Individual variation affects departure rate from the natal pond in an ephemeral pond-breeding anuran

2008 ◽  
Vol 86 (4) ◽  
pp. 260-267 ◽  
Author(s):  
Nathan D. Chelgren ◽  
Daniel K. Rosenberg ◽  
Selina S. Heppell ◽  
Alix I. Gitelman
Keyword(s):  
Body Size ◽  
Individual Variation ◽  
Environmental Variability ◽  
Pitfall Traps ◽  
Intrinsic State ◽  
Time To Event ◽  
Rana Aurora ◽  
Size At Metamorphosis ◽  
Event Model ◽  
And Behavior

Frogs exhibit extreme plasticity and individual variation in growth and behavior during metamorphosis, driven by interactions of intrinsic state factors and extrinsic environmental factors. In northern red-legged frogs ( Rana aurora Baird and Girard, 1852), we studied the timing of departure from the natal pond as it relates to date and size of individuals at metamorphosis in the context of environmental uncertainty. To affect body size at metamorphosis, we manipulated food availability during the larval stage for a sample (317) of 1045 uniquely marked individuals and released them at their natal ponds as newly metamorphosed frogs. We recaptured 34% of marked frogs in pitfall traps as they departed and related the timing of their initial terrestrial movements to individual properties using a time-to-event model. Median age at first capture was 4 and 9 days postmetamorphosis at two sites. The rate of departure was positively related to body size and to date of metamorphosis. Departure rate was strongly negatively related to time elapsed since rainfall, and this effect was diminished for smaller and later metamorphosing frogs. Individual variation in metamorphic traits thus affects individuals’ responses to environmental variability, supporting a behavioral link with variation in survival associated with these same metamorphic traits.

Effects of individual variation in age and size at metamorphosis on growth and survivorship of southern toad (Bufo terrestris) metamorphs

1999 ◽  
Vol 77 (6) ◽  
pp. 944-951 ◽  
Author(s):  
Christopher W Beck ◽  
Justin D Congdon
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Individual Variation ◽  
Growth And Survival ◽  
Bufo Terrestris ◽  
Size At Metamorphosis ◽  
Total Growth ◽  
Survival And Growth ◽  
Toad Bufo ◽  
Positive Effect

We conducted two experiments with the southern toad (Bufo terrestris) to examine whether individual variation in (i) metamorph body size and metabolic rate and (ii) age and size at metamorphosis were related to differences in survivorship or growth rate of postmetamorphic individuals. Results from the first experiment indicated that neither initial body size nor metabolic rate was related to survivorship or growth. Results from the second experiment showed that (i) size at metamorphosis was positively correlated with survivorship to first census (after 2 weeks), (ii) age and size at metamorphosis had no significant effect on survivorship from first to second census (after 2 months), (iii) size at metamorphosis had a marginally significant positive effect on survivorship from metamorphosis to second census, and (iv) age and size at metamorphosis were not significantly correlated with total growth. Our results suggest that in the southern toad, size at metamorphosis may lead to early differences in survival, size, and growth that later disappear. Furthermore, early differences in growth and survival attributable to size at metamorphosis are not due to size-related differences in metabolic rate. Therefore, although age and size at metamorphosis affect metabolic rate, they may not be related to fitness via effects on postmetamorphic survival and growth.

scholarly journals Plasticity and flexibility in the anti-predator responses of treefrog tadpoles

2021 ◽  
Vol 75 (10) ◽  
Author(s):  
Castellano Sergio ◽  
Racca Luca ◽  
Friard Olivier
Keyword(s):  
Life History ◽  
Body Size ◽  
Natural Selection ◽  
Phenotypic Plasticity ◽  
Plastic Response ◽  
Heritable Variation ◽  
Size At Metamorphosis ◽  
Adaptive Phenotypic Plasticity ◽  
Similar Body ◽  
And Behavior

