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The prior residence effect consists of a higher probability of territory owners to win a fight against intruders, as observed in several territorial species across animal kingdom. However, in investigations on territorial behavior, intruder traits have been assumed as fixed. Thus, we used a territorial species as experimental model to evaluate the effect of intruder traits on aggressive behavior of territory owners. During fights staged between territory owners and intruders, intruder traits, linked with visual signals of social status (dominant-subordinate position), modulate fighting behavior of territory owners, but prior residence effect still occurred. Intruder traits must be addressed more effectively for improving the theoretical understanding of territoriality. [ABSTRACT FROM AUTHOR]

The evolutionary origins of how modern humans share and use space are often modelled on the territorial-based violence of chimpanzees, with limited comparison to other apes. Gorillas are widely assumed to be non-territorial due to their large home ranges, extensive range overlap, and limited inter-group aggression. Using large-scale camera trapping, we monitored western gorillas in Republic of Congo across 60 km2. Avoidance patterns between groups were consistent with an understanding of the "ownership" of specific regions, with greater avoidance of their neighbours the closer they were to their neighbours' home range centres. Groups also avoided larger groups' home ranges to a greater extent, consistent with stronger defensive responses from more dominant groups. Our results suggest that groups may show territoriality, defending core regions of their home ranges against neighbours, and mirror patterns common across human evolution, with core areas of resident dominance and larger zones of mutual tolerance. This implies western gorillas may be a key system for understanding how humans have evolved the capacity for extreme territorial-based violence and warfare, whilst also engaging in the strong affiliative inter-group relationships necessary for large-scale cooperation. [ABSTRACT FROM AUTHOR]

Objectives: Territoriality refers to the consistent defense of an area within the home range (HR) against intrusions of conspecifics. It implies exclusive space use with low degree of overlap among neighboring groups, high site fidelity, specific ranging behavior such as high mobility relative to HR size and frequent visits of territory borders, and monitoring behavior. We examined ranging behavior and use of space to evaluate territoriality in Pithecia aequatorialis in Ecuador. Materials and methods: Between 2005 and 2015, we monitored one main study group continuously and five additional groups for shorter periods (5 months to 2.5 years) at the Tiputini Biodiversity Station, in eastern Ecuador. We scored the location of the study groups at 20 min intervals during, on average, 5 days per month. We estimated saki HRs and core areas (CAs) using the fixed kernel density method (95 and 50%, respectively). Results: The average HR size was 57 ha and the average CA 14 ha. The degree of overlap between HRs of neighboring groups was low (2–9%). For the main study group, the average overlap between annual HRs was 82%. Mean daily path length across groups was 1,151 m; the defensibility index varied between 1.1 and 2.3 (values >1 are suggestive of territoriality), and the fractional monitoring rate varied between 0.06 and 0.15 (values >0.08 are suggestive of territoriality). Groups did not visit their HR borders (100 m inner buffer) more often than would be expected by chance. Travel speed and directness were comparable between the borders and the centers of groups' HRs. Discussion: Our multiyear study suggests that equatorial sakis show low degree of range overlap and high site fidelity and have the potential to be territorial, given their high mobility relative to HR size that allows for frequent border monitoring. Nevertheless, their movement patterns in border areas did not reveal evidence for monitoring behavior. [ABSTRACT FROM AUTHOR]

Territoriality arises when the benefits of resources exceed the costs of defending them. The dear enemy phenomenon, where familiar territorial neighbours refrain from intruding on one another and mutually reduce their defensive efforts, allows for reduction of these costs but requires discrimination between conspecifics. We hypothesized that territorial vocalizations in red squirrels (Tamiasciurus hudsonicus) are used for this discrimination. We performed a speaker replacement experiment where red squirrels (N = 41) were temporarily removed from their territories and replaced with a speaker broadcasting their own call, an unfamiliar call, or silence. Contrary to our prediction, there were no differences in overall intrusion risk among our three playbacks, but the identity of intruders did vary. Existing variation in familiarity within territorial neighbourhoods should be considered, rather than the binary classification of familiar or stranger, when studying dear enemy effects. We also discuss the variable importance of silence in acoustic territorial populations. [ABSTRACT FROM AUTHOR]

Previous studies on guanacos have reported that only territorial males create and maintain dung-piles. The aim of this analysis was to compare dung-pile use by territorial males with the use by females and young in family groups, and by bachelor males. Although territorial males showed the highest dung-pile use, all individuals dropped feces on piles frequently, in contrast to what was previously observed within other guanaco populations. Besides stressing the behavioral plasticity of guanacos, these results suggest an additional adaptive function of localized-defecation other than demarcating territory ownership by the territorial male. [ABSTRACT FROM AUTHOR]

Advertisement call is the most common signal used by anurans for intraspecific communication. However, some species have lost the ability to emit these vocalizations and are denoted as mute. Alternatively, these species may communicate by visual, tactile and chemical signals. The lack of advertisement call could be explained by the high background noise of breeding microhabitats. A model group to study alternative communication tactics is the genus Megaelosia, which is composed by seven mute species that inhabit noisy streams, and for which no information on intraspecific communication is available. We monitored a population of M. apuana and described its visual signalling during aggressive interactions between males. This interaction included visual signalling, physical combat, and the retreat of the smaller individual. No audible sound was detected during the whole aggressive interaction, reinforcing the genus muteness. This is the first report of any communication behaviour for the genus Megaelosia. [ABSTRACT FROM AUTHOR]

The roe deer (Capreolus capreolus) is considered a special case of territorial ungulate. This study aimed to contribute to the knowledge of male roe deer territoriality by exploring its spatial use and activity patterns. We divided the territorial period (March- August) into three two-month sampling periods and found that the home range (HR) size of 13 radio-collared males averaged from 47.9 ± 14.5 ha to 109.7 ± 31.9 ha. We classified the spatial behaviour of eight out of the 13 males into three groups and concluded that HR size variation alone did not explain the potential territorial status. Nevertheless, it was indicative of their territorial status when considered along with the bucks' age, spatial movements and activity levels. The activity levels of July-August were significantly lower than the activity levels of March-April. HR size variation of the males monitored significantly contributed to explain the variations in their activity levels. Old bucks were significantly less active than other males, especially during July-August. To sum up, we found an indication of an influence of spatial profiles on activity levels, though a larger sample will be needed in order to better understand differences in age and territorial status, and inter-individual differences in activity. [ABSTRACT FROM AUTHOR]

