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PubMed1997

Handling and isolation in three strains of rats affect open field, exploration, hoarding and predation.

Male albino (Al), brown hooded (Br) and black hooded (Bl) rats were raised in social isolation or in pairs, with or without systematic handling. At 90 and 180 days of age, the animals were individually tested for activity in an open field (Of), exploratory behavior in a complex environment, food hoarding (Hd) and insect predation (Pd). Multivariate analysis of the results showed significant influences of all three factors (strain, handling and social isolation) and interactions among them. Strain affected Of, Hd and Pd, with contrastingly high performances of Br in Of, Al in Hd and Bl in Pd. Handling increased Of and exploration scores in both test series. Isolation induced higher performances in all the four behaviors in the second test series. Accentuated and stable individual differences occurred in the performances off all the behaviors. The results emphasize the subtleness and complexity of the interplay of genetic and environmental influences and stress the independence of the regulatory processes of different behaviors.

Animals↗
PubMed2001

Antipredator responses and defensive behavior: ecological and ethological approaches for the neurosciences.

In nature, animals are exposed to a wide range of threats and dangers with predators being amongst the more prominent and intensely studied of these. The responses of prey to predators and various predator avoidance and antipredator behaviors have been extensively evaluated from ecological and ethological perspectives and more recent ethopharmacological and neuroscience approaches. Unfortunately, there has been relatively little interchange between the ecological-ethological and neuroscience areas with the latter often using responses to predators just simply as another 'model' system. There is, however, now a growing realization that integrative approaches incorporating ecological, evolutionary and neurobiological explanations are required for the understanding of behavior and its functions. This necessitates an incorporation of ecological and ethological concepts and validity with neuroscience approaches to the analysis of antipredator responses and defensive behavior. A number of selected ecological approaches that are used for the investigation of predator avoidance mechanisms and antipredator defensive behavior patterns are briefly reviewed here. These include examinations of how predation risk and its variation affect decision making in animals and how learning affects these responses. The trade-offs that are involved, how the risk of predation affects decisions concerning foraging behavior, mating and reproduction, as well as how varying levels of risk affect decisions relative to the type of defensive mechanisms utilized are briefly outlined. The utility of these approaches and their relevance to the design and interpretation of various neuroscience studies is addressed here.

Aggression↗
PubMed1991

Exposure to the calls of predators of mice activates defensive mechanisms and inhibits consummatory behaviour in an inbred mouse strain.

As two-minute exposures to the tape-recorded calls of barn and tawny owls activate endogenous opioid-mediated analgesia mechanisms in laboratory mice, the behavioural effects of the calls of a variety of predator and nonpredator species were ethologically assessed. While no clear effect could be seen on cage-orientated behaviour, the calls of the barn owl and tawny owl produced consistent increases in self-orientated, call-orientated and defensive behaviour indicating that these calls were recognised as belonging to predators. The call of the gull also produced an increase in defense, but, as this could be attributed to an increase in attend only, test animals may react to a change in stimulus properties without the gull call unequivocally representing a potential threat. These results indicate recognition of, and appropriate reaction to, the calls of known night-hunting, airborne primary predators of mice by an inbred laboratory strain.

Aggression↗
PubMedDate not supplied

Stimulus configuration and location in the visual field affect appetitive responses by the praying mantis, Sphodromantis lineola (Burr.).

Adult female praying mantises, Sphodromantis lineola (Burr.), were presented with computer-generated black rectangular stimuli that moved horizontally or vertically at 82 deg/s against a homogeneous white background. Both stimulus configuration (orientation in relation to direction) and the retinal location of the stimulus image affected the rate at which mantises responded appetitively (approached or struck at the stimulus). Mantises responded most to square stimuli (12.5 deg x 12.5 deg) when they moved horizontally or vertically through, or horizontally at 24.5 deg below the center of their visual field. Mantises also responded most to vertically (vs. horizontally) oriented rectangular stimuli (12.5 deg x 47 deg) that moved through their visual-field center, irrespective of whether the stimuli moved downward or horizontally. Upward moving stimuli elicited intermediate amounts of behavior with no configuration preference. Mantises did not demonstrate a configuration preference when rectangular stimuli moved > or = 24.5 deg outside of the visual-field center. Furthermore, mantises responded very little and demonstrated no configuration preferences to stimuli that moved less than approximately 83 deg through their visual field even if the stimuli moved through the visual-field center.

