Amphibia-Reptilia 32 (2011): 93-103

Activity and body orientation of galloti in different habitats and daily times

Martha L. Bohórquez-Alonso1, Enrique Font2, Miguel Molina-Borja1,*

Abstract. In , site selection is related to the acquisition of resources such as refuges, mates or prey, but also to the exploitation of sites suitable for thermoregulation. The latter process may be affected by posture and body axis orientation in relation to the sun as a way to optimize heat exchange throughout the day. Specific postures and body orientations could also contribute to more efficient signal transmission in social contexts. In this paper we analyze activity and body axis orientation of adult males and females of the lacertid Gallotia galloti in two localities of Tenerife with different structural habitats. We performed transects at both sampling localities in the morning and at midday during May and June of three years (2002-2004). The numbers of lizards detected per unit time during transects at both localities were similar; however, significantly more males than females were detected. Moreover, more lizards were found oriented parallel or perpendicular to the sun than in alternative (oblique) orientations. Heating rates were not different for copper lizard models oriented parallel or perpendicular to the sun, neither in the morning nor at midday, and there was no significant relationship between air temperature and lizard body orientation. This suggests that lizard body orientation is not constrained by thermoregulatory requirements. We discuss alternative hypotheses and conclude that body axis orientation in G. galloti lizards may reflect a compromise between the conflicting demands imposed by thermoregulation and social communication.

Keywords: communication, detection rates, , lateral signals, lizards.

Introduction Díaz et al., 1996; Ayers and Shine, 1997; See- bacher, 1999; Sartorius et al., 2002). The interplay between habitat characteristics, Site selection, posture and body axis orienta- behavioral patterns and thermoregulation has tion are also important for finding food, mates, received much attention in studies of lizard be- hiding from predators, and social interactions havior and ecology (Adolph and Porter, 1993; (Díaz, 1992; Whiting et al., 1993; Bauwens et Tracy, 1982). The location of ectotherms in al., 1996; Baird et al., 2001). Conspicuousness specific sites inside their home ranges has of- has been shown both empirically and theoreti- ten been interpreted in terms of opportuni- cally to be important for intraspecific commu- ties for thermoregulation, as it has important nication in many vertebrate (Endler and consequences for body temperature regulation Théry, 1996; Fleishman, 2000). Males of many (Pearson, 1977; Huey, 1982, 1991; Huey et species, for example, perform lateral displays al., 1984; Adolph, 1990; Schäuble and Grigg, during which their flanks are maximally ex- 1998; Melville and Schulte, 2001; Scheers posed to potential receivers (Chiszar, 1978). In and Van Damme, 2002). Posture and body lizards, lateral displays often reveal conspicu- axis orientation can also affect heating/cooling ous lateral and ventrolateral color patches that rates and body temperature in many are not clearly visible during routine activities (Bartholomew, 1982; Bauwens et al., 1996; (Cooper and Greenberg, 1992; Molina-Borja et al., 1998, 2006). A lizard’s location, orientation, and posture at any given time determine how 1 - Grupo Etología y Ecología del Comportamiento, Depar- the available light sources illuminate its body tamento de Biología , Facultad de Biología, Uni- surface and therefore affect the effectiveness of versidad de La Laguna, Tenerife, Islas Canarias, España 2 - Instituto Cavanilles de Biodiversidad y Biología Evolu- its visual signals (Rosenthal, 2006). For diurnal tiva, Universidad de Valencia, 46071 Valencia, España lizards, body axis orientation in relation to sun- *Corresponding author; e-mail: [email protected] light could be particularly important for com-

