scholarly journals Torpor reduces predation risk by compensating for the energetic cost of antipredator foraging behaviours

2018 ◽  
Vol 285 (1893) ◽  
pp. 20182370 ◽  
Author(s):  
Christopher Turbill ◽  
Lisa Stojanovski
Keyword(s):  
Body Temperature ◽  
Energy Saving ◽  
Predation Risk ◽  
Energy Intake ◽  
Foraging Behaviour ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Behavioural Responses ◽  
Perceived Predation Risk ◽  
Starvation Risk

Foraging activity is needed for energy intake but increases the risk of predation, and antipredator behavioural responses, such as reduced activity, generally reduce energy intake. Hence, the mortality and indirect effects of predation risk are dependent on the energy requirements of prey. Torpor, a controlled reduction in resting metabolism and body temperature, is a common energy-saving mechanism of small mammals that enhances their resistance to starvation. Here we test the hypothesis that torpor could also reduce predation risk by compensating for the energetic cost of antipredator behaviours. We measured the foraging behaviour and body temperature of house mice in response to manipulation of perceived predation risk by adjusting levels of ground cover and starvation risk by 24 h food withdrawal every third day. We found that a voluntary reduction in daily food intake in response to lower cover (high predation risk) was matched by the extent of a daily reduction in body temperature. Our study provides the first experimental evidence of a close link between energy-saving torpor responses to starvation risk and behavioural responses to perceived predation risk. By reducing the risk of starvation, torpor can facilitate stronger antipredator behaviours. These results highlight the interplay between the capacity for reducing metabolic energy expenditure, optimal decisions about foraging behaviour and the life-history ecology of prey.

scholarly journals Kinematics of males Eupalaestrus weijenberghi (Araneae, Theraphosidae) locomotion on different substrates and inclines

2019 ◽  
Author(s):  
Valentina Silva-Pereyra ◽  
C Gabriel Fábrica ◽  
Carlo M Biancardi ◽  
Fernando Pérez-Miles
Keyword(s):  
Energy Saving ◽  
The Body ◽  
Mechanical Work ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Time Lags ◽  
Gait Patterns ◽  
Unit Distance ◽  
Body Segments ◽  
Gait Parameters

Background: For males of several terrestrial spiders the reproductive success depends to their locomotors performances. However, their mechanics of locomotion has been scarcely investigated. Aim of this work was to describe the gait patterns, analyse the gait parameters, the mechanics of locomotion and the energy saving mechanisms of Eupalaestrus weijenberghi (Araneae, Theraphosidae) on different inclinations and surfaces. Methods: Tarantulas were collected and marked for kinematic analysis. Free displacements, both at level and on incline, were recorded using two different experimental surfaces: glass and Teflon. Body segments of the experimental animals have been measured, weighted and their centre of mass experimentally determined. Through the reconstruction of trajectories of the body segments, we estimate the mechanical internal and external works and analysed the gait patterns. Results: Four gait patterns have been described, but spiders mainly employed a walk-trot-like gait. Significant differences between the first two pairs and the second two pairs were detected. No significant differences were detected among different planes or surfaces in duty factor, time lags, stride frequency and stride length. However, postural changes were observed on slippery surfaces. The mechanical work at level was lower than expected. In all conditions, the external work, and within it the vertical work, accounted for almost all the total mechanical work. The internal work was extremely low, and did not increase with gradient. Discussion: Our results support the idea of the two quadrupeds in series: the anterior composed by the first two pairs of limbs, with more explorative and steering purpose, and the posterior more involved in supporting the body weight. The mechanical work to move one unit mass a unit distance is almost constant among the different species. However spiders show lower values than expected. Minimizing the mechanical work could help to limit the metabolic energy expenditure that, in small animals, is relatively very high. However, the energy recovery due to the inverted pendulum mechanics only account for a small part of energy saving. Adhesive setae present in the tarsal, scopulae and claw tufts, would participate in different ways during different moments of the step cycle, compensating part of the energetic cost on gradient, and helping to maintain constant the gait parameters.

