Host plant-based territoriality in the white peacock butterfly,Anartia jatrophae (Lepidoptera: Nymphalidae)

Mate locating behavior of Anartia jatrophaewas studied near Ochopee, Collier County, Florida. Males were individually marked, and focal animal samples were used to determine activity, residency, and interactions with other butterflies. We recaptured more than half of 53 marked males within the study area on subsequent days. Marked males restricted non-feeding activity to roughly circular areas typically less than 15 m in diameter. Males showed considerable site fidelity and chased both conspecifics and a variety of other insects. Typically, encountered individuals flew away, and the resident peacock male returned to perch near his previous perch. Encounters with conspecific males averaged 38 sec, three times longer than with other insects. Such site fidelity combined with aggressive interactions indicates territorial behavior. When male density more than doubled, site fidelity decreased, resident turnover increased, and areas that had not been defended at lower density were defended. Without exception, defended sites contained the larval host, Bacopa monnieri.In butterfly mating systems, defense of host plants appears to be much less common than defense of natural features such as landmarks.     

Are female red-winged blackbirds territorial?

Spacing behaviour of female red-winged blackbirds (Agelaius phoeniceus) was observed to determine whether resident females within a herem divide their mate's territory into sub-territories. Some results accorded with defence of sub-territories: (1) females were more aggressive (towards decoys and mounts) close to their own nests than further away; and (2) there was little overlap in the use of space betwee residents on a male's territory. Other results did not accord with defence of sub-territories: (1) when the nest site was eliminated from the analysis, spatial overlaps were large; (2) areas defended through aggression by different females overlapped greatly; and (3) areas defended through advertisement by different females overlapped greatly. I conclude that the spacing behaviour of female red-winged blackbirds does not meet a strict difinition of territoriality.     

Territoriality and male-biased sexual size dimorphism in Argia reclusa (Odonata: Zygoptera)

In Odonata, many species present sexual size dimorphism (SSD), which can be associated with male territoriality in Zygoptera. We hypothesized that in the territorial damselfly Argia reclusa, male–male competition can favor large males, and consequently, drive selection pressures to generate male-biased SSD. The study was performed at a small stream in southeastern Brazil. Males were marked, and we measured body size and assessed the quality of territories. We tested if larger territorial males (a) defended the best territories (those with more male intrusions and visiting females), (b) won more fights, and (c) mated more. Couples were collected and measured to show the occurrence of sexual size dimorphism. Results indicated that males are larger than females, and that territorial males were larger than non-territorial males. Larger territorial males won more fights and defended the best territories. There was no difference between the mating success of large territorial and small non-territorial males. Although our findings suggest that male territoriality may play a significant role on the evolution of sexual size dimorphism in A. reclusa, we suggest that other factors should also be considered to explain the evolution of SSD in damselflies, since non-territorial males are also capable of acquiring mates.     

Body size as a factor determining dominance in staged agonistic encounters between male brown anoles (Anolis sagrei)

The results of staged agonistic encounters between males indicate that body size is an important determinant of dominance in male brown anoles (Anolis sagrei). Larger males defended their perch sites more successfully than did smaller males, perched higher than smaller males, and were most often the first male to enter the other male's territory. Larger males also exhibited more challenge displays than did smaller males. Head-nods, a display given by subordinate individuals, were observed only in smaller males.     

Body size and its effect on male-male competition inHylaeus alcyoneus (Hymenoptera: Colletidae)

Body size largely determines the outcome of male-male competition in the banksia bee,Hylaeus alcyoneus. Large males invariably perch on and defend banksia flower spikes, whereas smaller males often nonaggressively patrol circuits that take them repeatedly to several flower spikes. Within the population of males perching on banksia spikes, larger individuals tend to monopolize inflorescences that are higher in banksia shrubs, whereas smaller males often occupy spikes closer to the ground. Perches defended by larger males are more quickly occupied by replacements when the original residents are experimentally removed and held in temporary captivity. When released, the original residents invariably return to and displace the smaller replacements that have taken their territories. When territory takeovers do occur, the winner is almost always larger than the previous resident, showing that residency effects are secondary to body size in determining territorial ownership.     

