Directional escape strategy by the striped plateau lizard (Sceloporus virgatus): turning to direct escape away from predators at variable escape angles

Behaviour ◽  
2016 ◽  
Vol 153 (4) ◽  
pp. 401-419 ◽  
Author(s):  
William E. Cooper
Keyword(s):  
Laboratory Studies ◽  
Turn Angle ◽  
Escape Strategy ◽  
Escape Angle ◽  
Degree Of Orientation ◽  
Reduce Risk ◽  
Sceloporus Virgatus ◽  
Straight Ahead

A prey’s orientation to a predator’s approach path affects risk of fleeing straight ahead. By turning to flee closer to straight away from the predator before fleeing, prey can reduce risk. Laboratory studies suggest that escape angles should lead away from predators and be unpredictable. I studied orientation, turn, and escape angles and in a study of striped plateau lizards,Sceloporus virgatus. Lizards fled away from a predator, but often not straight away. Escape angles were variable and bimodally distributed: one mode was straight away for distancing prey from predator and one was near 90°, which maintains ability to monitor the predator or requires turning by the predator. Turn angles increased as orientation shifted toward the predator. Escape angle was closer to straight away when turn angle was larger, but turning did not fully compensate for degree of orientation toward the predator. Directional escape strategies of diverse prey are compared.

Age, sex and escape behaviour in the Striped Plateau Lizard (Sceloporus virgatus) and the Mountain Spiny Lizard (S. jarrovii), with a review of age and sex effects on escape by lizards

Behaviour ◽  
2011 ◽  
Vol 148 (11-13) ◽  
pp. 1215-1238 ◽  
Author(s):  
William E. Cooper Jr.
Keyword(s):  
Sex Differences ◽  
Relevant Literature ◽  
Lizard Species ◽  
Escape Behaviour ◽  
Predator Prey ◽  
Escape Strategy ◽  
Escape Theory ◽  
Multiple Components ◽  
Sceloporus Virgatus ◽  
Age And Sex

AbstractEscape behaviour often differs between sexes, reproductive states and ages. Escape theory predicts that flight initiation distance (FID = predator–prey distance when escape begins) increases as predation risk and fitness increase, and decreases as cost of escaping increases. Similar predictions hold for distance fled and refuge entry, suggesting that age and sex differences in escape behaviour may occur when risk, fitness, and opportunity costs differ. I studied such differences in two lizard species and reviewed relevant literature on escape by lizards. In Sceloporus virgatus no difference occurred between sexes or female reproductive states in FID, distance fled, distance from refuge, or probability of entering refuge. In S. jarrovii juveniles had shorter FID and distance fled than adults; juveniles were closer than females to refuge, but this did not affect FID or distance fled. Juveniles were more likely than adults to be on rocks and use them as refuges. The literature review showed that sexual dimorphism in FID occurs in about 1/5 of species (male FID usually > female FID), but distance fled differed between sexes in only 1 of 21 species. Juveniles had shorter FID than adults in all of five species; the relationship between age and distance fled was highly variable. Reasons for patterns of age/sex differences are discussed. Because age and sex differences in these factors and escape strategy can alter multiple components affecting optimality, sometimes in opposite ways, these factors and escape strategy must be known to predict effects of age, sex and reproductive state on escape.

Escape strategy and vocalization during escape by American Bullfrogs (Lithobates catesbeianus)

2011 ◽  
Vol 32 (2) ◽  
pp. 213-221 ◽  
Author(s):  
William Cooper, Jr.
Keyword(s):  
Risk Factors ◽  
Euclidean Distance ◽  
Close Approach ◽  
Refuge Use ◽  
Alarm Signals ◽  
Lithobates Catesbeianus ◽  
Alarm Calling ◽  
Escape Strategy ◽  
Point Of Entry ◽  
Reduce Risk

AbstractAmerican bullfrogs, Lithobates catesbeianus, escape by jumping into water and submerging, often vocalizing as they flee. I studied effects of several risk factors on escape and refuge use and the association between vocalization by fleeing frogs and escape by other individuals nearby. Frogs on shore permitted equally close approach when approached along the shore or on a path perpendicular to shore. Frogs in water were more likely to flee when closer to shore and when approached more rapidly. Time spent submerged after fleeing was uncorrelated with proximity of the predator upon escape. Frogs spent longer submerged when they swam along shore away from the point of entry than when they surfaced directly offshore. Neither distance offshore nor Euclidean distance from the entry point upon emergence was related to time spent submerged. Bullfrogs may use unpredictability of distance and direction moved underwater and of duration of submergence as a strategy that reduce risk upon surfacing. When a focal frog vocalized as it fled, immediate escape by nearby nonfocal frogs was more frequent than when focal frogs (1) escaped without vocalization and (2) neither escaped nor vocalized. These findings are consistent with either alarm calling or benefit to the fleeing individual due to brief delay of attack by a predator. They are inconsistent with several other possible functions of calling during escape. Experimentation is needed to definitively test the hypothesis that calls during escape are alarm signals.

scholarly journals Escape strategy of Schreiber’s green lizards (Lacerta schreiberi) is determined by environment but not season or sex

