Showing papers on "Territoriality published in 2004"

Host social behavior and parasitic infection: a multifactorial approach

Abstract: I examined associations between several components of host social organization, including group size and gregariousness, group stability, territoriality and social class, and gastrointestinal parasite load in African bovids. At an intraspecific level, group size was positively correlated with parasite prevalence, but only when the parasite was relatively host specific and only among host species living in stable groups. Social class was also an important predictor of infection rates. Among gazelles, territorial males had higher parasite intensities than did either bachelor males or females and juveniles, suggesting that highly territorial individuals may be either more exposed or more susceptible to parasites. Associations among territoriality, grouping, and parasitism were also found across taxa. Territorial host genera were more likely to be infected with strongyle nematodes than were nonterritorial hosts, and gregarious hosts were more infected than were solitary hosts. Analyses also revealed that gregariousness and territoriality had an interactive effect on individual parasite richness, whereby hosts with both traits harbored significantly more parasite groups than did hosts with only one or neither trait. Overall, study results indicate that multiple features of host social behavior influence infection risk and suggest that synergism between traits also has important effects on host parasite load. Key words: Bovidae, group size, group living, parasite prevalence, parasite richness, strongyle nematodes, territoriality. [Behav Ecol 15:446–454 (2004)]

Territorial defense in a group-living solitary forager: who, where, against whom?

Abstract: Territoriality is of great significance for many species and a characteristic of most group-living animals. Territoriality is thought to lead to increased reproductive success by defending a particular area containing critical resources. I describe several factors that influence territorial aggression in free-ranging striped mice (Rhabdomys pumilio), a group-living solitary forager. I induced territorial aggression by attracting mice of different groups using bait either at territory boundaries or in front of nests. Striped mice are territorial and make decisions about whether or not to attack a mouse from another group based upon several factors: (1) the sex of the opponent: males are much more likely to attack strange males than strange females, whereas no sex specific aggression was observed in females; (2) the body size of the opponent: striped mice are much more likely to attack a strange mouse that is lighter than themselves; and (3) the location of encounters: striped mice are much more likely to attack strangers, even those significantly heavier than themselves, in front of the nest than at territory boundaries. These variations in territorial responses between different types of individuals may be due to the different ultimate consequences of territorial aggression for different animals.

Animal behaviour: Coalition among male fiddler crabs

Abstract: Seeing off a neighbour's intruder may be easier than negotiating with a larger usurper. Until now, no compelling evidence has emerged from studies of animal territoriality to indicate that a resident will strategically help a neighbour to defend its territory against an intruder1,2. We show here that territory-owning Australian fiddler crabs will judiciously assist other crabs in defending their neighbouring territories. This cooperation supports the prediction3 that it is sometimes less costly to assist a familiar neighbour than to renegotiate boundaries with a new, and possibly stronger, neighbour4.

The influence of territoriality and mating system on the evolution of male care: a phylogenetic study on fish

Abstract: Evolution of male care is still poorly understood. Using phylogenetically matched-pairs comparisons we tested for effects of territoriality and mating system on male care evolution in fish. All origins of male care were found in pair-spawning species (with or without additional males such as sneakers) and none were found in group-spawning species. However, excluding group spawners, male care originated equally often in pair-spawning species with additional males as in strict pair-spawning species. Evolution of male care was also significantly related to territoriality. Yet, most pair-spawning taxa with male care are also territorial, making their relative influence difficult to separate. Furthermore, territoriality also occurs in group-spawning species. Hence, territoriality is not sufficient for male care to evolve. Rather, we argue that it is the combination of territoriality and pair spawning with sequential polygyny that favours the evolution of male care, and we discuss our results in relation to paternity assurance and sexual selection.

Does interspecific territoriality reflect the intensity of ecological interactions? A theoretical model for interspecific territoriality

Abstract: In many studies, interspecific territorial behaviours among co-existing species have been used to infer the presence and the intensity of underlying ecological interactions between species, mainly resource competition However, the theoretical background of this inference is insufficient Hence, we constructed a simple theoretical model of interspecific territoriality assuming that interspecific territorial defence is the optimal behaviour We discuss the factors promoting interspecific territoriality and the relationship between interspecific territoriality and ecological interactions The model predicts that: (1) a territory holder preferentially excludes intruders of species with high ‘exclusion efficiency’; (2) the decision by the territory holder to exclude a certain species or not does not depend on the probability of finding intruders of the species or on the number of intrusions by the species; and (3) interspecific territoriality does not always reflect the intensity of ecological interactions between species These results indicate that the observation of interspecific territoriality does not necessarily indicate the intensity of ecological interactions In addition, if territory holders defend their territories as predicted by the present optimal model, the co-existence of competing species is promoted

