The trade-off between foraging activity and predation risk for Rana temporaria in different food environments

2000 ◽  
Vol 78 (5) ◽  
pp. 734-739 ◽  
Author(s):  
Peter Eklöv ◽  
Charlotta Halvarsson
Keyword(s):  
Predation Risk ◽  
Rana Temporaria ◽  
Food Resources ◽  
The Other ◽  
Foraging Activity ◽  
Trade Off ◽  
Predator Prey ◽  
Predation Mortality ◽  
Frog Rana Temporaria ◽  
Predatory Larva

We evaluated the trade-off between foraging activity and predation risk for larvae of an anuran species presented with different types of food resources. In the laboratory we examined the effects of benthic and phytoplankton resources and the two types combined on the activity and mortality of larvae of the common frog, Rana temporaria, exposed to predatory larva, Dytiscus marginalis. Predation mortality of tadpoles increased with the duration of the experiment and was highest in the presence of the phytoplankton resource alone. This was explained by a decrease in prey activity in the benthic- and combined-resource treatments when the predator was present, whereas in the phytoplankton treatment, the activity of the tadpoles were similar in the presence or absence of the predator. In the presence of the predator, prey mainly used the bottom of the aquarium in the benthic- and combined-resource treatments. In contrast, in the phytoplankton treatment they used the water column more than in the other treatments. In the presence of the predator, the prey had a lower consumption rate in the phytoplankton treatment than in the other treatments. Predator activity did not change among treatments. The results suggest that the trade-off between foraging activity and predation mortality for anuran larvae is strongly affected by the types of food resources present in the environment.

scholarly journals VIII. On the structure and development of the skull of the common frog ( Rana temporaria , L.)

1871 ◽  
Vol 161 ◽  
pp. 137-211 ◽  
Keyword(s):  
Rana Temporaria ◽  
The Other ◽  
Common Frog ◽  
Frog Rana Temporaria ◽  
The Subject ◽  
The Common ◽  
Working Out

Since the sending in of my last communication, that on the Skull of the Fowl, our knowledge of the morphology of the facial arches has been very greatly extended by Professor Huxley’s invaluable paper “On the Representatives of the Malleus and the Incus of the Mammalia in the other Vertebrata” (see Proc. Zool. Soc. May 1869, pp. 391-407). After comparing the components of the mandibular and hyoid arches in an extended series of vertebrate types, the author concludes his paper by saying (p. 406), “in the higher Amphibia changes of a most remarkable kind take place, of which I do not now propose to speak, as my friend Mr. Parker is engaged in working out that part of the subject.”

Effects of predator exposure on Hsp70 expression and survival in tadpoles of the Common Frog (Rana temporaria)

2011 ◽  
Vol 89 (12) ◽  
pp. 1249-1255 ◽  
Author(s):  
Jesper Givskov Sørensen ◽  
Volker Loeschcke ◽  
Juha Merilä ◽  
Anssi Laurila
Keyword(s):  
Predation Risk ◽  
Rana Temporaria ◽  
Cellular Level ◽  
Hsp70 Expression ◽  
Common Frog ◽  
Beneficial Effects ◽  
Prey Behavior ◽  
Frog Rana Temporaria ◽  
The Common ◽  
Free Ranging

Predator-induced changes in prey behavior and morphology are widespread, but little is known about physiological and cellular-level responses in prey in response to predation risk. We investigated whether predator (larvae of the dragonfly Aeshna Fabricius, 1775) presence elevated the expression level of heat-shock protein 70 (Hsp70)—a commonly found response to stress—in tadpoles of the Common Frog ( Rana temporaria L., 1758). In another experiment, we tested the survival of tadpoles in the presence of a free-ranging predator. Prior to this encounter, the tadpoles were exposed to either an Hsp-inducing environmental stress in the form of heat (31 °C) or to predator cues from a caged predator. We found no evidence for increased Hsp70 expression in tadpoles either in the presence of fed or starved predators. We did not find any effects of prior exposure to neither heat nor predator presence on survival at the end of experiment. Our results do not point to either Hsp70-mediated effect of predator-induced responses or to beneficial effects of the stress response on survival under predation risk.

scholarly journals To eat and not be eaten: diurnal mass gain and foraging strategies in wintering great tits

