Cleaner Wrasses Keep Track of the ‘When’ and ‘What’ in a Foraging Task1

In recent years evidence has accumulated that at least some animals can remember the ‘what’, ‘where’ and ‘when’ of personal experiences. Currently, evidence for such ability is taxonomically restricted to birds and mammals. Here, we demonstrate for the first time that cleaner wrasses Labroides dimidiatus are able to remember when they interacted with what after a single event. In nature, cleaners remove ectoparasites from other reef fishes, so‐called clients. Clients are depleted, non‐stationary food patches at the end of an interaction and replenished only after a delay. In our experiments, we presented twelve cleaners every 2.5 min, a choice between two of a total of four plates with different colours and patterns. One plate was always accessible but contained a non‐preferred food item while the other three contained a preferred food item, but allowed a next feeding event only after 5, 10 or 15 min. Thus, to maximise food intake, cleaners had to remember for each choice when they had last interacted with which plate. When confronted with two plates offering preferred food, cleaners showed an overall significant preference for the plate that allowed access during the trial. For six cleaners, the preference was significant. Also, on trials involving the always accessible plate, cleaners discriminated between trials in which they had to eat the non‐preferred food and trials on which they could eat the preferred food. In conclusion, cleaners are able to track the ‘when’ and ‘what’ (or possibly ‘who’) within a biologically meaningful time period.     

Flexibility in Food Extraction Techniques in Urban Free-Ranging Bonnet Macaques,Macaca radiata

Non-human primate populations, other than responding appropriately to naturally occurring challenges, also need to cope with anthropogenic factors such as environmental pollution, resource depletion, and habitat destruction. Populations and individuals are likely to show considerable variations in food extraction abilities, with some populations and individuals more efficient than others at exploiting a set of resources. In this study, we examined among urban free-ranging bonnet macaques, Macaca radiata (a) local differences in food extraction abilities, (b) between-individual variation and within-individual consistency in problem-solving success and the underlying problem-solving characteristics, and (c) behavioral patterns associated with higher efficiency in food extraction. When presented with novel food extraction tasks, the urban macaques having more frequent exposure to novel physical objects in their surroundings, extracted food material from PET bottles and also solved another food extraction task (i.e., extracting an orange from a wire mesh box), more often than those living under more natural conditions. Adults solved the tasks more frequently than juveniles, and females more frequently than males. Both solution-technique and problem-solving characteristics varied across individuals but remained consistent within each individual across the successive presentations of PET bottles. The macaques that solved the tasks showed lesser within-individual variation in their food extraction behavior as compared to those that failed to solve the tasks. A few macaques appropriately modified their problem-solving behavior in accordance with the task requirements and solved the modified versions of the tasks without trial-and-error learning. These observations are ecologically relevant – they demonstrate considerable local differences in food extraction abilities, between-individual variation and within-individual consistency in food extraction techniques among free-ranging bonnet macaques, possibly affecting the species’ local adaptability and resilience to environmental changes.     

BREEDING OF THE WHITE-BACKED AND RÜPPELL'S GRIFFON VULTURES, GYPS AFRICANUS AND G. RUEPPELLII

The breeding season of two species of griffon vultures are described. Rüppell's Griffon Vulture lays 2–3 months earlier than the White-backed Griffon. Young birds were hand-reared to determine their food requirements during growth; these estimates were combined with the food requirements of adult birds to make an estimate of the amount of food a parent bird needs to obtain when it is rearing young. The amount of food actually obtained by a group of birds was recorded from the size of the crops of birds returning to the breeding colony in the afternoon. The comparison of the estimates of the food obtained and the food required through the breeding season suggested that there may be a period during rearing when there was insufficient food available to satisfy the food requirements of both chick and adult. Chicks were found to have a very high survival rate and were probably receiving sufficient food. Presumably adult birds were not therefore receiving sufficient food, and the examination of a sample of adult birds for body condition through the breeding season showed a clear decline in their fat deposits. It was considered that in both species, breeding was timed so that the young left the nest at a period in the year when food conditions were good and the young birds could feed with little competition from adults. The parent birds therefore had to rear young during a season in the year when food conditions were not always adequate and they had to rely on utilising fat reserves. The food conditions for vultures during this study were probably favourable and during years of food shortage breeding may become impossible, or restricted to the most aggressive and dominant individuals.     

