Lizard energetics and the sit-and-wait vs. wide-foraging paradigm

Brown, Tracey K.; Nagy, Kenneth A.

doi:10.1017/cbo9780511752438.006

Cited by 12 publications

(19 citation statements)

References 67 publications

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“…2). Adjusting for mass, the mean FMR for P. husabensis was 0.116 kJ·g −0.952 ·d −1 , which was similar to the mean FMR for sit-and-wait foraging lizards (0.155 ± 0.079 kJ·g −0.952 ·d −1 ), but significantly lower (outside of the 95% confidence interval of the predicted value) than the mean value for actively foraging lizards (0.204 ± 0.069 kJ·g −0.952 ·d −1 ; Brown and Nagy 2007). We found that the mean WIR for P. husabensis (0.06 mL·d −1 ; Table 1) was 67% of that expected for a desert reptile of the same size (0.09 mL·d −1 ; Nagy and Peterson 1988), but this value was within the 95% confidence interval for the predicted value (0.05-0.15 mL·d −1 ), and thus was not significantly different.…”

Section: Discussionsupporting

confidence: 59%

“…For example, the actively foraging Western Sand Lizard (Pedioplanis undata (Smith, 1838)) and Namaqua Sand Lizard (Pedioplanis namaquensis (Duméril and Bibron, 1839)) spend 50% and 54% of their active time moving, respectively, while the sit-and-wait foraging Spotted Sand Lizard (Pedioplanis lineoocellata (Duméril and Bibron, 1839)) spends only 5% of its active time moving (Cooper and Whiting 1999). Actively foraging lizards, however, have higher FMRs (>30% higher) compared with sit-and-wait foragers (Brown and Nagy 2007), largely because the energetic costs of movement can be significant (Huey and Slatkin 1976;Hertz et al 1988). For example, the Bushveld Lizard (Heliobolus lugubris (Smith, 1838)), an actively foraging lacertid lizard in the Kalahari Desert, has a metabolic rate 12 times that of its resting metabolic rate while actively foraging; conversely, a sympatric sit-and-wait lacertid, P. lineoocellata, expends only 2.8 times its resting metabolic rate (resting metabolic rates do not differ between the species) while ambush foraging (Nagy Fig.…”

Section: Foraging Activity and Field Energeticsmentioning

confidence: 99%

“…2. Relationship between mass and field metabolic rate (FMR) for Husab Sand Lizards (Pedioplanis husabensis) (solid circles), plotted with the associated 95% confidence intervals, relative to the predicted FMR for a comparably sized active (FMR = 0.294x 0.875 , where x is mass (g)) versus sit-and-wait (FMR = 0.117x 1.014 , where x is mass (g)) foraging lizard (regressions from Brown and Nagy 2007). Figure appears in colour on the Web.…”

Section: Foraging Activity and Field Energeticsmentioning

confidence: 99%

“…Others species are active foragers that expend more energy because they actively search their environment for prey, often moving over large home ranges Karasov 1981, 1988;Nagy et al 1984;Brown and Nagy 2007). Although locomotor and other costs (such as predation) may be higher for active foragers, their higher prey encounter rates often provide an advantage over sit-and-wait foragers (Anderson and Karasov 1981;Nagy et al 1984).…”

Section: Introductionmentioning

confidence: 99%

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The actively foraging desert lizardPedioplanis husabensis(Husab Sand Lizard) behaviorally optimizes its energetic economy