2018 ◽  
Vol 285 (1874) ◽  
pp. 20172868 ◽  
Author(s):  
Maria Moiron ◽  
Kimberley J. Mathot ◽  
Niels J. Dingemanse
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Mass Gain ◽  
Random Regression ◽  
Foraging Strategies ◽  
Foraging Activity ◽  
Trade Off ◽  
Diurnal Patterns ◽  
Body Mass Gain ◽  
Starvation Risk

Adaptive theory predicts that the fundamental trade-off between starvation and predation risk shapes diurnal patterns in foraging activity and mass gain in wintering passerine birds. Foragers mitigating both types of risk should exhibit a bimodal distribution (increased foraging and mass gain early and late in the day), whereas both foraging and mass gains early (versus late) during the day are expected when the risk of starvation (versus predation) is greatest. Finally, relatively constant rates of foraging and mass gain should occur when the starvation–predation risk trade-off is independent of body mass. Using automated feeders with integrated digital balances, we estimated diurnal patterns in foraging and body mass gain to test which ecological scenario was best supported in wintering great tits Parus major . Based on data of 40 consecutive winter days recording over 12 000 body masses of 28 individuals, we concluded that birds foraged and gained mass early during the day, as predicted by theory when the starvation–predation risk trade-off is mass-dependent and starvation risk outweighs predation risk. Slower explorers visited the feeders more often, and decreased their activity along the day more strongly, compared with faster explorers, thereby explaining a major portion of the individual differences in diurnal patterning of foraging activity detected using random regression analyses. Birds did not differ in body mass gain trajectories, implying both that individuals differed in the usage of feeders, and that unbiased conclusions regarding how birds resolve starvation–predation risk trade-off require the simultaneous recording of foraging activity and body mass gain trajectories. Our study thereby provides the first unambiguous demonstration that individual birds are capable of adjusting their diurnal foraging and mass gain trajectories in response to ecological predictors of starvation risk as predicted by starvation–predation risk trade-off theory.

The First Record of Tesselated Snake, Natrix tesselata Laurenti, 1768 in the Central Chernozem Territory of Russia and Some Other Results of the Herpetological Research in the Upper Don

2011 ◽  
Vol 4 (2) ◽  
pp. 192-194
Author(s):  
Georgy A. Lada ◽  
V. Y. Nedosekin
Keyword(s):  
Rana Temporaria ◽  
First Record ◽  
Isolated Population ◽  
Common Frog ◽  
Northern Border ◽  
Frog Rana Temporaria ◽  
Bombina Bombina ◽  
Central Chernozem

A small isolated population of tesselated snake, Natrix tesselata was found in the Upper Don (Lipetsk Region, Russia). It is the first record of this species in the Central Chernozem Territory of Russia, which is separated from the northern border of the main range by the distance of about 200 km. An isolated population of common frog, Rana temporaria and phenetically peculiar population of fire-bellied toad, Bombina bombina are found here too. Faunistic aspect of new herpetological records is discussed.

scholarly journals Black Hole Algorithm for Sustainable Design of Counterfort Retaining Walls

2020 ◽  
Vol 12 (7) ◽  
pp. 2767 ◽  
Author(s):  
Víctor Yepes ◽  
José V. Martí ◽  
José García
Keyword(s):  
Black Hole ◽  
Sustainable Design ◽  
Retaining Walls ◽  
The Other ◽  
Trade Off ◽  
Construction Company ◽  
Geometric Variables ◽  
The Stability ◽  
The Cost ◽  
Black Hole Algorithm

The optimization of the cost and CO 2 emissions in earth-retaining walls is of relevance, since these structures are often used in civil engineering. The optimization of costs is essential for the competitiveness of the construction company, and the optimization of emissions is relevant in the environmental impact of construction. To address the optimization, black hole metaheuristics were used, along with a discretization mechanism based on min–max normalization. The stability of the algorithm was evaluated with respect to the solutions obtained; the steel and concrete values obtained in both optimizations were analyzed. Additionally, the geometric variables of the structure were compared. Finally, the results obtained were compared with another algorithm that solved the problem. The results show that there is a trade-off between the use of steel and concrete. The solutions that minimize CO 2 emissions prefer the use of concrete instead of those that optimize the cost. On the other hand, when comparing the geometric variables, it is seen that most remain similar in both optimizations except for the distance between buttresses. When comparing with another algorithm, the results show a good performance in optimization using the black hole algorithm.

Sign in / Sign up

Export Citation Format

Share Document