Behaviour ◽  
2015 ◽  
Vol 152 (11) ◽  
pp. 1527-1542
Author(s):  
Renáta Kopena ◽  
Gábor Herczeg ◽  
Pilar López ◽  
José Martín
Keyword(s):  
Physical Environment ◽  
Flight Initiation Distance ◽  
Reproductive Condition ◽  
Escape Behaviour ◽  
Independent Manner ◽  
Escape Strategy ◽  
Escape Angle ◽  
Sources Of Variation ◽  
Substrate Independent ◽  
Flight Initiation

Antipredator escape behaviour varies with several well-established sources of variation ranging from the physical environment to reproductive status. However, the relative roles of these sources are rarely assessed together. We measured (i) the distance to the nearest refuge that Schreiber’s green lizards, Lacerta schreiberi, maintained before an attack (refuge distance) and (ii) the distance lizards allowed a simulated predator to approach before fleeing (flight initiation distance, FID). Refuge distance was unaffected by studied variables. However, FID was positively related to refuge distance on grassy, but not on rocky substrates. Furthermore, refuge distance and escape angle interacted in a substrate-independent manner: lizards allowed predators close when refuges were close or when lizards had to flee towards the predator. In contrast, neither mating season nor sex affected FID. We suggest that the escape strategy of L. schreiberi is determined more by the physical environment than by sex or reproductive condition.

scholarly journals A systematic assessment of preclinical multilaboratory studies and a comparison to single laboratory studies

2021 ◽  
Author(s):  
Victoria Hunniford ◽  
Agnes Grudniewicz ◽  
Dean Ferguson ◽  
Joshua Ryan Montroy ◽  
Emma Grigor ◽  
...  
Keyword(s):  
Study Design ◽  
Treatment Effects ◽  
Median Number ◽  
Risk Of Bias ◽  
Laboratory Studies ◽  
Systematic Assessment ◽  
Reduce Risk ◽  
Mean Differences ◽  
Single Laboratory

Multicentric approaches are widely used in clinical trials to assess generalizability of findings, however they are novel in preclinical experimentation. We synthesized characteristics of multilaboratory studies and quantitatively compared them to single laboratory studies. We systematically identified sixteen in vivo interventional multilaboratory studies and matched them to 100 single laboratory studies by intervention and disease. Differences in standardized mean differences (DSMD) were calculated to compare treatment effects based on study design. The multilaboratory study design was applied across a range of diseases (e.g. stroke, diabetes, trauma). The median number of labs was 4 (range 2-6) and the median sample size was 111 (range 23-384). Multilaboratory studies adhered to practices that reduce risk of bias and were transparently reported. These studies demonstrated significantly smaller treatment effects than single lab studies (DSMD 0.72 [95% confidence interval 0.43-1]). Preclinical multilaboratory studies demonstrate trends that have been well recognized in clinical research (i.e. smaller treatment effects with greater rigour in study design). This approach may provide a method to robustly assess interventions and reproducibility of findings between laboratories.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

Cognitive Aging in a Precision Sport Context

1996 ◽  
Vol 1 (3) ◽  
pp. 166-179 ◽  
Author(s):  
Bo Molander ◽  
Lars Bäckman
Keyword(s):  
Older Adult ◽  
Cognitive Abilities ◽  
Cognitive Aging ◽  
Motor Performance ◽  
Intervention Programs ◽  
Laboratory Studies ◽  
High Arousal ◽  
Memory And Attention ◽  
Age Related ◽  
Principal Finding

Highly skilled miniature golf players were examined in a series of field and laboratory studies. The principal finding from these studies is that young and young adult players (range = 15-38 years) score equally well or better in competition than in training whereas older adult players (range = 46-73 years) perform worse in competitive events than under training conditions. It was also found that the impairment in motor performance on the part of the older players is associated with age-related deficits in basic cognitive abilities, such as memory and attention. These results support the hypothesis that older players may be able to compensate for age-related deficits under relaxed conditions, but not under conditions of high arousal. The possibility of improving the performance of the older players in stressful situations by means of various intervention programs is discussed.

Automation Surprise

2017 ◽  
Vol 7 (1) ◽  
pp. 28-41 ◽  
Author(s):  
Robert J. de Boer ◽  
Karel Hurts
Keyword(s):  
Flight Control ◽  
Representative Sample ◽  
Aviation Safety ◽  
Control Mode ◽  
Cognitive Errors ◽  
Laboratory Studies ◽  
Airline Pilots ◽  
Flight Operations ◽  
Widespread Phenomenon ◽  
Few Data

Abstract. Automation surprise (AS) has often been associated with aviation safety incidents. Although numerous laboratory studies have been conducted, few data are available from routine flight operations. A survey among a representative sample of 200 Dutch airline pilots was used to determine the prevalence of AS and the severity of its consequences, and to test some of the factors leading to AS. Results show that AS is a relatively widespread phenomenon that occurs three times per year per pilot on average but rarely has serious consequences. In less than 10% of the AS cases that were reviewed, an undesired aircraft state was induced. Reportable occurrences are estimated to occur only once every 1–3 years per pilot. Factors leading to a higher prevalence of AS include less flying experience, increasing complexity of the flight control mode, and flight duty periods of over 8 hr. It is concluded that AS is a manifestation of system and interface complexity rather than cognitive errors.

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