Animals↗
PubMed2005

Is more choice always desirable? Evidence and arguments from leks, food selection, and environmental enrichment.

Recent studies on humans show that too much choice can make subjects less likely to choose any item. I consider general adaptive and non-adaptive explanations of why such choice aversion, or its converse, might occur in animals. There are three questions: is more choice always preferred, does it ever lead to less consumption (or a lower probability of consumption), and may it result in worse items being selected ? A preference for choice is one of the main explanations for lek formation and I draw attention to previously unrecognised parallels with models of human shopping behaviour. There is indeed evidence of female preference for larger leks, although much of the observational data are open to other interpretations. Unfortunately nobody has looked for choice aversion where it is most to be expected, in leks larger than normally occur. Evidence that too much choice of males confuses females is strongest in acoustically advertising frogs, but the widespread decrease of mating skew in larger leks might also have this explanation. A model reanalyses data on skew in black grouse Tetrao tetrix and suggests that considering only a random subset of a large lek may increase the chances of selecting the better males: larger leks are more likely to include better males, but these are less likely to be selected. These opposing effects may lead to an optimum lek size, but only with a sufficient decline in choice accuracy with size. With food choice, very few studies have avoided confounding choice with food quality, by manipulating only flavour. The widespread phenomena of stimulus-specific satiety and novelty seeking imply that monotonous diets are aversive, but no studies test whether animals choose sites where they know food diversity to be greater. Operant experiments that demonstrate mild preferences for free choice concern choice about the means to get food rather than the food itself. In some insect species even moderate choice of diet can be deleterious, and studies on search images and the confusion effect may be evidence of this in vertebrates. Environmental enrichment of captive animals often relies on increasing the options available, but it need not be the choice itself that is beneficial. I consider briefly further areas in biology where choice preference or aversion are potentially important.

Adaptation, Biological↗
PubMed2001

Attack cone avoidance during predator inspection visits by wild finescale dace (Phoxinus neogaeus): the effects of predator diet.

When confronted by potential predators, many prey fishes engage in predator inspection behavior. Previous authors have argued that by selectively avoiding the predator's head during an inspection visit (attack cone avoidance), individual inspectors may reduce their local risk of predation. In field trials, we investigated the effects of predator diet cues on the presence of 'attack cone avoidance' during predator inspection visits. Wild, free-ranging finescale dace (Phoxinus neogaeus) were exposed to the combined cues of a model predator and a distilled water control or the odor of a yellow perch (Perca flavescens) fed dace (with alarm pheromone), swordtail (Xiphophorus helleri) (lacking Ostariophysan alarm pheromone), or perch that were food deprived for four days. Finescale dace modified their predator inspection behavior following exposure to the odor of a perch fed dace (fewer dace present, reduced frequency of inspections, and an increased per capita inspection rate) compared to those exposed to the odor of a perch fed swordtails, perch that were food deprived, or a distilled water control. In addition, dace inspected the tail region more often only when the model predator was paired with the odor of a perch fed dace. In all other treatments, dace inspected the head region of the model predator more often. These data suggest that attack cone avoidance of inspecting prey fishes may be more likely to occur in high-risk situations, such as in the presence of conspecific alarm pheromones in the diet of potential predators.

Animals↗
PubMed2003

Alteration of kairomone-induced antipredator response of the freshwater amphipod Gammarus roeseli by sediment type.

The importance of sediment type and of kairomones released by juvenile burbot (Lota Iota) on behavioral responses of the freshwater amphipod Gammarus roeseli was studied in laboratory experiments. In the absence of kairomones. G. roeseli preferred coarse substrates; the highest preference was shown for the most coarse sediment. In the presence of kairomones, the amphipods preferred the less-coarse substrate pebbles over gravel. This difference is an effective antipredator response; G. roeseli is able to hide efficiently in the interstices of the pebbles. Juvenile burbot have a low foraging efficiency on pebbles and preferentially forage in the interstices of coarser sediments. G. roeseli responded differently to kairmones in different sediment types. The amphipods decreased their activity only in pebbles. In gravel, the rate of exploration behavior increased, and on a bare surface, the area containing fish kairomones was avoided.

