Search

Species' niche depends on several ecological and evolutionary factors. Phylogenetically close species may present niche conservatism, retaining their ancestral ecological characteristics. Alternatively, in a situation of limited resources, species can differentiate themselves through changes in their ecological and morphological characteristics to reduce niche overlap, thus facilitating coexistence. In this study, we investigated the ecological niche of two phylogenetically closely related cryptobenthic reef fish species that co-occur in the southern Brazilian coast, Parablennius pilicornis and P. marmoreus. We examined possible overlap in three niche dimensions (thermal, spatial and trophic) to verify if species hold phylogenetic niche conservatism or are partitioning some niche dimension. For this, we studied their densities, microhabitat affinities and diets among four rocky reefs of southern Brazil. The two species presented differences in thermal distribution, and their abundance differed according to depth strata, but no differences were found for microhabitat preferences. They also presented a similar omnivorous diet, with crustaceans and algae as main prey types. The Pianka's niche overlap values did not differ from the values expected in the null model for thermal and depth, and it was higher than expected by chance for microhabitat and diet. Considering all the niche dimensions analysed together, the total niche overlap was greater than expected at random. These results suggest that the two species are successfully coexisting despite considerable niche overlap. Thus, their coexistence may not depend on the evolution of divergent patterns of resource use, but on the evolutionary history of the species., Author(s): Angela M. Canterle [sup.1] , Lucas T. Nunes [sup.1] , Luiz G. R. Oliveira-Santos [sup.2] , Sergio R. Floeter [sup.1] Author Affiliations: (1) grid.411237.2, 0000 0001 2188 7235, Marine [...]

ABSTRACT.--The purpose of this study was to assess how bird communities are grouped in vegetation types between the breeding and non-breeding seasons in two consecutive years as well as the [...]

We investigated if there are aspects of perches that are more attractive for hummingbirds, such as perch height, diameter, and distance from a food patch. The study was conducted in a fragment of Atlantic Forest of the Itacolomi State Park, in Minas Gerais, Brazil, with artificial feeders simulating a rich food patch. Characteristics of perches used by the recorded hummingbirds, such as height, diameter and distance from the food patch, were measured. From the six hummingbird species recorded visiting the artificial feeders, two preferentially used perches with certain characteristics: Thalurania glaucopis used more perches at a height of 0.51-1.0 m (intermediary high), and Leucochloris albicollis used more perches located 1.1-2.0 m distance from the food patch. T. glaucopis was territorial and defended the food patch; L. albicollis was subordinate and did not defend the food patch. The other species seemed to use perches randomly. Our results suggest that hummingbirds used perches according to their social status. Territorial species use perches primarily as platforms for defense and observation of the territory, as well as places of rest between feeding events; subordinate species use perches mainly as resting places during feeding bouts in the absence of the dominant species. Received 29 June 2015. Accepted 28 November 2015. Key words: perch diameter, perch distance, perch height, Trochilidae., Hummingbirds have the highest rates of aerobic metabolism among vertebrates during flight (Suarez et al. 1990). These birds must constantly balance high-energy expenditure with their rate of energy consumption. Perches [...]

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. Key words: territorial behaviour, territoriality, aggression, nose tapping, Eastern Red-backed Salamander, Plethodon cinereus, geographic variation, body size, agonistic encounter, threat displays. Le comportement territorial consiste en l'utilisation de l'agressivite et de l'annonce pour defendre une zone fixe. Si, chez la salamandre cendree (Plethodon cinereus (Green, 1818)), la territorialite prevaut en Virginie (E.-U.), pres de la limite meridionale de l'aire de repartition, peu d'etudes ont tente de determiner si les populations septentrionales presentent un comportement territorial. Nous avons verifie la presence de certaines conditions prealables au comportement territorial chez P. cinereus a la limite septentrionale de son aire, pres de North Bay, Ontario (Canada). Dans des essais en laboratoire, nous avons constate que les P. cinereus adultes males presentaient un faible degre d'agressivite, et les salamandres intruses dans l'enceinte experimentale tentaient de s'en echapper plus souvent que les individus residents. Nous avons egalement constate que les P. cinereus etaient capables de distinguer les substrats qui leur etaient familiers d'autres substrats, ce qui pourrait indiquer une communication pherormonale et la possibilite d'annoncer la presence du territoire. Cependant, si les couples male-femelle etaient repandus en six sites d'echantillonnage durant la saison des amours, les salamandres adultes presentaient uniformement une repartition spatiale aleatoire en dehors de cette saison. Notre etude donne a penser que, si les P. cinereus locaux presentent un faible degre d'agressivite, ils pourraient ne pas defendre de zones fixes. Il est possible que le comportement territorial dans des climats frais ne presente generalement pas d'avantages pour P. cinereus, puisque les taux d'evapotranspiration y sont plus faibles et l'activite d'approvisionnement moins restreinte par rapport aux climats plus meridionaux. [Traduit par la Redaction] Mots-cles : comportement territorial, territorialite, agressivite, tapement du museau, salamandre cendree, Plethodon cinereus, variation geographique, taille du corps, rencontre agonistique, attitudes menacantes., Introduction Territoriality is the use of overt aggression and advertisement in the defense of a fixed area that becomes exclusive with respect to intruders (Brown and Orians 1970). While territoriality [...]