Group living animals often engage in corporate territorial defence. Territorial group vocalizations can provide information about group identity, size and composition. Neighbouring groups may use this information to avoid unfavourable direct conflicts. Giant otters are highly social and territorial animals with an elaborate vocal repertoire. They produce long-range screams when they are alert or excited, i.e. in an alarm, isolation or begging context. Long-range screams are not only produced by one individual at a time (‘single screams’) but also by multiple group members simultaneously, resulting in a highly conspicuous ‘group chorus’. Wild giant otters regularly produce group choruses during interactions with predators, when they detect intruders in their territory or before group reunions after separation. Since single screams and especially group choruses probably contribute to the groups’ corporate territorial defence, we hypothesized that group identity is encoded in single screams and group choruses. We analysed vocalizations from five wild and three captive giant otter groups and found statistical evidence for a group signature in group choruses. Results for single screams were less conclusive, which might have been caused by the comparatively lower sample size. We suggest that giant otters may gain information on group identity by listening to group choruses. Group identity likely constitutes important social information for giant otters since territory boundaries of neighbouring groups can overlap and direct inter-group conflicts are severe. Therefore, group chorusing may contribute to the mutual avoidance of members from different groups. [ABSTRACT FROM AUTHOR]

Conspicuous, colorful displays are often used by animals to communicate within and between species. Previously, researchers have manipulated specific components of color signals (i.e., hue, total reflectance, and/or chroma) using paints, photographs, videos, or filters. However, these manipulations may not adequately mimic the spectrum of color signals outside the range of human perception. Thus, these methods are inappropriate for organisms with unconventional visual systems, such as stomatopods (mantis shrimp). Here, we describe a novel application of a femtosecond laser to increase total reflectance of the stomatopod meral spot, a distinct area on the raptorial appendage used in territorial contests. Ultrafast lasers provide a programmable way to precisely manipulate patch total reflectance of live stomatopods without causing collateral damage. We tested how experimentally increasing meral spot reflectance impacted receiver behavior during territorial contests. Contests in which receiver stomatopods faced an opponent with a lightened meral spot were shorter and receivers showed increased rates of agonistic behaviors. This result suggests that lighter meral spots indicate lower fighting ability; thus, receivers are more willing to engage in a contest. This research provides the first demonstration that stomatopods can detect and assess achromatic variation in contests. Furthermore, we demonstrate that ultrafast lasers provide a powerful tool to investigate achromatic signaling, particularly for organisms whose size, aquatic habitat, or visual system otherwise prevent realistic alterations to color signals (e.g., butterflies, jumping spiders, or decapod crustaceans). This study advances our knowledge about stomatopod visual communication and offers a valuable tool for future research. [ABSTRACT FROM AUTHOR]

Upon hearing a conspecific signal, animals must assess their relationship with the signaller and respond appropriately. Territorial animals usually respond more aggressively to strangers than neighbors in a phenomenon known as the “dear enemy effect”. This phenomenon likely evolved because strangers represent a threat to an animal's territory tenure and parentage, whereas neighbors only represent a threat to an animal's parentage because they already possess a territory (providing territory boundaries are established and stable). Although the dear enemy effect has been widely documented using behavioral response variables, little research has been conducted on the physiological responses of animals to neighbors versus strangers. We sought to investigate whether the dear enemy effect is observed physiologically by exposing territorial male song sparrows ( Melospiza melodia ) to playback simulating a neighbor or a stranger, and then collecting blood samples to measure plasma testosterone levels. We predicted that song sparrows would exhibit increased testosterone levels after exposure to stranger playback compared to neighbor playback, due to the role testosterone plays in regulating aggression. Contrary to our prediction, we found that song sparrows had higher testosterone levels after exposure to neighbor playback compared to stranger playback. We discuss several explanations for our result, notably that corticosterone may regulate the dear enemy effect in male song sparrows and this may inhibit plasma testosterone. Future studies will benefit from examining corticosterone in addition to testosterone, to better understand the hormonal underpinnings of the dear enemy effect. [ABSTRACT FROM AUTHOR]

Aggressive signaling is an important component in animal communication, as it provides an efficient mechanism for settling conflicts over resources between competitors. In songbirds, a number of singing behaviors have been proposed to be aggressive signals used in territory defense, including song rate. Although aggressive signaling in songbirds has received considerable research attention, adequate evidence for most putative aggressive signals is not available. In this study, we experimentally investigated whether the song rate of male wood warblers Phylloscopus sibilatrix is a signal of their aggressive intent in male-male interactions. We found that males responded differentially to simulated territorial intrusions depending on the song rate of an intruder. Moreover, males that continued to sing during territorial contests increased their song rates, and this behavior predicted the strength of aggressive escalation by the signaler. These results suggest that song rate is an aggressive signal during male-male interactions in the wood warbler. We also found high intra-individual repeatability in the strength of aggressive response to simulated intrusions, likely reflecting differences in personality (aggressiveness) or quality of male wood warblers. We conclude that changes in singing rate may be an efficient mechanism of signaling immediate shifts in motivation of signalers during territorial contests, especially in species that lack large repertoires or have simple songs. [ABSTRACT FROM AUTHOR]

