Observations sur la socio-écologie du mandrill

Six months were spent in Gabon tracking troops of Mandrills (Mandrillus sphinx) in 1973 and 1974. During two survey-periods of three months each about 2,000 kilometers were covered by foot in the forest and 6,000 by road. Contacts were only established 39 times, totalling 48 hours of actual observation time. Mandrills and drills never occur together in the same areas. Mandrills were always found to live in the lower forest layers, large adult males at the ground level, smaller females and juveniles in the undergrowth and the middle layer. Large rivers cannot be crossed by mandrills, these forest baboons being unable to swimm. The basic social unit is made of a large adult male (one for 25 individuals on average), 5 to 10 females (with or without infants) and about 10 juveniles. During the dry season, as many as 6 or 7 such harems might associate together, forming troops of 200 individuals or more. Excess adult males live a solitary existence in the forest. Mandrill troops have a very wide home range, in the order of tens of square kilometers. The average speed of movement of a group during the day was found to be 1.32 km/h, and the average distance covered 8 km per day. The diet is very varied, mostly vegetarian with possibly a small animal component. Breeding is apparently seasonal, most births occuring from January to April. Besides man, major predators include leopards and the Crowned hawk-eagle ( Stephanoetus coronatus). Temporary associations with duikers (Cephalophus callypigus) and calaos (Tropicranus albocristatus ) have been observed. Three types of vocalizations were distinguished : a contact call emitted mainly by females and juveniles, an alarm call used by females and subadults, and a rallying call emitted by the leader male. Olfactory marking by the secretion of the sternal glands is performed on tree trunks. When the troop is quietly foraging juvenile and subadult individuals tend to stay in front and around the females, the leader male staying to the rear. When frightened, the adult male leads the troop, followed by the females and the younger individuals. In the rain forest Mandrills exploit the less productive layers, at the ground level or in the undergrowth. Their social structure and the large size of their home range may be considered as adaptive to this poor environment

Foraging strategy of Wandering Albatrosses through the breeding season : a study using satellite telemetry

Satellite telemetry of Wandering Albatrosses (Diomedea exulans) breeding on the Crozet Islands, southwestern Indian Ocean, revealed two distinct foraging strategies during successive stages of the breeding season: systematic foraging over extensive distances; and use of specific areas close to the colony. During early incubation, Wandering Albatrosses foraged over pelagic waters at an average range of 1,284 kin. The length of the foraging trips decreased towards the end of the incubation period. During the first month of chick rearing when parents brood alternately for short periods, the foraging range, distance covered, and area prospected were further reduced. Males tended to return to an individual foraging area, located at the edge of the continental shelf, that had previously been visited during the long trips of the incubation period. Females mostly prospected pelagic waters just off the shelf. After the chick had been left alone on the nest, birds exhibited a two-fold strategy, combining long foraging trips over pelagic waters with short trips over the shelf. Generally, both sexes headed for and foraged over an extensive pelagic sector. Some males also foraged over the Kerguelen shelf. Females tended to forage over more northerly waters than males. The duration of the foraging trips was most closely related to the total distance covered, but also to the maximum range during the long trips of the chick-rearing period and to a lesser extent during the incubation period. There were no such significant relationships in the case of short trips. During long pelagic foraging trips, the birds had a looping course that was determined by the wind direction, suggesting random foraging with respect to prey distribution. We were able to show that Wandering Albatrosses use two foraging strategies to cope with the constraints imposed by the different stages of the breeding cycle, the availability of prey, and the distribution of the prey. Use by Wandering Albatrosses of two foraging strategies may be a compromise based on the simultaneous need to satisfy the different food requirements of chicks and parents

Quelques expériences de comestibilité de lépidoptères gabonais faites avec le mandrill, le cercocèbe a joues grises et le garde-bœufs

