Development of sexual and protective behavior of female crickets <Emphasis Type="Italic">Gryllus argentinus</Emphasis> Sauss. at the prereproductive and reproductive periods of imaginal ontogenesis

Data are presented about the development of reproductive and defense behavior of noncopulated female crickets Gryllus argentinus Sauss. in the beginning of the imaginal ontogeny. The character of interaction of females with “virtual” males (the “supporting ball” method-“trackball”) was studied. The forms of female motor reactions to models of intraspecies male sound signals-the calling and aggressive songs-are described and analyzed. The character of the development of female acoustic behavior is described as judged by change in the forms of motor reactions in the course of the imaginal ontogeny. It is shown that immediately after the imaginal molt the reproductive behavior is not formed yet but it matures gradually within a few days. At the early stages of the imaginal ontogeny passive defense behavior is found to be most clearly expressed.     

Sex Differences in Territorial Behavior Exhibited by the Spotted Hyena (Hyaenidae, Crocuta crocuta)

Spotted hyenas ( Crocuta crocuta ) are gregarious carnivores that defend group territories against encroachment by neighboring conspecifics. Here we monitored the behavior of members of one clan of free-ranging spotted hyenas during border patrols, 'wars' with neighboring clans, and other interactions with alien intruders, to document differences between the sexes in territorial behavior in this species. We also examined the possibility that the probability or rate of attack on alien hyenas encountered within the clan's territory would vary with the sex of the intruders. Initiation and leadership of most cooperative territorial behaviors were by adult female clan members, although border patrols were occasionally conducted by groups composed exclusively of resident males. The vast majority of alien intruders into the territory of the study clan were males. Resident females were more likely to attack intruding females than intruding males, but hourly rates of aggression directed by females towards aliens did not vary with intruder sex. Resident males were more likely than resident females to attack alien males, and resident males directed significantly higher hourly rates of aggression towards intruding males than females. Although female leadership in most cooperative territorial behaviors distinguishes spotted hyenas from many mammalian carnivores, other sex differences in the territorial behavior of spotted hyenas resemble those documented in other gregarious predators. Sex differences observed in hyena territoriality are consistent with the hypothesis that male and female clan members derive different selective benefits from advertisement and defense of group territories.     

Evidence of helping behavior in a free-ranging population of communally breeding warthogs

Cooperative breeding societies are defined by the presence of helpers. Defining helping behavior in cooperatively breeding mammals has been difficult because lactation limits the ability of individuals to provision non-genetic young. As a consequence, “helping” behavior has frequently included predator and conspecific defense and thermoregulation. However, these behaviors are often associated with the benefits of group living and their expression may not warrant a species’ classification as a cooperative breeder (e.g., many ungulates and pinnipeds). In this study, we examine cooperative breeding behavior in the common warthog, Phacochoerus africanus. Warthogs exhibit substantial variation in breeding strategies and females will raise their young alone or in association with other females. The size of warthog groups varies throughout the year and we investigate fission and fusion of individual breeding groups to elucidate the costs and benefits of adopting different reproductive strategies. We found that the cohesion of female groups was related to parturition suggesting that there are benefits to sociality that are related to the production and care of offspring. Additionally, we found that reproductively-aged group members will help other group members by both babysitting and adopting the group’s offspring indicating active selection for cooperation. We did not witness any incidences of yearling group members exhibiting these behaviors indicating differential trade-offs to cooperation possibly related to the helper’s age/experience.     

Cooperative Territorial Defense in the Australian Magpie,Gymnorhina tibicen (Passeriformes,Cracticidae), a Group-living Songbird

Comparison of populations that vary in cooperative behavior can point to factors that influence the evolution of cooperative breeding. In this paper we study cooperative territorial defense in two populations of the Australian magpie. These populations differed in social organization; in New Zealand group breeding was the norm and in Queensland simple pair breeding was the norm. We used caged territorial intruders to examine experimentally the participation of males, females, and juveniles in synchronous territorial defense. Within a population in Queensland and a population in New Zealand, adult males and females participated in cooperative defense significantly (p < 0.05 at least) more often together than alone. Between populations, Queensland pairs differed significantly (p < 0.01 at least) from New Zealand pairs in the level of response. As group size increased, percapita input in defense decreased in both populations. We discuss the importance of synchronous defense as a cooperative behavior in this species.     

