TY - JOUR AU - Herczeg, Gábor AU - Herrero, A AU - Saarikivi, J AU - Gonda, A AU - Jantti, M AU - Merila, J TI - Experimental support for the cost-benefit model of lizard thermoregulation: the effects of predation risk and food supply JF - OECOLOGIA J2 - OECOLOGIA VL - 155 PY - 2008 IS - 1 SP - 1 EP - 10 PG - 10 SN - 0029-8549 DO - 10.1007/s00442-007-0886-9 UR - https://m2.mtmt.hu/api/publication/1879995 ID - 1879995 N1 - Z9: 9 WC: Ecology Megjegyzés-22021450 Z9: 9 WC: Ecology Megjegyzés-22021499 Z9: 9 WC: Ecology Megjegyzés-22021520 Z9: 9 WC: Ecology AB - Huey and Slatkin's (Q Rev Biol 51:363-384, 1976) cost-benefit model of lizard thermoregulation predicts variation in thermoregulatory strategies (from active thermoregulation to thermoconformity) with respect to the costs and benefits of the thermoregulatory behaviour and the thermal quality of the environment. Although this framework has been widely employed in correlative field studies, experimental tests aiming to evaluate the model are scarce. We conducted laboratory experiments to see whether the common lizard Zootoca vivipara, an active and effective thermoregulator in the field, can alter its thermoregulatory behaviour in response to differences in perceived predation risk and food supply in a constant thermal environment. Predation risk and food supply were represented by chemical cues of a sympatric snake predator and the lizards' food in the laboratory, respectively. We also compared males and postpartum females, which have different preferred or "target" body temperatures. Both sexes thermoregulated actively in all treatments. We detected sex-specific differences in the way lizards adjusted their accuracy of thermoregulation to the treatments: males were less accurate in the predation treatment, while no such effects were detected in females. Neither sex reacted to the food treatment. With regard to the two main types of thermoregulatory behaviour (activity and microhabitat selection), the treatments had no significant effects. However, postpartum females were more active than males in all treatments. Our results further stress that increasing physiological performance by active thermoregulation has high priority in lizard behaviour, but also shows that lizards can indeed shift their accuracy of thermoregulation in response to costs with possible immediate negative fitness effects (i.e. predation-caused mortality). LA - English DB - MTMT ER - TY - JOUR AU - Herczeg, Gábor AU - Gonda, A AU - Saarikivi, J AU - Merila, J TI - Experimental support for the cost-benefit model of lizard thermoregulation JF - BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY J2 - BEHAV ECOL SOCIOBIOL VL - 60 PY - 2006 IS - 3 SP - 405 EP - 414 PG - 10 SN - 0340-5443 DO - 10.1007/s00265-006-0180-6 UR - https://m2.mtmt.hu/api/publication/1879998 ID - 1879998 N1 - Z9: 12 WC: Behavioral Sciences; Ecology; Zoology Megjegyzés-22021451 Z9: 12 WC: Behavioral Sciences; Ecology; Zoology AB - According to Huey and Slatkin's [Q Rev Biol 51:363-384, 1976] cost-benefit model of behavioural thermoregulation, lizards should adjust their thermoregulatory strategy between active thermoregulation and thermoconformity (no thermoregulation) according to the costs (time and energy spent thermoregulating, exposure to predators), benefits (optimised physiological performance) and thermal quality of environment associated with a given situation. However, Gilchrist's [Am Nat 146:252-270, 1995] model of thermal specialisation suggests that apparently costly mechanisms of behavioural thermoregulation can greatly increase fitness if the optimal body temperature is achieved. Field studies of ectotherm thermoregulatory strategies under extreme cold conditions and experiments testing the effects of cool environments on thermoregulatory behaviour are surprisingly scarce. We conducted laboratory experiments to test if common lizards Zootoca vivipara (an active thermoregulator in the field) are able to switch between active thermoregulation and thermoconformity in response to different thermal environments. We found that lizards in treatments with an opportunity to reach their preferred body temperature thermoregulated accurately, maintained their level of daily activity and improved their body condition considerably. In contrast, lizards in the treatment where the preferred body temperature could not be reached became thermoconformers, decreased their daily activity (except for gravid females) and did not increase their body condition. Our results show that lizards can indeed change their thermoregulatory strategy but stress that maintaining the preferred body temperature and, thus, optimising the physiological performance have high priority in lizard behaviour. LA - English DB - MTMT ER - TY - JOUR AU - Herczeg, Gábor AU - Kovács, Tibor AU - Hettyey, Attila AU - Merila, Juha TI - To thermoconform or thermoregulate? An assessment of thermoregulation opportunities for the lizard Zootoca vivipara in the subarctic JF - POLAR BIOLOGY J2 - POLAR BIOL VL - 26 PY - 2003 IS - 7 SP - 486 EP - 490 PG - 5 SN - 0722-4060 DO - 10.1007/s00300-003-0507-y UR - https://m2.mtmt.hu/api/publication/1880001 ID - 1880001 N1 - Z9: 10 WC: Biodiversity Conservation; Ecology AB - The general model of thermoregulation of ectotherms predicts that thermally challenging environments select for evolution of thermoconformity. Studies of reptilian thermoregulation at climatic extremes are rare and, in the subarctic zone, completely lacking. Thermal characteristics of the habitat of the lizard Zootoca vivipara were studied in the subarctic zone, at the northern margin of its distribution, where lizard density was already extremely low. We found that, during the activity period, the preferred body temperatures of Z. vivipara were not available for a thermoconformer, but available for 7 h for a thermoregulator in an average day. Therefore, thermoconformity is unberieficial and accurate thermoregulation should be the appropriate strategy. We hypothesise that the extremely low lizard abundance at our subarctic study site is caused by the short activity season and the large daily temperature fluctuations, with night temperatures occasionally falling below zero even during the activity period. LA - English DB - MTMT ER -