Abstract Tadpoles can respond to perceived predation risk by adjusting their life history, morphology, and behavior in an adaptive way. Adaptive phenotypic plasticity can evolve by natural selection only if there is variation in reaction norms and if this variation is, at least in part, heritable. To provide insights into the evolution of adaptive phenotypic plasticity, we analyzed the environmental and parental components of variation in predator-induced life history (age and size at metamorphosis), morphology (tail depth), and behavior of Italian treefrog tadpoles (Hyla intermedia). Using an incomplete factorial design, we raised tadpoles either with or without caged predators (dragonfly larvae, gen. Aeshna) and, successively, we tested them in experimental arenas either with or without caged predators. Results provided strong evidence for an environmental effect on all three sets of characters. Tadpoles raised with caged predators (dragonfly larvae, gen. Aeshna) metamorphosed earlier (but at a similar body size) and developed deeper tails than their fullsib siblings raised without predators. In the experimental arenas, all tadpoles, independent of their experience, flexibly changed their activity and position, depending on whether the cage was empty or contained the predator. Tadpoles of the two experimental groups, however, showed different responses: those raised with predators were always less active than their predator-naive siblings and differences slightly increased in the presence of predators. Besides this strong environmental component of phenotypic variation, results provided evidence also for parental and parental-by-environment effects, which were strong on life-history, but weak on morphology and behavior. Interestingly, additive parental effects were explained mainly by dams. This supports the hypothesis that phenotypic plasticity might mainly depend on maternal effects and that it might be the expression of condition-dependent mechanisms. Significance statement Animals, by plastically adjusting their phenotypes to the local environments, can often sensibly improve their chances of survival, suggesting the hypothesis that phenotypic plasticity evolved by natural selection. We test this hypothesis in the Italian treefrog tadpoles, by investigating the heritable variation in the plastic response to predators (dragonfly larvae). Using an incomplete factorial common-garden experiment, we showed that tadpoles raised with predators metamorphosed earlier (but at similar body size), developed deeper tails, and were less active than their siblings raised without predators. The plastic response varied among families, but variation showed a stronger maternal than paternal component. This suggests that plasticity might largely depend on epigenetic factors and be the expression of condition-dependent mechanisms.

scholarly journals Intraspecific Variation in Maximum Ingested Food Size and Body Mass in Varecia rubra and Propithecus coquereli

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Adam Hartstone-Rose ◽  
Jonathan M. G. Perry
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Individual Variation ◽  
Size Variation ◽  
Maximum Size ◽  
Least Squares Regression ◽  
Scaling Relationship ◽  
Varecia Rubra ◽  
Food Size ◽  
The Relationship

In a recent study, we quantified the scaling of ingested food size (Vb )—the maximum size at which an animal consistently ingests food whole—and found that Vb scaled isometrically between species of captive strepsirrhines. The current study examines the relationship between Vb and body size within species with a focus on the frugivorous Varecia rubra and the folivorous Propithecus coquereli. We found no overlap in Vb between the species (all V. rubra ingested larger pieces of food relative to those eaten by P. coquereli), and least-squares regression of Vb and three different measures of body mass showed no scaling relationship within each species. We believe that this lack of relationship results from the relatively narrow intraspecific body size variation and seemingly patternless individual variation in Vb within species and take this study as further evidence that general scaling questions are best examined interspecifically rather than intraspecifically.

Human Behavior, Demography, and Paleoenvironment on the Colorado Plateaus

1985 ◽  
Vol 50 (3) ◽  
pp. 537-554 ◽  
Author(s):  
Jeffrey S. Dean ◽  
Robert C. Euler ◽  
George J. Gumerman ◽  
Fred Plog ◽  
Richard H. Hevly ◽  
...  
Keyword(s):  
Adaptive Systems ◽  
Agricultural Intensification ◽  
Environmental Variability ◽  
American Southwest ◽  
Sociocultural Factors ◽  
Mobility Shift ◽  
Resource Stress ◽  
Settlement Location ◽  
Regional Population ◽  
And Behavior

Archaeological and paleoenvironmental data are integrated in an investigation of culture change among the Anasazi of the American Southwest by a conceptual model of the interaction among environment, population, and behavior, the major determinants of human adaptive systems. Geological, palynological, and dendrochronological reconstructions of low and high frequency environmental variability coupled with population trends are used to specify periods of regional population-resource stress that should have elicited behavioral responses. Examination of these periods elucidates the range of responses employed and clarifies the adaptive contributions of mobility, shift of settlement location, subsistence mix, exchange, ceremonialism, agricultural intensification, and territoriality. These results help differentiate responses that are triggered by environmental variability from those stimulated primarily by demographic or sociocultural factors. These analyses also demonstrate the adaptive importance of amplitude, frequency, temporal, spatial, and durational aspects of environmental variability compared to the commonly invoked but simplistic contrast between “favorable” and “unfavorable” conditions.

scholarly journals Emergence ecology of the critically endangered Urothemis edwardsii in a new colonized site in El Kala National Park (Algeria): conservation implications

2019 ◽  
pp. 137-142
Author(s):  
Baaloudj Affef
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Sexual Size Dimorphism ◽  
The Body ◽  
Microhabitat Selection ◽  
Conservation Implications ◽  
And Behavior ◽  
The Relationship ◽  
The Vertical Distribution ◽  
Dragonfly Species