Hilltopping Behavior of Polistes commanchus navajoe (Hymenoptera: Vespidae)

Males of the paper wasp Polistes commanchus aggregate in large numbers on hilltops in central and southeastern Arizona where individual males defend perch sites on shrubs, trees or rocks. Residents chase intruders away quickly and exhibit strong site fidelity at their perches. Takeovers are rare as are prolonged battles for possession of a site. Males have only weak preferences for peaktop perch sites as opposed to those lower on hillsides, and a similarly weak preference for perches in shrubs as opposed to those on rocks. Receptive females appear occasionally at the male aggregation sites to mate with perch holders. The relatively weak territoriality exhibited by P. commanchus may stem in part from the high density of males at peaktops and the correspondingly high rate of interactions. The evolution of hilltopping in a species whose reproductive females are clumped spatially at nest sites poses a puzzle for the ecological analysis of mating systems.     

Why are Male Columbian Ground Squirrels Territorial?

Male territorial defence is a component of many vertebrate mating systems and is often regarded as a tactic for acquiring mates. Traditionally considered within the context of overt site‐specific defence, territoriality actually may have several components which encompass a variety of behavioural tactics (e.g. post‐copulatory mate‐guarding, defence of resources that females need, defence of area around females) that underlie a mating system. The purpose of our study was to evaluate such influences on the territorial behaviour of male Columbian ground squirrels in southwestern Alberta, Canada. Males were dominant and territorial if they defended a minimum convex polygon activity range by chasing other males more within the activity range than they were chased. Subordinate males had no territory and were chased throughout their ranges, but they competed for mates by increasing chases in their activity range when nearby females were oestrous. Dominant males exhibited conditional breeding tactics, tending to chase other dominant males from their territory when nearby females were oestrous, but travelling outside their activity ranges to chase subordinate males when females were not oestrous. Although females mated first with a dominant male on whose territory they resided (and in order from oldest to youngest if several territories overlapped), mating pairs were not exclusive, as females usually mated with additional males. Males also guarded females after copulation and defended females directly just before oestrus, rather than defending territory per se during those times. Thus, males possess a repertoire of behaviours that complement site‐specific territoriality, and territory ownership serves to facilitate a first mating with females that live on the territory.     

Influences on variation in territorial tenures of male white-faced dragonflies (Leucorrhinia intacta) (Odonata: Libellulidae)

Some individuals in species with extended periods of territorial occupancy may change territory locations within a single bout of territorial activity. Length of occupancy of mating territories among males in a local population of white-faced dragonflies (Leucorrhinia intacta) varied from more than 6 h to 15 min or less. Males with short tenures often established territories in several locations on the pond during a day. Several hypotheses have been proposed to explain shifting territorial sites rather than remaining in a single site during one bout of territoriality. We attempted to test the hypothesis that males shift to leave low-quality sites. Site quality may be affected by costs of defense in relation to intruder rate and the mating benefits of holding the territory. To test whether variation in these possible effects of benefits and costs of territoriality influenced tenure, we manipulated local quality of oviposition substrate and perch density. The quality of oviposition substrate, but not perch density, influenced both potential benefits and costs of territoriality. Female density was higher in areas with good substrate, but so were rates of males intruding into the territories, rates of chasing by territorial males, and local density of territorial males. More matings occurred in areas with good substrate, but among males with tenures of 15 min or more, mating success per male and tenure lengths did not differ statistically among treatments. Defense costs were low for all treatments and perhaps were not an important influence on tenure duration. Territorial males in this population probably adjusted local density to expected mating success by initial choice of site rather than by varying tenure length. Variation in tenure length at a site resulted, in part, from stochastic external factors, such as predation attempts.     