© Koninklijke Brill NV, Leiden, 2011. DOI:10.1163/017353710X542994 94 M.L. Bohórquez-Alonso, E. Font, M. Molina-Borja munication; depending on the lizard’s orienta- exhibited when first observed in the field (still tion relative to the sun at different times of the or moving). day, parts of its body could be differentially il- We hypothesized 1) that the number of active luminated, making the animal more or less con- should be lower in Teide National Park spicuous to potential receivers. (more severe weather conditions) in comparison Gallotia lizards (fam. Lacertidae) are en- to Güimar (near sea level, with much less dras- demic from the (Arnold, 1973). tic daily and seasonal weather variation); 2) that They are typical heliothermic lizards that de- males should be more active – therefore, more pend on exposure to the sun to warm themselves easily detected – than females in both sites due and perform their daily activities. G. galloti gal- to their active role with regards to reproduction loti is distributed in the southern and central (i.e. males tend to be more active and wide- parts of Tenerife Island, from the sea shore up ranging than females, particularly during the re- to altitudes of >2000 m a.s.l. in Teide National productive season); 3) that more lizards should be detected in the morning (when temperatures Park. They occupy ecologically diverse habi- are lower) than at midday; 4) given that males tats which differ in vegetation, type of substrate, are more often than females exposed and in- and temperature regimes. Lizard seasonal activ- volved in intraspecific interactions, we expected ity begins in April and peaks in May, June and to find a different distribution of body orienta- July, with decreasing levels of activity during tions in males and females; 5) on the other hand, the hottest summer months and in winter; how- if body orientation is important for thermoregu- ever, active animals may also be seen on warm lation we also should expect perpendicular ori- winter days (unpublished observations). During entations to be more frequently displayed in the the day they are mostly active in the early morn- morning than at midday. ing, reduce activity in the hottest hours of the midday, and may resume it in the late after- noon (Díaz, 1994; own unpublished observa- Materials and methods tions). However, it is not known if males and Study areas and species females are equally active and if the number of We selected two different habitats in Tenerife, one at Mal- individuals of each sex differs both within and país de Güimar (28◦18N, 16◦22W, referred to as Güimar between different habitat types. in the remainder of the text), a natural protected area in the In this work we present the results of a study SE of the island close to sea level, and the other in the pe- riphery of Teide National Park (28◦18N, 16◦33W, here- of male and female lizard activity and body ori- after referred to as Teide) in the centre of the island, around entation in two habitats from Tenerife with dif- 2000 m a.s.l. Although they are relatively close (ca. 20 km ferent ecological characteristics and represent- apart), the two study sites have different ecological char- acteristics due to the altitudinal difference between them. ing different thermal environments. We took ad- The site at Güimar is a protected natural space with dark- vantage of differences in type of substrate, veg- brown to black lava fields that provide many rough sur- faces and crevices, and with dispersed xeric plants includ- etation, and solar radiation intensity between ing Euphorbia canariensis, Plocama pendula, Euphorbia the two sites in order to explore possible differ- balsamífera,andPeriploca laevigata, The habitat at Teide ences in activity and body orientation of G. gal- is high montane scrubland and the main plants are Spar- tocytisus supranubius, Descourainia bourgeana, Adenocar- loti lizards. The main aim of the study was to pus viscosus, Nepeta teydea, Erysimum scoparium,andPte- look for sex-related differences in activity and rocephalus lasiospermus. The substrate at this site is com- specific body orientations relative to sunlight in posed of granulated pumice with dispersed rock piles. Ther- mal regimes at the two sites are also very different, Teide two different daily periods and in the two habi- having cold winter months with temperatures sometimes ◦ tats. Activity was analyzed in two ways: as the decreasing below 0 C. However, during most of the year the clouds stay below 1900 m a.s.l., so that the entire Na- number of lizards that can be located outside tional Park always gets sunny days. In Güimar, tempera- their refuges and as the type of behavior they tures never fall below 14◦C. Ultraviolet (UV) radiation at Body orientation in Gallotia 95 ground level is more intense in Teide than in Güimar. (http:// at a distance where noosing or capturing by hand would be www.aemet.es/es/eltiempo/observacion/radiacionuv/). feasible. The lizard G. galloti galloti (Bischoff, 1982), one of To estimate operative temperatures and assess the effect two subspecies inhabiting the island, occurs at high den- of body axis orientation we recorded temperature changes sities in both study areas. It is a medium-sized lizard with inside a copper tube the size of a medium-sized lizard mean snout-to-vent length 107.3 mm and 87.4 mm for males (Bakken and Gates, 1975; Hertz et al., 1993) placed on a and females, respectively (Molina-Borja and Rodríguez- roughly flat stone on the ground and with either parallel or Domínguez, 2004). The species shows sexual dimorphism perpendicular orientations relative to sunlight. The copper in body size and coloration (Molina-Borja et al., 