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.     

Intergroup encounters in wild white-faced capuchins (Cebus capucinus)

Wrangham (1980) hypothesized that knowledge of the nature of intergroup encounters is crucial to understanding primate social relationships and social organization. I studied a single social group of wild white-faced capuchins over a period of 26 months and observed 44 encounters between social groups during 3703 hr of observation. All intergroup encounters consisted of predominantly hostile social interactions. However, nonaggressive interactions between males of different social groups occurred in a few cases. Adult males were the sole participants in 39 encounters and the primary participants in all 44 encounters. The alpha male was the most frequent participant. High-ranking females participated aggressively in five encounters, and low-ranking females never participated. There was no stable intergroup dominance hierarchy. I hypothesize that the need for male-male cooperation in intergroup aggression is an important factor influencing the quality of intragroup male-male relationships. Behavior during intergroup encounters is consistent with the idea that intergroup behavior is related to male reproductive strategies, but inconsistent with the idea that intergroup aggression is related to female defense of resources. The possibility that males are “hired guns” (Wrangham, 1980) cannot be ruled out.     

Male territoriality and mating system in the European beewolf Philanthus triangulum F. (Hymenoptera: Crabronidae): evidence for a “hotspot” lek polygyny

The evolution of the mating system of a species is strongly influenced by the spatial and temporal distribution of females and/or resources. Here, we describe aspects of the territorial behavior of males of a solitary digger wasp, the European beewolf (Philanthus triangulum) and characterize the mating system. We show that beewolf males establish small territories that do not contain any resources essential to females. These territories are intensively scent-marked with a pheromone from a cephalic gland and are defended against intruders in combat flights. We provide evidence that scent-marking constitutes a chemical display and that the pheromone serves to attract receptive females and, thus, represents a sex pheromone. Using spatial statistics, we show that beewolf territories are clumped in space both with respect to other male territories and, more importantly, with respect to female nesting sites. Additionally, the proportion of days a territory is occupied by a male is correlated with the number of female nests in the vicinity. Taking into account that beewolf males do not defend or provide resources essential to females, but merely display chemically to attract females for mating in an aggregation of territories close to female nesting sites, we conclude that the European beewolf exhibits a hotspot lek polygyny with female nesting sites constituting “hotspots” for lek formation.     

Communication inGalago crassicaudatus

The olfactory, visual and, auditory communicative behaviors of a colony of feralGalago crassicaudatus (four males ad three females) observed over a two year period are documented. The enclosure was constructed to simulate a natural environment, but all stimulus possibilities available in the wild were not present and several new ones were introduced. It is not known how many of such differences may have affected the animals' behavior, however not all behaviors observed in the wild appear in the lab. The characteristics of several calls are described in detail and illustrated with sonagrams. These include an agonistic call, a sexual call, a possible alarm or mobbing call, a possible territorial or spacing call and a “low grunting sound” which appears in contexts of sexual and territorial calls. Compared to “higher” primates these galagos exhibit a small number of vocalizations. The communicative system appears directly correlated to social organization.     

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.     