Changing tactics: dominance, territoriality, and the responses of "primary" males to competition from conditional breeders in the variegated pupfish (Cyprinodon variegatus)

Using variegated pupfish, we examined the flexibility in "primary" male tactics when dealing with the aggressive costs of competition. Analogous to conditional mating strategies, we expected primary males to exhibit one of two interrelated tactics (i.e. dominance or territoriality) in response to different numbers of competitors. In the field, competitors influenced aggression. Primary males defended territories; residents facing more intruders engaged in more chases and obtained fewer spawns per female. In the laboratory, primary males showed dominance at low density, controlling most of the aquarium. With increasing competitor numbers, primary males reduced the area controlled and defended territories. Territories occurred with intermediate to high competitor numbers and only under male-biased sex ratios. During these interactions, aggression was highest and competitors were too many for dominant males to suppress the assertions made by each subordinate to increase its rank. Relinquished control of the entire domain enabled a previously subordinate male to establish a territory in the undefended portion of the aquarium. Reduction in defended area related to a reduction in territorial males' spawning success relative to dominants. These results suggested that primary males, like conditional breeders, would adopt the tactic that enabled them to spawn despite the constraints of competition.     

Song repertoires in the red-winged blackbird (Agelaius phoeniceus): A test of the Beau Geste hypothesis

Song repertoires in the red-winged blackbird (Agelaius phoeniceus) were studied to test the hypothesis that song repertoires have evolved to mimic high density. Results were consistent with predictions of this hypothesis. (1) Song types within a repertoire were as variable as those sung by different males. (2) Males often switched song type when they switched perch. (3) Males with large repertoires sang at faster rates than those with small repertoires, but repertoire size did not affect bout length or bout rate. (4) Rate of habituation was a function of repertoire size. (5) Empty territories occupied by speakers broadcasting song repertoires were more successfully defended than those occupied by speakers broadcasting single song types. These results are also consistent with the hypothesis that song repertoires function to signal the status of the singer.     

Group encounters and territoriality in wild Alaotran gentle lemurs (Hapalemur griseus alaotrensis)

During a 3 month field study, 18 group encounters between four groups of Alaotran gentle lemurs (Hapalemur griseus alaotrensis) were observed in the Lake Alaotra marshland in Madagascar. Behaviors observed during group encounters are described, and quantitative data on intergroup interactions and ranging patterns are discussed in the context of territoriality. Intergroup interactions varied in their intensity, ranging from visual monitoring, scent marking, and display locomotion to penetrating the neighboring range. A quarter (27%) of the encounters were aggressive, involving chases and confrontation displays, and no affiliative interactions were observed. Both adult males and females were involved in intergroup encounters, with males playing more active roles. All encounters took place in the small overlapping areas of neighboring home ranges. The outcome of an aggressive encounter was determined by its location, with the resident group always driving out the intruding one. The Alaotran gentle lemur actively advertised and consistently defended a large area of its home range against intrusion of neighboring groups and can therefore be considered territorial. Am. J. Primatol. 46:251–258, 1998. © 1998 Wiley-Liss, Inc.     

Field playback of loud calls to gibbons (Hylobates lar): territorial,sex-specific and species-specific responses

We present the results of an experimental study of territoriality among monogamous lar gibbons (Hylobates lar), scoring vocal and movement responses to field playback of their loud calls. Playback of neighbouring groups' male-female duets on territory borders, and of these duets and music controls in territory centres, indicated a general territorial response. Responses to playback of a strange male's solo and of a strange female's solo in territory centres indicated that resident males would evict deeply intruding males and pairs but not necessarily females, and that resident females would evict deeply intruding females but probably not males or pairs. Vocal responses also implied that, although males carry the burden of routine territory defence in border disputes involving chases and special calls, the female part of the daily duet also contributes to routine exclusion of outside females. Responses of lar females to playback of the solo of a female capped gibbon (H. pileatus) suggested that the females of one species cannot sex the calls of females of the other species. This could partly account for the existence of bigamous mixed-species groups at the interface between the two species. This result also implies that female calls contribute to routine exclusion of conspecific females, and thus to the maintenance of monogamy.     

