Effects of Variation in Food Intake on Locomotory Performance of Juvenile Garter Snakes

Ford, Neil B.; Shuttlesworth, Gladis

doi:10.2307/1445298

Cited by 59 publications

(55 citation statements)

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“…embryonic development) (Dessauer and Fox, 1959;Garstka et al, 1985;Ford and Karges, 1987), but it is not well understood how the phase of the reproductive cycle may influence the metabolic costs of digestion and activity. Thamnophis marcianus is particularly well suited for such examinations because females continue to consume large meals throughout much of the reproductive cycle and, as an actively foraging species, these snakes exhibit a high propensity for physical activity (Ford and Shuttlesworth, 1986;Seigel et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

Patterns of oxygen consumption during simultaneously occurring elevated metabolic states in the viviparous snake,Thamnophis marcianus

Jackson

Leu

Ford

et al. 2015

Journal of Experimental Biology

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Snakes exhibit large factorial increments in oxygen consumption during digestion and physical activity, and long-lasting sub-maximal increments during reproduction. Under natural conditions, all three physiological states may occur simultaneously, but the integrated response is not well understood. Adult male and female checkered gartersnakes (Thamnophis marcianus) were used to examine increments in oxygen consumption (i.e. V O2 ) and carbon dioxide production (i.e. V CO2 ) associated with activity (Act), digestion (Dig) and post-prandial activity (Act+Dig). For females, we carried out these trials in the non-reproductive state, and also during the vitellogenic (V) and embryogenic (E) phases of a reproductive cycle. Endurance time (i.e. time to exhaustion, TTE) was recorded for all groups during Act and Act +Dig trials. Our results indicate that male and non-reproductive female T. marcianus exhibit significant increments in V O2 during digestion (∼5-fold) and activity (∼9-fold), and that Act+Dig results in a similar increment in V O2 (∼9-to 10-fold). During reproduction, resting V O2 increased by 1.6-to 1.7-fold, and peak increments during digestion were elevated by 30-50% above non-reproductive values, but values associated with Act and Act+Dig were not significantly different from non-reproductive values. During Act+Dig, endurance time remained similar for all of the groups in the present study. Overall, our results indicate that prioritization is the primary pattern of interaction in oxygen delivery exhibited by this species. We propose that the metabolic processes associated with digestion, and perhaps reproduction, are temporarily compromised during activity.

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Section: Introductionmentioning

confidence: 99%

Patterns of oxygen consumption during simultaneously occurring elevated metabolic states in the viviparous snake,Thamnophis marcianus

Jackson

Leu

Ford

et al. 2015

Journal of Experimental Biology

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“…Ford and Shuttlesworth, 1986;Garland and Else, 1987;Garland, 1988;Tsuji et al, 1989;Huey et al, 1990;Jayne and Bennett, 1990;Sorci et al, 1995;Wilson et al, 2002;Herrel and Bonneaud, 2012). Most studies exploring trade-offs at the whole-animal level find that high performers in one task are also high performers in other tasks, or find no trade-off between tasks at all (Garland and Else, 1987;Tsuji et al, 1989;Huey et al, 1990;Jayne and Bennett, 1990).…”

Section: Introductionmentioning

confidence: 99%

Does individual quality mask the detection of performance trade-offs? A test using analyses of human physical performance

Wilson

Niehaus

David

et al. 2014

Journal of Experimental Biology

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Why are performance trade-offs so rarely detected in animals when their underlying physiological basis seems so intuitive? One possibility is that individual variation in health, fitness, nutrition, development or genetics, or 'individual quality', makes some individuals better or worse performers across all motor tasks. If this is the case, then correcting for individual quality should reveal functional trade-offs that might otherwise be overlooked. We tested this idea by exploring trade-offs in maximum physical performance and motor skill function in semiprofessional soccer players. We assessed individual performance across five maximum 'athletic' tasks providing independent measures of power, stamina and speed, as well as five soccer-specific 'motor skill' tasks providing independent measures of foot control. We expected to find functional trade-offs between pairs of traits (e.g. endurance versus power/speed tasks or specialist-generalist performance) -but only after correcting for individual quality. Analyses of standardised raw data found positive associations among several pairs of traits, but no evidence of performance trade-offs. Indeed, peak performance across a single athletic task (degree of specialisation) was positively associated with performance averaged across all other athletic tasks (generalist). However, after accounting for an individual's overall quality, several functional trade-offs became evident. Within our qualitycorrected data, 1500 m-speed (endurance) was negatively associated with squat time (power), jump distance (power) and agility speedreflecting the expected speed-endurance trade-off; and degree of specialisation was negatively associated with average performance across tasks. Taken together, our data support the idea that individual variation in general quality can mask the detection of performance trade-offs at the whole-animal level. These results highlight the possibility that studies may spuriously conclude certain functional tradeoffs are unimportant or non-existent when analyses that account for variation in general quality may reveal their cryptic presence.

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“…However, despite the pervasiveness of physiological arguments when tested at the level of the whole animal, most intraspecific studies have found no evidence of the trade-off between speed and endurance (e.g. Ford & Shuttlesworth 1986;Garland & Else 1987;Garland 1988;Huey et al 1990;Jayne & Bennett 1990;Sorci et al 1995;Dohm et al 1996;Wilson et al 2002;but see Van Damme et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Constraints on muscular performance: trade–offs between power output and fatigue resistance

Wilson

James

2004

Proc. R. Soc. Lond. B

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An important functional and evolutionary constraint on the physical performance of vertebrates is believed to be the trade-off between speed and endurance capacity. However, despite the pervasiveness of physiological arguments, most studies have found no evidence of the trade-off when tested at the whole-animal level. We investigated the existence of this trade-off at the whole-muscle level, the presumed site of this physiological conflict, by examining inter-individual variation in both maximum power output and fatigue resistance for mouse extensor digitorum longus (EDL) muscle using the work-loop technique. We found negative correlations between several measures of in vitro maximum power output and force production with fatigue resistance for individual mouse EDL muscles, indicating functional trade-offs between these performance parameters. We suggest that this trade-off detected at the whole-muscle level has imposed an important constraint on the evolution of vertebrate physical performance.

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Effects of Variation in Food Intake on Locomotory Performance of Juvenile Garter Snakes

Cited by 59 publications

References 0 publications

Patterns of oxygen consumption during simultaneously occurring elevated metabolic states in the viviparous snake,Thamnophis marcianus

Patterns of oxygen consumption during simultaneously occurring elevated metabolic states in the viviparous snake,Thamnophis marcianus

Does individual quality mask the detection of performance trade-offs? A test using analyses of human physical performance

Constraints on muscular performance: trade–offs between power output and fatigue resistance

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