In many animal taxa, behavior varies both among individuals (animal "personalities") and within individuals ("plasticity"). Personality and plasticity may co-vary if individuals differ in responsiveness to changes in their environment ("I × E" interaction). The nature and fitness implications of individual differences in behavioral plasticity in the wild are poorly understood. In territorial animals, fitness depends fundamentally on resource-defense behavior-their response to various threats from conspecific competitors. Such systems thus offer an ideal opportunity to investigate individual differences in behavioral plasticity. We used male superb fairy-wrens (Malurus cyaneus) to test for individual differences in the intensity and plasticity of territorial defense behavior. Using captive assays, we identified behavioral types on the basis of fast versus slow exploration of a novel environment (the "proactive-reactive" axis of behavior). Then we simulated territorial intrusions in the wild, using playback of experimentally manipulated songs that differed in trill length in a pair-wise design. Although previous work suggests that proactive individuals are more aggressive and less responsive than reactive individuals, we found no support for these differences in the context of territorial defense in the wild. Fast explorers (proactive) and slow explorers (reactive) responded equally aggressively to a simulated territorial intrusion overall. Furthermore, although fast explorers responded equally strongly to the two different playback stimuli, there was little evidence that slow explorers differentiated between the two stimuli, and this "I × E" interaction was not statistically significant. Further work is needed to determine the prevalence in the wild of personality-related differences in behavioral plasticity. [ABSTRACT FROM AUTHOR]

Social dynamics in territorial species often reflect underlying variation in aggression and other aspects of social dominance among individuals. In ornate tree lizards ( Urosaurus ornatus), males differing in dewlap color differ in social dominance: while blue males are the dominant, aggressive morph and always territorial, yellow males tend to exhibit a less-aggressive satellite behavioral tactic. However, in habitats with fewer available territorial resources, yellow males defend territories and increase in relative abundance. These observations suggest that consideration of social dominance alone may be insufficient to explain U. ornatus' territorial dynamics in the wild. Here, we tested how both dominance and another important behavioral trait, boldness, contribute to the outcome of territorial disputes in tree lizards. We recorded the territorial behavior of blue and yellow male tree lizards (entered in pairs) in an experimental arena. At the end of each trial, we then approached each male and recorded whether it fled (shy) or not (bold) in response to our approach. As expected, dominant blue males exploited the higher quality perch more often than yellow males. However, when approached by a simulated predator, blue males were more likely to flee than yellow males. Thus, while blue males are more dominant, yellow is likely the bolder morph. As a result, this morph may be better equipped to defend territories in riskier environments. We conclude that although dominance asymmetries may predictably drive initial territorial interactions among competing males, variation in other behaviors (like boldness) may perturb the long-term outcome of these interactions across variable environments. [ABSTRACT FROM AUTHOR]

Home range sizes of territorial animals are often observed to vary periodically in response to seasonal changes in foraging opportunities. Here we develop the first mechanistic model focused on the temporal dynamics of home range expansion and contraction in territorial animals. We demonstrate how simple movement principles can lead to a rich suite of range size dynamics, by balancing foraging activity with defensive requirements and incorporating optimal behavioral rules into mechanistic home range analysis. Our heuristic model predicts three general temporal patterns that have been observed in empirical studies across multiple taxa. First, a positive correlation between age and territory quality promotes shrinking home ranges over an individual’s lifetime, with maximal range size variability shortly before the adult stage. Second, poor sensory information, low population density, and large resource heterogeneity may all independently facilitate range size instability. Finally, aggregation behavior toward forage-rich areas helps produce divergent home range responses between individuals from different age classes. This model has broad applications for addressing important unknowns in animal space use, with potential applications also in conservation and health management strategies. [ABSTRACT FROM AUTHOR]

This paper gives an analysis of the size of populations of sika deer (Cervus nippon) that were introduced to the Czech Republic at the end of the 19th century. Control methods are applied to underlying data taken from the official statistics of the Czech Statistical Office with the aim to check retrospectively their accuracy. Based on statistical data of third level territorial administrative units available, the recent population expansion of sika deer in the Czech Republic is evaluated as well as the manner and intensity of their spread into new, previously unpopulated areas. Results of applied control methods indicate errors in population management due to underestimation of overall population size data, in particular in the category of female deer. [ABSTRACT FROM AUTHOR]

Territoriality is an important male behavioral trait used in mate selection of butterflies, but the factors determining the outcome of territorial contests remain controversial. We studied the foraging and territorial behaviors of males in the Parnassius imperator butterfly. Adult males were selective about nectar sources, but they did not defend nectar flowers. By contrast, they fought over areas of bare rocks because bare rocks were used as lek locations to attract and court receptive females. The ownership of a lek, rather than sex pheromones or wing pigments, played the key role in attracting females. In an owner replacement experiment, the owner of a territory always defeated intruders, indicating that perching order, not relative body size, determined the outcome of territorial contests. Territories are small areas of bare rocks that lack food resources, so intruders do not challenge the ownership of a resident in a location where they can easily find vacant territories. Males that first perch in a territory have an advantage compared to intruders in that they can forage on flowers in the vicinity of the territory. This may help explain why satiated owners always defeated fatigued intruders. Our findings suggest that early perching on bare rock allows male butterflies of P. imperator to occupy a territory, attract receptive females and exclude later-arriving competitors. [ABSTRACT FROM AUTHOR]

Due to its conspicuous manifestations and its capacity to shape the configuration and dynamics of wild populations, territorial behavior has long intrigued ecologists. Territoriality and other animal interactions in situ have traditionally been studied via direct observations and telemetry. Here, we explore whether noninvasive genetic sampling, which is increasingly supplementing traditional field methods in ecological research, can reveal territorial behavior in an elusive carnivore, the wolverine ( Gulo gulo). Using the locations of genotyped wolverine scat samples collected annually over a period of 12 years in central Norway, we test three predictions: (1) male home ranges constructed from noninvasive genetic sampling data are larger than those of females, (2) individuals avoid areas used by other conspecifics of the same sex (intrasexual territoriality), and (3) avoidance of same-sex territories diminishes or disappears after the territory owner's death. Each of these predictions is substantiated by our results: sex-specific differences in home range size and intrasexual territoriality in wolverine are patently reflected in the spatial and temporal configuration of noninvasively collected genetic samples. Our study confirms that wildlife monitoring programs can utilize the spatial information in noninvasive genetic sampling data to detect and quantify home ranges and social organization. [ABSTRACT FROM AUTHOR]

