarding. Opportunities for polygynous matings by males, assessed by comparing the sizes, distances between and mating synchrony of neighbouring pairs, appeared both low and of limited value. Males therefore benefit most from guarding a larger, more fecund female. Females spent longer cleaning when paired with a large male, indicating that the benefits of guarding a high-quality mate may extend outside of the reproductive period for socially monogamous species. These results add to an increasing number of studies on coral reef fish showing mate-guarding behaviour and benefits to males and females from sequestering a single mate. Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.      

Experimental analysis of monogamy in the Caribbean cleaner goby, Gobiosoma evelynae

To investigate factors promoting monogamy, we studied the reproductive behaviour and ecology of the monogamous Caribbean cleaner goby at two sites near St Croix, U.S. Virgin Islands. We assessed mate fidelity and the amount of time required to acquire a new mate in experimentally widowed males and females. We also measured behavioural responses of pair members and single females to experimentally introduced conspecific intruders of both sexes. Finally, we evaluated the distribution of suitable habitat relative to existing goby territories. We found that pairs often separated due to males abandoning females and moving to a new territory, that most widowed fish soon acquired a new mate, and that there was strong aggression towards large same-sex intruders. We also found an abundance of suitable, unoccupied habitat. We conclude that pairs are maintained by intrasexual aggression that is related to both mate availability and other resources, such as high-quality, food-rich cleaning stations. Combined with observations of frequent pair separation, interterritory male movement, and relatively rapid remating by both sexes, these results suggest a complex mating system that is best classified as serial monogamy. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.      

Mated pairs of owl monkeys (Aotus nancymaae) exhibit sex differences in response to unfamiliar male and female conspecifics

In socially monogamous species, mate‐guarding could be a reproductive strategy that benefits both males and females, especially when males contribute to parental care. By actively guarding mates, males may reduce their chances of being cuckolded, whereas females that mate‐guard may reduce the likelihood that their mates will desert them or acquire additional mates, and hence limit or reduce paternal care of offspring. Owl monkeys (Aotus spp.) are socially monogamous with biparental care of young and, hence, potential beneficiaries of mate‐guarding. We presented mated pairs of captive owl monkeys (A. nancymaae) with unfamiliar male and female conspecifics, to determine if either member of the pair exhibits intraspecific aggression toward an intruder or stays close to its mate, behaviors indicative of mate‐guarding. Male mates were more responsible for the maintenance of close proximity between mates than females. Male mates also exhibited elevated levels of behavior that signify arousal when presented with a male conspecific. These responses by mated male owl monkeys are consistent with patterns that may help prevent cuckoldry. Am. J. Primatol. 72:942–950, 2010. © 2010 Wiley‐Liss, Inc.     

Mate fidelity in a polygamous shorebird,the snowy plover (Charadrius nivosus)

Social monogamy has evolved multiple times and is particularly common in birds. However, it is not well understood why some species live in long‐lasting monogamous partnerships while others change mates between breeding attempts. Here, we investigate mate fidelity in a sequential polygamous shorebird, the snowy plover (Charadrius nivosus), a species in which both males and females may have several breeding attempts within a breeding season with the same or different mates. Using 6 years of data from a well‐monitored population in Bahía de Ceuta, Mexico, we investigated predictors and fitness implications of mate fidelity both within and between years. We show that in order to maximize reproductive success within a season, individuals divorce after successful nesting and re‐mate with the same partner after nest failure. Therefore, divorced plovers, counterintuitively, achieve higher reproductive success than individuals that retain their mate. We also show that different mating decisions between sexes predict different breeding dispersal patterns. Taken together, our findings imply that divorce is an adaptive strategy to improve reproductive success in a stochastic environment. Understanding mate fidelity is important for the evolution of monogamy and polygamy, and these mating behaviors have implications for reproductive success and population productivity.     

