Fight versus flight: the interaction of temperature and body size determines antipredator behaviour in tegu lizards

Barros, Fábio Cury de; Carvalho, José Eduardo de; Abe, Augusto Shinya; Kohlsdorf, Tiana

doi:10.1016/j.anbehav.2009.10.006

Cited by 40 publications

(37 citation statements)

References 36 publications

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“…The difference in the minimum T b at which movement was observed in the heterothermic mammals reflects different species-specific T b minima that are metabolically defended during torpor [4,7]; in the lizard, it was the lowest T b at which movement was recorded. Reptiles must function effectively at low T b to avoid predators and capture prey [24]. The main function of the ability by torpid mammals to move from shelters to the surface and seek sun exposure appears to be energy conservation, because small marsupials can save up to 80 per cent of arousal costs by basking [13].…”

Section: Discussionmentioning

confidence: 99%

Cool running: locomotor performance at low body temperature in mammals

2012

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Mammalian torpor saves enormous amounts of energy, but a widely assumed cost of torpor is immobility and therefore vulnerability to predators. Contrary to this assumption, some small marsupial mammals in the wild move while torpid at low body temperatures to basking sites, thereby minimizing energy expenditure during arousal. Hence, we quantified how mammalian locomotor performance is affected by body temperature. The three small marsupial species tested, known to use torpor and basking in the wild, could move while torpid at body temperatures as low as 14.8-17.98 8 8 8 8C.Speed was a sigmoid function of body temperature, but body temperature effects on running speed were greater than those in an ectothermic lizard used for comparison. We provide the first quantitative data of movement at low body temperature in mammals, which have survival implications for wild heterothermic mammals, as directional movement at low body temperature permits both basking and predator avoidance.

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Section: Discussionmentioning

confidence: 99%

Cool running: locomotor performance at low body temperature in mammals

2012

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“…This change is often coupled with a decrease in locomotor speed and an increase in the frequency of bipedalism (Kohlsdorf and Biewener, 2006). If lizards cannot sprint at (or near) maximum capacity, then their ability to elude predators would be affected (McMillan et al, 2011;De Barros et al, 2010;Okafor, 2010), particularly on uneven substrates containing obstacles. Whereas some studies have examined bipedal locomotion in lizards from a biomechanical standpoint (Hsieh and Lauder, 2004;Kohlsdorf and Biewener, 2006;Olberding et al, 2012;Van Wassenbergh and Aerts, 2013), the present study will examine a mechanistic link between bipedalism and ecologically relevant features of the habitat (obstacles).…”

Section: Introductionmentioning

confidence: 99%

The effects of multiple obstacles on the locomotor behavior and performance of a terrestrial lizard

Parker

McBrayer

2016

Journal of Experimental Biology

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Negotiation of variable terrain is important for many small terrestrial vertebrates. Variation in the running surface resulting from obstacles (woody debris, vegetation, rocks) can alter escape paths and running performance. The ability to navigate obstacles likely influences survivorship through predator evasion success and other key ecological tasks (finding mates, acquiring food). Earlier work established that running posture and sprint performance are altered when organisms face an obstacle, and yet studies involving multiple obstacles are limited. Indeed, some habitats are cluttered with obstacles, whereas others are not. For many species, obstacle density may be important in predator escape and/or colonization potential by conspecifics. This study examines how multiple obstacles influence running behavior and locomotor posture in lizards. We predict that an increasing number of obstacles will increase the frequency of pausing and decrease sprint velocity. Furthermore, bipedal running over multiple obstacles is predicted to maintain greater mean sprint velocity compared with quadrupedal running, thereby revealing a potential advantage of bipedalism. Lizards were filmed running through a racetrack with zero, one or two obstacles. Bipedal running posture over one obstacle was significantly faster than quadrupedal posture. Bipedal running trials contained fewer total strides than quadrupedal ones. But on addition of a second obstacle, the number of bipedal strides decreased. Increasing obstacle number led to slower and more intermittent locomotion. Bipedalism provided clear advantages for one obstacle, but was not associated with further benefits for an additional obstacle. Hence, bipedalism helps mitigate obstacle negotiation, but not when numerous obstacles are encountered in succession.

