Multiple matings in the blue gourami, Trichogaster trichopterus (Pisces,Belontiidae)

The reproductive behaviour of the blue gourami, Trichogaster trichopterus, was examined in 15 bisexual pairs and 22 trios maintained in 75-litre aquaria for 23 days. During this time, 74 spawning episodes occurred among 26 different pairs and trios. Sixty-nine of these spawnings were directly observed. Both males and females were capable of mating repeatedly with the same or different partners with as little as 20 to 24 h separating successive spawnings. Females often mated with two males in the same afternoon, while only one male succeeded in mating with two females in one day. It is concluded that blue gouramis probably do not form pair bonds and that both sexes will mate with differet partners when the physical environment permits two or more males to maintain territories in the same aquarium.     

Pair territoriality in the longnose filefish,oxymonacanthus longirostris

The longnose filefish,Oxymonacanthus longirostris, usually lives in heterosexual pairs, the male and female swimming together and sharing the same territory. Pair territoriality in the species was examined in detail in relation to sexual differences in territorial defense activities. Rigorous pair territoriality was maintained only during the breeding season, although pairs used their home ranges exclusively to a certain extent, during the non-breeding season. The frequency of aggression against other conspecific pairs in the breeding season was higher than in the non-breeding season. Agonistic interactions appear to be over both mates and food resources, the strict pair territoriality in the breeding season possibly being due to mutual mate guarding. In intraspecific aggressive interactions, males usually led their partner females when attacking intruders. The feeding frequency of males was much lower than that of females in the breeding season. Mate removal experiments indicated that females could not defend their original territories solitarily and their feeding frequency decreased. Conversely, males could defend territories solitarily without a decrease in feeding frequency. These results suggest that males contribute most to the defense of the pair territory, with females benefiting from territorial pair-swimming with their partner males.     

Female defense polygyny in the territorial triggerfish <Emphasis Type="Italic">Sufflamen chrysopterum</Emphasis>

The occurrence of polygyny requires specific environmental conditions such as female aggregation or patchy resource distribution. However, it is difficult to determine the factors responsible for polygyny in species in which the territories of both sexes overlap. To overcome this, we performed female removal experiments in the polygynous triggerfish Sufflamen chrysopterum (Balistidae) in the Okinawa coral reef. Both sexes defended their territories exclusively against consexuals of the same species, and female aggregation was absent. Each male territory included 1–3 female territories, and nonterritorial males were significantly smaller than territorial males. Further, the body size of territorial males was positively correlated with that of the largest female in their territories, and larger males tended to mate with more females. The results of the female removal experiments (n = 10 females) indicated that females competed for better territories rather than larger mates. In contrast, males abandoned the territories once the females emigrated. These results strongly suggest that males defend females rather than sites and compete for larger and a greater numbers of females. Thus, in S. chrysopterum, female defense polygyny occurs in the absence of female aggregation.     

Space,density and extra-pair matings have opposing impacts on male and female reproductive success

Many territorial species have a mating system characterized by males establishing home ranges in the breeding grounds prior to females, resulting in males competing for territories and females choosing a mate upon their arrival. It remains unknown, however, how the outcomes of decisions surrounding territory establishment and mate choice are influenced by the spatial configuration of the breeding grounds. We use a spatially explicit, individual-based model to investigate the sex-specific effects of these decisions on reproductive success. In our model, males that arrive earlier obtain higher quality territories and improve their chances for extra-pair copulations. Females can choose their mate to maximize the quality of the male or to attempt to minimize the density of other females near their nesting site to avoid competition. Females therefore face a tradeoff between high-density regions around high-quality males and low-quality males in areas of low competition. Our model predicts a negative correlation between male and female reproductive success under a wide range of conditions when the majority of the territories are on the margins of the breeding area. Most notably, this sexual conflict arises as an edge effect suggesting that fragmentation of breeding habitats could impact the consequences of mate choice in many species with territorial breeding habits.     

Female mate preference in an invasive phytopathogen vector: how learning may influence mate choice and fecundity in Diaphorina citri

In some arthropods, females learn in the context of reproduction to refine their mate choices and avoid males displaying traits associated with impotency. Previous studies have shown that males of the Asian citrus psyllid, Diaphorina citriKuwayama (Hemiptera: Psyllidae), associate female odor with copulatory rewards. However, it is unclear whether females similarly learn about male traits. We compared mate choice in females previously mated to either blue or orange males and found that females may associate male color with reproductive success, and avoided blue males after previous experience. Orange males mated more frequently than blue males and appeared to be more sexually aggressive in their mating attempts. In addition, females mated to orange males laid approximately twice as many eggs as those mated to blue males. We dissected male psyllids and measured the size of their reproductive organs to determine whether abdominal color was associated with reproductive development. Our morphometric analysis indicated that blue males may not be physiologically immature compared with orange males. Rather, blue males displayed larger testes and seminal vesicles than orange males, suggesting that differences in reproductive output may be behavioral in nature. Based on our data, we suggest that females learn about the appearance and mating behaviors of blue and orange males from early mating experiences, and subsequently avoid blue males in future matings. Although the roles of blue males within a population are unclear, it is possible that blue morphs may specialize in other functions such as dispersal.     