Ecological theory predicts that generalist predators should damp or suppress long-term periodic fluctuations (cycles) in their prey populations and depress their average densities. However, the magnitude of these impacts is likely to vary depending on the availability of alternative prey species and the nature of ecological mechanisms driving the prey cycles. These multispecies effects can be modeled explicitly if parameterized functions relating prey consumption to prey abundance, and realistic population dynamical models for the prey, are available. These requirements are met by the interaction between the Hen Harrier (Circus cyaneus) and three of its prey species in the United Kingdom, the Meadow Pipit (Anthus pratensis), the field vole (Microtus agrestis), and the Red Grouse (Lagopus lagopus scoticus). We used this system to investigate how the availability of alternative prey and the way in which prey dynamics are modeled might affect the behavior of simple trophic networks. We generated cycles in one of the prey species (Red Grouse) in three different ways: through (1) the interaction between grouse density and macroparasites, (2) the interaction between grouse density and male grouse aggressiveness, and (3) a generic, delayed density-dependent mechanism. Our results confirm that generalist predation can damp or suppress grouse cycles, but only when the densities of alternative prey are low. They also demonstrate that diametrically opposite indirect effects between pairs of prey species can occur together in simple systems. In this case, pipits and grouse are apparent competitors, whereas voles and grouse are apparent facilitators. Finally, we found that the quantitative impacts of the predator on prey density differed among the three models of prey dynamics, and these differences were robust to uncertainty in parameter estimation and environmental stochasticity. Key words: aggregative response; birds of prey; Circus cyaneus; host-parasite; intrinsic population cycles; Monte Carlo Markov chain; multispecies functional response; parameter uncertainty; predator-prey model; prey-switching; stochasticity; territoriality.