Experimental assessment of problem solving by <Emphasis Type="Italic">Milvago chimango </Emphasis>(Aves: Falconiformes)

We report a preliminary assessment of problem solving as an estimate of behavioural innovation and learning ability of a generalist and abundant raptor, Milvago chimango, under controlled conditions in aviaries. Experimental tests consisted in presentation of a Plexiglas box with four lids leading to isolated pieces of meat. We recorded time to first contact with the box and time from this first contact to gaining access to the pieces of meat. We recorded the number of attempts to open the box and reach the first portion of meat, and the total number of lids opened by each individual during five successive daily sessions. We found that individuals of M. chimango quickly approached and made contact with the Plexiglas box, and responded successfully to the novel feeding problem of reaching the food inside. In our study, performance of individuals was enhanced after solution of the novel task for the first time, as indicated by the progressively reduced time taken to access the food. Further, some individuals gained access to an increasing number of sections of the Plexiglas box during subsequent sessions, suggesting significant learning ability. Our results indicated M. chimango has a remarkable ability to obtain food in a novel situation, an observation that agrees with anecdotal reports of opening of receptacles to obtain food in urban environments. The results support the idea of behavioural plasticity in this species.     

Response to novel food in infant chimpanzees: Do infants refer to mothers before ingesting food on their own?

We investigated infant response toward novel food in captive chimpanzees under the condition in which they can explore such items freely together with their mother. Infants first approached novel foods rather than familiar ones when presented simultaneously. However, they did not ingest novel food immediately, but always sniff-licked it first. Infants tended to pay attention to their mothers before mouthing or ingesting novel foods themselves, but never did so with familiar ones. In response to the infant's activity, mother chimpanzees were tolerant rather than actively interfering. Those results imply that chimpanzee infants respond to novel foods in a neophobic way and refer to their mother for some kind of cue before attempting to ingest them.     

Evaluation of respiration parameters in a few generations and clones of <Emphasis Type="Italic">Simocephalus vetulus</Emphasis> (Crustacea,Cladocera) under controlled conditions

Cladocera use their thoracic filter limbs, animated by rhythmic and persistent movements, for food collecting and gas exchanges. Several researches have been performed on Daphnia magna in natural environments and in laboratory to identify the adaptations developed toward a decrease or a lack in oxygen. However, no experiment was performed on cladocerans living exclusively in littoral areas, which need efficient adaptations to survive an always changing environment especially regarding oxygen concentration. These changes require from organisms that they spend additional energy in order to satisfy their need in oxygen. The present laboratory experiments were based on a typical inhabitant of littoral areas, Simocephalus vetulus, and on individuals which came directly from natural environments. Respiration rate and NADH fluorescence in filter limb muscles, as a marker of tissue oxygenation, were analysed on 20 families distributed over five generations, all acclimated and cultured under constant food supply conditions. The results underlined differences among generations especially due to body dimensions, and consequently to filter dimensions. As opposed to our former hypothesis, small and young individuals appeared to be more active and thus display a more efficient respiration than big and old Simocephalus.     

Patterns in foraging and nesting ecology in the neotropical ant, <Emphasis Type="Italic">Gnamptogenys moelleri</Emphasis> (Formicidae,Ponerinae)

Summary This study provides quantitative field data on the natural history and foraging behaviour of the Neotropical bromeliad-nesting ant Gnamptogenys moelleri (Ponerinae) in a sandy plain forest in Southeast Brazil. The ant nested on different bromeliad species and the nests were more frequently found in bigger bromeliads. The species used a wide array of invertebrates in its diet, hunting for live prey and scavenging the majority of the items from dead animals. The food items varied greatly in size (1 to 26 mm). Hunting was always performed by solitary workers. Retrieving was performed by solitary workers (small items), or by a group of 3 to 12 workers recruited to the food source (large items). Almost all G. moelleri foraging activity was restricted to the nest bromeliad. In the warm period more ants left the nest to forage, and foraging trips achieved greater distances compared to the cool season. Trap data revealed that overall availability of arthropod prey is higher in the summer than in the winter. The opportunism in nest site use and in foraging behaviour, the small foraging area, as well as the seasonal differences in foraging activity are discussed and compared with other tropical ants.Received 30 May 2003; revised 22 September 2003; accepted 3 October 2003.     

