Exclusive core areas and intrasexual territoriality in Eurasian red squirrels (<Emphasis Type="Italic">Sciurus vulgaris</Emphasis>) revealed by incremental cluster polygon analysis

When animal home ranges overlap extensively in species lacking overt territorial behaviours, identifying exclusive core areas within individual ranges can be difficult. By analysing the size and overlap of successively smaller core areas among individual Eurasian red squirrels (Sciurus vulgaris), we determined exclusive areas within the home ranges of resident males and females. Possible effects of habitat composition and food supplies were explored by monitoring squirrels in different conifer forests and during years with low and high tree seed production. Using outlier-exclusive cores (OEC) revealed that the total ranges consisted of large sally zones (on average, 35% of the total minimum convex polygon [MCP] range) around home ranges with multi-nucleate cores. The mean OEC home range size did not differ between the sexes but was larger with poor food availability. Home ranges (99% incremental cluster polygons [ICP]) overlapped extensively between sexes (average overlap high food–low food: males by females 21–40%, females by males 43–45%) and among males (males by males 26–44%), while intrasexual overlap among females was low (9–10%). The overlap of inner cores among females rapidly approached zero, suggesting the intrasexual territoriality of 75% core areas. This was not the case among male squirrels, for which intrasexual overlap averaged only 4% at 50% but 18% at 75% core areas. Even the smallest inner cores had some degree of intersexual overlap, indicating that complete territoriality did not occur in this species. Female home ranges were more strongly affected by annual fluctuations in food supplies than male ranges. Females reduced the size of their food-based intrasexual territories when food availability increases. Males probably benefit from using larger home ranges and core areas, which overlap with the ranges of several females, by increasing their probability of successful mating.     

Space use and territoriality of wolverines (<Emphasis Type="Italic">Gulo gulo</Emphasis>) in northern Scandinavia

Space use and territoriality influence population structure and dynamics and is therefore an important aspect in understanding the ecology of animals. We investigated spatial and temporal space use of wolverines (Gulo gulo) in northern Scandinavia. We estimated home ranges of 24 radio-marked individuals (17 females and seven males). Male home ranges (mean 669 km²; SE = 211) were significantly larger than female home ranges (mean 170 km²; Wilcoxon–Mann–Whitney; P = 0.001) and encompassed or included parts of up to five different females. Home range sizes of reproducing (170 km²; SE = 51) and barren (171 km²; SE = 63) adult females did not differ. Wolverines in Scandinavia exhibit intrasexual territoriality, with male home ranges totally exclusive and female home ranges either exclusive or with little home range overlap. Overlap between wolverine territories is most likely explained by intrasexual tolerance and kinship.     

Pair territoriality in the longnose filefish,oxymonacanthus longirostris

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

Effects of high density on spacing behaviour and reproduction in Akodon azarae: A fencing experiment

We studied the short term spacing behavioural responses of Pampean grassland mouse (Akodon azarae) with regard to population density in four 0.25 ha enclosures (two control and two experimental) in the 2011 breeding season. Based on the hypothesis that A. azarae breeding females exhibit spacing behaviour, and breeding males show a fusion spatial response, we tested the following predictions: (1) home range size and intrasexual overlap degree of females are independent of population density values; (2) at high population density, home range size of males decreases and the intrasexual home range overlap degree increases. To determine if female reproductive success decreases at high population density, we analyzed pregnancy rate, size and weight of litters, and period until fecundation in both low and high enclosure population density. We found that both males and females varied their home range size in relation to population density. Although male home ranges were always bigger than those of females in populations with high density, home range sizes of both sexes decreased. Females kept exclusive home ranges independent of density values meanwhile males decreased home range overlap in high breeding density populations. Although females produced litters of similar size in both treatments, weight of litter, pregnant rate and period until fecundation varied in relation to population density. Our results did not support the hypothesis that at high density females of A. azarae exhibit spacing behaviour neither that males exhibit a fusion spatial response.     

