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Adherence to Bergmann's rule by lizards may depend on thermoregulatory mode: support from a nocturnal gecko.
Oecologia 2015; 178(2):427-40O

Abstract

Bergmann's rule predicts an increase in body size with decreasing environmental temperature; however, the converse pattern has been found in the majority of lizards studied to date. For these ectotherms, small body size may provide thermal benefits (rapid heat uptake when basking), which would be highly advantageous in cold environments. Yet such an advantage may not exist in nocturnal lizards (which do not avidly bask), in which Bergmann's rule has not been closely studied. We have examined whether the body size of a primarily nocturnal gecko, Woodworthia "Otago/Southland" changed with elevation and operative temperature (determined using physical copper models). In a laboratory study, we investigated whether thermoregulatory mode (heliothermy or thigmothermy) alters the effect of body size on heating and cooling rates. This gecko followed Bergmann's rule, thereby showing the opposite of the dominant pattern in diurnal lizards. Size at maturity, maximum size of adults and size at birth were larger at higher elevations and at lower operative temperatures. Using physical models, we found that large body size can confer thermal benefits for nocturnal lizards that remain within diurnal retreats. Bergmann's rule should not be dismissed for all lizards. Our results clearly support Bergmann's rule for at least one thigmothermic species, for which large body size may provide thermal benefits. Future studies on Bergmann's rule in lizards should consider thermoregulatory mode. We advocate that this ecogeographic rule be examined in relation to operative temperature measured at field sites. Finally, we predict that climate warming may weaken the relationship between body size and elevation in this gecko.

Authors+Show Affiliations

Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand, sophie.penniket@gmail.com.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

25663371

Citation

Penniket, Sophie, and Alison Cree. "Adherence to Bergmann's Rule By Lizards May Depend On Thermoregulatory Mode: Support From a Nocturnal Gecko." Oecologia, vol. 178, no. 2, 2015, pp. 427-40.
Penniket S, Cree A. Adherence to Bergmann's rule by lizards may depend on thermoregulatory mode: support from a nocturnal gecko. Oecologia. 2015;178(2):427-40.
Penniket, S., & Cree, A. (2015). Adherence to Bergmann's rule by lizards may depend on thermoregulatory mode: support from a nocturnal gecko. Oecologia, 178(2), pp. 427-40. doi:10.1007/s00442-015-3239-0.
Penniket S, Cree A. Adherence to Bergmann's Rule By Lizards May Depend On Thermoregulatory Mode: Support From a Nocturnal Gecko. Oecologia. 2015;178(2):427-40. PubMed PMID: 25663371.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Adherence to Bergmann's rule by lizards may depend on thermoregulatory mode: support from a nocturnal gecko. AU - Penniket,Sophie, AU - Cree,Alison, Y1 - 2015/02/08/ PY - 2014/02/24/received PY - 2015/01/14/accepted PY - 2015/2/10/entrez PY - 2015/2/11/pubmed PY - 2016/1/29/medline SP - 427 EP - 40 JF - Oecologia JO - Oecologia VL - 178 IS - 2 N2 - Bergmann's rule predicts an increase in body size with decreasing environmental temperature; however, the converse pattern has been found in the majority of lizards studied to date. For these ectotherms, small body size may provide thermal benefits (rapid heat uptake when basking), which would be highly advantageous in cold environments. Yet such an advantage may not exist in nocturnal lizards (which do not avidly bask), in which Bergmann's rule has not been closely studied. We have examined whether the body size of a primarily nocturnal gecko, Woodworthia "Otago/Southland" changed with elevation and operative temperature (determined using physical copper models). In a laboratory study, we investigated whether thermoregulatory mode (heliothermy or thigmothermy) alters the effect of body size on heating and cooling rates. This gecko followed Bergmann's rule, thereby showing the opposite of the dominant pattern in diurnal lizards. Size at maturity, maximum size of adults and size at birth were larger at higher elevations and at lower operative temperatures. Using physical models, we found that large body size can confer thermal benefits for nocturnal lizards that remain within diurnal retreats. Bergmann's rule should not be dismissed for all lizards. Our results clearly support Bergmann's rule for at least one thigmothermic species, for which large body size may provide thermal benefits. Future studies on Bergmann's rule in lizards should consider thermoregulatory mode. We advocate that this ecogeographic rule be examined in relation to operative temperature measured at field sites. Finally, we predict that climate warming may weaken the relationship between body size and elevation in this gecko. SN - 1432-1939 UR - https://www.unboundmedicine.com/medline/citation/25663371/Adherence_to_Bergmann's_rule_by_lizards_may_depend_on_thermoregulatory_mode:_support_from_a_nocturnal_gecko_ L2 - https://dx.doi.org/10.1007/s00442-015-3239-0 DB - PRIME DP - Unbound Medicine ER -