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

Abstract: Individuals should defend sites when the expected benefits of the territory exceed the cost of defense. However, if territory qulaity is unpredictable or difficult to assess, the expected pattern of territorial behavior is less clear. In a Mediterranean wrasse, Symphodus ocellatus, mating success is skewed with 2% of nesting males getting more than 20% of the spawning success. Yet, variation in mating success is not explained by any known physical characteristic of males or their territories. Instead, females prefer nests with a recent history of mating success because males are less likely to desert the offspring she leaves behind. Thus, territory quality is transient and determined by interactions between the sexes. I measured the frequency of territorial takeovers and the uncertainty in mating success among days at a nest. Observations indicated that S. ocellatus males usurped their neighbor’s successful nests when males were unsuccessful and larger than their successful neighbor. Sites that achieved mating success had a significantly higher probability (0.84) of remaining sucessful between consecutive days than unsuccessful territories had of becoming successful (0.30). Unsuccessful males obtained higher and more certain fitness returns if they usurped a successful neighbor’s territory. Interactions within and between the sexes drive uncertainty in success, which influences territorial behavior in this species. Key words: territoriality, stochasticity, labridae, sexual conflict, assessment. [Behav Ecol 15:278–285 (2004)]

Competition for Mating Resources in a Territorial Damselfly (Odonata: Calopterygidae)

Abstract: The factors that determine contest outcomes among territorial male animals are complex and much debated. This study investigated how breeding resource availability and body size influence territorial contests of the Neotropical damselfly Hetaerina miniata. In our marked population, some males were territory owners while others were part of a wanderer contingent. Male territoriality was not correlated with availability of oviposition substrate. We predicted that territory owners would have an advantage in disputes. Removal experiments demonstrated that owners won significantly more territorial contests than did wanderers, and whereas males were significantly larger than females, male territorial status did not depend on body size. However contest outcome was not based solely on ownership because experimentally removed individuals regained their territories from new owners (intruders). We suggest that intrinsic resource holding potential based on other morphological and physiological factors, such as energy...

Territoriality and War in International Crises: Theory and Findings, 1918–2001

Abstract: The ongoing interest in the effects of territoriality on conflict among states makes it necessary to integrate and examine the existing claims on this topic and to apply them to the empirical data on crisis, conflict, and war. The early literature on territoriality has presented a unidimensional model explaining the occurrence of war. Its major claim accords well with common sense: the more salient the territorial conflict between states, the more likely is the outbreak of war between them. Conventional wisdom and the existing literature about territoriality and violence suggest a simple cause-effect relationship between these two variables (see, for example, Most and Starr 1980; Diehl 1985, 1991, 1992; Diehl and Goertz 1988; Thompson 1990; O'Loughlin and Anselin 1991; Starr 1991; Goertz and Diehl 1992; Ruggie 1993; Gleditsch 1995; Kocs 1995; Gray 1996).' Yet, the concept of territoriality has not always been clearly defined. Nor has it been consistently operationalized or tested across a large number of cases. Furthermore, most empirical data relate to war situations but not to the complex escalation patterns that unfold in the course of an international confrontation and do not always end with full-scale war.2 The fact that neighbors confront one another, and sometimes even fight, does not automatically validate the link between territoriality and conflict. To determine if such a relationship exists, one must compare nonwar with war situations and explore several dimensions of territoriality in these diverse situations. Such an analysis is the purpose of this essay. So, how important is territoriality in explaining international conflict? This is the major research question explored in this essay. More specifically, it will focus on the extent to which territory is a driving force in the outbreak of crises, violence, and even war. The argument is made that the role of territory has not yet been fully examined. It does appear to have a causal effect on violence, but a comprehensive theory of territoriality and war has yet to be established. Stated differently, territoriality may be, in part, an extension of the power context for interstate rivalry and the outbreak of hostilities. For the weaker states in the system, it is a major constraint, but this does not always make territory a necessary or sufficient condition for violence or war. In order to devise a theory of territoriality, the nature of the impact that territory has on war must be explained. Political scientists need to investigate what it is in territoriality that triggers interstate conflict, crisis, and war. The goals of this essay are geared to meeting this challenge by formulating three

Responses to conspecific scent marks and the ontogeny of territorial marking in immature terrestrial salamanders