Mating system structure and population density in a polygynous lizard, Sauromalus obesus (= ater)

Increases in population density often are associated with achange in mating system structure in numerous taxa. Typically,male interactions are minimal in extremely low density populations.As density increases, males exhibit territoriality but if densitybecomes too high, the energetic cost of defending a territorywill eventually outweigh the reproductive benefits associatedwith territoriality. Consequently, males in high density populationsmay abandon territoriality and adopt dominance polygyny, lekking behavior, or scramble competition. We investigated the relationshipbetween population density and mating system structure in threepopulations of the chuckwalla, Sauromalus obesus (= ater),near Phoenix, Arizona. Densities in the Phoenix Mountains (2.7chuckwallas/ha) were lower than any population previously studied.In the Santan Mountains (10.9 chuckwallas/ha), densities weresimilar to populations studied in the Mojave Desert, and inthe South Mountains (65 chuckwallas/ha), densities were the highest yet recorded. Male mating behavior was examined by determininghome range overlap and by making direct behavioral observations.Male home range size decreased with increasing population density.There was little overlap in home ranges among males in allthree populations, whereas home ranges of males and femalesconsistently overlapped, indicating that males were strictly territorial. This conclusion was supported by behavioral observationsof interactions among individuals in a natural setting. Thenumber of females wihin male territories was correlated withfood resources (plants) in all three populations. Female homerange size appeard to be related to food resources whereasmale home ranges appeared to be related to female distribution,population density, and geology. The retention of territoriality in spite of high population densities raises new questions aboutthe relationship between density and resource defense.     

Dynamics in space use of American mink (Neovison vison) in a fishpond area in Northern Germany

Telemetry of American mink Neovison vison revealed seasonal and sexual variations in home-range size, intersexual- and partially intrasexual range overlaps and spatial dynamic of territorial system. From 2003 to 2006, 14 mink (nine males and five females) were radio-tracked in a fishpond area in northern Germany. We observed comparatively large home ranges. Both sexes reduced their large summer home ranges to smaller ones in the winter period. In both seasons, male mink used significantly larger areas than female mink. During the mating season, males considerably enlarged their home ranges and roamed nearly through the entire study area. These variations and diversity of range size were discussed in connection with thermoregulatory behaviour, prey availability and distribution, population density and stability of the social system. Analysing intraspecific static interactions, we observed high intersexual overlapping rates in both the summer and winter periods. But there were no or rather very low levels of intrasexual overlapping. However, in the summer period, large home ranges of neighbouring males also overlapped to some extent, but temporal avoidance of adjacent territory holders was observed. Consequently, our results reveal intrasexual territoriality, with males having larger territories, overlapping those of females. The shifting of stable temporary home ranges observed within one season or between the same seasons of consecutive years demonstrates the highly dynamic nature of spatial behaviour among American mink. All these recorded characteristic features of spatial behaviour should be considered when planning mink control projects and measures for the management of this invasive carnivore.     

繁殖期不同时段赤腹松鼠巢域的变化

繁殖期巢域的研究对了解繁殖期间动物的社群关系、种群动态、繁殖策略等有重要作用。2009 年3 ～12月和2010 年3 ～9 月对洪雅县赤腹松鼠的巢域面积变化进行观察。使用最小凸多边形(Minimum convex polygon,MCP)法计算赤腹松鼠各时期的巢域面积,结果显示: (1)整个繁殖期,雄性赤腹松鼠的巢域面积为1.34 ±0. 34 hm² ,显著大于雌性的巢域面积(0.60 ± 0. 08 hm² ); (2)雄性赤腹松鼠在求偶交配期主动增加其巢域面积,可能会增加雄性与雌性的遇见率,从而增加与雌性的交配数量;雌性赤腹松鼠在求偶交配期不主动增加巢域面积,而是具有较为稳定的活动范围。在妊娠育幼期雌性的巢域面积会减小,这可能是雌性为提高后代的成活率,在增加能量和降低捕食风险两者间做出的权衡;(3)整个繁殖期,雌性赤腹松鼠间无巢域重叠现象,而雄性间存在巢域重叠。两性之间仅在求偶交配期存在巢域重叠现象,因此,雌性赤腹松鼠在繁殖期有较强的领域性。     

Social organization and space use in California voles: seasonal,sexual, and age-specific strategies