There are several alternative hypotheses about the effects of territoriality, kinship and prey availability on individual carnivore distributions within populations. The first is the land-tenure hypothesis, which predicts that carnivores regulate their density through territoriality and temporal avoidance. The second is the kinship hypothesis, which predicts related individuals will be clumped within populations, and the third is the resource dispersion hypothesis, which suggests that resource richness may explain variable sociality, spatial overlap or temporary aggregations of conspecifics., Research on the socio-spatial organization of animals is essential in understanding territoriality, intra- and interspecific competition, and contact rates that influence diverse ecology, including disease transmission between conspecifics and courtship behaviours., We explored these hypotheses with data collected on a solitary carnivore, the cougar ( Puma concolor), from 2005 to 2012 in the Southern Yellowstone Ecosystem, Wyoming, USA. We employed 27 annual home ranges for 13 cougars to test whether home range overlap was better explained by land tenure, kinship, resource dispersion or some combination of the three., We found support for both the land tenure and resource dispersion hypotheses, but not for kinship. Cougar sex was the primary driver explaining variation in home range overlap. Males overlapped significantly with females, whereas the remaining dyads (F-F, M-M) overlapped significantly less. In support for the resource dispersion hypothesis, hunting opportunity (the probability of a cougar killing prey in a given location) was often higher in overlapping than in non-overlapping portions of cougar home ranges. In particular, winter hunt opportunity rather than summer hunt opportunity was higher in overlapping portions of female-female and male-female home ranges., Our results may indicate that solitary carnivores are more tolerant of sharing key resources with unrelated conspecifics than previously believed, or at least during periods of high resource availability. Further, our results suggest that the resource dispersion hypothesis, which is typically applied to social species, is applicable in describing the spatial organization of solitary carnivores. [ABSTRACT FROM AUTHOR]

Territorial behaviour is the use of aggression and advertisement in the defense of a fixed area. In the Eastern Red-backed Salamander ( Plethodon cinereus (Green, 1818)), territoriality is prevalent in Virginia, USA, near the southern extent of its range, but few studies have examined whether northern populations exhibit territorial behaviour. We tested for some prerequisites of territorial behaviour in P. cinereus at the northern extent its range, near North Bay, Ontario, Canada. In laboratory trials, we found that adult male P. cinereus exhibited a modest degree of aggression, and intruding salamanders attempted to escape the experimental chamber more often than residents. We also found that P. cinereus were able to differentiate between familiar and unfamiliar substrates, suggesting pheromonal communication and a potential for territorial advertisement. However, while male-female pairs were common at six sampling sites during the mating season, adult salamanders consistently exhibited a random spatial distribution during the nonmating season. Our study suggests that local P. cinereus exhibit low-level aggression but may not defend fixed areas. One possibility is that P. cinereus may generally not benefit from territorial behaviour in cooler climates, as evapotranspiration rates will be lower and foraging activity less restricted compared with more southern climates. [ABSTRACT FROM AUTHOR]

In territorial species, at least 1 of the 2 individuals involved in an extrapair mating has to leave its territory in order to copulate with the extrapair partner. However, data on extraterritorial forays are difficult and time-consuming to acquire, and extensive datasets on foraying behavior are rare. Here, we use an automated recording system to investigate forays of individual blue tits (Cyanistes caeruleus) to other pair's nest-boxes during early spring, when extrapair matings occur. The study has 3 aims. 1) To describe daily and seasonal variation in the frequency of foraying behavior. 2) To investigate which individuals perform forays. 3) To investigate whether male and female visits to other pair's nest-boxes predict the occurrence of extrapair paternity. We find that males visited foreign nestboxes more frequently than females, and that the majority of visits occurred in the morning hours, but not around dawn. Male visits to a foreign nest-box were unrelated to the social and the visited females' fertile period. Male body size, but not age predicted the occurrence of forays. Males that forayed were more likely to sire extrapair offspring with the female they visited compared with nonvisiting males. Whether males copulate during such visits or whether females seek extrapair copulations from visiting males remains unknown. However, male forays to a foreign nest-box coincided with the presence of the resident female at the same nest-box more often than expected by chance. This indicates that visits to foreign nest-boxes could be an opportunity for extrapair mate assessment or extrapair copulations. [ABSTRACT FROM AUTHOR]

Utilizamos arneses de tipo mochila para sujetar transmisores satelitales de 55g y 100g (PTTs, en sus siglas en inglés) en siete individuos adultos territoriales de Aquila chrysaetos durante un estudio de la ecología de dicha especies en el Suroeste de América del Norte. El porcentaje de tiempo empleado en acicalamiento por parte de cuatro individuos adultos, tras 1 a 6 semanas de haber sido equipados con los PTTs, no difirió del tiempo empleado durante el mismo periodo por cuatro individuos adultos territoriales no equipados con los PTTs. Sin embargo, sólo dos de las siete águilas territoriales equipadas con los PTTs no murieron o no se quitaron sus transmisores en el primer o segundo año tras haber sido equipados y una de ellas fue expulsada aparentemente de su territorio. Nuestras observaciones, aunque limitadas en número, sugieren un análisis en mayor profundidad sobre el posible impacto negativo de los emisores satelitales de tipo PTT en A. chrysaetos. Instamos a la realización de meta-análisis colaborativos para entender mejor cómo influye la instalación de emisores satelitales en el comportamiento y supervivencia de A. chrysaetos a largo plazo. [ABSTRACT FROM AUTHOR]

An experiment was designed to test the hypothesis that an internally generated sense of spatial orientation contributes to navigation by rats in the Morris water task and to determine whether this strategy is dependent on vestibular cues. Rats were trained in a standard hidden platform procedure in which they received 8 daily swim trials. In a probe test, rats were carried in an opaque box to a pool located in a novel adjacent environment. During transport, 1 cohort of rats received a disorientation procedure, composed of gentle rotation in the box, while a second cohort served as transport controls. Upon being placed in the pool in the novel room, controls displayed a preference for the pool quadrant predicted by a retained directional response across rooms, whereas disoriented rats failed to display a preference for the same quadrant. Furthermore, control rats swam faster and more directly toward the target quadrant. Together, these findings suggest that rats retain a directional response based on vestibular cues across environments, which can be used to disambiguate geometrically equivalent locations in a novel room and apparatus. [ABSTRACT FROM AUTHOR]

The article discusses analysis of animals' territorial behavior with the help of mathematical models. Topics discussed include interaction mechanism of the territorial patterns, predictive theory for ecology, and self-organization of animals in their territories. Other topics include territorial interactions, spatial patterns, and statistical methods for analysis.