Abstract: We investigated the ontogeny of responses to scent marks in immature terrestrial salamanders (Salamandra lanzai) that inhabit the southwest Alps In this species, sexual maturity is usually reached at about 8 years, and adults exhibit territoriality One should expect territoriality to take place largely before the acquisition of sexual maturity if sexual competition is not the main force driving territoriality However, both the difficulties for inexperienced animals to find a suitable territory and size-related competition may delay the acquisition of territoriality in juveniles We performed choice tests with juveniles belonging to two age groups (1±1 years old versus 4±1 years old) Each focal animal was offered, in random order, the choice between two shelters, one without scent and the other containing one of the following scents: own, same-aged animal, a juvenile belonging to the other age group, or adult female We also performed choice tests with adult females for which the scents of two juveniles belonging to a different age group were successively offered in a random order Older juveniles were strongly attracted toward their own shelter and mostly avoided the shelters that contained the scent of juveniles of about the same age and of adult females Adult females avoided the scents of older juveniles but not younger juveniles These results therefore suggest that older juveniles use territorial marking Conversely, young juveniles behaved randomly with respect to their own scents and to those of a same-aged juvenile, and they were significantly attracted towards the odor of an older animal, especially adult females Both older juveniles and adult females displayed a random behavior toward the scents of young juveniles Our results suggest that young juveniles do not defend territories but use spaces occupied by older individuals

Intrasexual territoriality in woodchucks (marmota monax)

Abstract: Species demonstrating intraspecific variation in social systems can be powerful models for understanding evolution of those systems. As a group, marmots exhibit several types of spacing systems, usually involving some degree of territoriality. Researchers have described populations of 1 species, the woodchuck, Marmota monax, as territorial and as nonterritorial, and such variation has been linked to ecological conditions. I used direct observations of individually recognized animals to describe the spacing system of a high-density population of Marmota monax in southern Maine. This population exhibited intrasexual territoriality. Home range overlap generally was higher between males and females than between same-sex individuals, and woodchucks tended to approach more members of the same sex more quickly compared with members of the opposite sex. Time spent scent marking varied across the active season but did not vary by sex. Males had larger home ranges than females, and home range sizes varied over time, perhaps in response to resources. Amount of overlap also was greater in some years than others, and such changes may be related to kinship. Philopatry and timing of dispersal also vary in this species and have implications for the evolution of sociality.

Territoriality and social construction of space in children's play

Abstract: In order to illustrate the social construction of space and the phenomenon of territoriality, free play episodes among 2-6 year-old children, selected from video-records taken at a day-care center, are presented. The selection was guided by the identification of interactional sequences in which either individual children or groups of children delimit, defend / fight over, or try to have access to particular spatial areas, in the course of several play modalities. The analysis highlights children’s early capacities in terms of social use of space, construction and management of social relations. The use of “territoriality” and other terms to refer to temporary control over space is discussed and contrasted with the strictly biological and with the geopolitical uses of the concept. Functional distinctions between these several situations where the concept is used are suggested. It is proposed that, in the present case, territorial behaviors have communication functions, express interpersonal connections in the group and are part of the process of identity construction.

Unweaving the Threads: Territoriality, National Ownership of Land and Asylum Policy

Abstract: Bounded territorial space has characterised the sovereign state. Although much attention has been given to the ‘positive’ attributes of bounded territorial space, the ‘structuring effect’ of conceptions of territory on our thinking about political membership and the treatment of admission seekers has been overlooked. The lack of attention to the spatial powers that national statism mobilises may be problematic, but it is hardly surprising. Territory has been viewed as an objective reality. As such, it is seen as a politically innocent concept. It is the land that a state has marked out as ‘its own’, by fixing boundaries and erecting walls in order to keep intruders and invaders out. As Herz has put it, [states] ‘have been surrounded by a “wall of defensibility”, relatively impermeable to outside penetration and thus capable of satisfying one fundamental urge of humans protection’. Regulating the permeability of the border, that is, the degrees of closure, has been a prerogative of sovereign states and the way by which they define their symbolic and political boundaries. Nationhood, in its various understandings and manifestations, has legitimised these boundaries. Territories have become national homelands; they are the object of supreme identification and exclusive loyalty, and are presumed to be the best place for individuals to live in.

Comunidad andina, conceptos de territorialidad y procesos de transición

Abstract: Traditional concepts of territoriality used by some Andean communities individualize the topography and relate locally established boundaries to parts of the human body. Following this logic, territory and residence are understood not only as the tangible sign of the possessions of a defined social group, but also as an indicator of the existence of the ancestors and as a means of communicating with them via direct routes. Recently, as much due to the dynamic of political processes as for reasons connected to changes in the social organization and ecological system, the parameters of this concept of territoriality have begun to alter profoundly.