Intraspecific selectivity,compensatory feeding and flexible homeostasis in the phagotrophic flagellate <Emphasis Type="Italic">Oxyrrhis marina</Emphasis>: three ways to handle food quality fluctuations

The phagotrophic flagellate Oxyrrhis marina shows a strong stoichiometric plasticity when fed differently grown Rhodomonas salina. We tested whether differently pre-conditioned O. marina displayed selective feeding behaviour from a mixture of nitrogen and phosphorus depleted R. salina. We observed selective feeding of O. marina, always selecting phosphorus rich R. salina independent of the pre-conditioning of the protists. In a second experiment, O. marina was again pre-conditioned either with nitrogen- or phosphorus-depleted R. salina and was refed with either of the differently limited R. salina in single food treatments (not in a mixture). The phagotrophic flagellate displayed compensatory feeding which means that O. marina feed more on the food source which they were not given before. Due to its stoichiometric plasticity, O. marina might handle bad quality food by following the stoichiometry of its prey and additionally by active selective feeding towards P-rich algae to enhance growth. Post-ingestion selection might as well be an important feature which means that ingested elements in excess are quickly excreted and scarce elements are ingested through accelerated food uptake.     

Taste preferences and behavior of testing gustatory qualities of food in stone loach <Emphasis Type="Italic">Barbatula barbatula</Emphasis> (Balitoridae,Cypriniformes)

Extraoral and intraoral taste preferences of stone loach Barbatula barbatula to 21 free amino acid (L-isomers) and 4 classic taste substances were established. It was found that most amino acids (19), as well as citric acid and calcium chloride are suppressants, i.e., significantly decrease grasping of artificial pellets. Such action is most typical of cysteine, glutamine, asparagine, and citric acids. The number of deterrent stimuli among the used substances is smaller than that of suppressants. Only aquatic chironomid extract has positive gustatory properties. The remaining substances have no pronounced taste properties. Touching of a pellet by barbels is an obligatory element of behavior of testing by fish of pellet properties always preceding grasping. It was found that the subsequent development of feeding behavior of fish proceeds according to one of the possible behavioral stereotypes of testing by fish of taste properties of food items. The revealed behavioral response stereotypes differ in the number of manipulations performed by fish with a food item (rejections and repeated graspings) and in the duration of its retention. Stereotype selection is determined by the extraoral taste attractiveness of the food item for fish.     

White Storks, <Emphasis Type="Italic">Ciconia ciconia</Emphasis>, forage on rubbish dumps in Poland—a novel behaviour in population

Information on the foraging of White Storks on rubbish dumps, a novel behaviour in Central European populations, is presented. Observations were first made in 1999 and to date; they have been recorded on sixteen locations in Poland. From one to 348 White Storks (median = 2, N = 116) were observed on rubbish dumps, and most of the records (86%) were of 1–3 birds. Birds foraging on rubbish dumps were recorded from late March to early September, but the highest numbers were seen during the summer months. Most of the birds (77%, N = 171) were recorded foraging directly on an area where rubbish had been thrown, while a minor fraction (16%) was seen on neighbouring recultivated grassy areas. Dumps were used as an additional food source probably in areas where natural foraging grounds are limited. The increased frequency of observations during the summer months probably resulted from the greater nutritional needs of large nestlings which force the adults to find alternative food sources or foraging habitat shift by non-breeding birds.     