TErritorial defence and mating success in males of the small heath butterfly, coenonympha pamphilus L. (Lepidoptera: Satyridae)

It has long been recognized that territorial defence in male butterflies must be some sort of mating strategy and that the territories are used as mating stations. However, so far, no systematic study has established the adaptive significance of territorial behaviour. This study is an attempt to fill this gap. By comparing the distribution of territories with the distribution of locations where wild and released virgin females mated this study shows that, in the small heath butterfly (Coenonympha pamphilus), males in territories have higher mating success than males outside territories. This supported the hypotheses that the function of territorial behaviour is to secure more matings and that the territories are mating stations. Wing length measurements suggest the same. Large males residing in territories tended to mate more often than small males, which were usually found outside territories. Since resident males were larger than non-resident males, this size difference was used to see how territorial occupancy influenced longevity. Mark-recapture of measured males revealed no significant correlation between wing length and the further life expectancy of males, strongly suggesting that the mating success of males in territories is also higher when measured over their whole lifetime.     

The Behavioral Significance of Male Body Size in the Tarantula Hawk Wasp Hemipepsis ustulata (Hymenoptera: Pompilidae)

Large males of the tarantula hawk wasp Hemipepsis ustulata appear to have an advantage in the competition for mates. Large males are more likely to acquire perch territories used to scan for incoming receptive females and territorial males appear more likely to mate than non‐territorial males. In addition, among the males that do secure a mate, those that intercept a female on a territory are larger than those that do so elsewhere. Despite the mating advantages apparently enjoyed by larger males of this species, average male size has remained essentially constant over the last 25 yr. Moreover, larger males are not seen to employ certain competitive tactics that might otherwise enhance their reproductive success. Thus, larger males did not preferentially visit the most popular landmark territory compared to a site that attracted fewer visitors overall. Nor were larger males more likely to return to potential territories after marking, capture, and release, either immediately or on a subsequent day. Finally, although large males made up a significantly greater proportion of the males captured at two territories as the 2005 flight season progressed, over all the years of the study, receptive females have not been concentrated in the latter part of the flight seasons.     

Male dimorphism, territoriality and mating success in the tropical damselfly, Paraphlebia zoe Selys (Odonata: Megapodagrionidae)

The tropical damselfly Paraphlebia zoe has two male morphs: a black-winged (BW) male which is associated with territorial defense of oviposition sites; and a hyaline-winged (HW) male similar in appearance to females, and, compared to the black morph, less frequently found defending territories. In a wild population of this species, we first assessed the relationship between phenotypic traits [male morph, size and territorial status (being territorial or non-territorial)], their role on mating success, and the degree to which a particular territory may contribute to male mating success. Second, to relate a physiological basis of being territorial we compared both morphs in terms of muscular fat reserves and thoracic muscle, two key traits related to territory defense ability. Males of both morphs defended territories although the BW males were more commonly found doing this. BW males were larger than HW males and size predicted being territorial but only within HW males (territorial males were larger) but not in BW males. Male mating success was related to territorial status (territorial males achieved a higher mating success), but not to morph or size. Furthermore, territory identity also explained mating success with some territories producing more matings than others. The BW morph stored more fat reserves which may explain why this morph was more likely to secure and defend a place than the HW morph. However, the HW morph showed higher relative muscle mass which we have interpreted as a flexible strategy to enable males to defend a territory. These results are distant to what has been found in another male dimorphic damselfly, Mnais pruinosa, where the advantage of the non-territorial morph relies on its longevity to compensate in mating benefits compared to the territorial morph.     