Consortships and conceptions in captive rhesus macaques (Macaca mulatta)

A captive group of rhesus macaques (Macaca mulatta) was observed during the breeding season to determine if consortship behavior, rather than promiscuous matings, resulted in higher reproductive success for either partner. The 38 adult females in this group were observed “in consort” with the 5 adult or 4 subadult males on 179 occasions. Most of these consortships were short-term, lasting less than one day. Six females engaged in consortships with one male that spanned more than three days, but the majority of these long-term associations did not result in a pregnancy with that male. The term “consortship” has been traditionally accepted as a specific nonhuman primate mating pattern, but the exact nature of this behavioral pattern and its evolutionary importance have been less clearly understood. Consort behavior could be considered a precursor to a monogamous mating system if long-term exclusive sexual associations resulted in higher reproductive success for the participants. But this study demonstrates that for rhesus macaques, who exhibit both consort behavior and more promiscuous matings, there is no clear reproductive advantage to long-term consortships. In light of the inconsistent use of the term consortship, the possible adaptive significance of an exclusive male-female sexual association for the evolution of human mating patterns needs to be reevaluated.     

Juvenile social play and yearling behavior and reproductive success in female Belding’s ground squirrels

Benefits of play behavior have been described for individuals during the juvenile period; however, it is less clear whether benefits of juvenile play commonly extend beyond the period of juvenile development. I evaluated possible associations between juvenile social play and yearling maternal territorial behavior and reproductive success in female Belding’s ground squirrels (Urocitellus beldingi). Higher rates of juvenile social play were associated with greater intensity of territorial aggressive and vigilant behavior during gestation but not later phases of the yearling reproductive cycle, suggesting that both juvenile play and later experience may influence maternal territorial behavior in yearling females. Juvenile social play was also a reliable predictor of whether a yearling female successfully weaned a litter, raising the possibility that juvenile play behavior influences yearling reproductive success via effects on maternal territorial behavior in female U. beldingi. Other factors were also related to reproductive success in yearling females. Body mass at the beginning of the yearling reproductive period was not correlated with juvenile social play but was associated with the likelihood of successfully weaning a litter. Yearling females whose mother was still alive were more likely to wean a litter than those whose mother was not alive. Mothers and yearling daughters tended to have maternal territories near each other, and mothers with a surviving yearling daughter expressed aggressive behavior at elevated rates and directed aggression toward intruders on the daughter’s territory. Overall, results of the study suggest that juvenile social play is among the variables that influence maternal territorial behavior and reproductive success in yearling female U. beldingi, and are consistent with the idea that juvenile play has benefits beyond the juvenile period for female U. beldingi.     

Partners coordinate territorial defense against simulated intruders in a duetting ovenbird

Duets in breeding pairs may reflect a situation of conflict, whereby an individual answers its partner's song as a form of unilateral acoustic mate guarding or, alternatively, it may reflect cooperation, when individuals share in territory defense or safeguard the partnership. The degree of coordination between the sexes when responding to solo versus paired intruders may elucidate the function of songs in duets. We examined this issue in a study with rufous horneros (Furnarius rufus), a duetting, socially monogamous Neotropical species with low levels of extrapair paternity. We exposed social pairs during the nonbreeding season to playbacks of duets, male solos, female solos, and control heterospecific songs. Partners approached all conspecific stimuli together and responded by singing quickly, at higher rates and by coordinating ~80% of their songs into duets. For both sexes, most response variables (seven of nine) did not vary across conspecific treatments. These results suggest that partners duet and coordinate behaviors to cooperatively defend common territories. However, females spent more time in territorial vigilance, and partners were highly coordinated (correlated responses) in response to duets and female solos in comparison with male solos. This indicates that female intrusions (paired or solo) might be more threatening than male intrusions in the nonbreeding season, especially for territorial females, and that females are less cooperative with their partners in territory defense against male intruders.     

The Tradeoff Between Territorial Defense and Foraging in the Great Tit (Parus major)

We analyze territorial behavior in terms of decisions abouttime allocation.Such decisions must be made whenever time investedin territorial defense cannot be devoted to feeding, and viceversa. We describe the ecology and territorial behavior of thegreat tit (Parus major) to show that a tradeoff exists, andthen outline a series of laboratory and field experiments inwhich the value of feeding or defense was experimentally manipulated.Territorialmale great tits began to invest more heavily in territorialvigilance after encountering intruders, but the increase invigilance depended on the rate at which they could feed, aswell as their hunger level. We outline a dynamic analysis thattakes account of the fact that the optimal tradeoff will changeas hunger is reduced. The results of an experimental test ofthis dynamic model are also presented. We briefly review othertechniques whereby territorial tradeoffs have been investigated.     