Un entomologiste et un éthologiste se sont livrés à une série d’expériences de comestibilité au Gabon. Il s’agissait de tester des lépidoptères africains sur des primates (Cercocebus albigena et Mandrillus sphinx) et des oiseaux (Bubulcus ibis) maintenus en captivité à proximité des lieux de récolte. Les proies étaient présentées soit séparément et vivantes (800 papillons), soit fraîchement tuées et disposées sur un plateau au milieu d’autres (500 papillons). Les réactions du prédateur étaient évaluées suivant une échelle graduée des comportements. Le lot de quatre man drills comprenait un sujet naïf, un sujet sauvage et deux sujets captifs depuis quelques mois : nous avons suivi l’évolution de leur choix en fonction de leur expérience antérieure. Bien que cette expérimentation n’ait pas été conduite systé matiquement et se veuille avant tout une investigation préliminaire, un certain nombre de faits sont apparus comme probables : — les espèces de singes et d’oiseaux testés semblent manger dans la nature des papillons, même nocturnes; — les primates, sous la pression du milieu, modifieraient leur comportement alimentaire beaucoup plus facilement que les oiseaux et cela, même à l’état adulte ; — les primates supérieurs comme les mandrills et les cercocèbes font preuve d’un comportement prédateur plus complexe et moins stéréotypé que celui des Lémuriens, par exemple ; — les proies considérées comme non-comestibles se répartissent en réalité en une majorité de moyennement comestibles et une minorité de non-comestibles vrais ; •— les prédateurs sont d’autant plus précis dans leur choix, qu’ils sont plus expérimentés, mais le « stress » dû à l’ingestion d’une espèce vraiment non-comestible affine brusquement — ou fait apparaître — la sélectivité et les techniques de gustation ; l’ingestion d’un non-comestible amène le prédateur à une généralisation qui est à la base même des phénomènes de mimétisme. Cette généralisation est d’autant plus étendue que l’expérience a été plus désagréable. L’étendue de la générali sation varie aussi suivant les individus. Les espèces voisines du modèle non-comestible, ou même l’autre sexe, constituent des mimes moins spectaculaires, mais tout aussi protégés que ceux mis en évidence dans les séries mimétiques.Some preliminary experiments were made with Mandrills, a Grey-cheeked Mangabey and Cattle egrets in the Gabon, to determine the palatability of native butterflies and moths. The monkey predators were kept individually in large cages and prey were offered to them on trays. The serial order of selection of each individual prey and the reactions of each predator were noted. A similar testing procedure was used for cattle egrets. Among the four mandrills tested certain behavioural differences were noted between a subadult male bred in captivity though without any previous experience with insects, two other mandrills kept captive for some months, and a wild adult female freshly caught for the experiment. At first the naive male indiscriminately accepted all butterflies and moths presented to him. However the consumption of but one member of a « distasteful» species ( Anaphe sp. $ ) made him immediately more cautious in his choice ; any other prey offered from then on, was individually examined before being eaten. Moths resembling the distasteful Anaphe female were subsequently avoided. All the other monkeys with previous field experience were, from the start, highly selective in their choices and never accepted distasteful species. The degree of generalization appea red to covary inversely according to the degree of previous field experience of the individual predator. The choices of the two wild cattle-egrets were also well established from the start and never varied during the experiments. Therefore it appears that local butterflies and moths are familiar to these three predator species which probably learn gradually those which are palatable and those which are not

Socio-écologie du Skua antarctique a Pointe Géologie

Le statut taxonomique du Skua est discuté. La distribution géographique circum-antarc tique de l’espèce, sa taille plus petite que celle des autres Skuas, sa coloration plus claire, sa voix beau coup plus aiguë et la quasi-absence d’hybridation nous paraissent bien confirmer une place à part. Les données de terrain et celles obtenues à partir du fichier de baguage, qui couvre aujourd’hui 15 années, permettent de préciser certains aspects de la biologie de cette espèce : migration, dimorphisme sexuel, longévité, fidélité au nid et au partenaire, ainsi que leur valeur de survie. Les Skuas sont des oiseaux opportunistes par exellence puis qu’ils sont à la fois pêcheurs, rapaces et charognards. C’est ce dernier aspect qui est à l’origine de l’expérience naturelle qui a été réalisée involontairement sur la population de Pointe Géologie. Au cours des vingt dernières années, les déchets de la base française de Terre Adélie ont constitué un apport de nourriture qui a provoqué un essor de la population de Skuas de l’archipel. La population globale a quadruplé (80 en 1964 à 320 en 1977), le nombre de couples reproducteurs a presque doublé de l’été austral 1964/1965 à celui de 1976/1977. En conséquence, la distance entre les nids est tombée de 110 mètres en 1965 à 65 mètres en 1976. La fécondité est passée de 44 œufs pondus en 1965/1966 à 63 en 1976/1977. Par contre, la mortalité au stade des œufs a aug menté de 18 % en 12 ans. Cette relation entre densité et mortalité explique que le nombre de poussins à l’envol s’est maintenu de 1964/1965 à 1976/1977. La ponte qui est de deux œufs a toujours étonné les auteurs antérieurs qui se demandaient pourquoi un seul poussin par nid arrive généralement à s’envoler. Or, en pleine période d’expansion de la population (1965/1966) les deux poussins achevaient généralement leur croissance (9 sur 10) alors qu’actuellement et à nouveau, seul un poussin survit par nid. De plus les Skuas qui, il y a 10 ans, étaient constamment vus en train d’attaquer les poussins de Manchots Adélie ne le font plus qu’exceptionnel lement aujourd’hui. Il semble que lors de l’installation de la base, la population de Skuas de Pointe Géologie ait été en équilibre avec les res sources naturelles. L’apport de la décharge a permis un accroissement rapide de la population et a mis en évidence la signification biologique de l’existence d’un deuxième poussin qui n’arrivait pas à survivre. La population reproductrice suivit avec quelque retard la po pulation globale par suite du facteur limitant qu’a dû devenir la surface des îlots rocheux. La source principale d’alimentation n’étant plus le Manchot Adélie, le cycle reproducteur du Skua s’est complètement désynchronisé de celui-ci (des pontes de remplacement apparaissent maintenant un mois et demi après les dernières observées il y a une dizaine d’années). Aujourd’hui, la population de Skuas semble à nouveau en équilibre avec les ressources alimentaires, aussi bien naturelles qu’artificielles, aussi est-il rare de voir survivre le deuxième poussin.The breeding colony of Antarctic skuas Stercorarius mac- cormicki of Pointe Géologie, Adélie Land, has been studied since 1965. The number of birds present at the colony site increased from 80-90 in 1965/66 to 320 in 1976/77, and the number of breeding pairs from 29 to 40 during this period. In the same time interval, the average distance between nests was reduced from 110 to 65 m. The stability of the pair-bond is shown to be advantageous in Antarctic skuas. Breeding is higher in long-established pairs (Table I). The yearly production of eggs by the breeding birds increased from 44 in 1965/66 to 63 in 1976/77. However, the mortality rate of eggs increased in the same time period from 31 % to 48.6 %. The number of fledglings consequently remained more or less constant, ranging from 26 to 33 depending upon the year. This spectacular increase in the number of breeding pairs and in their fecundity apparently results from an artificial increase in the carrying capacity of the habitat. The establishment of a garbage dump close to the buildings of the French Antarctic base led to a progressive change in the food habits of the Antarctic skuas. Whereas these “ opportunistic ” birds originally preyed upon Adélie penguins’ eggs, chicks and carcases, they quickly began to feed exclusively upon human garbage. The use of this new permanent food source led to a rapid increase in the local population between 1970 and 1972. This population is now levelling off, having apparently reached a new equilibrium with the available resources. During the stage of exponential increase, most pairs successfully raised two chicks instead of one ; this is no longer the case now. The adaptation to a new food source has also changed the timing of the breeding season of the Antarctic skua. Instead of being closely synchronised with the breeding season of the sympa- tric Adélie penguins, the laying of Antarctic skua eggs now tends to be spread upon a much longer time period. Whereas the longest time interval between the first- and the last-laid eggs was 14 days in 1964/65, it reached 58 days in 1976-77

