Differences In Escape Behavior Research Articles

COMPARATIVE ESCAPE BEHAVIOR OF CHIHUAHUAN DESERT PARTHENOGENETIC AND GONOCHORISTIC WHIPTAIL LIZARDS

We characterized differences in escape behavior among syntopic parthenogenetic and gonochoristic whiptail lizards (Teiidae: Aspidoscelis) in western Texas by performing 2 experiments. The first experiment revealed that Aspidoscelis exsanguis (parthenogenetic) allowed a human simulated predator to approach significantly closer than Aspidoscelis neomexicana (parthenogenetic), and both species allowed a significantly closer approach than Aspidoscelis tigris (gonochoristic). Furthermore, A. neomexicana and A. exsanguis did not flee as far as A. tigris, but this difference in flight distance was not statistically significant. Temperature was not correlated with approach distance or flight distance for any of the above species. The second experiment determined that, when captured, Aspidoscelis tesselata (parthenogenetic) was more likely to release cloacal contents on a human captor than A. tigris (gonochoristic).

Postnatal Protein Malnutrition Affects Inhibitory Avoidance and Risk Assessment Behaviors in Two Models of Anxiety in Rats

Protein malnutrition induces structural, neurochemical and functional alterations in the central nervous system, leading to alterations in behavioral function. In order to study the effects of early protein malnutrition on inhibitory avoidance and escape behaviors we used the elevated T-maze (ETM), while the risk assessment behaviors were evaluated by the canopy stretched attend posture (SAP) test. Rat pups were fed by lactating females receiving 16% (control) or 6% (malnourished) protein diets during the lactation period. After weaning the animals received the same diets until 49 days of age, when all animals started receiving a lab chow diet. Behavioral tests were started at 70 days of age. ETM results showed lower inhibitory avoidance in malnourished animals, without differences in escape behavior. SAP test results showed higher exploration and lower risk assessment behaviors in malnourished animals compared to control. These results suggest that malnourished animals are less anxious and/or more impulsive as measured by these two animal models and that malnutrition seems to affect differently behavioral strategies underlying fear and anxiety responses.

Maturational and gender differences in rodent escape strategies: Possible implications for preclinical models of anxiety

This study profiles two clearly dissociable escape strategies (jumping and backing off) in a newly established preclinical model of extreme anxiety (i.e., the unstable elevated plus maze) and examines the contribution of ontogeny and gender to the behavioral profiles exhibited. Clear age-related differences in escape behavior were found: Although the younger animals exhibited all the preparatory behaviors appropriate to flight from the apparatus—that is, attempting to back off, backtracking, preparing to jump, turning, and scanning—the older animals more readily translated these into actual escape. There were no significant sex-related differences in escape rates or in three of the escape-related behaviors— that is, backtracking, attempting to back off, and preparing to jump. Clear dissimilarities were, however, found in a number of other escape-linked behaviors: Females scanned, end-reached, and turned more than males. These results indicate that ontogeny and gender significantly contribute to the behaviors exhibited in aversive situations and might explain at least some of the inconsistent results frequently obtained in preclinical models of anxiety.

Modulation of attack behavior and its effect on feeding performance in a trophic generalist fish,

This study examines the ability of a temperate marine fish, Hexagrammos decagrammus, to modulate its prey capture behavior in response to differences in prey type. This species has an extremely broad diet, feeding on prey which demonstrate very different anti-capture behaviors. Video-taped attacks on three shrimp species, one crab and pieces of shrimp were analyzed to determine the relative contributions of suction-feeding and ram-feeding behaviors to prey capture. The prey capture behaviors used by the predator were related to differences in escape behavior among the three shrimp species. H. decagrammus used behaviors characteristic of other ram-feeding predators when feeding on the two most elusive shrimp species: high attack velocity, attack initiated at a greater distance from the prey, and greater movement of the predator relative to the prey. Strikes at crabs and pieces of shrimp elicited strikes more typical of other suction-feeding predators, with lower attack velocities, shorter initial predator­prey distances and greater relative movement of the prey towards the predator. Attacks on the least elusive shrimp species showed elements of both ram and suction feeding. Modulation of attack velocity increased capture success on elusive prey, supporting the hypothesis that diet diversity is associated with the presence of a repertoire of feeding behaviors. These data suggest that functional differences in prey anti-capture behavior, as well as the functional versatility of the predator, must be addressed in ecomorphological studies that try to correlate predator morphology with diet.

Escape Behavior of Dalbulus and Baldulus Leafhoppers (Homoptera: Cicadellidae)

Differences in escape behavior were observed in the laboratory among six Dalbulus spp. and the closely related Baldulus tripsaci . Escape behavior is defined as sudden movement—e.g., flight—of insects from their hosts in response to external stimuli, such as mechanical jarring of the host plant. D. elimatus, D. maidis, D. guevarai , and D. gelbus were most responsive to the mechanical stimulus. D. elimatus and D. maidis are principally maize and teosinte host specific, whereas D. guevarai and D. gelbus utilize maize and Tripsacum spp. as hosts. D. tripsacoides, B. tripsaci , and D. quinquenotatus were the least responsive to the mechanical stimulus and are Tripsacum specialists. Except for B. tripsaci and D. quinquenotatus , males of species tested were more responsive than females. Five geographical populations of D. maidis were tested for escape response. Populations from Brazil and Mexico, where maize is grown seasonally, were more responsive than D. maidis taken from Peru, Costa Rica, and Colombia, where maize is grown continuously. Males were more responsive than females for all D. maidis geographical populations tested. Escape behavior is discussed with respect to predation, to trivial and migratory flights, and to risks involved with escape by flight.

Generality of the failure-to-escape (helplessness) phenomenon in rats

A series of four experiments investigated a number of parameters reported to produce “helplessness” in rats. Consistent differences in escape behavior were not found between inescapably shocked and restrained rats when a FR 1 shuttling response was used. Escape latencies also did not differ between groups when a reduced shock intensity was employed during escape training in FR 2 procedure or when an increased FR 3 response was employed during escape training. Findings are discussed in terms of the robustness of the failure-to-escape phenomenon from which “helplessness” in the rat is inferred.