Territorial behaviour in corn mice, <Emphasis Type="Italic">Calomys musculinus</Emphasis> (Muridae: Sigmodontinae), with regard to mating system

We studied territorial behaviour of Calomys musculinus, a promiscuous-polygynous species, in order to test the predictions that during the breeding period, home-range-owner females are more aggressive than home-range intruders and that males do not display territorial behaviour. At the core of the breeding season, we conducted 136 intrasexual and 66 intersexual encounters. The study was carried out in four 0.25-ha enclosures, each containing one independent population. We studied territorial behaviour utilising focal animal sampling to record behaviour. Encounters were conducted in a circular opaque arena (COA) near the home-range’s activity mathematical centre (AMC). Amicable behaviour was not observed in any of the 78 trials among females. The rates of aggressive and submissive behaviour per female–female encounters varied in relation to whether they were home-range owners or intruders, the former being aggressive, the latter submissive. So we could link these drives to the territorial behaviour of C. musculinus. This result fits well with the already known territoriality of C. musculinus during the breeding season. In contrast, the 58 intrasexual male encounters did not show direct aggressive interactions between them. The rates of the different behaviours between males did not vary in relation to whether they were home-range owners or intruders. In our study, which took place during the breeding period, C. musculinus males were nonterritorial, and they never exhibited aggressiveness towards females.     

Social relations between adult males and females of Japanese monkeys in the arashiyama B troop

Some dyads of Japanese monkey adult males and females show remarkable spatial proximity and frequent exchanges of social behaviors. It is suggested that some kind of “affinity” exists between them. Females obtain much unilateral benefit from “proximity effects”; even lowranking females can dominate high-ranking females as long as they stay nearby their “affinitive” males. Males acquire female followers in return. Mating relations and female mother-daughter relations play important roles in forming new “affinitive relations.” Once monkeys have formed “affinitive relations,” however, they seldom mate with each other, as if they were kin-related. Therefore, the acquisition of female followers appears inconsistent with a male's strategy for reproducing many genes in the next generation. This study was financed partly by the Cooperative Research Fund of the Primate Research Institute, Kyoto University. The outline of this paper has already been published inTakahata (1980b).     

Reproductive patterns in mantled howler monkeys: Estrus,mate choice and copulation

The present study was undertaken to evaluate non-random mating patterns in two groups of mantled howler monkeys in two tropical dry forest habitats. Sexual dimorphism, female estrus stage, male dominance rank, sexual solicitations and copulations were assessed. Males are significantly larger than females, but female weight varies more than male weight. The length of female estrus cycles is comparable in both habitats, but females in the more strongly seasonal habitat demonstrate greater estrus synchrony relative to their numbers. Males solicit potential mates more frequently than females, a pattern explained by the relatively high rate of sexual solicitation by high-ranking males. Females in “peak” estrus solicit “alpha” males, while females in other stages of estrus solicit males equally by rank. Intersexual aggression occurs rarely, and “forced copulations” are attempted but, apparently, are unsuccessful. Sexual solicitations by “alpha” males and “peak” estrus females are most likely to lead to copulation, and “alpha” males are more likely to copulate than “gamma” males. In general, latencies from first solicitation to copulation are expensive in time, especially for high-ranking males. Estimated annual reproduction success favors high-ranking males, and results indicate that male and female mating behavior is mutually coordinated and controlled.     