Ornamental colors reveal age in the king penguin

We investigated whether delayed plumage maturation occurred in king penguins (Aptenodytes patagonicus). Therefore we examined the relationships between age and sex on spectral properties and size of two colored plumage patches and a UV-reflective beak spot, using known-age cohorts. Unlike the colored patch on the breast, we found age differences in ear and beak coloration. These results suggest that head ornaments in king penguins could signal sexual maturity or social status. No sex differences were found in the intensity of colored ornaments, which can result from mutual mate choice or genetic correlation between sexes. Size of colored patches did not relate to age or sex

Transcriptome analysis in non-model species: a new method for the analysis of heterologous hybridization on microarrays

Background: Recent developments in high-throughput methods of analyzing transcriptomic profiles are promising for many areas of biology, including ecophysiology. However, although commercial microarrays are available for most common laboratory models, transcriptome analysis in non-traditional model species still remains a challenge. Indeed, the signal resulting from heterologous hybridization is low and difficult to interpret because of the weak complementarity between probe and target sequences, especially when no microarray dedicated to a genetically close species is available. Results: We show here that transcriptome analysis in a species genetically distant from laboratory models is made possible by using MAXRS, a new method of analyzing heterologous hybridization on microarrays. This method takes advantage of the design of several commercial microarrays, with different probes targeting the same transcript. To illustrate and test this method, we analyzed the transcriptome of king penguin pectoralis muscle hybridized to Affymetrix chicken microarrays, two organisms separated by an evolutionary distance of approximately 100 million years. The differential gene expression observed between different physiological situations computed by MAXRS was confirmed by real-time PCR on 10 genes out of 11 tested. Conclusions: MAXRS appears to be an appropriate method for gene expression analysis under heterologous hybridization conditions

Detection of Avian Malaria Infections in Wild and Captive Penguins

Forster, 1781) were tested by enzyme-linked immunosorbent assays for the presence of avian malaria antibodies (Ab). Plasmodiurn falciparum sporozoite (R32tet32) and gametocyte (P.F.R27) antigens were used. Specificity of anti-5". demersus, anti-duck, anti-chicken, and anti-turkey IgG labeled with alkaline phosphatase was determined for homologous and heterologous sera of 8 avian species (including 6 penguin species). The penguin conjugate was the most specific for the various penguin species immunoglobulins. It was possible to detect penguin immunoglobulins at a dilution of 10~4•". The relative binding of anti-S. demersus IgG was equal to relative binding of commercial conjugates. Kinetic profiles and overall magnitudes of malarial Ab detected by the 2 antigens were not significantly different. Antarctic P. adeliae were negative for malarial Ab, all New Zealand M. antipodes were positive, and the positivity prevalence of the remaining penguins ranged from 33 to 92%. Antibody titers and the prevalence of infection of wild S. demersus were significantly lower than those reported for captive North American S. demersus