The adaptive significance of non-contact mate guarding by males of the dragonfly,Nannophya pygmaea Rambur (Odonata: Libellulidae)

InNannophya pygmaea, ovipositing females were frequently disturbed by conspecific males. Disturbed females often copulated with one of these males or flew away from the pool. Females which flew away from the pool due to male disturbance often returned later the same day and mated with different males. A territorial male would guard his ovipositing mate by hovering above her, presumably trying to prevent her from moving out of his territory. A non-territorial male would also guard his mate in a similar way, both at a vacant water area which was not occupied by any territorial males, or within the territory of a resident male. In addition, both territorial and non-territorial males chased intruding males in an attempt to prevent their mates from being stolen. Territorial males defended their mates better than non-territorial males. Both males and females often mated more than once in the course of a single day. Some territorial males copulated with a new female while another mate oviposited in their territories. This observation supported the “multiple mating hypothesis” proposed by Alcock (1979) and Uéda (1979) but other evidence suggested that this is an inadequate explanation for the non-contact guarding ofN. pygmaea.     

The Haremic Mating System and Mate Choice in the Wide-Eyed Flounder, Bothus podas

The social structure and reproductive behaviour of the wide-eyed flounder, Bothus podas, was studied in the coastal waters around the Azorean Islands. Both sexes are territorial throughout the year. Adult males defend large territories, which include several smaller female territories. Intraspecific agonistic behaviour was frequent and differed between sexes: males were more aggressive towards other males, while females were only aggressive towards each other and juveniles. During the reproductive season and only at dawn, territorial males court and mate successively with females in their territories, and females seem to show mating fidelity to their dominant male. Such territoriality and mating patterns indicate a haremic social system in the wide-eyed flounder. In order to identify potential factors influencing female mate choice acting on this haremic system, we examined male mating success and some of its potential correlates. We found no evidence for female preference for any of the males' physical or territory characteristics. However, courtship effort was strongly correlated with the total number of attempted and successful spawnings, indicating that females seem to mate preferentially with males that court them more vigorously. Thus, our data suggest that courtship plays an important role in determining male mating success in the wide-eyed flounder and, that it may possibly serve as an honest indicator of male `quality' for female choice.     

The influence of age and experience with conspecifics on territorial behavior inDrosophila melanogaster

Drosophila melanogastermales initiated aggressive behavior toward other males and defended territories several hours after they were able to court and mate females. Males that were 3 days or more posteclosion were more successful at holding territories than younger males. Three-day-old males established territories more readily and escalated more often against territory residents than males that were 1 day old. Residents did not usually force young males from territories until they were a few hours posteclosion. The development of territorial behavior was not affected by familiarity or prior exposure to females. Males held in isolation established territories more quickly and behaved more aggressively than males held in groups. Males that previously held territories were more likely to reestablish them after a disturbance.     

Territoriality as a paternity guard in the European robin, Erithacus rubecula

To investigate the relative importance of paternity defences in the European robin we used behavioural observations, simulated intrusions and temporary male removal experiments. Given that paired males did not increase their mate attendance, copulation rate or territory size during the female's fertile period, the most frequently quoted paternity assurance strategies in birds were absent. However, males with fertile females sang and patrolled their territories more regularly, suggesting that territorial motivation and vigilance were elevated when the risk of cuckoldry was greatest. In addition, there was a significant effect of breeding period on response to simulated intrusions: residents approached and attacked freeze-dried mounts more readily in the fertile period. During 90-min removals of the pair male in the fertile period, neighbours trespassed more frequently relative to prefertile and fertile period controls and appeared to seek copulations with unattended females. When replaced on their territories, males immediately increased both song rate and patrolling rate in comparison with controls. We propose that male robins sing to signal their presence, and increase their territorial vigilance and aggression in the fertile period to protect paternity. Copyright 2000 The Association for the Study of Animal Behaviour.     

Queuing in space and time reduces the lek paradox on an antelope lek

Lek systems, where females often use centrality to assess male quality, highlight a general paradox in evolutionary biology: how can female preferences for males providing good genes persist when consequential strong directional selection is predicted to deplete additive genetic variance in male quality and thereby obliterate benefits of choosiness? An explanation contributing to the resolution of this lek paradox may be that genetic variance is retained when an indirect mate choice cue, such as centrality on a lek, is an imperfect indicator of male genetic quality. Here I investigate whether the presence of alternative male mating tactics limits the reliability of centrality as a quality indicator in lek-breeding topi antelopes. Whereas males establishing territories directly on the central lek were relatively large, smaller peripheral males regularly shifted their territories centripetally and in this way also occasionally obtained central territories. By such opportunistic queuing, small males could increase their mating success drastically; however, their territorial tenure in the lek centre was relatively short, consistent with moderate competitive ability. These results suggest that male topi antelopes can obtain central lek territories through alternative mating tactics, providing scope for variance in male quality on the central lek. In a separate finding, the mating success of central males was found to increase during territorial tenure, independent of estimated age. The demonstration of queuing in both space and time on a mammalian lek highlights the importance of considering male tactical dynamics over time in order to avoid an inflated appearance of the lek paradox.     