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Many terrestrial mammals will deposit scent marks and over-marks, the latter being the overlapping scent marks of two conspecifics. Studies have shown that male rodents that are exposed to the overlapping scent marks of two female conspecifics later spend more time investigating the mark of the top-scent female than that of the bottom-scent female. This suggests that over-marking is a form of competition and that the top-scent female is more likely than the bottom-scent female to be chosen as a potential mate. Thus, females should over-mark the scents of neighboring females at a rate that will maximize their chances of attracting males. However, meadow voles live in areas that may contain patchy food availability and residents may differ in their nutritional status. Females in a better nutritional state may be more likely than those in poorer nutritional states to indicate their presence in an area, signal possession of a territory, and to attract mates. Thus, we tested the prediction that female meadow voles, Microtus pennsylvanicus, that were not food deprived would deposit more over-marks than female voles that were food deprived for 6 h. Food-deprived female voles and female voles that had continuous access to food deposited a similar number of scent marks and used a similar proportion of those marks as over-marks when they encountered the scent marks of female conspecifics. These findings suggest that the nutritional status of female voles does not affect their ability to signal their presence in an area marked by a female conspecific. [ABSTRACT FROM AUTHOR]

We conducted a long-term study to assess how tenure and territorial behaviors influence reproductive success among male Steller sea lions ( Eumetopias jubatus (Schreber, 1776)). Copulations by males ( n = 44) that maintained territories on a rookery in the Gulf of Alaska from 2001 to 2009 were observed using a remote video system. Approximately half of postpartum females copulated with a male in a different territory from where they gave birth. Nearly two-thirds of territorial males with known tenure were unsuccessful in copulating during their first year. Number of copulations for territorial males increased from acquisition year to year 2 with no change in subsequent years. Cluster analysis of tenure and territorial tactic variables for 15 males with observed lifetime reproductive success was used to describe multiple reproductive strategies. Characteristics of the two most successful strategies were the following: ( i) males typically copulated in their first year, retained the same territories for 3-5 years, and occupied centrally located coastal territories where the highest percentage of females gave birth and ( ii) males did not copulate until at least their third year and occupied peripheral territories with fewer births for a longer tenure of 7-8 years. Results indicated that lifetime reproductive success was not achieved solely by time on the breeding area; rather, it was achieved from a combination of tenure and territorial tactics. [ABSTRACT FROM AUTHOR]

Residents are more likely to win territorial disputes than intruders. One explanation for this prior resident advantage is that residents place a higher value on the resource and are therefore more motivated to win. Although value asymmetry models of animal contests often assume that contestants use information about resource value, information on the proximate cues affecting territorial behaviour is often lacking. We use a simple model system - territorial behaviour in the masked birch caterpillar ( Drepana arcuata) to identify factors that affect territorial behaviour. Late instar caterpillars occupy solitary silken leaf shelters, which they defend against wandering conspecifics with a vibratory display. We evaluated how a caterpillar identifies itself as the owner and the factors that influence a resident's motivation to signal. To do so, we conducted three experiments between size-matched residents and intruders to assess how residency duration and shelter quality independently affected territorial displays during the early stages of a contest. Experiment 1 ( Time Exp.) demonstrated that resident signalling rates increase with increased duration on the leaf prior to introducing the intruder. Residents also signal more than intruders after residency periods of 1-3 min and longer, demonstrating that residents gather information about resource value shortly after occupying a leaf. Experiment 2 ( Squatter Exp.) aimed to disentangle the effects of time on the leaf and silk accumulation. Squatters (individuals in a shelter made by another) placed for 1-3 min on a leaf containing a full silk shelter signalled more to intruders than did caterpillars placed on a fresh leaf for 1-3 min. Experiment 3 ( Shelter Removal Exp.) showed that residents whose shelters had been removed signal less than those occupying an intact shelter, despite an equal length of time investing in them. Our experiment is the first to covary both prior residency duration and territory quality, and we find that the motivation of caterpillars to signal is a function of both of these attributes. [ABSTRACT FROM AUTHOR]

Juveniles' behaviors are often influenced by the behaviors of conspecifics. Most experimental studies of the influence of conspecific behavior vary the social environment by the presence or absence of conspecifics or investigate the impact of the outcome of social encounters (winner/loser effects) but less frequently expose individuals to variation in behavioral phenotypes present in the social environment. Based on previous work showing that juveniles of the salamander Plethodon cinereus are likely to interact frequently with non-parental adults, I hypothesized that territorial adults in the social environment alter the future behaviors of juveniles. I measured the intracohort social behaviors of juvenile salamanders collected from two geographic areas, Michigan ( MI) and Virginia ( VA), before and after housing with ostensibly territorial ( VA) or non-territorial ( MI) adults. There were overall effects of adult territoriality and aggression on the behavior of juveniles. However, juveniles from populations in MI were especially susceptible to behavioral modification. Compared with behaviors prior to being housed with adults, MI juveniles increased investigatory and escape behaviors in juvenile-juvenile interactions after being housed with adults that displayed territorial behaviors and decreased investigatory and escape behaviors after being housed with non-territorial adults. This study shows that not only is a specific behavior, territoriality of adult salamanders, a social environment that modifies future juvenile behaviors, but the effects of social environment may differ between populations. [ABSTRACT FROM AUTHOR]