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“…We focused on anti-predatory responses exhibited by juvenile and adult tegus at 22.5°C. From a previous study (de Barros et al, 2010) we know that, as body temperature decreases, most adults shift from running away to turning aggressive at 22°C, but juveniles remain evasive, and therefore at this temperature, the behavioural differences become prominent (see Table S1 to access behaviour frequencies in each experimental temperature and Table S2 and Fig. S3 for detailed analyses showing differences in anti-predatory behaviour between ontogenetic classes at lower temperatures).…”

Section: Methodsmentioning

confidence: 99%

“…For example, the agamid lizard Trapelus pallida exhibits a temperature-dependent shift from evasive to aggressive behaviours that could be explained by increased thermal sensitivity of muscles used for sprinting in comparison to those involved in biting . Such a temperature-dependent shift in behaviour also has an ontogenetic dimension: adults of tegu lizards (Salvator merianae) run away from a predator at high temperatures but choose combat when it is cold, whereas juveniles exhibit the same flight strategy within a wide range of thermal conditions (de Barros et al, 2010). Given that ontogenetic development encompasses modifications at different levels of organization, it is plausible to predict that morpho-physiological parameters could at least partially explain the differences between adult and juvenile tegus in the antipredatory responses exhibited at lower temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…Based on this hypothesis, we predict: (1) that enhanced glycolytic scopes in the limb musculature of juveniles compensate for the impairment imposed by small body sizes and allow these individuals to flee from predators even at limiting thermal conditions involving low temperatures; and (2) that modifications of shape, involving relative limb proportions or jaw length, also explain differences in anti-predatory behaviour between the ontogenetic classes of tegu lizards. To test this prediction, we combine behavioural results for recently hatched juveniles and adult tegus reported in de Barros et al (2010) with new data for body morphometry and muscle biochemistry obtained in hindlimb and head muscles sampled from the same individuals. The integrative approach used here explores interactions among the multiple dimensions that are likely to determine whether a given prey will fight or flee when facing a predator.…”

Section: Introductionmentioning

confidence: 99%

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Beyond body size: muscle biochemistry and body shape explain ontogenetic variation of anti-predatory behaviour in the lizard Salvator merianae (Squamata: Teiidae)

Barros

Carvalho

Abe

et al. 2016

Journal of Experimental Biology

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Anti-predatory behaviour evolves under the strong action of natural selection because the success of individuals avoiding predation essentially defines their fitness. Choice of anti-predatory strategies is defined by prey characteristics as well as environmental temperature. An additional dimension often relegated in this multilevel equation is the ontogenetic component. In the tegu Salvator merianae, adults run away from predators at high temperatures but prefer fighting when it is cold, whereas juveniles exhibit the same flight strategy within a wide thermal range. Here, we integrate physiology and morphology to understand ontogenetic variation in the temperature-dependent shift of anti-predatory behaviour in these lizards. We compiled data for body shape and size, and quantified enzyme activity in hindlimb and head muscles, testing the hypothesis that morphophysiological models explain ontogenetic variation in behavioural associations. Our prediction is that juveniles exhibit body shape and muscle biochemistry that enhance flight strategies. We identified biochemical differences between muscles mainly in the LDH:CS ratio, whereby hindlimb muscles were more glycolytic than the jaw musculature. Juveniles, which often use evasive strategies to avoid predation, have more glycolytic hindlimb muscles and are much smaller when compared with adults 1-2 years old. Ontogenetic differences in body shape were identified but marginally contributed to behavioural variation between juvenile and adult tegus, and variation in antipredatory behaviour in these lizards resides mainly in associations between body size and muscle biochemistry. Our results are discussed in the ecological context of predator avoidance by individuals differing in body size living at temperature-variable environments, where restrictions imposed by the cold could be compensated by specific phenotypes.

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Fight versus flight: the interaction of temperature and body size determines antipredator behaviour in tegu lizards

Cited by 40 publications

References 36 publications

Cool running: locomotor performance at low body temperature in mammals

Cool running: locomotor performance at low body temperature in mammals

The effects of multiple obstacles on the locomotor behavior and performance of a terrestrial lizard

Beyond body size: muscle biochemistry and body shape explain ontogenetic variation of anti-predatory behaviour in the lizard Salvator merianae (Squamata: Teiidae)

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