1997, model (around 13 cm long) had a small hole that allowed 2006), and during the breeding period (April to June) males the insertion of the sensing tip of a thermometer (thermo- can be seen wandering over their home ranges where they couple probe) attached to a Hobo data logger. We checked find females, food, and refuges (Molina-Borja, 1985). Males temperatures inside the copper tube 5 min after putting it on are more colorful than females, and both sexes have lateral the ground. The use of more realistic (in morphology and and ventro-lateral blue patches that also show reflectance color pattern) models has been shown to exert little influ- in the near UV range (Molina-Borja et al., 2006). Male col- ence on operative temperatures for small lizards (Shine and oration appears more vivid during the breeding season when Kearney, 2001). Moreover, a high correlation (r = 0.99) be- males patrol their home ranges. These home ranges may tween temperatures in a copper model very similar to ours overlap and, when two males meet, threat displays, fights and those of lizard carcasses was found for G. galloti by and/or chases may occur (Molina-Borja, 1985). During ag- Díaz (1994) in a southern Tenerife population. onistic interactions, as part of their displays, the contestants Air temperature was measured using a H8 Hobo data depress the gular area and compress the body laterally, thus logger (0.1◦C precision) provided with an external sensor making more visible the rows of blue/UV patches located placed at ground level (1 cm above a flat stone), both at laterally and ventro-laterally on both sides of their trunks the beginning and at the end of each transect, and both in (Molina-Borja, 1981, 1985; Molina-Borja et al., 1997). a sunny and a shaded patch as a way to sample the two most extreme microenvironments. Weather and wind intensity Data collection were also recorded using the following categories: sunny (1), partly cloudy (2) and completely overcast (3), and no Observations were conducted during 80-100 m long tran- wind (0), soft breeze (1), mildly windy (2) and windy (3). sects that took around 30 min to walk. Transects were hap- hazardly oriented and located in different parts of the habi- Statistical analyses tat in order to avoid re-sampling individuals. Each transect was run only once to further minimize the risk of lizard As we detected a low number of juvenile and newborn re-sampling and pseudo-replication. We selected two daily specimens during transects, their data were not included in times to do transects, one in the morning (1000-1030 h, local the statistical analyses. Mean air temperature was analyzed time) and another at midday (1230-1300 h) in May and June with ANOVAs taking sampling sites and daily times as of 2002-2004. For estimations of lizard activity, counts were fixed factors. Due to data departure from parametric test made of all the lizards found within 2.5 m of the transect line assumptions, comparisons of temperatures inside copper and results expressed as detection rate (i.e. number of lizards tubes parallel or perpendicular to sunlight were performed detected per minute) and as total number of lizards/transect. with Mann-Whitney U tests. Sex, age class and time when each specimen was initially To test for differences in the number of lizards detected detected were noted. We recorded the orientation of the lon- per minute (arcsin square root transformed) at both sam- gitudinal body axis of each specimen in relation to sunlight pling daily times, analysis of covariance was used taking in three categories: perpendicular (shadow cast by the lizard sampling site and sampling time as fixed factors and air to one side), parallel (shadow ahead or behind the lizard’s temperature as a covariate. Lizard activity was further an- body), and oblique (any angle intermediate between paral- alyzed by summarizing our behavioral observations during lel and perpendicular). The first two categories have been transects and assigning individuals to two broad categories referred to as “positive” and “negative” orientation, respec- of “Moving” or “Still” when first detected. The significance tively (Heath, 1965, cited in Pough et al., 2003). We also of the association between these two behavioral categories noted the behavior pattern (from the published ethogram for and sex was tested by G-tests of independence (Sokal and the species, Molina-Borja, 1981, 1987) exhibited by each Rohlf, 1995). We also used goodness-of-fit G tests to com- individual when first detected, if it was located in a sunny, pare observed and expected numbers of lizards in each of sun-shaded or shaded location, and any other individuals the three body orientation categories (parallel, perpendicu- found in its vicinity (within 1 m of the focal animal). Lizard lar, and oblique). Expected values were calculated assuming observations were made through binoculars at a distance of equiprobability of the three body axis orientations. As there at least 10 m to avoid possible disturbance to the animals. are potentially more oblique than parallel or perpendicular A total of 69 transects were performed, 39 in Güimar (19 in orientations, this provides a very conservative estimate of the morning and 20 at midday) and 30 in Teide (15 at each the relative use of parallel and perpendicular body axis ori- sampling time). entations. In some cases, to increase the power of statistical Lizard body temperature could not be recorded as the tests we pooled data from separate contingency tables but lizards are very wary and cannot be approached in the field only after a heterogeneity test (Zar, 1999) confirmed that 96 M.L. Bohórquez-Alonso, E. Font, M. Molina-Borja