We intensively monitored space use and movement in Microtus californicus over a 2-year period that included 1 year of high density (maximum 618/ha) and one of low (minimum 5/ha); historically this population has exhibited cycles of 2 or 4 years. Adults of both sexes dispersed at the start of the breeding season, culminating in the establishment of intrasexually exclusive territories. In females, these territories persisted throughout life, except that many young females recruiting during the breeding season established contiguous, overlapping, or adjacent home ranges with their mothers. This female philopatry explains the conclusion of previous workers that females of this species are non-territorial. In the dry (non-breeding) season, females had smaller ranges that often overlapped and were clustered. Adult males moved breeding territories at a modal interval of 6 weeks; this is consistent with their avoidance of inbreeding with philopatric daughters. Ranges overlapped 1–4 adult females at any one time, and a cohort of 7 long-lived males overlapped an average of 16.4 females during their tenure on the grid. The period of maximum overlap with adult females varied among individual males, and did not correlate with the time of maximum body weight. Ranges of males in the dry season overlapped extensively, with persistent associations among some individuals. In the lowdensity year, ranges of some adults failed to overlap intersexually. Juvenile males dispersed gradually between 3 and 13 weeks of age (half before 9 weeks), with some leaving after reaching sexual maturity; a few remained philopatric. Of juvenile females, 47% remained philopatric with the rest disappearing before 9 weeks of age. New understanding of vole social behavior, dispersal, and space use is achieved by focusing on the seasonal dynamics of spatial relationships among individuals with respect to age, sex, and relatedness.     

Social organization of Galagos in Kenyan coastal forests: I. Galago zanzibaricus

The social organization of Galago zanzibaricus was studied for the first time and the study included data from two different sites in the coastal forests of Kenya. A combination of mark-recapture and radio-tracking techniques was used to investigate patterns of inter- and intrasexual home range overlap. Associations in sleeping groups indicated social ties between individuals. Patterns of range use were established by radio-tracking focal individuals. Adult males generally had nonoverlapping ranges, shared with one or two females and their offspring with which the male regularly slept. Young females remained longer in their natal ranges than males and reproduced within their natal ranges. Range size and distance traveled per night were similar between the sexes; both sexes probably defended territories. None of the other galago (bushbaby) species studied to date show the degree of close male-female association found in G. zanzibaricus. This study thus extends the variety of social organization documented in nocturnal prosimians.     

Spawning dynamics of orange roughy,Hoplostethus atlanticus,in mid-slope waters of New Zealand

Synopsis The social and reproductive biology of the sand tilefish,Malacanthus plumieri (Malacanthidae), was studied at Glover's Reef, Belize, where this species occurs in colonies over sand-rubble flats. Individuals each occupy a home burrow refuge and a surrounding home range. Home range overlap among adjacent fish of the same sex is low, and individuals defend exclusive use of much of their home range against all conspecifics except mates (i.e., territoriality). Areas defended by males overlap the territories of up to 6 females; and male territory area is positively related to the number of female residents. Males maintain dominance over females within their territories by aggression, including intervention into some female disputes. Females spawn pelagically-dispersed eggs as frequently as every day. Each female spawns near her burrow, almost exclusively with the male whose defended area encompasses her territory (harem polygyny). Tilefish colonies therefore consist of a mosaic of female territories over which adjacent male territories are superimposed. Histological evidence and observation of behavioral sex change in one female revealed thatM. plumieri is capable of protogynous sex reversal. Females did not change sex in response to removal of one male. Occurrence of small transitional fish indicates that the onset of sex change is controlled by factors other than size-related social hierarchies within harems or colonies.     

Duetting: A Daily Routine of Laniarius funebris,the Slate-coloured Boubou (Aves,Laniidae)

This is a review of mustelid spacing patterns. The Mustelinae appear to have intrasexual territories where ♂♂ are territorial against ♂♂, ♀♀ against ♀♀, but there is extensive territory overlap between sexes. Mustelids of other subfamilies appear to have variations on this theme; usually female territories are replaced by territories of family groups of one adult ♀ and her most recent offspring. Sea otters and European badgers do not appear to fit into these organizational schemes. There is a strong correlation between degree of intrasexual territoriality, sexual dimorphism in body size, degree of body elongation and degree of carnivory. It is suggested that energy requirements of individuals may tie these correlations together.     