Urothemis edwardsii is one of the most threatened dragonfly species in the Mediterranean. Recent investigations and conservation efforts have increased the local geographic distribution of the species in Northeast Algeria, where a new population (named El Graeate) has been discovered. In the absence of information about the biology and behavior of U. edwardsii in this new site, a study was conducted on the emergence ecology of the species taking into account the temporal pattern of emergence, sex ratio, body size and microhabitat selection. Emergence, which was quite asynchronous, lasted for 50 days, with 50% of the population emerging within the first half of the period. Sex ratio at emergence was slightly female biased despite the absence of sexual size dimorphism, suggesting that size is not the only driving force behind mortality bias during the larval stage. There was a slight seasonal increase in the body size of exuviae (exoskeletons) in both sexes. Microhabitat selection, assessed as the vertical stratification of exuviae at ecdysis, was positively correlated with the height of supporting plants, but the relationship reached a plateau suggesting that there are predetermined limits to the vertical distribution of exuviae. These data will be essential for the future species protection, restoration and management attempts in the region.

Abstract P119: High Stress Reasons for Immigration Affect Diabetes Risk, Body Size and Behavior: The Africans in America Study

Circulation ◽  
2018 ◽  
Vol 137 (suppl_1) ◽  
Author(s):  
Sara M Briker ◽  
J Damascene Kabakambira ◽  
Rafeal L Baker ◽  
Christopher W DuBose ◽  
Lilian S Mabundo ◽  
...  
Keyword(s):  
Body Size ◽  
Sleep Duration ◽  
Allostatic Load ◽  
High Stress ◽  
The United States ◽  
Washington Dc ◽  
Subsaharan Africa ◽  
Medical Histories ◽  
And Behavior ◽  
Visceral Adipose

Introduction: Leaving Africa to live in the United States is stressful. Due to oversecretion of glucocortoids and catecholamines, stress has biologic consequences. No data exists on whether Africans who come to America for reasons associated with high stress have a higher rate of conditions such as obesity, diabetes and hypertension than Africans who come for low stress reasons. Goals: Working with the Africans in America cohort and using allostatic load score (ALS) to measure biologic stress, our objectives were to (a) rank by ALS the 5 most common reasons for immigration (work, study, asylum/refugee, family unification and lottery); (b) divide the cohort in to 2 groups: high stress (combining the individuals with the 3 reasons with the highest ALS) and low stress (combining the individuals with the lowest ALS); (c) compare body size, visceral adipose tissue (VAT), glucose, BP, sleep duration and smoking in Africans with high and low stress. Methods: OGTT and abdominal CT scans were performed in 114 African immigrants (68% male, age 41±10, range22-62y) born in subSaharan Africa but living in Washington, DC. Results: Ranked from highest to lowest, ALS for each reason for immigration was: work 3.18±1.71; asylum/refugee 2.68±1.46; study 2.66±1.88; family 1.77±1.27; lottery 1.60±1.27. Hence, high stress reasons for immigration were: work, asylum/refugee and study. Low stress reasons were: family and lottery. ALS in high vs. low stress reasons for immigration were: 2.81±1.74 vs. 1.72±1.25, P<0.01. BP did not vary by group. However, Africans with high stress had a higher BMI, more VAT and hyperglycemia than Africans with low stress (Table). Africans with high stress also had a greater tendency to sleep <7h per night and smoke (Table). Conclusions: High stress reasons for immigration include work, asylum/refugee and study. As obesity, hyperglycemia, and behaviors such as decreased sleep duration and smoking are associated with high stress reasons for immigration, medical histories when possible should include reason for immigration.

scholarly journals Phenology of hatching, emergence, and end-of-season body size in young-of-year coho salmon in thermally contrasting streams draining the Copper River Delta, Alaska

2019 ◽  
Vol 76 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Emily Y. Campbell ◽  
Jason B. Dunham ◽  
Gordon H. Reeves ◽  
Steve M. Wondzell
Keyword(s):  
Body Size ◽  
Environmental Variability ◽  
Coho Salmon ◽  
Growing Season ◽  
Early Life History ◽  
Growth And Survival ◽  
Individual Fitness ◽  
Marked Variability ◽  
Thermal Regimes ◽  
Body Sizes

Phenology can be linked to individual fitness, particularly in strongly seasonal environments where the timing of events has important consequences for growth, condition, and survival. We studied the phenology of coho salmon (Oncorhynchus kisutch) hatching and emergence in streams with contrasting thermal variability but in close geographic proximity. Following emergence, we tracked body sizes of cohorts of young-of-year fish until the end of the growing season. Hatch and emergence occurred at the same time among streams with marked variability in thermal regimes. We demonstrate that this can be explained in part by the thermal units accumulated during embryo development. At the end of the first growing season, there were some differences in body size, but overall fish size was similar among streams despite strong differences in thermal regimes. Collectively, these results provide novel insights into the interactions between environmental variability and the early life-history stages of coho salmon, furthering our understanding of the consequences of phenology on growth and survival for individuals within the critical first summer of life.

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