Table 1. Total number of males and females detected during Mean number of lizards detected taking air transects (numbers in parentheses) performed at both sam- pling locations. temperature as covariate did not differ between sites (F1,46 = 0.01, P = 0.92), nor between Location Sampling time Males Females sampling times (F1,46 = 2.18, P = 0.14). Güimar Morning (19) 57 40 The interaction between site and sampling time Midday (20) 44 37 was likewise not significant (F1,46 = 1.62, Teide Morning (15) 83 31 = Midday (15) 46 15 P 0.21). The effect of the covariate was in turn non-significant (F1,46 = 0.07, P = 0.79). Males were detected at a higher rate than contingency tables could be safely assumed to have come females both in Güimar (t = 2.83, df = 25, from the same statistical population. For all statistical cal- P = 0.009) and Teide (t = 5.54, df = 18, P = culations we used two-tailed tests and a significance level 0.0003, fig. 1), and also in both daily sampling = of α 0.05. times within each site (data not shown).

Lizard behavior and location Results When first sighted the lizards were more fre- Temperature, lizard detection rates and quently performing the behaviour patterns weather conditions “still” and “walking” (table 2). Lizards were ob- Air temperatures at sunny patches ranged 22.3- served more frequently in sunny patches dur- ◦ ◦ ing the morning and in partially or completely 49.8 C in Güimar and 31.9-54 C in Teide. Air shaded locations during midday transects both temperatures at shaded patches ranged 26.3- ◦ ◦ at Güimar (G test of independence, G = 33.2 C and 23.2-28.0 C, respectively in Güi- adj 7.059, df = 1, P<0.01) and at Teide (G = mar and Teide. Mean values were significantly adj 11.76, df = 1, P<0.001). Very rarely were higher at midday than in the morning tran- other lizards detected within 1 m of the focal sects (F1,44 = 36.64, P<0.00001 for sunny lizard. Of all individuals detected in the morn- patches; F1,35 = 8.52, P = 0.006 for shaded ing or at midday, only three males and three fe- patches), and there was a significant effect of lo- males had another lizard in their vicinity at each cality, with higher mean temperatures in Teide of the two sampling sites. (F = 8.64, P = 0.005 for sunny patches; 1,44 Most individuals detected were “Still” rather F = 18.14, P = 0.00018 for shaded 1,35 than “Moving” at both sites and sampling times patches); however, the interaction between site (fig. 2). There was no significant relationship and sampling time was not significant (F = 1,44 between sex and activity (G test of indepen- 0.0001, P = 0.99 for sunny patches; F = 1,35 dence, G = 1.484, df = 1, 0.50

0.70; and Total numbers of individuals from each sex adj G = 1.359, df = 1, 0.50

Figure 1. Mean (± 95% CI) detection rates of males and females at both study sites.

Table 2. Percentages of lizards performing several behaviour patterns during transects at both sampling sites and times.