We investigated territoriality, prospecting, and dispersal behavior in cooperatively breeding Pohnpei Micronesian Kingfishers (Todiramphus cinnamominus reichenbachii) throughout the annual cycle using radiotelemetry and color-band resights. Mean home-range size was 6.3 ha and territories were 8.1 ha. Within territories, Micronesian Kingfishers shared 63% of their home-range space with coterritorial occupants, and 3% was shared with extraterritorial conspecifics. Birds on cooperative territories had larger home ranges that overlapped more with coterritory occupants' home ranges than birds in pair-held territories. Despite evidence suggesting that resources necessary for survival and reproduction occurred on each territory, Micronesian Kingfishers of all age and sex classes made extraterritorial prospecting movements. Prospecting was rare; it comprised only 4.3% of our observations. When birds departed on forays, they were gone for ~1.9 h and returned to home territories before sunset. Prospecting by dominant birds was temporally correlated with courtship and nest initiation, and birds were observed at neighboring nest sites with opposite-sex conspecifics during the period when females were available for fertilization. Juveniles and helpers prospected throughout the year and made repeated homesteading movements to dispersal destinations before dispersing. Mean dispersal distance for radiomarked individuals was 849 m. Results suggest that prospecting in Micronesian Kingfishers is a complex behavior that provides information for dispersal decisions and familiarity with dispersal destinations. Additionally, extraterritorial movements may provide covert opportunities for reproduction, which have potential to profoundly influence the distribution of fitness among helper and dominant Micronesian Kingfishers. Received 29 August 2005, accepted 14 March 2006. Key words: Caroline Islands, dispersal, foray, Halcyon cinnamomina, homesteading, Micronesia, prospecting, Todiramphus cinnamominus. RESUME.--Au cours du cycle annuel, nous avons etudie la territorialite, la prospection et le comportement de dispersion chez des Martins-chasseurs cannelle (Todiramphus cinnamominus reichenbachii) cooperant pour la reproduction. Pour ce faire, la telemetrie et la re-observation d'oiseaux marques de bagues colorees ont ete utilises. Le domaine vital moyen s'etendait sur 6,3 ha et les territoires, sur 8,1 ha. Les martins-chasseurs partageaient 63% de leur domaine vital avec les autres occupants du territoire et 3% avec leurs congeneres extraterritoriaux. Les oiseaux occupant des territoires en cooperation avaient des domaines vitaux plus grands qui chevauchaient davantage celui des autres occupants du territoire que les couples d'oiseaux occupant seuls le territoire. Malgre des signes evidents suggerant la presence des ressources necessaires a la survie et la reproduction dans chaque territoire, les martins-chasseurs des deux sexes et de toutes les classes d'age ont effectue des deplacements extraterritoriaux de prospection. La prospection etait rare, comptant seulement pour 4,3% de nos observations. Lorsque les oiseaux partaient pour une incursion, ils s'absentaient pendant ?1,9 h et revenaient dans leurs territoires avant le coucher du soleil. La prospection par les oiseaux dominants etait correlee dans le temps avec la parade nuptiale et l'initiation des nids. Ces oiseaux etaient observes des sites de nidification voisins en compagnie de congeneres du sexe oppose pendant la periode oh les femelles pouvaient etre fertilisees. Les juveniles et les aides au nid prospectaient tout au long de l'annee. Ils ont effectue des deplacements repetes vers des destinations de dispersion avant la dispersion elle-meme. La distance moyenne de dispersion chez les individus munis d'emetteurs etait de 849 m. Les resultats suggerent que la prospection chez les Martins-chasseurs cannelle est un comportement complexe qui les informe dans leur decisions de dispersion et leur permet de se familiariser avec les destinations de dispersion. De plus, les mouvements extraterritoriaux peuvent fournir des opportunites clandestines pour la reproduction, lesquelles ont le potentiel d'influencer profondement la distribution du fitness parmi les martins-chasseurs dominants et les aides au nid.

The marine otter (Lontra felina) is a little-known South American otter of conservation concern. We report the 1st detailed information on its activity patterns, home ranges, core areas, and territoriality from 6 otters radio-tracked near a fishing village in central Chile. Marine otters were solitary; females exhibited intrasexual territoriality, but there was no territoriality between males or between sexes. Home ranges were [less than or equal to]4,134 m long and < 110 m wide, and range size did not differ between sexes. Marine otters spent 81% of their time on land, mostly resting, with no preference for day or night. Hence, core areas were associated with resting places and dens. Otters concentrated their activity in the littoral zone associated with refuges on land and with fishing waste, which was used as a food resource. Availability of land refuges, combined with their proximity to food resources, could be a decisive factor influencing the distribution of L. felina. Key words: fishery waste, home range, land refuges, Lontra felina, marine otter, territoriality

Least blossom bats, Macroglossus minimus (Pteropodidae), were monitored by radiotelemetry in lowland rainforest for up to 22 days in Kau Wildlife Area, Madang Province, Papua New Guinea. Based on 1,502 radiotelemetry positions, mean home range for 18 individuals was 5.8 ha [+ or -] 4.6 SD, and mean core-use area was 1.5 [+ or -] 1.3 ha. The mean long axis of the home ranges was 495 [+ or -] 258 m. Activity hotspots were associated with flowering bananas, the primary food resource of least blossom bats at Kau. During the day, M. minimus roosted singly in subcanopy or canopy foliage and showed fidelity to a day-roost area. Mean day-roost area was 0.5 [+ or -] 0.4 ha. Adult males appeared to exclude conspecifics from rich, compact feeding territories in primary forest. Overlap in home range occurred primarily in gardens and between subadults and other bats. Key words: core-use area, day-roost area, Musa, radiotelemetry

The male stripe-backed wren, Camphylorhynchus nuchalis, learns repertoires of stereotyped calls, known as WAY calls, from older male relatives. Such vocalizations are usually specific to patrilineal family groups. Playback experiments were used to determine whether the species can recognize the calls of different family groups. They were found to discriminate between the calls of unrelated neighbouring groups and unfamiliar groups, although they did not distinguish calls of males in other groups from calls of their own groups, when the males were from the same patriline.