Territorial defence of space and feeding sites by a plethodontid salamander

Two series of experiments were conducted, one in field enclosures and another in the laboratory, to test the hypothesis that the salamander Desmognathus monticola (family Plethodontidae) defends its refuges and feeding sites against conspecific intruders. When two identical cover sites were provided as refuges in the laboratory, residents and intruders occupied separate cover sites significantly more often than the same sites. Residents did not, however, show strong preference for the same site, nor did they consistently defend a specific site. When food supplements were provided consistently at the same cover sites in field enclosures, resident D. monticola occupied and defended the feeding sites significantly more frequently against intruders than the non-feeding cover sites. Individuals not receiving food supplements also excluded intruders from the occupied cover sites but did not defend a specific cover site. Residents in enclosures where no food supplements were provided were significantly more active at night, outside cover sites, than residents receiving food supplements. Individual D. monticola exhibit territoriality by excluding intruders from the refuges they occupy. Providing food supplements increases the site specificity of individuals and decreases the amount of time spent in nocturnal activity.     

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

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

Interspecific territoriality in males of the tube blenny <Emphasis Type="Italic">Neoclinus bryope</Emphasis> (Actinopterygii: Chaenopsidae)

Territoriality was investigated in the tube blenny Neoclinus bryope (Actinopterygii: Chaenopsidae) at rocky intertidal areas of Banda Beach, Tateyama Bay, central Japan. Males used small holes as spawning nests, usually staying at the nest and maintaining the area while showing exclusive behaviors. Their home ranges were limited to areas within 30 cm distance from the nest for over 2 months. Four heterospecific fishes were threatened when they approached to within 6–14 cm of the nest holes, and two species of carnivorous snails were removed at points 0–30 cm from the nest entrance. There were no significant differences between the distances from the nest entrances to the points defended against fish and those used for foraging. As the four heterospecific species have similar feeding habits to those of N. bryope, the area defended against fishes may function as a foraging territory. At 24 h following the removal of nest owners, carnivorous snails had gathered to actively prey on eggs, indicating that the area defended against snails may function as a territory for protection against egg predators. Although the positions of females where males started courtship displays were significantly farther than the foraging points and the positions of threatened fishes, males displayed no territoriality against conspecific males. The fact that males did not leave the nest hole during the courtship suggests that it may be costly to maintain a courtship territory. These results show that males of tube blenny maintain territories for egg guarding and for protecting food resources around their nest holes in the spawning season.     

Resident female Northern Lapwings Vanellus vanellus fight to exclude settlement by secondary females

In systems with bi‐parental care, sexual conflict theory states that a transition from monogamy to polygyny should increase fitness prospects for males and reduce fitness prospects of resident females. Behavioural observations of Northern Lapwings Vanellus vanellus suggested that resident females try to monopolize their breeding resources by attacking females prospecting for secondary status, and males commonly respond by intervening on behalf of the prospecting females. In four territories the resident females successfully defended their monogamous status, in nine territories the resident females made at least one successful eviction before being forced to accept polygyny and in nine territories observed eviction attempts were unsuccessful. These observations indicate that mating status in Northern Lapwings is partly determined by the competitive ability of resident females.     

Aggression in harlequin frogs: male-male competition and a possible conflict of interest between the sexes

Long-term field observations and experimental manipulations were made on a population of harlequin frogs, Atelopus varius, in Costa Rica to document seasonality of intra- and intersexual aggression, determine the function of aggression, and identify the factors that influence success in aggressive encounters. Both males and females defended portions of their home range and exhibited site fidelity. Males were more aggressive towards other males during the pre-breeding and breeding seasons, whereas females were more aggressive towards other females during the post-breeding season. For up to several months prior to oviposition, males attempted to amplex (clasp) females without courtship behaviour, while females chased males from their territories and attempted to dislodge males that amplexed them. In staged encounters the winner was usually the apparent resident, regardless of body size. Frogs from a high-density population were more aggressive than individuals from a low-density population. Subadult males were as aggressive and as likely to win encounters as adult males. The function of aggression seemed to be related to the bizarre reproductives behaviour observed in these frogs. There seemed to be male-male competition for mates, as the operational sex ratio strongly favoured males, oviposition was asynchronous, and amplexus lasted for at least several weeks. Female-female aggression may have been related to defence of foraging or shelter sites, but aggression towards males was likely to be an attempt to thwart unwanted amplexus.     