Basking Still Walking Foot-waving Display Running Eating Courting

Morning Güimar 1.25 70.62 24.37 2.50 0.00 1.26 0.00 0.00 Teide 0.65 73.51 21.45 0.65 0.65 1.25 1.91 0.00 Midday Güimar 0.00 67.75 22.84 0.86 0.00 7.66 0.00 0.88 Teide 0.00 58.85 25.54 0.00 0.00 15.55 0.00 0.00 among separate contingency tables for each sex, were found oriented parallel to the sun rays, site or time when the transect was conducted whereas the frequencies with which females (heterogeneity chi-square = 4.264, P>0.5). adopted parallel and perpendicular orientations A contingency table analysis of pooled data were very similar (12 and 11, respectively, out from all individuals at the two sampling sites of a total of 29 females). showed that lizards exhibit a significant prefer- Mean operative temperatures were 36.8 and ◦ ence for parallel and perpendicular orientations 43.5 C respectively for morning and midday ◦ (goodness-of-fit G test, Gadj = 29.561, df = 2, sampling times at Güimar and 37.9 and 45.8 C P<0.001; fig. 3). for those at Teide. Moreover, operative temper- There was no statistically significant associ- atures were not significantly different for cop- ation between sex and body orientation for any per tubes oriented perpendicular or parallel to locality or sampling time (G tests of indepen- the sun, neither in morning (Mann-Whitney U dence, P>0.1 in all cases), suggesting that test, Z =−0.48, P>0.05) or midday hours males and females do not differ in the frequency (Z =−0.69, P>0.05). with which they adopt the different body orien- tations. However, a separate analysis consider- ing only those individuals that occupied sunny Discussion patches when first detected revealed a signifi- Lizard activity in relationship to environmental cant association between sex and body orienta- temperature tion in the data from morning transects at Güi- mar (Gadj = 6.851, df = 2, 0.05

Figure 2. Frequency of males and females found “Moving” or “Still” at both sampling sites and daily times.