Home range and ranging pattern in the slender loris(Loris tardigradus lydekkerianus)

The home range and ranging pattern of the slender loris (Loris tardigradus lydekkerianus) was studied for 21 months in a scrub jungle in Dindigul, Tamil Nadu, south India. Sixteen individuals were observed for a total of 2261 hours. Home ranges were measured for eight adult individuals and eight juvenile and subadult individuals. Males had significantly larger home ranges than the females, and home range size increased post-weaning. The ranging patterns involved minimal female intrasexual overlap, large male intrasexual overlap and large intersexual range overlap.     

Home range and territory in the striped plateau lizard (Sceloporus virgatus)

Observations of home range sizes, home range locations, and behavioural interactions were used to determine the spatial distribution of a population of striped plateau lizards (Sceloporus virgatus). A comparison of home ranges and nearest-neighbour distances indicates that females have clearly defined territories. In contrast, the home ranges of males overlap extensively. Although males have similar nearest-neighbour distances to those of females, their home range sizes are larger. Much of the overlap among males appears to be associated with the courtship of females, suggesting that males have exchanged defence of exclusive territories for an increased home range area and a larger number of potential mates. Aggressive interactions among males were considerably more conspicuous than those among females, and the clear territorial pattern of females as opposed to males was unexpected on the basis of the frequency of behavioural interactions alone.     

Noninvasive genetic sampling reveals intrasex territoriality in wolverines

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.     

Space Use and Social Mating System of the Hantavirus Host, <Emphasis Type="Italic">Oligoryzomys longicaudatus</Emphasis>

The long-tailed mouse, Oligoryzomys longicaudatus (Cricetidae: Sigmodontinae), is the major host of Andes hantavirus, the etiological agent of hantavirus pulmonary syndrome in the south of Argentina and Chile. Studying the ecology of this species is necessary to understand how Andes hantavirus is maintained in nature. In this study, we examine the home range size and intra- and intersexual overlap degree of male and female O. longicaudatus in order to elucidate the mating system of this species. To our knowledge, this research provides the first documentation, obtained from a specific design, of spacing and mating systems in this species in Argentina. The study was conducted seasonally from April (autumn) 2012 to October (spring) 2013 in a shrubland habitat of Cholila, Andean region, Argentina. We studied spacing patterns using 59 and 51 home ranges established by adult males and females, respectively, in two 3.24 ha capture-marked and recapture grids. Significant differences between sexes in home range size and overlap degree were found. Male home ranges were always larger than those of females. We observed exclusive space use both among males and females (13.15 ± 18.67, and 3.60 ± 3.43%, respectively). Considering only those males that get access to receptive females (40%), average intersexual overlap value was about 30.82 ± 19.73%. Sexual differences in home range sizes and the spatial avoidance between breeding males, that would reflect intrasexual competition for receptive females, allows us to propose a polygynous mating system for O. longicaudatus.     

Happily together forever: temporal variation in spatial patterns and complete lack of territoriality in a promiscuous rodent

The availability of resources, their effect on population density and territoriality, and the ways in which these factors are interwoven with mating systems are important determinants of small mammal space use. It is often difficult to study these patterns in an integrated way, however, especially because long-term data are needed but not readily available. In this paper, we investigate effects of population density, season and breeding status on home range patterns of the promiscuous rodent Mastomys natalensis using monthly capture-mark-recapture data collected over 17 years in a 3-ha grid. Home ranges were estimated using minimum convex polygons bounded by trap locations, and home range overlap and visitation rates were calculated as a measure of territoriality. As higher population densities coincide with increased resource availability, we predicted that home range sizes would correlate negatively with density. Furthermore, as M. natalensis is promiscuous and population densities are generally high, we predicted that territoriality would be low, and home range overlap would therefore be high. Contrary to expectations the home ranges of female adults increased with population density, although those of male adults and subadults followed the expected decrease. Home range overlap and visitation rates were generally high, and increased significantly with population density. More importantly, they were never lower than those of simulated datasets consisting of randomly moved home ranges. These results therefore suggest that M. natalensis displays a complete lack of territoriality that is rarely seen in small mammals but still meets predictions based on knowledge of density and mating system.     