Tandem Recruitment and Foraging in the Ponerine Ant <Emphasis Type="Italic">Pachycondyla harpax</Emphasis> (Fabricius)

Tandem running is a common recruitment strategy in ant species with small colony sizes. During a tandem run, an informed leader guides a usually naïve nestmate to a food source or a nest site. Some species perform tandem runs only during house hunting, suggesting that tandem running does not always improve foraging success in species known to use tandem running as a recruitment strategy, but more natural history information on tandem running under natural conditions is needed to better understand the adaptive significance of tandem recruitment in foraging. Studying wild colonies in Brazil, we for the first time describe tandem running in the ponerine ant Pachycondyla harpax (Fabricius). We asked if foragers perform tandem runs to carbohydrate- (honey) and protein-rich (cheese) food items. Furthermore, we tested whether the speed and success rate of tandem runs depend on the foraging distance. Foragers performed tandem runs to both carbohydrate food sources and protein-rich food items that exceed a certain size. The probability to perform a tandem run and the travelling speed increase with increasing foraging distances, which could help colonies monopolize more distant food sources in a competitive environment. Guiding a recruit to a food source is costly for leaders as ants are ~66% faster when travelling alone. If tandem runs break up (~23% of all tandem runs), followers do not usually discover the food source on their own but return to the nest. Our results show that tandem running to food sources is common in P. harpax, but that foragers modify their behaviour according to the type of food and its distance from the nest. Competition with other ants was intense and we discuss how tandem running in P. harpax might help colonies to build-up a critical number of ants at large food items that can then defend the food source against competitors.     

The influence of the food size,distance and food site on food carrying behavior in rats (Rattus norvegicus)

The behavior to foods in rats (Rattus norvegicus) was investigated in a seminatural enclosure and in a straight alley in the laboratory. In both situations, the size of food (0.045-, 1-, and 3-g pellets were used in the enclosure and 0.045-, 0.2-, 1-, and 3-g pellets in the alley) and distance between food sites and nest site (1.8, 3.6, 5.4, and 7.2 m in the enclosure and 2, 4, and 6 m in the alley) were varied. In both situations, when food was presented in only 1 place, the food carrying behavior increased as the size of food increased from 0.045 to 1-g. One and three g pellets were always carried, regardless of the distance to nest. On the other hand, when multiple food sites were presented in the alley, rats were more likely to carry small pellet from the further food site, whereas large pellet was always carried and were not influenced by the distance. The behavior to foods in the enclosure, however, was not influenced in either food site condition. This might be due to the difference in familiarity to the environment and anxiety from perceived predation risk.     

Genetic factors affecting food‐plant specialization of an oligophagous seed predator

Several ecological and genetic factors affect the diet specialization of insect herbivores. The evolution of specialization may be constrained by lack of genetic variation in herbivore performance on different food‐plant species. By traditional view, trade‐offs, that is, negative genetic correlations between the performance of the herbivores on different food‐plant species favour the evolution of specialization. To investigate whether there is genetic variation or trade‐offs in herbivore performance between different food plants that may influence specialization of the oligophagous seed‐eating herbivore, Lygaeus equestris (Heteroptera), we conducted a feeding trial in laboratory using four food‐plant species. Although L. equestris is specialized on Vincetoxicum hirundinaria (Apocynaceae) to some degree, it occasionally feeds on alternative food‐plant species. We did not find significant negative genetic correlations between mortality, developmental time and adult biomass of L. equestris on the different food‐plant species. We found genetic variation in mortality and developmental time of L. equestris on some of the food plants, but not in adult biomass. Our results suggest that trade‐offs do not affect adaptation and specialization of L. equestris to current and novel food‐plant species, but the lack of genetic variation may restrict food‐plant utilization. As food‐plant specialization of herbivores may have wide‐ranging effects, for instance, on coevolving plant–herbivore interactions and speciation, it is essential to thoroughly understand the factors behind the specialization process. Our findings provide valuable information about the role of genetic factors in food‐plant specialization of this oligophagous herbivore.     