Abstract: It has been suggested that invasion of the personal space by flock members is the main trigger of aggressive interactions in the domestic fowl (Gallus gallus domesticus). In large and dense groups of birds high frequency of attacks should be expected as the chances of invading the personal space of others is likely to occur. However, other studies suggest that after surpassing a certain group size the frequency of aggressive interactions decline. It is possible that the behaviour of the individuals themselves may be more relevant in this context. To test this hypothesis we analysed the onset of aggressive interactions in a laying strain of domestic fowl from videotaped behavioural sequences. A total of 60 interactions were analysed, for which we recorded the location (XY coordinates) of the giver (G) and receiver (R) of an aggression, the position of the two closest individuals to G (G1, G2) and to R (R1, R2), in addition to the behaviour and head orientation of all these birds with the software Chickitizer®. Distances between pairs of birds were calculated as Euclidean distances and analysed by mixed model ANOVA. Behaviours were ordered by ranges of activity and differences analysed by Kruskal–Wallis. Our results indicate that inter-individual distances at the onset of an aggressive interaction varied according to the specific pair of individuals, but contrary to the expected, distances between the G-R remained similar to the distance among the G-G1 and G-G2. R birds however, were consistently involved in more energetic demanding behaviours and with their head oriented towards G. These results suggest that aggression in the domestic fowl does not depend on the invasion of the critical distance per se, but would greatly depend on the activity level and directionality of the individuals which would be perceived as a threat by the aggressor. [Copyright &y& Elsevier]

The Svalbard rock ptarmigan ( Lagopus muta hyperborea) is an endemic subspecies of rock ptarmigan inhabiting the high Arctic archipelagos of Svalbard and Franz Josefs Land. This ptarmigan species exists at low population densities, with little interannual variations in population numbers, and limited habitat for breeding with less than 5 % of the land area in Svalbard constituting medium to high quality breeding habitat. Unander and Steen () hypothesized, based on a descriptive study, that territories sufficiently attractive for breeding could be a limiting factor of the Svalbard rock ptarmigan population. Here, we use experimental data from a 3-year removal experiment (1984-1986) to test their hypothesis by comparing breeding density, demography (sex and age ratios) and body mass of birds between experimental removal plots and control locations. We found evidence of surplus birds by showing that both sexes of Svalbard rock ptarmigan replaced quickly in vacant territories after removal of the resident birds, and that breeding densities were similar for the experimental and control populations. Replaced males in the breeding population weighed less than males in the initial breeding population and tended to be younger. Experimental harvest during the preceding spring had no effect on male body mass, population sex ratio or the proportion of juvenile males in the pre-breeding population the following spring. The documented surplus of male and female Svalbard rock ptarmigan and a lack of impact on breeding densities from removal of birds leave a proportion available for harvest. [ABSTRACT FROM AUTHOR]

Collective animal behavior studies have led the way in developing models that account for a large number of individuals, but mostly have considered situations in which alignment and attraction play a key role, such as in schooling and flocking. By quantifying how animals react to one another's presence, when interaction is via conspecific avoidance rather than alignment or attraction, we present a mechanistic insight that enables us to link individual behavior and space use patterns. As animals respond to both current and past positions of their neighbors, the assumption that the relative location of individuals is statistically and history independent is not tenable, underscoring the limitations of traditional space use studies. We move beyond that assumption by constructing a framework to analyze spatial segregation of mobile animals when neighbor proximity may elicit a retreat, and by linking conspecific encounter rate to history-dependent avoidance behavior. Our approach rests on the knowledge that animals communicate by modifying the environment in which they live, providing a method to analyze social cohesion as stigmergy, a form of mediated animal-animal interaction. By considering a population of animals that mark the terrain as they move, we predict how the spatiotemporal patterns that emerge depend on the degree of stigmergy of the interaction processes. We find in particular that nonlocal decision rules may generate a nonmonotonic dependence of the animal encounter rate as a function of the tendency to retreat from locations recently visited by other conspecifics, which has fundamental implications for epidemic disease spread and animal sociality. [ABSTRACT FROM AUTHOR]

The function and evolution of avian plumage colouration has been the subject of many studies over the past decade, but virtually all of this research has focused on the plumages of sexually mature individuals. The colours and patterns of juvenal plumage, which is worn by altricial songbirds only for the first few months of life, have been the focus of few studies. We develop the idea that distinctive juvenile appearance may be a signal of sexual immaturity, serving to reduce aggression from conspecific adults. We use a comparative phylogenetic approach to test this hypothesis in the thrushes (Family Turdidae). Honest signals of reproductive immaturity should be more valuable when juveniles fledge into environments with aggressive adult conspecifics. Therefore, we predicted that distinctive juvenile appearance would be more likely to evolve in species with extended breeding seasons and high levels of territoriality. Because many tropical bird species exhibit year-round territoriality and elongated breeding seasons, we used breeding latitude as a proxy for these variables. As predicted, distinctive juvenile appearance was significantly correlated with occupancy of tropical latitudes. While alternative explanations cannot be ruled out and more tests of the hypothesis are needed, the observed associations between breeding latitude and distinctiveness of juvenal plumage are consistent with our hypothesis that distinctive juvenal plumage evolved as a signal of sexual immaturity. [ABSTRACT FROM AUTHOR]

Abstract: We studied the ranging behaviour and spatial relationships between seven roe deer during more than 4 years in a partly wooded 14.2-ha enclosure. The animals (three young males, four adult females) were monitored with GPS telemetry collars. As expected, the surface area and overlap of the males’ bimonthly ranges decreased, and the distance between their arithmetic centres increased, as they became adult and, for two of them, territorial. Unexpectedly, females also tended to space out, the surface area and overlap of their bimonthly ranges being minimal in May to June, i.e. during the birth period. The distance between their arithmetic centres reached its maximum at the same time. Overlap between females’ ranges was consistently lower than those between males and females’ ranges, or between 1-year old males’ ranges. Our results raise the questions of female seasonal territoriality and of independence of the spacing systems of the two sexes in roe deer. [Copyright &y& Elsevier]

