Risk factors affecting escape behavior by the desert iguana, Dipsosaurus dorsalis: speed and directness of predator approach, degree of cover, direction of turning by a predator, and temperature

2003 ◽  
Vol 81 (6) ◽  
pp. 979-984 ◽  
Author(s):  
W E Cooper Jr.
Keyword(s):  
Risk Factors ◽  
Body Temperature ◽  
Escape Behavior ◽  
Primary Response ◽  
Single Individual ◽  
Factors Affecting ◽  
Escape Theory ◽  
Approach Distance ◽  
Dipsosaurus Dorsalis ◽  
Air Temperatures

Escape from predators by desert iguanas (Dipsosaurus dorsalis) conforms to predictions of optimal escape theory based on risk. I simulated an approaching predator to study risk factors. The primary response variable was approach distance (= flight-initiation distance), i.e., the distance between predator and prey when the prey initiates escape. In additional studies, I recorded whether lizards permitted me to approach close enough to noose them (an indicator of wariness) and the method of escape. Approach distance was greater when the predator approached rapidly than slowly and directly than indirectly, and when the predator turned toward the lizard rather than away. It was greater in open than in more densely covered habitats, which may reflect greater risk due to conspicuousness and (or) a greater distance to refuge. Early in the day at lower air temperatures, desert iguanas permitted a closer approach before initiating escape. While basking after emergence from burrows, lizards escaped into burrows; later in the day they fled. Lizards that fled had high body temperatures; a single individual captured immediately after entering a burrow had a lower body temperature. Lizards presumably enter burrows when low body temperature limits the running speed, but burrow use is costly because attainment of the activity temperature is delayed because of time elapsed and the temperature decrease in burrows.

Incubation temperatures of the northern shoveler

1979 ◽  
Vol 57 (5) ◽  
pp. 1052-1056 ◽  
Author(s):  
Alan D. Afton
Keyword(s):  
Regression Analysis ◽  
Body Temperature ◽  
Multiple Regression Analysis ◽  
Cooling Rate ◽  
Breeding Season ◽  
Factors Affecting ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Temperature Records ◽  
Incubation Temperatures

Egg air cell and nest air temperatures, measured in nests of wild northern shovelers near Delta, Manitoba, Canada, averaged 36.1 and 32.0 °C, respectively. Mean brood patch temperature of one captive incubating hen was 39.5 °C. Body temperature of 16 wild incubating hens averaged 41.1 °C. An egg cooling rate of 0.22 °C/1 °C h−1 was calculated from temperature records of 170 incubation recesses. Factors affecting egg cooling during recesses were investigated using multiple regression analysis. Statements in the literature that incubation by Anatidae begins upon termination of laying are not supported by available data. Incubation by waterfowl, as in passerines, apparently begins gradually during the laying period. Air and ground temperatures, by influencing egg cooling rates during incubation, may have been important ultimate factors determining the breeding range and timing of the breeding season for the northern shoveler.

Risk factors affecting escape behaviour by Puerto Rican Anolis lizards

2006 ◽  
Vol 84 (4) ◽  
pp. 495-504 ◽  
Author(s):  
W.E. Cooper
Keyword(s):  
Risk Factors ◽  
Puerto Rican ◽  
Ground Level ◽  
Flight Initiation Distance ◽  
Running Speed ◽  
Escape Behaviour ◽  
Factors Affecting ◽  
Narrow Temperature Range ◽  
Approach Distance ◽  
Flight Initiation

Approach distance (flight initiation distance) and escape methods depend on predation risk. I studied escape methods and effects of risk factors (temperature, perch height and orientation, conspicuousness) on approach distance in seven Puerto Rican anoles. Approach distance increased as temperature decreased in Anolis gundlachi Peters, 1876, presumably because of decreasing running speed, but not in other species (probably because of narrow temperature range). Perch height and approach distance varied inversely in four arboreal species that escape upward, positively in two grass–bush species that are more conspicuous when higher and flee downward, and were unrelated in cryptic Anolis stratulus Cope, 1861. Approach distance was shortest in cryptic A. stratulus and shorter intraspecifically in three species for partially concealed lizards and at sites providing more cover in two species. Approach distance was shorter for A. gundlachi on vertical than nonvertical perches, suggesting that ease of escape upward affects assessed risk. Escape behaviours have been proposed to vary among anole ecomorphs. Grass–bush species fled downward as proposed, or horizontally near ground level. Contrary to predictions of escape downward by trunk–ground and upward by trunk–crown anoles, all arboreal species escaped upward. Only trunk anoles were proposed to use squirreling, but species from four ecomorphs did as well.

Factors affecting escape behavior of Iberian green frogs (Rana perezi)

2005 ◽  
Vol 83 (9) ◽  
pp. 1189-1194 ◽  
Author(s):  
José Martín ◽  
Juán José Luque-Larena ◽  
Pilar López
Keyword(s):  
Body Size ◽  
Predation Risk ◽  
Vegetation Cover ◽  
Escape Response ◽  
Water Surface ◽  
Escape Behavior ◽  
Theoretical Models ◽  
Factors Affecting ◽  
Approach Distance ◽  
Rana Perezi

Theoretical models and empirical evidence suggest that prey should not flee immediately upon detecting an approaching predator, but instead should adjust their escape response to minimize the costs of flight. Similarly, after deciding to escape, animals should tend to adjust the magnitude and characteristics of their escape response according to the perceived level of predation risk. Although these hypotheses have been tested in some prey types, it remains for their applicability to a wider range of taxa to be ascertained and for a larger variety of microhabitat and environmental conditions to be considered. We simulated predator approaches to Iberian green frogs (Rana perezi Seoane, 1885) in the field. Frogs were approached while they were foraging alone at the edge of water, and they escaped by jumping into the water. Results showed that escape decisions of frogs are influenced by microhabitat variables and body size. Both the approach distance allowed to the predator and the distance jumped by the frogs in response to the approach were positively correlated with the initial distance of the frog from the water's edge; they were also dependent on vegetation cover at the edge of and in the water. Small frogs appeared to rely on crypsis more than large frogs and allowed shorter predator approach distances. They also remained still on the water surface after jumping more often than large frogs. We conclude that such flexibility in the escape response may allow frogs to reduce predation risk without incurring excessive costs.