Size and overlap of home range inCalomys musculinus (Muridae: Sigmodontinae)

Home range size and overlap ofCalomys musculinus (Thomas, 1913) was examined in relation to sex and breeding periods. The study was carried out in four 0.25 ha enclosures, in a natural pasture, between October 2002 and July 2003. The four enclosures functioned as independent populations and each was considered a replicate. The capture, mark and recapture method was used. Home range size and overlap inC. musculinus depended on sex and period. Home range size of males was always larger than that of females. Females showed a small degree of intra-sexual home range overlap during the breeding period. In general, male home ranges overlapped with females. We conclude that differences in home range size inC. musculinus is determined by sex and breeding period. Moreover, the degree of inter- and intra-sexual home range overlap during the breeding period suggests that both males and females ofC. musculinus use space differently. Females did not share their home range with other females, while males fully shared it with both sexes, and male spacing is influenced by the distribution of females. A promiscuous-polygynous mating system is suggested forC. musculinus.     

Interindividual interactions of Molina’s hog-nosed skunksConepatus chinga in the Pampas grassland of Argentina

During one year, we radiotracked two female and two male Molina’s hog-nosed skunksConepatus chinga (Molina, 1782), a little studied mephitid, in the Pampas of central Argentina, to analyze the static and dynamic interactions between individuals. Mean home range overlap was large (44.5%), but males shared a smaller proportion of their home ranges than females. The average percentage of localizations in the overlap area (39.3%) indicates that these areas were not marginal sections of individual home ranges, but this value was greater for individuals of different genders than intrasexual dyads. The Coefficient of Spatial Association confirmed that the distances between individuals of different sexes were smaller than between animals of the same sex. During simultaneous locations, females were closer than males, but reciprocal distances between individuals varied over the time. These patterns are congruent with those described as typical for mustelids and mephitids. Our results confirm that an analysis of home range overlap should not be considered complete without the study of dynamic interactions among individuals and their temporal variations, which are necessary to overcome the limitations of spatial overlap analysis.     

Spatial structuring and dispersal in a high density population of the California vole Microtus californicus

Space use patterns of California voles are described from intensive live-trapping data obtained during the late breeding season in a peak density year. Operational sex ratios were strongly female biased. Breeding males had mutually exclusive home ranges that overlapped the home ranges of one to several females. The average male home range was larger than the average female home range and tended to encompass female home ranges in their entirety. Breeding females had home ranges that often overlapped extensively with the home ranges of other breeding females. The degree of overlap, however, tended to be either very high or very low, indicating that groups of females may act territorially among themselves. Family groups that may include members of sequential litters formed at high density. Males on experimental removal grids had larger home ranges than males on the high density grids and some became wanderers while most females had home ranges comparable to those on the high density grids.
Dispersers onto low density grids were not a random sample of the high density population; large breeding adults and small juveniles were under-represented. No sex differences in dispersal were noted. Immigration into the high density populations was probably negligible.     

The Round-Eared Sengi and the Evolution of Social Monogamy: Factors that Constrain Males to Live with a Single Female

Animal dispersion in space and time results from environmental pressures, and affects the outcome of a species' social organization. When females are solitary, males may either roam or be pair-living. We studied possible environmental influences affecting the social organization of the round-eared sengi ( Macroscelides proboscideus ) in a semi-desert in South Africa, using trapping and radio-tracking across 2.5 yr. Adult sex ratios did not deviate from 1:1 and we found no indication of sexual dimorphism in body mass. Females maintained exclusive areas, which had little overlap (<4%) with neighbouring females (NF), and males overlapped predominately only with the home range of single females. Generally, inter- and intra-sexual overlap with neighbouring individuals was low (3–6%) for both sexes, indicating territoriality and pair-living. Pairs were perennial and territories were maintained year-round. However, males generally maintained much larger areas than females, which were sensitive to population density. Male space use appeared to be primarily limited by the presence of neighbouring males. Female home ranges were smaller-sized despite changes in population density, possibly for energetic efficiency. Some paired males attempted to take over widowed females, but shifted back to their original home range following the intrusion of an un-paired male. We conclude that social monogamy is the predominant social organization in round-eared sengis in a semi-desert that may have resulted from females living solitarily in small exclusive territories, balanced sex ratios, and from a low variation of body mass between males.