OCHOTERANAE from TWO Area Is Represented by the Mountains Located at the Edge POPULATIONS in GUERRERO, of a Small Cultivated Valley

74 SHORT NOTES

HERPETOLOGICAL JOURNAL, Vol. 7, pp. 74-76 (1997) produce torrential rains. During the dry season the river is dry. The other study population of ochoteranae was BODY TEMPERATURES OF THE S. located in the Zitlala Mountains at km 1, rural road MEXICAN LIZARD SCELOPOR US Acatlan-Zitlala, Guerrero (1250 m in elevation). This OCHOTERANAE FROM TWO area is represented by the mountains located at the edge POPULATIONS IN GUERRERO, of a small cultivated valley. Some plant species ob MEXICO served in the area were Pithecellobium dulce, Prosopis juliflora, Bursera spp., Acacia spp., and Mimosa sp. JULIO A. LEMOS-ESPINAL1, GEOFFREY R. The only crop observed in the mountains was Zea mays. SMITH2·', AND ROYCE E. BALLINGER3 Lizards were captured by hand, noose, or rubber band. Body temperatures (Tb; to the nearest 0.1°C) 1fnstituto Nacional de lnvestigaciones Forestales y were obtained using quick reading cloaca! thermom Agropecuaria, Progreso Mexico, D. F. Mexico #5, 41100, eters. Care was taken to prevent temperature from 2Department of Biology, Earlham College, Richmond, being influenced by handling; thus all lizards requiring Indiana 473 74, USA extensive capture effort were excluded from tempera ture recording. Body temperatures were measured only 3School of Biological Sciences, University of Nebraska, from active lizards (i.e. foragingor basking), and were Lincoln, Nebraska USA 68588, taken throughout the day. Air temperature (T; at 5 cm *Author fo r correspondence above substrate where lizard was firstobserve d, using a shaded bulb to nearest 0.1 °C) and substrate temperature Information on the thermal ecology of populations (T,; on substrate where lizard was first observed, using of the same species living in different habitats or eleva a shaded bulb to nearest 0.1°C) were measured at the tions is needed if an understanding of the relative roles site of capture. We also measured snout-vent length of physiology, thermal environments, and phylogeny in (SVL; to nearest mm) using a ruler. determining body temperatures in lizards is to be We used linear regression analyses to determine the reached. Even among closely related species (e.g. con relationships between Tb and T. , T, , and SVL. Compari geners), there can be significant variation both in active sons of Tb between sexes and between populations were body temperatures and in the extent to which body tem made using analysis of covariance to control forthe ef peratures are influenced by environmental fect of environmental temperatures on Tb . Either T. or temperatures (e.g. Sceloporus; Lemos-Espinal, Smith, T, were used as covariate in the analysis of covariance, & Ballinger, in press). Body temperatures can even depending on which variable explained the larger por vary among populations of the same species, particu tion of the variance in Tb (i.e. which regression had the larly when they occur in diffe rent habitats or at higher r2 value). diffe rent elevations (Grant & Dunham, 1990; Van Lizards in the Cafi6nde! Zopilote population had an Damme, Bauwens, & Verheyen, 1990; Smith & average SVL of 44.5 ± 1.4 mm (N = 33; range = 28 - 62 Ballinger, 1994b; Lemos-Espinal & Ballinger, 1995). mm). The average Tb was 34. 1 ± 0.82°C (N = 34); The thermal ecology of the genus Sceloporus has average T. and T, were 27.0 ± 0.7°C (N = 34) and 29.2 ± been relatively well studied, and recent studies have 0.9°C (N = 34), respectively. Body temperatures in this expanded our knowledge to species from relatively population increased with T. (N = 34, r2 = 0.38, P < unstudied regions of the genus' range (e.g. Mexico) 0.0001; Tb = 16.0 + 0.67TJ Body temperatures also (see Lemos-Espinal, Smith, & Ballinger, in press for increased with T, , and T, explained more variation in Tb review). In this note, we report on an additional species than T. (N = 34, r2 = 0.56, P < 0.000 1; Tb = 14.2 + of Sceloporus from Mexico whose thermal biology has 0.68TJ The Tb of an individual in this population was not been previously studied, S. ochoteranae. In addi not related to its SVL (N = 33, r2 = 0.009, P = 0.59). tion, we compare two populations of S. ochoteranae Males and females from the Cafi6n de! Zopilote from two distinct habitats and elevations. population did not differ significantly in Tb (ANCOVA