Monogamy and sex role reversal in the pipefish Corythoichthys haematopterus

We observed the mating pattern and social behaviour of the pipefish Corythoichthys haematopterus in temperate waters of Japan during three successive breeding seasons. Males cared for a clutch in their brood pouch for 9-19 days until hatching and had several broods in the season with nonbrooding intervals of only 1 or 2 days. The population sex ratio was female biased and some females were always excluded from reproduction. Although males were sometimes courted by unmated females together with their regular partners, they always mated with the latter. The pair bond was maintained until the next season if both members survived. When males lost their partners, they remated with neighbouring unmated females within a few days. In contrast, widowed females remained unmated for a long time. Females had larger home ranges and were more active in courtship displays than males. This pipefish provides the first example of sex role reversal among monogamous syngnathid fish. We suggest that mate guarding by females is a primary proximate factor for maintenance of monogamy in this fish. Copyright 2001 The Association for the Study of Animal Behaviour.     

Monogamy in marine fishes

The formation of long-term pair bonds in marine fish has elicited much empirical study. However, the evolutionary mechanisms involved remain contested and previous theoretical frameworks developed to explain monogamy in birds and mammals are not applicable to many cases of monogamy in marine fish. In this review, we summarise all reported occurrences of social monogamy in marine fish, which has so far been observed in 18 fish families. We test quantitatively the role of ecological and behavioural traits previously suggested to be important for the evolution of monogamy and show that monogamous species occur primarily in the tropics and are associated with coral reef environments in which territory defence and site attachment is facilitated. However, there is little evidence that obligately monogamous species are smaller in body size than species that can adopt a polygynous mating system. We review the evidence pertaining to six hypotheses suggested for the evolution of monogamous pair bonds: (1) biparental care, (2) habitat limitation, (3) low population density/low mate availability/low mobility, (4) increased reproductive efficiency, (5) territory defence, and (6) net benefit of single mate sequestration. We outline predictions and associated empirical tests that can distinguish between these hypotheses, and assess how generally each hypothesis explains monogamy within and between breeding periods for species with different types of territories (i.e. feeding only or feeding and breeding). Hypotheses (1) and (2) have limited applicability to marine fishes, while hypotheses (3)-(5) have little empirical support beyond the species for which they were designed. However, the role of paternal care in promoting monogamous pair bonds is not explicit in these hypotheses, yet paternal care has been reported in more than 70 monogamous marine fish. We show that paternal care may act to increase the likelihood of monogamy in combination with each of the proposed hypotheses through decreased benefits to males from searching for additional mates or increased advantages to females from sequestering a single high-quality mate. Among species defending breeding and feeding territories, the benefits, both within and between reproductive periods, of sequestering a single high-quality mate (hypothesis 6) appear to be the best explanation for socially monogamous pairs. For species without parental care (i.e. holding only feeding territories), territory defence (hypothesis 5) in combination with the benefits of guarding a large mate (hypothesis 6) could potentially explain most instances of monogamy. Empirical studies of marine fishes over the past two decades are therefore slowly changing the view of monogamy from a mating system imposed upon species by environmental constraints to one with direct benefits to both sexes.     

Genetic and behavioural evidence of monogamy in a mammal,Kirk's dik-dik (Madoqua kirkii).

Little is known about the mating behaviour of monogamous mammals. Here, we present behavioural and genetic evidence of fidelity in a socially monogamous dwarf antelope, Kirk''s dik-dik. DNA microsatellite analysis revealed no evidence of extra-pair paternity (EPP) in dik-diks: mothers'' partners matched the paternal genotype in all 12 juveniles tested. One likely reason for the absence of EPP is that males guard their mates closely during oestrus and over-mark all female scent, thereby reducing the likelihood of other males attempting to mate. In addition, males may be limited in their ability to search for extra-pair populations (EPCs) by activities associated with pair-bond maintenance. Year-round, males maintained proximity within pairs, followed their females'' activity patterns, and spent approximately 64% of their time with their partners. However, males did attempt to obtain EPCs when the opportunity arose, and genetic monogamy in dik-diks is probably best explained by the behaviour of females: in contrast to many monogamous female birds, female dik-diks do not appear to seek EPC partners. We propose that females avoid extra-pair males because they are unable to mate with them without instigating a potentially dangerous conflict.     

