How flies time when they're having brunch

Coordinated timing of circadian clocks is thought to be crucial for optimal energy homeostasis. In this issue of Cell Metabolism, Xu et al. (2008) explore the fruit fly as a model system to examine the links between clocks, feeding, and metabolism.     

Animal cognition: monkey meteorology

Mangabey monkeys have been shown to rely on memory of recent trends in temperature and solar radiation to decide whether to feed on a particular patch of fruit. These observations reveal a rich mental representation of the physical environment in monkeys and suggest foraging may have been an important selective pressure in primate cognitive evolution.     

Animal cognition: 1900-2000

During the 20th century there has been considerable progress in the study of animal cognition, based on essential ideas that were developed earlier. These essential ideas include the metaphors of the animal, the questions, the sources of hypotheses, and the types of explanations. The progress cannot be generally characterized as continuous improvement, cyclic changes, or discrete steps, but the quality of the empirical results has increased substantially since the first experiments in the field. Improvements in research methods have been primarily responsible for this progress. These have included improvements in animal husbandry, stimulus control, apparatus design, the measurement of behavior, experimental procedures, and data analysis. In the last third of the century the computer has led to major improvements in all stages of the research process in animal cognition. Although they have greatly improved the quality of the empirical results, they have not led to a general theory of animal cognition. In the near future the available research methods are likely to lead to further progress in the developments of quantitative theories of animal cognition.     

Animal cognition: know your enemy

Food-storing corvids are able to remember which individual saw them store food, and take preventive action that is tailored to that particular competitor's knowledge. This raises the question of whether abilities like 'theory of mind' have arisen independently more than once in evolution.     

The cost of reproduction in rosehip flies,Rhagoletis basiola: Eggs are time

Summary The hypothesis was tested that egg-laying by rosehip fruit flies,Rhagoletis basiola, would lead to reduced adult survivorship compared with oviposition-deprived flies, through experimental manipulation. Oviposition-deprived flies were assigned to two groups: mated and spinster. All three treatment groups were permitted to spend equal time and energy exploring and handling hosts but only the former group were allowed to deposit eggs (three/day). Results clearly showed that ovipositing flies suffered significantly higher mortality rates and that mated and spinster flies produced similar survivorship patterns. I consider these results both as a foraging problem (i.e. laying eggs in inferior hosts can cost both eggs and life) and as a more general life history problem.     

Animal cognition: bring me my spear

Chimpanzees regularly hunt mammals, but use only their hands and teeth: for the first time, chimpanzees have now been found to make tools in order to spear mammalian prey.     

Animal cognition: monkey looks contradict Hume

Wild rhesus monkeys have been found to attend to causal anomalies, suggesting that they make inferences about possible and impossible physical transformations in the absence of direct relevant experience.     

Animal cognition: great apes wait for grapes

Humans may be patient when it comes to money, but chimpanzees are willing to wait longer than humans for food, suggesting patience is neither innate nor uniquely human.     

Animal cognition: concepts from apes to bees

New research shows that honeybees can classify arrangements of two visual patterns according to their spatial configuration. Can bees learn relational concepts of 'above' and 'below'? And are the underlying psychological processes comparable in humans and other primates facing similar tasks?     

Animal cognition: monkeys recall previously seen images

A recent study has found that rhesus macaques can recall newly presented shapes: this demonstration of recall in non-human primates suggests that some animals have recollection processes similar to those of humans.     

Animal cognition: multimodal tactics of orangutan communication

Orangutans select different tactics for repairing failed communication, depending upon how well they are understood: they repeat signals if they are partially understood and switch tactics entirely if completely misunderstood.     

Animal cognition: crows spontaneously solve a metatool task

A recent study found that tool-manufacturing New Caledonian crows spontaneously solved a metatool task in which the birds used a tool to obtain a second, longer tool that could then be used to obtain food that was otherwise out of reach.     

Flexible mate choice when mates are rare and time is short

Female mate choice is much more dynamic than we once thought. Mating decisions depend on both intrinsic and extrinsic factors, and these two may interact with one another. In this study, we investigate how responses to the social mating environment (extrinsic) change as individuals age (intrinsic). We first conducted a field survey to examine the extent of natural variation in mate availability in a population of threespine sticklebacks. We then manipulated the sex ratio in the laboratory to determine the impact of variation in mate availability on sexual signaling, competition, and mating decisions that are made throughout life. Field surveys revealed within season heterogeneity in mate availability across breeding sites, providing evidence for the variation necessary for the evolution of plastic preferences. In our laboratory study, males from both female‐biased and male‐biased treatments invested most in sexual signaling late in life, although they competed most early in life. Females became more responsive to courtship over time, and those experiencing female‐biased, but not male‐biased sex ratios, relaxed their mating decisions late in life. Our results suggest that social experience and age interact to affect sexual signaling and female mating decisions. Flexible behavior could mediate the potentially negative effects of environmental change on population viability, allowing reproductive success even when preferred mates are rare.     

Animal cognition: rooks team up to solve a problem

A recent study has found that rooks team up to get food in a cooperative instrumental task, but they may have difficulties in understanding when cooperation is necessary and how it works.     

Fish are like flies are like frogs: Conservation of dorsal-ventral patterning mechanisms

Genetic analysis of Drosophila has shown that a morphogenetic gradient of the Transforming Growth Factor-β family member dpp patterns the embryonic dorsalventral axis. Molecular and embryological evidence from Xenopus has strongly suggested a similar role for Bmp-4, the dpp homolog, in patterning the dorsalventral axis of chordates. A recent report has now identified mutations in two genes, dino and swirl, that disrupt dorsal-ventral patterning in the zebrafish Danio rerio⁽¹⁾. Characterization of these mutations parallels findings from Drosophila, thus establishing a genetic framework for the analysis of dorsalventral patterning in a vertebrate.     

The agent is right: when motor embodied cognition is space-dependent

The role of embodied mechanisms in processing sentences endowed with a first person perspective is now widely accepted. However, whether embodied sentence processing within a third person perspective would also have motor behavioral significance remains unknown. Here, we developed a novel version of the Action-sentence Compatibility Effect (ACE) in which participants were asked to perform a movement compatible or not with the direction embedded in a sentence having a first person (Experiment 1: You gave a pizza to Louis) or third person perspective (Experiment 2: Lea gave a pizza to Louis). Results indicate that shifting perspective from first to third person was sufficient to prevent motor embodied mechanisms, abolishing the ACE. Critically, ACE was restored in Experiment 3 by adding a virtual "body" that allowed participants to know "where" to put themselves in space when taking the third person perspective, thus demonstrating that motor embodied processes are space-dependent. A fourth, control experiment, by dissociating motor response from the transfer verb's direction, supported the conclusion that perspective-taking may induce significant ACE only when coupled with the adequate sentence-response mapping.     

Animal cognition: chimpanzee alarm calls depend on what others know

After a wild chimpanzee encounters a model of a dangerous snake, whether or not he gives an alarm call depends on his perception of another individual's knowledge.