Although testosterone (T) has well known organizational and activational effects on aggression, the relationship between the two is not always clear. The challenge hypothesis addresses this problem by proposing that T will affect aggression only in fitness-enhancing situations. One way to test the challenge hypothesis is to examine the relationship between T and different types of aggression. Chimpanzees, Pan troglodytes, show aggressive behaviours in several contexts and provide an opportunity for such a test. Here we show that urinary T influences a form of male chimpanzee reproductive aggression, territorial boundary patrols. In contrast, T does not affect predatory behaviour, a form of aggression that has no immediate link to male reproduction. While these results are consistent with the challenge hypothesis, our results indicate that male chimpanzees experience a significant drop in urinary T during hunts. Additional analyses reveal that males who share meat with others display this decrease. The reason for this decrement is unclear, but we hypothesize that the relative lack of aggression that results from voluntary sharing episodes and the tolerance engendered by such acts may be contributory factors. [Copyright &y& Elsevier]

Experiments have shown that interspecific interactions within consumer guilds can alter patterns of distribution, abundance and size of species. Plastic behavioural responses can be modulated by agonistic interactions. In many cases, consumers compete for space and shelters, and these interactions change the manner in which they exploit food. This study investigates the consequences of competition in the spatial and temporal organization of behaviour of intertidal grazers, which share algal resources and the use of rock crevices while resting, but exhibit different body sizes, spatial behaviour and foraging modes. We evaluate interaction strength between small gregarious Siphonaria lessoni and the larger territorial keyhole limpet Fissurella crassa and between S. lessoni and the medium-size gregarious chiton Chiton granosus. Using field manipulations and artificial arenas in the laboratory, we tested whether the use of crevices, micro-spatial distribution and activity are modified by the density of conspecifics and the presence of heterospecifics. Our results show that small-scale spatial segregation observed in the field between S. lessoni and C. granosus result from species-specific differences in habitat use. In turn, we found evidence that spatial segregation between F. crassa and S. lessoni results from highly asymmetric interference competition in the use of shelters. The presence of F. crassa reduced the use of crevices and growth rates of S. lessoni. Effects on growth rates are assumed to result from exposure to harsh environmental conditions rather than food limitation. Thus, neither gregarious behaviour nor differences in activity were sufficient to prevent competition with the larger grazer. Our study illustrates the importance of competition for shelters, which results in behavioural changes of the smaller-sized species, and how these plastic responses can translate into differences in growth rates. Use of shelters can thus be modulated by environmental conditions in a species-specific as well as an interactive manner within consumers' guilds. [ABSTRACT FROM AUTHOR]

Physical strength and resource value are two key determinants of fighting success in most species. We investigated the role that resource value plays in determining fight outcome for a territory centred on a burrow in a fiddler crab, Uca annulipes. Males fought harder (escalated fights) for a territory during the mating period (when the burrow is also used for mating and breeding) than in the nonmating period (when it has value as a shelter). In both periods, having a burrow also allows access to the surrounding mudflat surface, where crabs forage. We confirmed earlier studies showing that males with regenerated claws are weaker competitors that are disproportionately evicted from their burrow during the nonmating period. Unexpectedly, however, males with a regenerated claw were not disproportionately evicted during the mating period. Fights at this time were also more escalated. We suggest this is because, when the disputed resource is also required for breeding, even weak males need to obtain and defend a burrow if they are to accrue any fitness. During the mating period, individuals with low resource-holding potential can improve their chances of mating if they escalate fights for burrows. [ABSTRACT FROM AUTHOR]

The relative scarcity of studies at the intersection of behavioral and population ecology is surprising given the presumed importance of behavior in density-dependent population regulation. Here we tested whether North American red squirrels ( Tamiasciurus hudsonicus) adjust their behavior in response to local population density and whether they use rates of territorial vocalizations in their local neighborhood to assess density. We examined these relationships using 18 years of live trapping and 20 years of behavioral data that were collected across natural variation in local population density. To disentangle the effects of population density on behavior from those due to changes in per capita food abundance or changes in the frequency of antagonistic interactions with neighbors, we also experimentally manipulated population density with long-term food supplementation as well as perceived population density with long-term playbacks of territorial vocalizations. The frequency with which squirrels emitted territorial vocalizations was positively associated with local population density. In contrast, antagonistic physical interactions observed between squirrels and territorial intrusions were rare and the frequency of intrusions was weakly and negatively, not positively, associated with population density. Squirrels experiencing naturally and experimentally high density conditions spent less time in the nest and feeding but more time being vigilant. Similar density-dependent changes in behavior were observed in response to our manipulations of perceived population density, indicating that vocalization rates and not physical interactions or food abundance were the mechanism by which squirrels assessed and responded behaviorally to changes in local density. [ABSTRACT FROM AUTHOR]

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Many temperate zone breeding birds spend their non-breeding period in the tropics where they defend individual territories. Unlike tropical birds that use song for breeding and non-breeding territorial defense, vocal defense differs strikingly between breeding and non-breeding territories in migrants. Song, restricted to males, is used during defense of breeding territories but callnotes are used to defend non-breeding territories. To explain why callnotes and not songs predominate in the non-breeding context, we present an empirical model based upon predictions from motivational/structural rules, ranging theory and latitudinal differences in extra-pair mating systems. Due to sex role divergence during breeding that favors singing in males, but not females, females may be unable to range male song. Ranging requires a signal to be in both the sender and receiver's repertoire to allow the distance between them to be assessed (ranged). Non-breeding territories of migrants are defended by both males and females as exclusive individual (androgynous) territories. Ranging Theory predicts callnotes, being shared by both males and females can, in turn, be ranged by both so are effective in androgynous territoriality. Where songs are used for non-breeding territorial defense both sexes sing, supporting the evolutionary significance of shared vocalizations in androgynous territorial defense. [ABSTRACT FROM AUTHOR]

The marking behaviour of the European badger ( Meles meles L., 1758) in a low-density population of NW Italy was investigated by examining the distribution and pattern of use of latrines in relation to space-use by a badger social group, as assessed by radiotracking. Latrines were mostly placed close to linear features and marked the core area of the group. The winter-spring peak in latrine use suggested that marking behaviour was correlated to reproductive cycle and involved in sexual advertisement. [ABSTRACT FROM AUTHOR]