Effects of predation risk factors on escape behavior by Balearic lizards (Podarcis lilfordi) in relation to optimal escape theory

2009 ◽  
Vol 30 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Dror Hawlena ◽  
Valentín Pérez-Mellado ◽  
William Cooper
Keyword(s):  
Risk Factors ◽  
Predation Risk ◽  
Escape Behavior ◽  
Weather Conditions ◽  
Predator Prey ◽  
Escape Theory ◽  
Approach Speed ◽  
Podarcis Lilfordi ◽  
Effects Of Temperature ◽  
Flight Initiation

AbstractEscape theory predicts that flight initiation distance (FID = predator-prey distance when escape begins) increases as predation risk increases. We tested effects of variation of approach speed and directness, predator persistence, concealment, and weather conditions on FID in the Balearic lizard (Podarcis lilfordi) by ourselves simulating predators. We examined effects of directness of approach on probability of fleeing and of repeated approach on entering refuge and distance fled. As predicted, FID was greater for faster approach speed, more direct approach, during second than first approaches, and when lizards were exposed than partially concealed. Other effects of directness of approach and repeated approach also were as predicted by greater assessed risk by the lizards. The proportion of individuals that fled was greater for direct than indirect approaches. The proportion of lizards that entered refuges and distance fled were greater during the second of two successive approaches. Effects of weather on FID were complex. FID was shortest in the warmest conditions with no noticeable wind, when lizards were active. Lizards were inactive and basked in the other conditions. FID was longest at 20°C without wind, and intermediate FID occurred at 18°C in windy conditions. We present hypotheses for weather effects. Tests are needed to unravel effects of temperature and wind speed. All predictions of escape theory for simple risk factors, i.e., all except than weather conditions, were confirmed. Escape theory successfully predicts FID for these risks in P. lilfordi, other lacertids, and more broadly, in ecologically and taxonomically diverse lizards.

Studying the Birth Outcome in Tikrit Teaching Hospital

2018 ◽  
Vol 1 (1) ◽  
pp. 55-57
Author(s):  
Areej Noaman
Keyword(s):  
Risk Factors ◽  
Developing Countries ◽  
Teaching Hospital ◽  
Birth Outcome ◽  
Morbidity And Mortality ◽  
Healthy Baby ◽  
Factors Affecting ◽  
Neonatal Deaths ◽  
Healthy Mother

  Background : A successful birth outcome is defined as the birth of a healthy baby to a healthy mother. While relatively low in industrialized world, maternal and fetal morbidity and mortality and neonatal deaths occur disproportionately in developing countries. Aim of the Study: To assess birth outcome and identify some risk factors affecting it for achieving favorable birth outcome in Tikrit Teaching Hospital

Does HbA1cc Play a Role in the Development of Cardiovascular Diseases?

2018 ◽  
Vol 24 (24) ◽  
pp. 2876-2882 ◽  
Author(s):  
Kailash Prasad
Keyword(s):  
Risk Factors ◽  
Cardiovascular Diseases ◽  
Cardiovascular System ◽  
Half Life ◽  
Serum Levels ◽  
Serum Glucose ◽  
Cvd Risk ◽  
Factors Affecting ◽  
Diagnosis And Management ◽  
Coronary Artery Atherosclerosis

Cardiovascular diseases (CVD) may be mediated through increases in the cardiovascular risk factors. Hemoglobin A1c (HbA1c) also called glycated hemoglobin is presently used for the diagnosis and management of diabetes. It has adverse effects on cardiovascular system. This review deals with its synthesis and effects on the cardiovascular system. The serum levels of HbA1c have been reported to be affected by various factors including, the lifespan of erythrocytes, factors affecting erythropoiesis, agents interfering glycation of Hb, destruction of erythrocytes, drugs that shift the formation of Hb, statins, and drugs interfering the HbA1c assay. Levels of HbA1c are positively correlated with serum glucose and advanced glycation end products ( AGE), but no correlation between AGE and serum glucose. AGE cannot replace HbA1c for the diagnosis and management of diabetes because there is no correlation of AGE with serum glucose, and because the half-life of protein with which glucose combines is only 14-20 days as compared to erythrocytes which have a half-life of 90-120 days. HbA1c is positively associated with CVD such as the carotid and coronary artery atherosclerosis, ischemic heart disease, ischemic stroke and hypertension.HbA1c induces dyslipidemia, hyperhomocysteinemia, and hypertension, and increases C-reactive protein, oxidative stress and blood viscosity that would contribute to the development of cardiovascular diseases. In conclusion, HbA1c serves as a useful marker for the diagnosis and management of diabetes. AGE cannot replace HbA1c in the diagnosis and management of diabetes. There is an association of HbA1c with CVD which be mediated through modulation of CVD risk factors.

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