One population was located in the Cafi6n de! with T, as the covariate: F1 •3 1 = 0.80, P = 0.38). Males

Zopilote north of Chilpancingo, Guerrero (600 m el had a mean Tb of 33.9 ± l.2°C (N = 19), whereas fe evation), 14 km south of Mexcala, a small town on the males had a mean Tb of 34.3 ± 1.1°C (N = 15). The Rio Balsas. The area is situated in arid tropical scrub interaction between sex and T, was not statistically sig (the most xeric portion of the Bosque Tropical nificant, suggesting the slopes of the Tb on T, regression Caducifolio of Rzedowski, 1988). Dominant vegeta did not diffe r between males and females and was tion includes the large cactus Neobuxbaumia sp., and therefore not included in the final ANCOVA model. trees such as Bursera spp. and Acacia sp. The area lies Lizards in the Zitlala Mountain population had an on the northern side of the Sierra Madre del Sur. There average SVL of 44.9 ± 0.8 mm (N = 57; range 31 - 59 is a pronounced rainy season from late May until Sep mm). The average Tb was 34.1 ± 0.2°C (N = 57), and tember at which time late afternoon and evening storms the average T. and T, were 23.2 ± 0.3°C (N = 57) and SHORT NOTES 75

28.1 ± 0.5°C (N = 57), respectively. Body temperatures Ballinger, 1995; S. jarrovi, Smith & Ballinger, l 994b; in this population increased with T. (N= 57, r2= 0.19, P S. virgatus, Smith & Ballinger, I 994a), but males have = 0.0007; Tb = 25.3 + 0.38T.); however, little of the · also been found to have higher Tb 's than females (S. variation in Tb was explained by Ta Body temperature cyanogenys, Garrick, 1974; S. scalaris, Smith, was also positively related to T, in this population (N = Ballinger, & Congdon, 1993), and lower Tb 's than fe 57, r2 = 0.08, P = 0.04), but, as with T., very little vari males (S. undulatus, Gillis, 1991 ). ation was explained. The Tb of an individual in this The two populations of S. ochoteranae living in dif population was not related to its SVL (N = 57, r2 = 0.03, fe rent habitats and diffe rent elevations appear to have p = 0.17). the same absolute preferred Tb (c. 34°C); however, Males and femalesfrom the Zitlala Mountain popu when the ambient temperature is considered, individu lation did not have significantly diffe rent Tb 's als in the Zitlala Mountain population appear to have a (ANCOVA with T. as the covariate: F1•54 = 0.03, P = higher mean Tb than individuals in the Cafi6n del 0.87). Males had a mean Tb of 34.1 ± 0.3°C (N = 42), Zopilote population (i.e. least squares means are differ whereas females had a mean Tb of 34.0 ± 0.5°C (N = ent). These results suggest that both populations 15). The interaction between sex and T. was not statis physiologically "prefer" or are active at the same abso tically significant, suggesting the slopes of the Tb on T. lute Tb , but that because of differences in the ambient regression did not differ between males and females conditions, Zitlala Mountain individuals must maintain and was therefore not included in the final ANCOVA a higher Tb relative to ambient temperatures than do in model. dividuals in the Cafi6nde! Zopilote. In other studies on Individuals fromthe two populations appear to have populations of the same species living along an very similar Tb 's. Indeed the mean Tb's are identical: elevational gradient, or in different habitat types, the 34. I ± 0.8°C (N = 34) forthe Cafi6n de! Zopilote popu results concerning Tb differences are mixed. In some lation and 34.1 ± 0.2°C (N = 57) for the Zitlala species, Tb 's diffe r between populations at different alti Mountain population. However, when compared using tudes or in diffe rent habitats (e.g., Grant & Dunham, ANCOVA with T. as the covariate, the populations 1990; Van Damme, Bauwens, Verheyen, 1990; Smith, have statistically significantly diffe rent Tb 's = Ballinger, & Congdon, 1993; Smith & Ballinger, (F1 88 11.1, P = 0.00 I). Comparing the least squares means of I 994b ), whereas in other species Tb's do not diffe r be these population generated by the ANCOV A, the tween populations at diffe rent altitudes or in diffe rent Cafi6ndel Zopilote (32.7 ± 0.5°C) has a lower mean Tb habitats despite diffe rences in environmental tempera than the Zitlala Mountain population (34.9 ± 0.4°C). tures (Adolph, 1990; Lemos-Espinal & Ballinger, The interaction between population and T. was not sta 1995; Smith & Ballinger, 1995). tistically significant, suggesting the slopes of the Tb on Acknowledgments. We thank two anonymous re r,, regression did not differ between the populations and viewers for their comments which improved the quality was therefore not included in the final ANCOV A of this note. Some financial support was provided by model. the School of Biological Sciences, University of Ne The mean Tb 's of the two populations of S. ochotera braska-Lincoln. Some logistic support for manuscript nae (c. 34°C) are well within the range of Tb's preparation and data analysis was provided by the previously reported for lizards in the genus Sceloporus Kellogg Biological Station, Michigan State University. (28.9°C in S. variabilis, Benabib & Congdon, 1992; and 37.5°C in S. horridus, see Lemos-Espinal, Smith, REFERENCES & Ballinger, in press, for review). Body temperatures of individuals in the Cafi6n del Zopilote population of Adolph, S. C. ( 1990). Infl uence of behavioral S. ochoteranae appear to be influenced to a greater ex thermoregulation on microhabitat use by two 71, tent by environmental temperatures than Tb 's of Sceloporus lizards. Ecology 315-327. individuals in the Zitlala Mountain population (i.e. had Benabib, M. & Congdon, J. D. ( 1992). Metabolic and slope of Tb on T. regression closer to one and larger r2 water-flux rates of free-ranging tropical lizards 65, values). Definite assignations ofthermoconformity and Sce/oporus variabilis. Physiol. Zoo/. 788-802. thermoregulation could not be made because appropri Garrick, L. D. (1974). Reproductive influences on ate null models (see Hertz, 1992) could not be behavioral thermoregulation in the lizard, Sceloporus 12, generated to directly assess the extent ofthermoregula cyanogenys. Physiol. Behav. 85-91. tion in these populations of lizards. Gillis, R. ( 1991 ). Thermal biology of two populations of In both populations of S. ochoteranae, males and fe red-chinned lizards (Sceloporus undulatus males did not diffe r in mean Tb . Within the genus erythrocheilus) living in diffe rent habitats in 25, Sceloporus, whether or not the body temperatures of southcentral Colorado. J. Herpetol. 18-23. males and femalesare the same or diffe rent appears to Grant, B. W. & Dunham, A. E. (1990). Elevational depend on the species being considered. Indeed, males covariation in environmental constraints and 1 ife and females have been found to have the same Tb in histories of the desert lizard Sceloporus merriami. Ecology 71, several species (S. gadoviae, Lemos-Espinal, Smith, & 1765-1 776. Ballinger, in press; S. grammicus, Lemos-Espinal & 76 SHORT NOTES