高黎贡山赧亢白眉长臂猿春季食物选择

2007年3月9日—4月28日,在高黎贡山赧亢跟踪观察白眉长臂猿(Hoolock hoolock)的春季食性及取食行为,将其行为分为食果、食果汁和食叶。采用瞬时扫描法记录白眉长臂猿的取食行为,取食的种类、部位和地点等。在其活动区域内,以取食树为中心设置20m×20m的利用样方和以随机方式设置同样大小的可利用样方各19个。在样方内收集与取食树及食物资源相关的6个因子的数据。统计食物种类和资源量、选择指数、取食点的选择性等。结果表明,赧亢白眉长臂猿春季取食的食物共10种,其中果实类植物3种,果汁类植物1种,嫩叶类植物6种。10种食物中,白眉长臂猿对印度木荷(Schima khasiana)的果实和缅甸木莲(Maglietia haokeri)的嫩叶呈弱选择,对其他8种食物资源均呈强选择。Mann-WhitneyU-检验结果表明,利用样方和可利用样方间的食物资源量及食物种类数均差异极显著,以利用样方的资源量大,每一样方食物种类较多。果实是赧亢白眉长臂猿春季的主要食物资源,而嫩叶是补充。呈强选择的食物并不一定是取食频次高的食物;反之,取食频次高的食物也不一定呈强选择。白眉长臂猿常选择易处理的果实和粗灰分含量少的嫩叶,且果实是它摄取水分的主要来源。白眉长臂猿通常选择食物资源和种类相对集中的区域取食,这可以减少动物因寻找食物所耗费的能量,同时获得多种食物,满足其生理对营养的需求。     

Feedback in the rabbit's central circadian system, revealed by the changes in its free-running food intake pattern induced by blinding, cervical sympathectomy, pinealectomy, and melatonin administration.

Long-term records of the number of food approaches per 30 min were obtained from 16 rabbits in constant light and after blinding. Optic nerve sectioning usually resulted in a shortening of the free-running period (tau; mean reduction = -0.26 hr) of the oscillator governing the rabbit's food intake pattern. Subsequent resection of both superior cervical ganglia always reduced this tau (mean = -0.41 hr), and it could be further shortened (mean = -0.24 hr) by chronic administration of melatonin. These observations led to experiments in which the food intake of 15 blinded rabbits was recorded before and after pinealectomy. This always resulted in a lengthening of tau (mean = +0.27 hr), which was never seen after subtotal or sham pinealectomy in 10 other blinded animals (mean = -0.05 hr). Sympathectomy also reduced tau (mean = -0.50 hr) in the pinealectomized rabbits, whereas it induced a smaller reduction (mean = -0.29 hr) after sham pinealectomy. These results, together with previous observations on the effect of sympathectomy on the retinal "dark" discharge and on the influence of the latter upon the food intake pattern, indicate that the cervical sympathetic nerves may form part of three feedback loops for the rabbit's central circadian system. These have separate postganglionic pathways; there are also differences in the circadian phasing of their activities and in their effects on tau.     

Genes,social transmission,but not maternal effects influence responses of wild Japanese macaques (<Emphasis Type="Italic">Macaca fuscata</Emphasis>) to novel-object and novel-food tests

Using long-term maternal pedigree data, microsatellite analysis, and behavioral tests, we examined whether personality differences in wild Japanese macaques (Macaca fuscata) are associated with additive genetic effects, maternal influences, or belonging to a particular social group. Behaviors elicited by novel-object tests were defined by a component related to caution around novel-objects (Ob-PC1) and behaviors elicited by novel food-tests were defined by correlated components related to consummatory responses (Fo-PC1) and caution around novel foods (Fo-PC2). The repeatability of Ob-PC1 was modest and not significant; the repeatabilities of Fo-PC1 and Fo-PC2 were moderate and significant. Linear mixed effects models found that sex, age, sex × age, provisioning, trial number, date, time of day, season, and distance to the closest monkey were not related to personality. Linear mixed effects models of females older than 2 years found that high rank was associated with greater caution around novel objects. Linear models were used to determine whether sex, age, group membership, maternal kinship, or relatedness had independent effects on the personality similarity of dyads. These analyses found that pairs of macaques that lived in the same group were less similar in their caution around novel objects, more closely related pairs of macaques were more similar in their tendency to eat novel food, and that pairs of macaques in the same group were more similar in how cautious they were around novel foods. Together, these findings suggest that personality in this population of wild monkeys was driven by rank, genetic effects, and group effects, the latter possibly including the need to exploit different niches in the environment.     