Territoriality is a widespread behaviour in animals and its analysis is crucial in several areas of behavioural, ecological and evolutionary research. Commonly, territory size is assessed through territory mapping and the application of simple area estimators such as minimum convex polygons. In the present study we demonstrate that territory size can be determined adequately with an active approach through intrusion experiments, a technique that is commonly used in behavioural research in other contexts. Tests with simulated data indicate that a minimum of twelve trials needs to be performed to establish reliable orders of relative territory size. To estimate absolute territory size, detailed hull techniques are most appropriate when analyzing point patterns of intrusion experiments, while the local convex hull estimator enables the construction of internal utilization distributions based on such point patterns. Additionally we suggest a 'stretch the centre' approach to emphasize the actual process of intrusion experiments in the construction of internal utilization distributions. To demonstrate the utility of the method, we apply all findings from the simulations to data from fieldwork with the model species Allobates femoralis, a territorial aromobatid frog from the lowland rainforest of French Guiana. [ABSTRACT FROM AUTHOR]

Males singing within their territories can change their song characteristics in order to interact with conspecifics; males may respond to territorial intrusions by vocalizing, approaching the intruder and/or displaying. I studied male-male interactions by quantifying vocal and behavioural responses of male spot-bellied bobwhites (Colinus leucopogon) toward playback of conspecific male songs. Male responses toward playback song depended on the quality of the territorial male's song relative to the playback stimulus. In this species males who sang songs with higher peak and low frequency, longer song duration, and lower song rate were less responsive to simulated territorial intrusions. Spot-bellied bobwhite males that sang in response to the playback increased the low frequencies of their songs relative to pre-playback song, a vocal behaviour related to dominance in males of other species. Males that approached the speaker sang longer songs, a characteristic associated with increased aggression or motivation to fight in other bird species. The results of this playback experiment suggest that male spot-bellied bobwhite song characteristics according to playback characteristics predict response to territorial intrusions and may, therefore, play an important role in male-male interactions. [ABSTRACT FROM AUTHOR]

Researchers have often assumed that scent marking serves a territorial function in callitrichines, although some controversy exists. To fulfill such a function, scent marks should 1) prevent intrusions, 2) ensure access to feeding resources, 3) enable avoidance of intergroup encounters, or 4) play an important role in the aggressive encounters between groups. We studied 13 saddleback tamarins ( Saguinus fuscicollis) belonging to 3 free-ranging groups, which formed mixed-species troops with moustached tamarins ( S. mystax) in the Amazonian rain forest of Peru. None of the predictions were confirmed. The tamarins used a border-marking strategy, marking more on the periphery of their territory. However, feeding trees in overlap and encounter areas received more scent marking but were still visited by neighboring groups. Intergroup encounters occurred more often than expected, and scent-marking frequency was not higher during them than when no other group was present. It appears that instead of defending a territory in the classic sense, the tamarins are optimizing signal transmission by depositing their scents where the probability of detection by neighbors is higher. Saddleback tamarins may use shared areas of their home ranges to exchange information with neighboring groups, perhaps regarding reproductive opportunities. [ABSTRACT FROM AUTHOR]

The article presents a research study which focuses on the commuting and territorial behaviours of black-backed jackals in Namibia. Researchers have sighted the territorial indication of these jackals in the presents of 50 million fur seals observed in the National West Coast Recreation Area and Cape Cross Seal Reserve. They found the various sizes of jackals' territory depending on the availability of prey.

Sick animals may change their feeding behaviour to compensate for infections. However, there is little information regarding whether infection affects (1) feeding behaviour of predators, (2) feeding behaviour using an experimental approach in the wild, (3) other costly behaviours and/or (4) physiological components of condition. We experimentally infected males of the predatory damselfly Hetaerina americana in a field experiment. We hypothesized that infection would reduce feeding behaviour. We further predicted a reduction in territorial activity, an increase in immune response (measured by the activity of phenoloxidase, PO) and a reduction of fat reserves and flight-associated muscle mass (two traits usually traded off with immune ability and territorial behaviour). We also infected males in a laboratory experiment that controlled for food supply and territorial activity, and measured the same physiological characters. Immune challenges in the field experiment unexpectedly increased feeding rate but did not change territorial activities. Muscle mass was reduced in the field but not in the laboratory, probably because of differences in the presence of energetically expensive territorial activities. In the laboratory, starvation and infection reduced PO activity and fat stores but did not affect muscle mass. Thus, our field and laboratory results support the idea that increased feeding compensates for infections in predators. [Copyright &y& Elsevier]

Interspecific territoriality may be adaptive if territories contain depletable resources that are valuable to both species, but it can also arise as a maladaptive by-product of intraspecific territoriality. In the latter scenario, sympatric species ought to diverge in ways that reduce interspecific fighting. We studied 4 Hetaerina damselfly species that can be found in sympatry in North America. Prior work showed that sympatric populations have diverged from each other in wing coloration and competitor recognition in 2 of the 4 sympatric species pairs (H. titia/H. occisa, H. titia/H. americana). Here, we show that sympatric populations of these 2 species pairs overlap completely in habitat use, and yet, interspecific territorial fights occur much less frequently than intraspecific fights. Experimentally manipulating the wing coloration of male H. occisa and H. americana to more closely resemble H. titia increased the rate of interspecific fights, which provides direct evidence that divergence in wing coloration is partly responsible for the low rate of interspecific fights. We found that interspecific fighting is also reduced in the other 2 species pairs (H. occisa/H. cruentata, H. americana/H. cruentata), even though prior work showed that heterospecific territory intruders are attacked just as aggressively as conspecific territory intruders. In these cases, however, the sympatric species differ sufficiently in habitat use to reduce the interspecific encounter rate and thereby account for the reduced rate of interspecific fighting. Thus, interspecific fighting is reduced relative to intraspecific fighting in all 4 species pairs, albeit through different mechanisms. [ABSTRACT FROM PUBLISHER]