Morphological and behavioural responses of frog tadpoles to perceived predation risk: A possible role for corticosterone mediation?

Ecoscience ◽  
2010 ◽  
Vol 17 (1) ◽  
pp. 100-108 ◽  
Author(s):  
Thomas J. Hossie ◽  
Bastien Ferland-Raymond ◽  
Gary Burness ◽  
Dennis L. Murray
Keyword(s):  
Predation Risk ◽  
Behavioural Responses ◽  
Frog Tadpoles ◽  
Perceived Predation Risk

scholarly journals Kinematics of males Eupalaestrus weijenberghi (Araneae, Theraphosidae) locomotion on different substrates and inclines

2019 ◽  
Author(s):  
Valentina Silva-Pereyra ◽  
C Gabriel Fábrica ◽  
Carlo M Biancardi ◽  
Fernando Pérez-Miles
Keyword(s):  
Energy Saving ◽  
The Body ◽  
Mechanical Work ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Time Lags ◽  
Gait Patterns ◽  
Unit Distance ◽  
Body Segments ◽  
Gait Parameters

Background: For males of several terrestrial spiders the reproductive success depends to their locomotors performances. However, their mechanics of locomotion has been scarcely investigated. Aim of this work was to describe the gait patterns, analyse the gait parameters, the mechanics of locomotion and the energy saving mechanisms of Eupalaestrus weijenberghi (Araneae, Theraphosidae) on different inclinations and surfaces. Methods: Tarantulas were collected and marked for kinematic analysis. Free displacements, both at level and on incline, were recorded using two different experimental surfaces: glass and Teflon. Body segments of the experimental animals have been measured, weighted and their centre of mass experimentally determined. Through the reconstruction of trajectories of the body segments, we estimate the mechanical internal and external works and analysed the gait patterns. Results: Four gait patterns have been described, but spiders mainly employed a walk-trot-like gait. Significant differences between the first two pairs and the second two pairs were detected. No significant differences were detected among different planes or surfaces in duty factor, time lags, stride frequency and stride length. However, postural changes were observed on slippery surfaces. The mechanical work at level was lower than expected. In all conditions, the external work, and within it the vertical work, accounted for almost all the total mechanical work. The internal work was extremely low, and did not increase with gradient. Discussion: Our results support the idea of the two quadrupeds in series: the anterior composed by the first two pairs of limbs, with more explorative and steering purpose, and the posterior more involved in supporting the body weight. The mechanical work to move one unit mass a unit distance is almost constant among the different species. However spiders show lower values than expected. Minimizing the mechanical work could help to limit the metabolic energy expenditure that, in small animals, is relatively very high. However, the energy recovery due to the inverted pendulum mechanics only account for a small part of energy saving. Adhesive setae present in the tarsal, scopulae and claw tufts, would participate in different ways during different moments of the step cycle, compensating part of the energetic cost on gradient, and helping to maintain constant the gait parameters.

Design of experimental food patches to measure foraging intensity for octopus: a case study with the giant Pacific octopus Enteroctopus dofleini

2020 ◽  
Author(s):  
Stephanie Chancellor ◽  
David Scheel ◽  
Joel S Brown
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Habitat Preferences ◽  
High Tide ◽  
Intertidal Habitat ◽  
Camera System ◽  
Subtidal Habitat ◽  
Enteroctopus Dofleini ◽  
Nontarget Species

ABSTRACT In a study of the foraging behaviour of the giant Pacific octopus Enteroctopus dofleini, we designed two types of experimental food patches to measure habitat preferences and perceptions of predation risk. The first patch successfully measured giving-up densities (GUDs), confirmed by octopus prey presence and higher foraging at sites with historically greater octopus presence. However, nontarget foragers also foraged on these experimental food patches. Our second floating patch design successfully excluded nontarget species from subtidal patches, and from intertidal patches at high tide, but allowed for foraging by E. dofleini. The second design successfully measured GUDs and suggested that octopus preferred foraging in a subtidal habitat compared to an intertidal habitat. We ascribe the higher GUD in the intertidal habitat to its higher predation risk relative to the subtidal habitat. The second patch design seems well suited for E. dofleini and, in conjunction with a camera system, could be used to provide behavioural indicators of the octopus's abundance, perceptions of habitat quality and predation risk.