et al. 2014

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The Husab Sand Lizard (Pedioplanis husabensis Berger-Dell' Mour and Mayer, 1989) is a recently described lacertid lizard endemic to a small region in the central Namib Desert. Although this species is of conservation concern, very little is known about how this lizard functions in its environment. We used the doubly labeled water method to measure the field energetics in this lizard species and we report on its foraging behavior. Pedioplanis husabensis had summer field metabolic rates (330 ± 140 J·d −1 ) that were similar to those of other similarly sized sit-and-wait foraging lizards (360 J·d −1 ), but only 43% that of an active foraging lizard of the same mass (770 J·d −1 ), despite using a movement-intensive, active foraging strategy. Additionally, the mean water influx rate (0.06 ± 0.03 mL·d −1 ) was 67% that of a desert reptile of the same size (0.09 mL·d −1 ). Active body temperatures were significantly lower in summer (34.3 ± 1.7°C) than they were in autumn (36.8 ± 1.6°C), and daily activity of lizards increased from 2.6 ± 0.9 h·d −1 in summer to 4.3 ± 1.9 h·d −1 in autumn. Relative to other species of actively foraging desert lizards, P. husabensis has lower energy requirements. Berger-Dell'Mour et Mayer, 1989, est un lézard lacertidé récemment décrit du centre du désert du Namib. Si l'espèce est préoccupante sur le plan de la conservation, on en sait très peu sur la manière dont ce lézard fonctionne dans son milieu. Nous avons utilisé la méthode de l'eau doublement marquée pour mesurer l'énergétique de cette espèce de lézard sur le terrain et nous faisons état d'observations sur son comportement d'alimentation. Même s'ils utilisent une stratégie d'alimentation très active, les P. husabensis présentaient des taux métaboliques estivaux sur le terrain (330 ± 140 J·j −1 ) semblables à ceux d'autres lézards de taille semblable employant une approche d'attente aux aguets pour s'alimenter (360 J·j −1 ), mais correspondant à seulement 43 % du taux d'un lézard à quête de nourriture active de même masse (770 J·j −1 ). En outre, le taux d'apport d'eau moyen (0,06 ± 0,03 mL·j −1 ) équivalait à 67 % de celui d'un reptile de milieu désertique de même taille (0,09 mL·j −1 ). Les températures corporelles en action étaient significativement plus faibles en été (34,3 ± 1,7°C) qu'en automne (36,8 ± 1,6°C) et l'activité quotidienne des lézards augmentait de 2,6 ± 0,9 h·j −1 l'été à 4,3 ± 1,9 h·j −1 l'automne. Comparativement à d'autres espèces de lézards de milieu désertique à quête de nourriture active, P. husabensis a des besoins en énergie plus faibles. [Traduit par la Rédaction] Mots-clés : Pedioplanis husabensis, désert du Namib, taux métabolique sur le terrain, eau doublement marquée. Résumé : Le lézard Pedioplanis husabensis

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Section: Discussionsupporting

confidence: 59%

Section: Foraging Activity and Field Energeticsmentioning

confidence: 99%

Section: Foraging Activity and Field Energeticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The actively foraging desert lizardPedioplanis husabensis(Husab Sand Lizard) behaviorally optimizes its energetic economy

et al. 2014

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“…We compared FMR to the predictive equations for lizards (generally), desert lizards of Nagy et al (1999), and wide foraging lizards of Brown and Nagy (2007). Feeding rates were compared to the equations of Nagy (2001) and water flux to the equations for tropical reptiles of Nagy (1982b) and desert reptiles of Nagy and Peterson (1988).…”

Section: Methodsmentioning

confidence: 99%

Life in the Lizard Slow Lane: Gila Monsters Have Low Rates of Energy Use and Water Flux

Gienger¹,

Tracy

Nagy

2014

Copeia

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Thermoregulatory behavior and high thermal preference buffer impact of climate change in a Namib Desert lizard

et al. 2017

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Abstract. Knowledge of the thermal ecology of a species can improve model predictions for temperatureinduced population collapse, which in light of climate change is increasingly important for species with limited distributions. Here, we use a multi-faceted approach to quantify and integrate the thermal ecology, properties of the thermal habitat, and past and present distribution of the diurnal, xeric-adapted, and active-foraging Namibian lizard Pedioplanis husabensis (Sauria: Lacertidae) to model its local extinction risk under future climate change scenarios. We asked whether climatic conditions in various regions of its range are already so extreme that local extirpations of P. husabensis have already occurred, or whether this micro-endemic species is adapted to these extreme conditions and uses behavior to mitigate the environmental challenges. To address this, we collected thermoregulation and climate data at a micro-scale level and combined it with micro-and macroclimate data across the species' range to model extinction risk. We found that P. husabensis inhabits a thermally harsh environment, but also has high thermal preference. In cooler parts of its range, individuals are capable of leaving thermally favorable conditions-based on the species' thermal preference-unused during the day, probably to maintain low metabolic rates. Furthermore, during the summer, we observed that individuals regulate at body temperatures below the species' high thermal preference to avoid body temperatures approaching the critical thermal maximum. We find that populations of this species are currently persisting even at the hottest localities within the species' geographic distribution. We found no evidence of range shifts since the 1960s despite a documented increase in air temperatures. Nevertheless, P. husabensis only has a small safety margin between the upper limit of its thermal preference and the critical thermal maximum and might undergo range reductions in the near future under even the most moderate climate change scenarios.

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Lizard energetics and the sit-and-wait vs. wide-foraging paradigm

Cited by 12 publications

References 67 publications

The actively foraging desert lizardPedioplanis husabensis(Husab Sand Lizard) behaviorally optimizes its energetic economy

The actively foraging desert lizardPedioplanis husabensis(Husab Sand Lizard) behaviorally optimizes its energetic economy

Life in the Lizard Slow Lane: Gila Monsters Have Low Rates of Energy Use and Water Flux

Thermoregulatory behavior and high thermal preference buffer impact of climate change in a Namib Desert lizard

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