Landmark Territoriality in the Neotropical Paper Wasps Polistes canadensis (L.) and P. carnifex (F.) (Hymenoptera: Vespidae)

Male Polistes canadensis and P. carnifex aggregate along crests of prominent ridges in Santa Rosa National Park, Costa Rica. At these sites males of both species defend territories (trees and shrubs) by chasing conspecific rivals. Territories do not contain nests or resources that are collected by females. Chasing by territorial males reduces the amount of time spent by intruders in a territory. I describe and contrast male territorial behavior of both species. Some male P. canadensis are territorial while others in the same area exhibit patrolling behavior, flying from one occupied territory to another. Males of P. carnifex exhibit territoriality only. Patrolling in P. canadensis is an outcome of relatively high male density along the ridge, rendering territories in short supply, as shown by the observation that experimentally vacated territories are seized rapidly by formerly patrolling males. Due to a high intraspecific intrusion rate, territorial male P. canadensis spend less time perching and more time flying and chasing intruders from their territories than do male P. carnifex. Males of these two species also differ in the placement of their territories along the ridgeline; P. canadensis occupy territories in saddles while P. carnifex occupy those at peaktops. I show that this divergent spatial pattern is not maintained by competitive exclusion of either species by the other, and I discuss alternative explanations for their separate spatial distributions. Comparative data suggest that males are territorial because females restrict matings to within territories, and I discuss alternative hypotheses to explain this bias in female behavior.     

Territorial behavior of the Korean wood-feeding cockroach, <Emphasis Type="Italic">Cryptocercus kyebangensis</Emphasis>

We investigated the territorial behavior of Cryptocercus kyebangensis from the viewpoint of offspring protection. Aggressive behavior against adult intruders occurred more frequently in resident adults with their young than those without their young. Resident adults without offspring more frequently attacked intruders of the same sex than those of the opposite sex, whereas those with offspring attacked regardless of the sex of adult intruders. In paired residents, cooperative territorial behavior occurred in a higher proportion in pairs with offspring than those without offspring. Responses of residents to nymphal intruders depended on the head capsule size of the intruders. Resident adults rarely attacked intruders smaller than their own offspring but frequently attacked larger intruders. Resident nymphs frequently attacked intruders smaller than themselves, whereas they escaped or showed jerking behavior when they encountered larger intruders. Electronic Publication     

The structure of affiliative relations in a primate community: Allogrooming in stumptailed macaques (Macaca arctoides)

Social grooming in 19 adult stumptailed macaques (a dominant male and 18 females) was studied by focal sampling and scanning methods. Significant individual differences were found with respect to both active and passive grooming intensity, active grooming being a more variable parameter. Individual preferences in partner choice are very strong, but among the factors examined, age was the only one influencing these preferences. Neither social rank nor kinship were significant. The proportion of active and passive contacts shows marked individual differences. Yet, there is a positive association between performed and received grooming. The “extortion hypothesis” is not supported by our results: high-ranking individuals performed on the average more, and received relatively less grooming than low-ranking ones. High grooming performance of the dominants may secure group integrity in species with a “soft” dominance style.     

Territoriality in the Malaysian giant ant Camponotus gigas (Hymenoptera/Formicidae)

In a 5-ha area of primary lowland rain forest in Borneo, we observed four polydomous colonies of the night-active giant ant Camponotus gigas. The nonoverlapping, three-dimensional territories in the canopy had a ground size up to 0.8 ha. C. gigas showed a distinct territorial behavior: (1) specific “barrack” nests, especially containing many majors, were situated at the borders and were established during long-term territorial conflicts; (2) trunk trails were regularly patrolled by majors that attacked alien conspecifics and some other ant species violently; and (3) sentinels, often involved in long-enduring conflicts with neighboring ant colonies, defended the borders at bridgeheads. Interspecific conflicts with sympatric Camponotus species always led to violent, “bloody” fights of all castes. Intraspecific conflicts, however, were solved by ritual fights (“front leg boxing”) of majors. C. gigas performed a de-escalation strategy to end short periods of true intraspecific “ant war” that we provoked experimentally. Artificially induced ritualized combats continued over weeks also in the absence of baits, indicating that borders may become established by long-term conflicts of attrition. We discuss the differences between ritual fights in desert and rain-forest ants and apply Lanchester's theory of battles to our findings. Received: October 17, 2000 / Accepted: May 14, 2001