Food-Offering Calls in Wild Golden Lion Tamarins (<Emphasis Type="Italic">Leontopithecus rosalia</Emphasis>): Evidence for Teaching Behavior?

Many animals emit calls in the presence of food, but researchers do not always know the function of these calls. Evidence suggests that adult golden lion tamarins (Leontopithecus rosalia) use food-offering calls to teach juveniles which substrate (i.e., microhabitat) to forage on, or in, for food. However, we do not yet know whether juveniles learn from this aspect of the adults’ behavior. Here we examine whether juveniles learn to associate food-offering calls with a foraging substrate, as a step toward assessing whether these calls qualify as teaching behavior. We compared the performance of four wild juvenile golden lion tamarins that were introduced to a novel substrate while exposed to playbacks of food-offering calls (experimental condition) to the performance of three juveniles that were exposed to the novel substrate without the presence of food-offering playbacks (control condition). We varied the location of the novel substrate between trials. We found that food-offering calls had an immediate effect on juveniles’ interactions with the novel substrate, whether they inserted their hands into the substrate and their eating behavior, and a long-term effect on eating behavior at the substrate. The findings imply that juvenile golden lion tamarins can learn through food-offering calls about the availability of food at a substrate, which is consistent with (but does not prove) teaching in golden lion tamarins through stimulus enhancement. Our findings support the hypothesis that teaching might be more likely to evolve in cooperatively breeding species with complex ecological niches.     

Detection of <Emphasis Type="Italic">Giardia,Entamoeba,</Emphasis> and <Emphasis Type="Italic">Cryptosporidium</Emphasis> in unprocessed food items from northern India

This study was conducted to evaluate the load of three food- and water-borne parasites, namely, Giardia, Entamoeba, and Cryptosporidium on food items that are consumed either raw or in an unprocessed state in the northern parts of India. A two-step diagnostic method was employed to assess the presence of Giardia and Cryptosporidium, the immunofluorescence assay (IFA) combined with the polymerase chain reactiion (PCR assay), whereas a Tech lab diagnostic kit in combination with PCR assay was used for accurate detection of Entamoeba histolytica in the samples. The methods for isolation and enrichment of cysts/oocysts from the various food items were tested and discussed here. Our results showed that the overall spectrum of incidence of the three parasites on food items in decreasing order were Giardia > Entamoeba > Cryptosporidium. When data were subjected to the chi-square test, the prevalence of all three parasites was found to be independent of the food items. To determine whether the presence of two types of parasites in a food item is uniform, a Poisson distribution test was conducted. On comparing the intensity of occurrence of the different parasites in various food items, it was observed that the occurrence of Giardia and Entamoeba was not of the same order at 5% level of significance only in case of samples of raw meat and milk. This confirmed that a high number of raw or unpasteurized milk and meat samples are more likely to be contaminated with Giardia than with Entamoeba. Therefore, our observations point to the unhygienic practices of food handlers being a major contributor in the transmission of parasites to unprocessed food products.     

Isolating structures of gerbils’ digestive tract (Gerbillidae, <Emphasis Type="Italic">Rhombomys,Meriones</Emphasis>) and their functional significance

The morphology of the digestive tract of three species of gerbils characterized by different food specialization—Rhombomys opimus, Meriones tamariscinus and M. meridianus—is considered. The correlation between areas of glandular and cornified epithelium is variable and depends greatly on the type of stomach filling and distribution of food mass in it. The bordering fold and ileocecal junction is not only able to isolate the forestomach and caecum significantly but also may be a mechanism of regulation of food movement through the digestive tract. The close location of ileum’s opening to the caecum and its outlet to the colon, as well as isolation of caecum’s cavity by a circular fold, could provide direct food transit from the ileum to the colon.