Hertz, P. E. (I992) . Temperature regulation in Puerto Smith, G. R. & Ballinger, R. E. ( 1995). Temperature Rican Ano/is lizards: a field test using null hypotheses. relationships of the tree lizard, Urosaurus ornatus, Ecology 73, 1405-1417. fromdesert and low-elevation montane populations in Lemos-Espinal, J. A. & Ballinger, R. E. (I995). the south western USA. J. Herpetol. 29, I 26-I 29. Comparative thermal ecology of the high-altitude Smith, G. R., Ballinger, R. E. & Congdon, J. D. (1993). lizard Sceloporus grammicus on the eastern slope of Thermal ecology of the high-altitude bunch grass the Iztaccihuatl Volcano, Puebla, Mexico. Can. J. lizard, Sceloporus scalaris. Can. J. Zoo!. 71, 2152- Zoo!. 73, 2 I 84-2 I 9 I. 2155. Lemos-Espinal, J. A., Smith, G. R. & Ballinger, R. E. Van Damme, R., Bauwens, D. & Verheyen, R. F. (1990). (MS). Thermal ecology of the lizard, Sceloporus Evolutionary rigidity of thermal physiology: the case gadoviae, in an arid tropical scrub forest. J. Arid of the cool temperate lizard Lacer/a vivipara. Oikos Environ. in press. 57, 61-67. Rzedowski, J. (1988). Vegetaci6n de Mexico. Mexico City, Ed. Limusa. Smith, G. R. & Ballinger, R. E. ( l 994a). Thermal ecology of Sceloporus virgatus from southeastern Arizona, with comparison to Urosaurus ornatus. J. Herpetol. 28, 65-69. Smith, G. R. & Ballinger, R. E. (I994b). Temperature relationships in the high-altitude viviparous lizard, Sceloporusjarrovi. Am. Midi. Nat. 131, 181-189. Accepted: 18. 9. 96