Figure 3. Frequency of males and females showing the three body axis orientations during the morning (top figures) and midday (bottom figures) sampling periods of Güimar (a and b) and Teide (c and d). Body orientation in Gallotia 99 comparison with morning transects. This result high altitudes than near the shore, close to sea is not unexpected given the absence of wind and level (Carrascal & Palomino, 2005), and per- the higher insolation rate – especially at midday, centages of lizard remains in kestrel pellets are with peaks reaching 800-1000 watts/m2 –in also significantly lower at high altitudes (J. Car- Teide National Park (Astrophysics Institute of rillo, personal communication). Canary Islands, http://www.iac.es/weather/otdata/) in comparison with the lava fields of Güimar, Lizard detection rates: Effects of sex close to sea level (550-600 w/m2, Solar Map, We detected significantly more males than fe- Technological Institute of Canary Islands). males (per unit time) at both sampling sites. Although fewer individuals were found dur- Previous observations have shown that dur- ing the morning in Güimar than in Teide, and ing the reproductive season G. galloti males more in the morning than at midday in Teide, move through their home ranges to find fe- the differences did not reach statistical signifi- males (Molina-Borja, 1985), a behavior also cance; likewise, detection rates were not signif- reported in other lizard species (Hews, 1990; icantly different in the two sites at any of the Ruby, 1981; Trivers, 1976). The differences in sampling times studied. The small number of in- detection rate between the sexes could be due to dividuals detected at midday in Teide is likely the higher activity levels of males and the com- due to lizards avoiding the high temperatures paratively reduced conspicuousness and/or ex- (upto54◦C) at sunny patches during that time. posure of females in open sites (Nicholson and Individuals of G. galloti from another popula- Spellerberg, 1989; Stamps, 1983). For exam- tion were also shown to avoid sunny patches at ple, a reduction in locomotor activity has been midday (Díaz, 1994). It is widely documented detected for pregnant females of some species that lizards adjust their activity to environmental (Cooper et al., 1990). Alternatively, it could be temperatures allowing body optima for differ- that there are more males than females in the ent physiological functions (Anguilletta et al., two populations studied. Complete census data 2002) and behavior patterns (Huey, 1982; Van for individuals of each sex are not currently Damme et al., 1991). For example, Podarcis his- available for our study sites. However, figures panica lizards control their body temperature by of can-trapped individuals in other studies con- adjusting their activity differentially in relation ducted at the same sites show that the propor- to daily time: they move less in the morning and tion of males is between 53.2 and 63.3% of to- shuttle between sunny places and shaded ones in tal adult individuals captured (our own unpub- the hottest midday hours (Bauwens et al., 1996). lished data); these figures are similar to the ones In Teide National Park, mean annual temper- obtained during the transects performed in the atures are much lower than at Güimar and con- current study (ranges of 48.1-59.2% and 53.8- ditions are adequate for lizard feeding and re- 62.9% of males at Güimar and Teide, respec- productive activities for a shorter time during tively). More studies are clearly needed to de- the year. However, we detected a similar den- termine whether males are more active – and sity of lizards in Teide than in Güimar. There- therefore easier to detect – than females or the fore, it seems that weather constraints are not sex ratio in this population is male-biased. the main factor affecting Gallotia galloti lizard distribution and population densities at high el- Body axis orientation evations. Other factors such as food availabil- ity and/or lower predation levels at higher al- The preferential use of parallel and perpendic- titudes may play an important role. Densities ular body orientations by individuals of G. gal- of kestrels (probably one of the most impor- loti at both sampling sites and daily times is in- tant lizard predators in the island) are lower at triguing. Waldschmidt (1980) also found paral- 100 M.L. Bohórquez-Alonso, E. Font, M. Molina-Borja lel and perpendicular orientations to be the most These biases in visual perception could be re- frequent in Uta stanburiana and Sceloporus un- sponsible for a preference for parallel and per- dulatus and interpreted them as behavioural re- pendicular orientations. sponses to the thermal environment. Perpendic- Site selection, body orientation, and posture ular body orientation in relation to sunlight in- are also important factors in visual communica- creases the proportion of the animal’s surface tion and signal transmission (Rosenthal, 2006). receiving solar radiation (i.e. its ‘view factor’) Lizards with their body parallel to sun rays and represents an efficient way of increasing could get both sides of their trunk equally il- body temperature, at least in the early morning luminated, while in a perpendicular orienta- hours (low solar azimuth). Parallel orientation, tion one side would be lit and the other in the on the other hand, minimizes the body surface shadow, at least during early morning and late exposed to the sun and therefore reduces radi- afternoon hours. With both body sides illumi- ant heat absorbance during the hottest part of nated the lizards would be conspicuous to con- the day. However, our data suggest that body specifics located to their left and to their right. axis orientation in G. galloti is not functional in Blue