Influence of Age and Prior Experience on Territorial Behavior and the Costs of Defense in Male Collared Lizards

In polygynous species where males maintain strong interseasonal philopatry to the same breeding territories, older individuals have prior experience defending their areas, whereas younger individuals are defending a territory for the first time. Theoretical and empirical studies predict that under such conditions the cumulative costs of defense may be lower for older experienced males as a consequence of familiarity with environmental and/or social conditions in their particular local habitats. We used quantitative data from focal observational studies and introduction experiments to test the hypothesis that older collared lizard males (Crotaphytus collaris) with prior territorial experience (3 yr+ males) acquire larger territories allowing them to court more, different females, with greater frequency without incurring higher defense costs. Consistent with this hypothesis, 3 yr+ males controlled significantly larger territories and courted more females, without having significantly higher rates of territory patrol, frequencies of advertisement display, or aggressive interactions with same‐sex competitors. Moreover, the intensity of responses to size‐ and age/experience‐matched tethered intruders by 3 yr+ males was lower than that by 2 yr males in their first season of territory defense. Our results support the hypothesis that age/prior occupancy of territories lowers defense costs allowing males to defend larger areas and increase opportunities to court females, perhaps increasing mating opportunities. By contrast, 2 yr males may need to respond more aggressively to intruders because their ownership of territories is tenuous as a consequence of shorter territory occupancy.     

Territorial and mating behavior ofXylocopa fimbriata F. andXylocopa gualanensis Cockerell from Costa Rica

The territorial and mating behavior of two Xylocopaspecies X. fimbriataF. and X. gualanensisCockerell from Costa Rica are described. Male territorial activity was common during February through April in the higher areas of a dry forest savanna. Both species maintained territories at the same location within hollows in the foliage of Ardesia revolutaH.B.K., a small evergreen tree which occurs commonly in the dry forest. Xylocopa fimbriatamaintained territories during early morning hours, whereas the territorial period for X. gualanensisoccurred during late afternoon. Males of both species infrequently marked territories. It is suggested that a secretion released from their mesosomal glands is wiped onto their legs during frequent leg-body and leg rubbing which occurs while males hover. The secretion is occasionally applied to marking points on vegetation by their secretion-contaminated legs. Males repeatedly marked select locations when females were near their territories regardless of whether females were searching nearby branches for nesting sites, gathering provisions, or passing through their areas. Some females oriented to and entered certain male territories. An example of female mate choice in selection of male territories is provided. Females flew into male territories from 2–4 cm down-wind of male scent-marked locations. As females approached these locations, males hovered downwind in close proximity to the females' approach path. As females hovered a few centimeters downwind of the scented focal point, males approached from downwind and mounted. The males behavior and the role of scent-marking in the reproductive behavior of lek polygyny is discussed.     

Mating tactics and male wing dimorphism in the damselfly,Mnais pruinosa costalis selys (Odonata: Calopterygidae)

Males of the damselfly,Mnais pruinosa costalis, exhibit wing color dimorphism: one form has orange wings, and the other hyaline wings which resemble female wings. The former is usually territorial and the latter uses sneaky mate securing tactics. When orange-winged males failed to establish territory, they became floaters that day. Hyaline-winged males perched around their territories and often, formed in tandem without any apparent courtship behavior when they found females. Their copulation frequency was higher and copulation duration longer than those of territorial males. A few females oviposited without remating. Total oviposition duration of females with which a hyaline-winged male mated was more than 32 min per male on average in a day Females that copulated with hyaline-winged males often remated with orange-winged residents before oviposition. Total duration of oviposition bouts of females after mating with floaters was short (15 min), while that with territorial residents was long (66 min). As a result, total oviposition duration of females with which an orange-winged male mated was about 40 min in a day. The reproductive success of the hyaline-winged males may be similar to that of the orange-winged males.     