Female mate guarding: no evidence in a socially monogamous species

To understand the behavioural aspects of sperm competition, the costs and benefits to both sexes should be considered. However, few studies have addressed the costs to females of their social mate engaging in extrapair copulations (EPCs). Measures of female mate guarding have concentrated on female solicitation and copulation; however, females may also control access to their mate by maintaining close proximity, as is common in males. I recorded the maintenance of pair proximity behaviour of an urban population of the socially monogamous European blackbird, Turdus merula, over three breeding seasons. There was no evidence that females guarded their mates to prevent them from engaging in EPCs, nor were there any effects of the potential quality indicators of age, body size or male bill colour on the intensity of mate guarding between individuals. The study adds to a small body of literature suggesting that female mate guarding may be found in (facultatively) polygynous species, but not in socially monogamous ones. Copyright 2000 The Association for the Study of Animal Behaviour.     

Territorial cooperation and social monogamy: factors affecting intersexual behaviours in pair-living snapping shrimp

Among the factors that may contribute to the evolution of social monogamy are selection for extended mate guarding of females and selection for territorial ‘cooperation’. Many socially monogamous taxa are also territorial, with ‘partners’ sharing a single territory, suggesting that one or both partners may benefit by sharing territorial maintenance. Snapping shrimp (genus Alpheus) are socially monogamous and territorial, living in excavated burrows or with host organisms, with females performing all parental care. The territorial cooperation hypothesis predicts that male and female partners share (1) territorial defence, resulting in a reduction in the risk of eviction from the burrow, (2) burrow construction duties, such that individuals in pairs spend less time in burrow construction relative to solitary individuals, and/or (3) foraging duties, by returning food to the burrow, where it is consumed by both partners. UsingA. angulatus as a model species, a territorial defence experiment revealed that females in pairs were significantly less likely than solitary females to be evicted by female intruders, but males in pairs were not significantly less likely than solitary males to be evicted by male intruders. A subsequent experiment revealed that paired males were significantly less likely to be evicted by an intruding male if paired with sexually receptive females than if paired with nonreceptive females. Another experiment revealed that (1) paired females spent significantly more time in burrow construction than paired males, and (2) both males and females consistently returned food items to the burrow, perhaps incidentally provisioning their mates. These data suggest that social monogamy may have been selected for in part because of the advantages of territorial cooperation, as both males and females are likely to benefit by dividing the labour of territorial defence and maintenance. These tests of the territorial cooperation hypothesis are synthesized with data from tests of the extended mate-guarding hypothesis to place snapping shrimp pairing behaviour into a larger construct incorporating both the influence of ecological pressures (territoriality) and mating interactions between the sexes. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Female mate choice,male-male competition and parental care in the river bullhead,Cottus gobio L. (Pisces,Cottidae)

Male body size was tested for its influence on female mate choice, male-male competition and ability to defend broods in the river bullhead, Cottus gobio L., a polygynous fish with paternal care. Females presented with two potential mates of different sizes significantly preferred to spawn with the larger male. Males smaller than, or 1·5 times longer than, the female were rarely selected as mates. Larger males were more successful in defending their brood from conspecifics, which may explain female preference for them. Unmated large males displaced smaller guarding males from their nests and retained the acquired egg masses. Competition between males for nest sites with eggs can be accounted for by the preference of females for males already guarding eggs: by seizing a nest containing egg masses, a male will increase his chance of being chosen.     

Monogamy in a feeding generalist, <Emphasis Type="Italic">Chaetodon trichrous</Emphasis>, the endemic Tahitian Butterflyfish