patches of G. galloti are located on the relation to body temperature regulation, as op- sides of the body and signal male fighting abil- erative temperatures were not significantly dif- ity during contests (Molina-Borja et al., 1998; ferent for tubes with parallel or perpendicular Huyghe et al., 2005; our own unpublished re- orientations (see also Shine and Kearney, 2001). sults), and therefore, making these patches more This agrees with the results of an experimental conspicuous to potential intraspecific receivers study showing that heating rates were not re- should be advantageous, at least for adult males lated to body orientation in Lacerta monticola during the reproductive season. Parallel orien- (Martín et al., 1995). Similarly, computer sim- tation in particular seems well suited to mak- ulations using data from the lizard Callisaurus ing a male’s coloration visible to a potentially dacronoides showed that body orientation did large audience. In fact, our results show that par- not influence body temperature (Muth, 1977). allel was the most frequent body orientation in There are several possible alternative – not males from both sites (fig. 5). Conspicuousness mutually exclusive – explanations for the pref- has obvious drawbacks as it may make lizards erential use of specific body axis orientations. more attractive for predators (e.g. Stuart-Fox et As the eyes of lizards are located laterally on al., 2003), but this cost should be negligible in the head, the intensity and spectral character- G. galloti, at least for aerial predators (there are istics of the light reaching both eyes would be no snake predators in Tenerife) such as kestrels more similar for a lizard oriented parallel to and buzzards, for which the lateral coloration sunlight than for a lizard adopting other body should be almost undetectable when lizards are orientations; this could be important to obtain seen from above. Cloudsley-Thompson (1994) adequate visual information from conspecifics reported that some lizards adopt a negative ori- or predators, particularly in those contexts in entation (body parallel to sun rays) as an an- which binocular cues may be important. Also, tipredator strategy that minimizes the lizard’s functional specialization of the cerebral hemi- body shadow making it more cryptic to visual spheres results in preferential use of one or the predators. However, this strategy would not be other eye for specific tasks and may impose fur- very effective in G. galloti, at least those mov- ther constraints on body axis orientation. Many ing on the black colored substrate of the lava lizards show a left-eye preference for viewing fields at Güimar. potential rivals and a right-eye preference for Both parallel and perpendicular body orien- viewing prey (Deckel and Jevitts, 1997; Hews tations were more common than oblique. This and Worthington, 2001; Bonati et al., 2008). indicates that G. galloti lizards could use these Body orientation in Gallotia 101 body orientations to get better cost/benefit ra- Ecology, p. 225-290. Gates, D.M., Schmerl, R.B., Eds, tios for specific functions. Thus, for example, Springer, New York. if the social system rewards certain individuals Bartholomew, G.A. (1966): A field study of temperature relations in the Galapagos marine iguana. Copeia 1966: for being exposed at sunny patches (e.g. to ad- 241-250. vertise territory ownership), a parallel body ori- Bartholomew, G.A. (1982): Physiological control of body entation should be expected in order to com- temperature. In: Biology of the Reptilia, Vol. 12, p. 167-204. Gans, C., Pough, F.H., Eds, Academic Press, municate more efficiently with others while London. not getting too hot. A similar explanation was Bauwens, D., Hertz, P.E., Castilla, A. (1996): Thermoreg- put forward for Galapagos iguanas, individu- ulation in a lacertid lizard: The relative contributions als adopting a negative orientation during the of distinct behavioral mechanisms. Ecology 77: 1818- 1830. hottest daily hours in order to avoid overheat- Bischoff, W. (1982): Die innerartliche Gliederung von Gal- ing (Bartholomew, 1966). Future experimental lotia galloti (Duméril et Bibron 1839) (Reptilia: Sauria: work will help to clarify the selective trade-off Lacertidae) auf Teneriffa, Kanarische Inseln. Bonn. that is responsible for the preference of G. gal- Zool. Beitr. 33: 363-382. Bonati, B., Csermely, D., Romani, R. (2008): Lateralization loti galloti lizards for parallel and perpendicular in the predatory behaviour of the common wall lizard body orientations. (Podarcis muralis). Behav. Proc. 79: 171-174. Carrascal, L.M., Palomino, D. (2005): Preferencias de hábi- tat, densidad y diversidad de las comunidades de aves en Tenerife (Islas Canarias). Anim. Biodiv. Conserv. 28: Acknowledgements. We thank José Díaz for his helpful 101-119. comments on an initial version of the manuscript. To Conse- jería de Medio Ambiente of the Cabildo Insular de Tenerife Chiszar, D. (1978): Lateral displays in the lower vertebrates: for the permission to perform the study in the natural pro- Forms, functions, and origins. In: Contrasts in Behav- tected area of Malpaís de Güimar and to Patronato of the ior. Adaptations in the Aquatic and Terrestrial Environ- Teide National Park for the permission to perform the study ments, p. 105-135. Reese, E.S., Lighter, F.J., Eds, John in the periphery of the Park. The present work was also pos- Wiley & Sons, New York. sible thanks to the research staying grant given to M.L.B.A. Cloudsley-Thompson, J.L. (1994): Predation and Defence within the ALE 2002 and ALE 2003 programs of the Agen- Amongst Reptiles. R & A Publishing, Somerset, Eng- cia Española de Cooperación con Iberoamérica (AECI). land. 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