Adaptation, Physiological↗
PubMed1989

Differences in cyclophosphamide-induced suppression of cricket predation in selectively bred strains of taste-aversion prone and resistant rats.

Cyclophosphamide-induced conditioned suppression of cricket predation was observed in taste-aversion-prone (TAP) but not in taste-aversion-resistant (TAR) rats. These TAP and TAR strains had been selectively bred for efficient or inefficient acquisition of cyclophosphamide-induced saccharin taste aversions (TAs). Equivalent preconditioning cricket predation was practiced by nonfasted subjects of both strains. TAR rats that ate crickets before a cyclophosphamide injection were thereafter voracious predators as were saline-injected and pseudoconditioning controls of both strains. However, conditioned TAP rats subsequently displayed a marked suppression of cricket predation. Predation can provide a deprivation-free and species-natural consummatory response for studies of strain differences in TA conditionability of TAP and TAR rats. In addition, the present results indicate that TAP and TAR strain differences in TA conditionability are not restricted to the saccharin solution that was the conditioned stimulus basis of prior strain development.

Animals↗
PubMed1989

Antipredator defensive behaviors in a visible burrow system.

Analyzed defensive behaviors in a seminatural setting through videorecordings of groups of 4 male and 4 female rats. Before cat exposure dominant males showed more offensive behavior, eating, drinking, and use of the open area than subordinates. Presentation of a cat in the open area produced changes in four subpatterns of defense over a 24-hr period: withdrawal; immobility and movement constraint; risk assessment; and suppression of nondefensive behaviors. All Ss showed pronounced and consistent changes in each of these patterns, but dominant males alone showed increased risk assessment-related corner runs. These results provide an extensive description of rat defensive behaviors in a seminatural and relatively unstructured situation and suggest that the anxiety process is initially associated with withdrawal and movement arrest, giving way to a crucial and long-lasting risk-assessment stage that provides information leading to either further defensiveness or a return to nondefensive behaviors. This analysis suggests new models for the study of anxiety.

Animals↗
PubMed2005

Unlearned appetite controls: watersnakes (Nerodia) take smaller meals when they have the choice.

Studies of appetite in mammals emphasize that meal size is learned, but lactation and parental care constrain testing of naive individuals. Neonatal reptiles, in contrast, are self-sufficient foragers. The authors examined the effect of prey size on meal size in primivorous (at first feeding) northern watersnakes (Nerodia sipedon). When offered an excess of small prey (2%-20% of snake mass), neonates ate significantly smaller meals (M = 23.5% of snake mass) than when offered a single huge item (range = 32%-55%). The authors conclude that (a) the taking of smaller meals is not a learned effect, (b) there may be a satiety threshold for meal size rather than a target, (c) oropharyngeal stimuli may provide satiety cues, and (d) huge meals may have fitness costs.

Age Factors↗
PubMed2006

Of snakes and flowers: does preferential detection of pictures of fear-relevant animals in visual search reflect on fear-relevance?

Previous research in visual search indicates that animal fear-relevant deviants, snakes/spiders, are found faster among non fear-relevant backgrounds, flowers/mushrooms, than vice versa. Moreover, deviant absence was indicated faster among snakes/spiders and detection time for flower/mushroom deviants, but not for snake/spider deviants, increased in larger arrays. The current research indicates that the latter 2 results do not reflect on fear-relevance, but are found only with flower/mushroom controls. These findings may reflect on factors such as background homogeneity, deviant homogeneity, or background-deviant similarity. The current research removes contradictions between previous studies that used animal and social fear-relevant stimuli and indicates that apparent search advantages for fear-relevant deviants seem likely to reflect on delayed attentional disengagement from fear-relevance on control trials.

Adolescent↗
PubMed1988

Biological correlates of behavioral development in the ant, Novomessor albisetosus (Mayr).

Physical changes are associated with temporal polyethism, the division of labor according to age. The period of developing ovaries corresponds with the age when workers are found with the brood and queen. Resorption of ovaries occurs at a time when workers no longer tend brood and queen. Two bursts of exoskeleton hardening and growth of the poison gland apparatus corresponds with a transitional period in the behavioral development of workers and finally with their development into nest defenders and foragers.

Age Factors↗