Butterflyfishes have been well studied for their feeding ecology and mating systems. In particular, studies of corallivorous butterflyfishes have supported models of monogamy based on their predictable, low quality food; a patch of coral that is economically defensible by a pair. Moreover, pairs often exhibit trade-offs in territorial defense (greater by males) and feeding (greater by females) that improve their reproductive success. However, this model has not been well tested for more generalist feeders. In addition, recent hypotheses for monogamy in fish have emphasized parental care, but butterflyfishes do not provide parental care. This study tests five hypotheses for monogamy in the endemic Tahitian butterflyfish, Chaetodon trichrous: 1) uniform distribution of limiting resources, 2) joint defense of a territory, 3) low mate availability, 4) predator detection, and 5) benefits of cooperative behavior. Chaetodon trichrous was the most abundant butterflyfish in bays. Pairs jointly patrolled feeding territories. They preferentially fed over hard substrate other than live coral, however, this substrate was available outside of territories. They also ate plankton. Pairs were sorted positively for size, and all pairs were heterosexual. Males were larger than their partners, but females fed at higher rates. These results suggest that C. trichrous is monogamous, but reject the hypotheses that pairs form for joint defense of a territory (pairs swam together), that pairs remain together because of low mate availability (frequent interactions with neighbors), or that pairs form for predator detection (no homosexual pairs). Monogamy in C. trichrous is associated with the uniform distribution of hard substrate, although this resource is not limiting. Further, the higher feeding rate of females may represent a benefit provided by their monogamous mates.     

Mate choice in the monogamous and polychromatic Midas cichlid, Cichlasoma citrinellum

Choice of mate in the Midas cichlid, Cichlasoma citrinellum (Günther, 1864), has been examined from a number of perspectives, proceeding from general species attributes to individual differences.
The Midas cichlid discriminates against closely-related, highly-similar Cichlasoma , and recognizes sex, probably chemically in both cases. It is polychromatic and changes from the normal (N) pattern to gold (G) or even white at almost any age. Gold colouration inhibited attack and made it difficult to mate an N female with a G male; the inhibiting effect was cancelled by using a larger N female.
Because the Midas cichlid is also biparentally monogamous, early experience could easily influence later choice of mate. G females of G × G parents preferentially spawned adjacent to G males; N females of N × N spawned mainly before N males. N females of G × G pairs, however, showed no preference.
Groups of females were reared by all four combinations of two colours and two sexes, or by no parents. Females reared by identically pure-coloured parents responded most to males of those colours, whereas females raised by mixed-colour parents did not discriminate. Females reared without parents preferred N males. Regardless of their own or their parents' colour, juveniles spent more time with N juveniles and behaved less aggressively towards them, compared to G juveniles.
Fish were offered a choice among potential mates that differed in aggressiveness, size or breeding experience. Males did not choose on the basis of those traits. Females preferred large, aggressive, experienced males. Pairs with large aggressive males more readily kept a breeding territory, and aggressive experienced males guarded young more effectively. All females were equally aggressive in protecting their young.     

Part-Time Mate Guarding Affects Paternity in Male Reed Buntings (Emberiza schoeniclus)

Male mate guarding by close following has been reported in many socially monogamous bird species and is generally believed to function as a paternity guard. Many aspects of the dynamics and effectiveness of this behavior are still however poorly understood. Here, we describe the temporal variation in mate guarding behavior in male reed buntings (Emberiza schoeniclus) with a particular focus on how males allocate their mating effort between mate guarding and extrapair mating in a context of intense sperm competition. In our highly synchronous study population most males have to balance the simultaneous and mutually exclusive demands of mate guarding and seeking extrapair copulations (EPCs). We found that males frequently switched between guarding their mates and performing intrusions to neighboring territories. Both activities seemed to have significant fitness payoffs, as male mate guarding effort had a positive effect on paternity, and a large fraction of extrapair fertilizations occurred during the days when the sire guarded its own female. The reed bunting is thus an example of how discontinuous or part‐time mate guarding can still be effective in securing paternity. Female reed buntings were not particularly active in initiating EPCs as they never were observed performing extraterritorial forays. We argue that the absence of female‐initiated EPCs is a prerequisite for males to trade mate guarding against seeking EPCs. Otherwise, if females circumvent male mate guarding by timing their EPCs to periods of male absence, males should guard their mates almost continuously or rely on alternative paternity guards.     