Family-based winter territoriality in western bluebirds, Sialia mexicana: the structure and dynamics of winter groups

Winter residency is characteristic of the majority of cooperatively breeding birds, but the composition and dynamics of winter groups have been examined in relatively few. In 1996-1998, we examined winter territoriality in the western bluebird, a year-round resident that shows a limited degree of helping behaviour in central coastal California, U.S.A. In spring, most western bluebirds breed as socially monogamous pairs, but a small proportion of pairs (3-16%) have additional breeding-age males helping at the nest, usually assisting parents or brothers. We found that year-round residents commonly wintered in family groups that defended territories similar to those used in spring. Winter groups had an even sex ratio and formed early in the autumn, when hatch-year birds dispersed. More females than males left their natal groups to be replaced by an influx of immigrant hatch-year birds. Winter groups typically consisted of breeders and one or two sons from the prior breeding season along with one or more immigrant females. A second period of dispersal occurred in spring when winter groups broke up and most birds other than the breeding pair left the winter territory. When they bred, yearling males and females often bred with unrelated individuals from their winter groups. Sons were more likely to remain on the study area as yearlings when they wintered with both parents than when they wintered with just one parent. We suggest that young males stay the winter due to benefits of remaining in family groups on mistletoe-based winter territories. Subsequent localized dispersal of sons then leads to opportunistic kin-based interactions later in life. Copyright 2001 The Association for the Study of Animal Behaviour.     

The behaviour of male orchid bees (Apidae,Hymenoptera, Insecta) and the question of leks

The male territories of two species of orchid bees, Eulaema meriana and Euglossa imperialis, are described. These territories consist of a perch, where the males display on the trunk of a tree, and a route flown from and back to the perch. Territories are located in treefalls or other large light gaps in tropical forest. The territories of these two species differ in the height of the perch and amount of light reaching it, size of the perch tree, and period of activity. A definition of lek is given. These male euglossines form facultative leks in large treefalls. The relationships between male territories, female foraging ranges, and collection of aromatic material by males are discussed.     

Nectar and flower production of Lobelia telekii inflorescences, and their influence on territorial behaviour of the scarlet-tufted malachite sunbird (Nectarinia johnstoni)

The alpine zone of Mount Kenya is a typical equatorial, high-altitude habitat with a harsh environment, large fluctuations in physical conditions and an impoverished flora and fauna. A common flowering plant is Lobelia telekii , which has large inflorescences with up to 2000 flowers. The long hanging bracts of this plant ameliorate the physical environment around the flowers, damping the fluctuations in temperature and relative humidity. The scarlet-tufted malachite sunbird ( Nectarinia johnstoni ) is a highly active nectarivore that obtains most of its food from the nectar of L. telekii. Sunbirds are more likely to visit the younger, male flowers at the apex of the inflorescence, which are larger and contain twice as much sugar as the older, female flowers lower down the spike. Male flowers will gain from multiple visits by exporting more pollen, while female flowers probably need to be visited only a few times for successful fertilization. Male sunbirds were resident on their territories all year and vigorously defended them from conspecifics. All territories contained about four times the number of flowers visited by the territory occupants in a day. Males on territories with a large number of flowers suffered more intrusions than males on low quality territories and spent more time in flight. After an intrusion the resident male frequently fed near where the intrusion took place. Males that subsequently attracted mates defended about twice as many flowers as males that did not breed, although undefended inflorescences were present. Some males apparently defended territories suitable for a pair, others only for a single bird.