scholarly journals Determination of Maintenance Energy Requirements for Fattening Castrated Korean Black Goats (Capra hircus coreanae)

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1543
Author(s):  
Sang-Ho Moon ◽  
Yeong Sik Yun ◽  
Na Yeon Kim ◽  
Sanguk Chung ◽  
Qi Man Zhang ◽  
...  
Keyword(s):  
Body Weight ◽  
Energy Intake ◽  
Energy Levels ◽  
Average Daily Gain ◽  
Nutrient Digestibility ◽  
Metabolic Energy ◽  
Energy Requirements ◽  
Capra Hircus ◽  
Maintenance Energy ◽  
Daily Gain

Twelve adult (10 months old) castrated Korean black goats, with an average initial body weight of 24.98 ± 3.7 kg, were used in this experiment to determine their maintenance energy requirements. Dry matter intakes (g/d, p = 0.945) were not affected by energy levels, but metabolic energy intake (kcal/d, p < 0.002) and average daily gain (g/d, p < 0.001) were significantly increased at higher energy levels. Nutrient digestibility was similar in the treatments, but crude fat digestibility increased with the addition of protective fat powder (p = 0.001). The energy required for fattening the castrated Korean black goats was estimated using the correlation between metabolic energy intake per dietary body weight and average daily gain per dietary body weight. The Y-axis intercept value was calculated to be 108.76 kcal/kg BW0.75 (p < 0.05, r2 = 0.6036), which was the metabolic energy requirement for maintaining the lives of the fattening Korean black goats. The estimated energy requirements of the black goat can improve specification techniques, such as the energy level and the amount of feed supply required for domestic black goats.

Modification of 0+ perch foraging behaviour by indirect cues of predation risk

2006 ◽  
Vol 15 (2) ◽  
pp. 118-124 ◽  
Author(s):  
J. Wanzenbock ◽  
V. N. Mikheev ◽  
A. F. Pasternak
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Indirect Cues

Perceived predation risk, parasitism, and the foraging behavior of a freshwater snail (Potamopyrgus antipodarum)

1998 ◽  
Vol 76 (10) ◽  
pp. 1878-1884 ◽  
Author(s):  
Edward P Levri
Keyword(s):  
Predation Risk ◽  
Foraging Behavior ◽  
Freshwater Snail ◽  
Potamopyrgus Antipodarum ◽  
Plain Water ◽  
Fish Diet ◽  
Fish Predator ◽  
Size Dependent ◽  
Individual Size ◽  
Perceived Predation Risk

Foraging behavior can be influenced by such factors as predation risk, individual size, and parasite infection. Snails (Potamopyrgus antipodarum) placed in tanks with large rocks were exposed to four types of water: (1) water with crushed snails, (2) water from a tank in which fish (Gobiomorphus cotidianus) were fed only trout chow, (3) water from a tank where the fish were also fed snails, and (4) plain water. Snails could respond by moving to the top of rocks (where algal food was present) or to the bottom of rocks (where the predation risk was lower). The snails responded to fish chemicals by moving to the bottom of rocks. The response was dependent on snail size and fish diet. Smaller snails moved to the bottom of rocks more than larger snails did. Trematode-infected snails were found on top of the rocks more than other classes of snails, but infected snails still moved to the bottom of rocks in response to the fish predator. Snails eaten by fish in the field tend to be smaller than snails in the overall available population. Thus, snails that are more vulnerable to predation respond more intensely to the odor of fish by moving to the bottom of rocks. This size-dependent response to fish appears to be independent of the occurrence of trematode infection.

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