A natural territorial advantage associated with small size is reported for the first time, in males of the aposematic nymphalid butterfly Heliconius sara in subtropical Brazilian forest. Their wings are around 3% shorter that males caught away from mating territories. Smaller resident returned to territories over longer periods and it was observed that intruders will retreat faster when confronting smaller than average territory owners.

A new study investigates whether the behaviour of male territorial nightingales is influenced by either of two asymmetrically interacting rivals simulated by recordings in which one male overlaps the song of another. The results show that nightingales show more intense response near the song of the overlapper rather than the overlapped, and also suggests that information on rivals' behaviour may be used by individuals to decide which strategies to choose in possible interactions with other songsters.

It is widely believed that monogamy in mammals has evolved because males are unable to defend more than one, widely dispersed, female range. A new study investigates the theory in the monogamous antelope Kirk's dik-dik. The study shows substantial variations in territory quality and finds no link between reproductive success and territory size. It is concluded that female dispersion does not influence monogamy and that monogamy may have evolved because of male mate guarding.

There have been few studies to show the effect of forest fragmentation on the activities of forest bird species. A new study investigates the effect of forest fragmentation on five territorial passerine species. White-throated sparrows, golden-crowned kinglets, black-throated green warblers, Swainson's thrush and dark-eyed junco were observed to study their behavioural responses to treeless gaps in a mature forest in Quebec. It is shown that the size of the gap crossing influences the behaviour of forest birds, with forest specialists less likely than forest generalists to defend territories across gaps.

A new study investigates the local movements of common loons to assess the frequency, ecological causes and timing of multiple-lake usage. The investigation of color-marked birds in Northern Wisconsin and the Upper Peninsula of Michigan shows five different classes of multi-lake usage: territorial defensive movement, long-distance movement by young birds, post-reproductive wandering, pre-breeding territory shifts and dispersal of displaced breeders. It is suggested that a management strategy that preserves only the lakes on which loons nest may not ensure successful nesting.

The trait for male and female lions to declare their territory by roaring has been used in a study designed to assess group territoriality in two populations African lions. Lionesses in the Serengeti region of Tanzania use the number of opponents they hear roaring to assess the likelihood of winning a territory contest in order to avoid unwinnable disputes. A comparison, using playback experiments, between the lionesses of the Serengeti and their counterparts in the Ngorongoro Crater, living at much higher densities, shows that lionesses in the latter group are more aggressive than those on the plain, probably due to the greater difficulty in holding territory.

A study to find if adult female diana monkeys (Cercopithecus diana) are involved in territorial calling bouts and to examine the link between male and female calling patterns, involved data collection in an 18-month field analysis in Sierra Leone. Territorial calling bouts and inter-group encounters involved female chatter-scream vocalizations. Female calls have a territorial role.

Paternity in slender mongooses (Herpestes sanguineus) is not dominated by any one association member. Intimate links between members is possible. These association of males are coalitions that deny other males access to females inside a shared territory.

Red-capped cardinals are able to identify immediately an interloper that has just been expelled from a contiguous territory due to the distinct behavioral motifs accompanying the expulsion. Interlopers from a non-adjacent territory have a greater chance of escaping immediate defection. Consequently, interlopers evicted from one territory avoid the contiguous regions in preference for distant ones.

Territorial animals often exhibit relatively lower levels of aggression toward familiar territorial neighbors than toward strangers. Habituation to a neighbor or its communication signals has been proposed to account for this reduced aggression between adjacent territorial neighbors. The authors asked whether discrimination between neighbors and strangers by territorial male bullfrogs (Rana catesbeiana) could result from habituation of the aggressive response to repeated presentations of the acoustic communication signals of a simulated new neighbor calling from an adjacent territory. In 3 field playback experiments, the authors found evidence for 5 response characteristics that operationally define habituation. Moreover, aggressive response decrements persisted between nights of chorusing and were specific to an individually distinct property of male advertisement calls. The authors suggest that reduced aggression between neighboring territorial male bullfrogs could result from long-term, stimulus-specific habituation to the advertisement calls of a new neighbor.