Social Monogamy in the Big-Clawed Snapping Shrimp, Alpheus heterochelis

Social monogamy has evolved independently in many taxa, and often involves biparental care of the young. Where it does not, mate guarding and shared territoriality have been invoked as causal factors. We evaluated mate guarding and shared resource defence (a common shelter) as factors that could have led to social monogamy in the snapping shrimp, Alpheus heterochelis. This species is found in male–female pairs that defend a common shelter together. Female receptivity lasts only for a few hours immediately after her periodic moult. Their monogamous pair bond may represent mate guarding or joint defence of a territory. Monogamy in A. heterochelis seems most importantly driven by the cryptic nature of the female's moult cycle. We found that males did not discriminate among females at different intermoult stages for pairing, nor did they modulate their defence of mate and shelter (vs. the risk in finding a new shelter and mate) according to female moult stage. This, together with the short period of female receptivity before her single copulation per cycle, make extended mate guarding the most efficient method for a male to secure a mating opportunity. Comparing eviction rates of paired and unpaired shelter residents by conspecific intruders provided no evidence of enhanced resource defence that would confer a selective advantage to a pair. Male presence during the moult is beneficial for the female, as searching for a male during her soft-bodied receptive phase would put her at mortal risk. Our results show empirically for the first time that guarding may be beneficial, even if males are not able to assess the female's reproductive stage. This extends the theoretical framework for understanding the evolution of social monogamy in taxa without biparental care of young.     

The social organization of a sexually dimorphic honeyeater: the Crescent Honeyeater Phylidonyris pyrrhoptera,at Wilsons Promontory,Victoria

The social organization of the sexually dimorphic and dichromatic Crescent Honeyeater Phylidonyris pyrrhoptera (Latham 1801) was studied at Wilsons Promontory National Park between January 1994 and January 1997. All breeding attempts at one site were followed during the spring and summer of 1996. Most pairs were multibrooded, with pair-bonds maintained throughout the study. Breeding males held well-defined territories. Females, although generally restricting their activities to within their mate’s territory, visited other males’ territories more frequently than did their mates and did so close to the time of egg laying. Males aggressively chased intruding males, but appeared to permit intrusions by non-mate females. Circumstantial evidence suggests some males may kill neighbour’s nestlings. Female Crescent Honeyeaters are solely responsible for nest construction and incubation. While both sexes attended nestlings, males contributed to parental care significantly less than females. Males also provided significantly less parental care than has been reported for monomorphic species of honeyeater. Single syllable calls are given throughout the year. Peaks in the rate of double and multisyllable calls corresponded with peaks in breeding activity. Only males were observed uttering loud multisyllable calls. In contrast to predictions arising from sexual selection theory and observations of the mating system of sexually dimorphic hummingbirds, the population of Crescent Honeyeaters studied exhibited a socially monogamous mating system. However, the very limited male role in parental care and non-observance of male territory boundaries by females suggest the genetic mating system may not be one of monogamy.     

Non-breeding behaviour of Magenta Petrels Pterodroma magentae at Chatham Island, New Zealand

Magenta Petrels Pterodroma magentae were caught at light-attraction stations on southwest Chatham Island, New Zealand, and most were fitted with transmitters. Of 52 captured since 1993, 71% were males, and all 36 tracked adequately proved to be non-breeders in the breeding season of capture. Our data indicated no sex bias in their probability of being captured at lights. Males provided 86% of trackings, and 87% of trackings of birds flying over the breeding area were males. Males landed 118 times; females 13 times. Only males were found on the ground, by night and day, apparently unassociated with burrows (three with and ten without transmitters), but subsequently digging burrows ( n  = 8). Of 19 birds banded as fledglings up to 2000, males were first recaptured nearing 4 years old (at lights and on the ground) and a female nearing 6 years old (in burrow). Among 37 fledglings, the sex ratio was even. Nine tracked males occupied burrows, as did two females, but the latter were older recaptures (10+ and 25+ years old). It appears that only males claimed existing, or dug new, burrows. They then attracted a mate to the burrow by means unknown, but from among females frequenting an inshore courtship area near the colony, or occasionally flying over the colony, at night. Females established in burrows, but then losing their mate, were able to re-mate there, by calling from near the burrow or by attracting a mate in flight or from the postulated inshore courtship area. Both sexes sometimes took years to pair or re-mate, possibly reflecting the dearth of available mates.