Uncertainty in territory quality affects the benefits of usurpation in a Mediterranean wrasse

Individuals should defend sites when the expected benefits ofthe territory exceed the cost of defense. However, if territoryqulaity is unpredictable or difficult to assess, the expectedpattern of territorial behavior is less clear. In a Mediterraneanwrasse, Symphodus ocellatus, mating success is skewed with 2%of nesting males getting more than 20% of the spawning success.Yet, variation in mating success is not explained by any knownphysical characteristic of males or their territories. Instead,females prefer nests with a recent history of mating successbecause males are less likely to desert the offspring she leavesbehind. Thus, territory quality is transient and determinedby interactions between the sexes. I measured the frequencyof territorial takeovers and the uncertainty in mating successamong days at a nest. Observations indicated that S. ocellatusmales usurped their neighbor's successful nests when males wereunsuccessful and larger than their successful neighbor. Sitesthat achieved mating success had a significantly higher probability(0.84) of remaining sucessful between consecutive days thanunsuccessful territories had of becoming successful (0.30).Unsuccessful males obtained higher and more certain fitnessreturns if they usurped a successful neighbor's territory. Interactionswithin and between the sexes drive uncertainty in success, whichinfluences territorial behavior in this species.     

Social organization in the pheasant (Phasianus colchicus): harem formation, mate selection and the role of mate guarding

Harem formation and mate selection were studied in the pheasant in order to determine the advantages of territorial harem defence polygyny to the two sexes. We investigated the factors affecting harem size and the advantage to a female in remaining with one territorial male during breeding.
Female group size declined during late March and early April as females moved from large overlapping ranges into smaller, more widely dispersed breeding ranges. The proportion of female groups accompanied by males increased during this period.
Some males had a disproportionate share of females. Settled females were monogamous but, because a female's nest was generally outside the male's territory, her home range was larger than his territory.
Harem members were usually from the same winter group. Harem size was not related to territory quality in terms of food supply or nesting cover. Females were loyal to one male in more than one year even if his territory position changed. Older, territory-owning males had more females, both adult and immature, than males with newly-established territories. Harem size was not correlated with territory size.
We conclude that the mating system of the pheasant is based on mate guarding which protects females not only from the risk of predation or injury, but also from excessive energy expenditure incurred through being chased by other males. When escorted by a territorial male, females spent three times as much time feeding, one-fifth as much time running, and one-tenth as much time alert, as they did when not guarded.     

Duets defend mates in a suboscine passerine, the warbling antbird (Hypocnemis cantator)

Despite the widespread occurrence of avian duets, their adaptivesignificance is poorly understood. It is generally assumed thatthey function in the joint defense of territories, but no studyhas successfully distinguished between this hypothesis, whichinvokes cooperation between the sexes, and mate defense, whichinvokes conflict. Further, most duetting studies have focusedon oscine passerines, the songs of which are learnt and relativelycomplex. We therefore tested the mate defense hypothesis inthe warbling antbird (Hypocnemis cantator), an Amazonian suboscinethat produces simple sex-specific songs and duets. Acousticanalysis of songs showed (1) that solos were often producedby males, but rarely by females; (2) that duets consisted ofa male song and a female reply; and (3) that, although femalesong was invariable, a swift reply resulted in males producingshorter songs with fewer notes. These results suggest that duetting,and the structure of duets, is chiefly a product of female behavior,a scenario more suggestive of conflict than cooperation. Toinvestigate this idea we carried out playback experiments, whichshowed that (4) the response to solo songs was sex specific(i.e., male solos elicited a strong response from paired males,and female solos elicited a strong response from paired females);(5) males and females responded to same-sex solos more stronglythan to duets; and that (6) females answered their partner'ssongs more often, and more rapidly, in response to female solosthan male solos or duets. Although it can be argued that sex-specificresponses to solo song result from intrasexual territorial defense,we cannot use the same reasoning to explain (5) or (6). Instead,these observations imply that solitary intruders were more threateningthan paired intruders, and thus that the perceived threat wasto the partnership rather than the territory. Taken together,findings (1) to (6) suggest that females adjust their vocalbehavior in relation to the level of perceived threat to thepartnership, and duet with males in order to repel same-sexrivals. This study therefore strengthens support for the matedefense hypothesis, and suggests that conflict—ratherthan cooperation—may have played a major role in the evolutionand maintenance of avian duets.     

Timing of mate-locating by males in relation to female activity in the carpenter beeXylocopa varipuncta (Hymenoptera: Apidae)

Males of the carpenter beeXylocopa varipuncta Patton wait for females to visit them as they hover at landmark territories along ridgelines on some spring afternoons. While hovering, males advertize their presence by releasing a pheromone that attracts passing females. If males have limited time to invest in territorial hovering and signaling, then they should engage in these activities more often at times when mate-searching females are most likely to visit landmark territories. The number of females flying near male territories varies greatly over the course of afternoons and from day to day. Measures of female activity and male territorial activity were highly correlated at one study site, both in terms of changes within afternoons and in terms of day-to-day fluctuations. This result supports the hypothesis that males ofX. varipuncta time their mateattracting behavior to maximize contacts with receptive females.