Répertoire et contextes sociaux des cris unitaires du colobe vert (procolobus verus) dans le Parc National de Taï (PNT), Côte d\'Ivoire

Pour caractériser l\'environnement social et écologique du Colobe Vert (Procolobus verus), des observations régulières par tranche de 15 minutes d\'animaux focaux dans trois groupes ont été méné. Les observations et les enregistrements de cris occasionnels (Ad libitum) ont permis de répertorier huit (8) types de cris unitaires émis par différentes classes de sexes et d\'âges. Ces cris peuvent être regroupés en quatre catégories selon les contextes sociaux dans lesquels ils interviennent : les cris a, b et c en cas de prédation et de trouble (présence de prédateur, cris d\'alarme d\'autres espèces), les cris f et g en situation de conflit (combat entre individus), les cris b, c et e en contexte de stabilité (calme apparent), et les cris b, c et e pour signaler des rencontres inter-groupes (rencontre avec d\'autres groupes de singes).In order to knod how Olive Colobus monkeys (Procolobus verus) interact with their social and ecological environment, we carried out regular observations by 15 minutes old section of focal animals in three groups. These observations associated with the recordings of occasional calls (Ad libitum) enabled us to index eight (8) types of unit calls emitted by various sex and age classes. These calls can be gathered into four types according to social contexts in which they happened : the calls a, b and c in context of predation and disturbance (presence of predator, alarm calls from other monkey species), the calls f and g in a situation of conflict (fights between individual), the calls b, c and e as a signal of stability (peaceful context), and the calls b, c and e in case of intergroup encounters (encounter with other monkey groups). Keywords: Colobe Vert, vocalisation, cri unitaire, contexte social, communication, Parc National de Taï, Côte d'Ivoire.Olive Colobus, vocalization, unit call, social context, communication, Taï National Park, Ivory Coast.Sciences & Nature Vol. 4 (2) 2007: pp. 137-14

Assessing Host-Virus Codivergence for Close Relatives of Merkel Cell Polyomavirus Infecting African Great Apes

It has long been hypothesized that polyomaviruses (PyV; family Polyomaviridae) codiverged with their animal hosts. In contrast, recent analyses suggested that codivergence may only marginally influence the evolution of PyV. We reassess this question by focusing on a single lineage of PyV infecting hominine hosts, the Merkel cell polyomavirus (MCPyV) lineage. By characterizing the genetic diversity of these viruses in seven African great ape taxa, we show that they exhibit very strong host specificity. Reconciliation analyses identify more codivergence than noncodivergence events. In addition, we find that a number of host and PyV divergence events are synchronous. Collectively, our results support codivergence as the dominant process at play during the evolution of the MCPyV lineage. More generally, our results add to the growing body of evidence suggesting an ancient and stable association of PyV and their animal hosts

Neural Correlates of Threat Perception: Neural Equivalence of Conspecific and Heterospecific Mobbing Calls Is Learned

Songbird auditory areas (i.e., CMM and NCM) are preferentially activated to playback of conspecific vocalizations relative to heterospecific and arbitrary noise [1]–[2]. Here, we asked if the neural response to auditory stimulation is not simply preferential for conspecific vocalizations but also for the information conveyed by the vocalization. Black-capped chickadees use their chick-a-dee mobbing call to recruit conspecifics and other avian species to mob perched predators [3]. Mobbing calls produced in response to smaller, higher-threat predators contain more “D” notes compared to those produced in response to larger, lower-threat predators and thus convey the degree of threat of predators [4]. We specifically asked whether the neural response varies with the degree of threat conveyed by the mobbing calls of chickadees and whether the neural response is the same for actual predator calls that correspond to the degree of threat of the chickadee mobbing calls. Our results demonstrate that, as degree of threat increases in conspecific chickadee mobbing calls, there is a corresponding increase in immediate early gene (IEG) expression in telencephalic auditory areas. We also demonstrate that as the degree of threat increases for the heterospecific predator, there is a corresponding increase in IEG expression in the auditory areas. Furthermore, there was no significant difference in the amount IEG expression between conspecific mobbing calls or heterospecific predator calls that were the same degree of threat. In a second experiment, using hand-reared chickadees without predator experience, we found more IEG expression in response to mobbing calls than corresponding predator calls, indicating that degree of threat is learned. Our results demonstrate that degree of threat corresponds to neural activity in the auditory areas and that threat can be conveyed by different species signals and that these signals must be learned

A chemically modified antibody mediates complete eradication of tumours by selective disruption of tumour blood vessels

These results reinforce the concept that vascular shutdown can induce a curative avalanche of tumour cell death. Immuno-photodynamic therapy may be particularly indicated for squamous cell carcinoma of the skin, which we show to be strongly positive for markers of angiogenesis

Down from the treetops: Red langur (Presbytis rubicunda) terrestrial behaviour

Using direct observations and camera traps at eight sites across Indonesian Borneo we show how red langurs (Presbytis rubicunda) are more terrestrial than previously believed, regularly coming to the ground. This unusual behavior has been found at six of the eight sites surveyed. We find that red langurs come to the ground more frequently in disturbed forests, specifically ones which have been impacted by logging, fire, and hunting, though more data are needed to confirm this as a direct correlation. We also found a trend towards decreased ground use with increased elevation of the habitat. When on the ground, red langurs are predominantly engaged in feeding (50% direct observations, 61% camera traps) and traveling (29% direct observations, 13% camera traps). Red langurs are found on the ground throughout the day, at similar times to activity periods of the apex predator, the Sunda clouded leopard (Neofelis diardi). We suggest that ground use by red langurs could be an adaptation to disturbed forest to exploit additional food sources and to facilitate travel

Referential labelling in Diana monkeys

Animal semantic communication has received considerable theoretical and empirical attention because of its relevance to human language; Advances have been made by studies of alarm-call behaviour in nonhumans. In monkeys, for example, there is evidence that recipients have a fairly sophisticated understanding of a call's meaning; that is, the predator type usually associated with a certain alarm call. Little is known, however, about the mental mechanisms that drive call production in nonhuman primates. In some nonprimate species, it has been found that signallers do not respond to a predator's physical features put instead seem to respond to its relative threat or direction of attack. In these species, therefore, alarm calls do not denote different predator categories but,simply reflect different types or levels of danger. Because different predator categories;typically impose-different types and degrees of threat it is entirely possible that nonhuman primates also respond to threat rather than a predator's category. This study examined how wild Diana monkeys, Cercopithecus diana, of the Tai forest, Ivory Coast, label predation events. By altering playback stimuli and the position of a concealed speaker, I investigated whether Diana monkeys respond with acoustically different alarm calls depending on a predator's (1) distance (close versus far), (2) elevation (above versus below), or (3) category (eagle versus leopard). Analysis of male and female alarm-call behaviour showed that Diana monkeys consistently responded to predator category regardless of immediate threat or direction of attack. Data further suggested that, in addition to predator category, monkeys' alarm calls might also convey information about the predator's distance. (C) 2000 The Association for the Study of Animal Behaviour.</p