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Although many factors have been shown to influence the evolution of species recognition signals in a wide variety of taxa, it is difficult to draw general conclusions because of fundamental differences in the morphologies and ecologies of the animals considered. In this study, two morphologically and ecologically similar lizard genera (Sceloporus and Liolaemus) are used to provide replicate examples of the evolution of a complex visual display. New data on the headbob displays of 16 Liolaemus species are presented. As in other taxa, phylogenetic analyses show that evolutionary changes in display structure have been rapid, leaving little, if any, phylogenetic information in the display structure. Evolutionary changes in display structure also do not appear to be closely associated with any major habitat characteristics. Despite this rapid evolution, Liolaemus lizards produce headbob displays that are remarkably simple in structure in comparison to those produced by Sceloporus, perhaps compensating for lower complexity by frequent use of other visual displays such as forelimb and tail waves.

The ability to assess and respond to predation risk is a strong selective force. Detection of predators is carried out by one or more sensory modalities, but the use of chemoreception has significant advantages. This study examines the chemosensorial assessment of snake predation risk and corresponding behaviours in different species and populations of Liolaemus lizards naturally exposed to different levels of snake predation pressure. The species studied were sympatric (Liolaemus lemniscatus), parapatric (L. nigroviridis) and allopatric (L. fitzgeraldi) to the saurophagous snake, Philodryas chamissonis. Additionally, two populations of L. lemniscatus from areas differing in snake densities were compared. Chemo-assessment of predation risk was determined by comparing the number of tongue-flicks (TF) and the behavioural responses of lizards submitted to three treatments (with semiochemicals of snake, conspecifics, and without semiochemicals – control). The results suggest that Liolaemus lizards can chemo-assess snake predation risk, but this was modulated by the predation pressure experienced by lizards in their natural habitats. When exposed to snake semiochemicals, the sympatric prey showed less chemical exploratory behaviour (i.e. lower number of TF), a higher frequency of antipredator behaviours that would reduce its detection by a predator, and did not show the behaviour triggered by conspecific semiochemicals. The parapatric prey showed similar number of TF across different treatments, suggesting an absence of recognition of snake semiochemicals; however, it did show antipredatory behaviours when confronted with snake semiochemicals. The allopatric prey showed similar behaviour in all treatments. Both populations of the sympatric species, L. lemniscatus, showed a similar ability to detect predation risk when confronted with snake semiochemicals (i.e. similar number of TF), but antipredatory behaviours were diminished, and marking behaviours were present in the population subject to lower predation pressure. Relaxed predation pressure from a predator that releases and detects semiochemicals had similar consequences at species and population levels.

We explored chemical discrimination of own vs. novel space by different age classes (neonates, juveniles, and adults) of the lizard Liolaemus bellii, during pre- and post-hibernation seasons. We recorded the number of tongue flicks (TF) lizards produced during 10 min in their own or a novel enclosure. Age class and season affected chemical discrimination. Only adults and neonates discriminated their own space, albeit using different strategies: while adults made fewer TF in their own enclosure, neonates made more TF in their own enclosure. This difference was interpreted in terms of different requirements for discrimination of individuals during their lives. Increased chemical exploration by juveniles and adults at the onset of the post-hibernation season was associated with food-searching and reproductive behaviors.

The chemical composition of secretions of precloacal pores from two populations of the lizard Liolaemus fabiani (Puilar and Punta-Brava) were compared. This is an endemic species from the Atacama Salt Flat (26°46'S 68°14'W; 2400 m) in northern Chile, restricted to the internal lakes of the salt flat. Interpopulational differences in the chemical composition of the secretions were expected considering that populations have genetic differences and are subject to different thermal conditions. By using GC-MS, a total of 44 compounds were found belonging to three categories: n-alkanes, long-chain carboxylic acids, and steroids. Six compounds were found in all the individuals studied: tetradecanoic, pentadecanoic, hexadecanoic, hexadecenoic, octadecanoic, and octadecenoic acids. The secretions of both populations had similar types and proportions of the different compounds, except for cholesterol and hexanoic acid, which were more abundant in the Puilar population. These differences can be ascribed to the different environmental conditions to which populations are subjected. The adaptive meaning of these differences is discussed.

La biodiversidad de todo el planeta se encuentra amenazada debido a los efectos del calentamiento global, y dentro de los vertebrados, los anfibios son los mas afectados por este problema. Los anfibios dependen de fuentes externas de calor para alcanzar y mantener una adecuada temperatura corporal, lo cual tiene un impacto significativo en su adecuacion biologica. Por lo tanto, un aumento en la temperatura media del ambiente afectara, probablemente en forma negativa, el desempeno general de los anfibios. Esto hace que sea imperativo incrementar nuestro escaso conocimiento respecto a la termorregulacion de anfibios. El objetivo de este trabajo es contribuir al conocimiento de la termorregulacion de estos organismos mediante el estudio de la ecologia termica en invierno de una de las especies de mas amplia distribucion en Chile, Pleurodema thaul. Los individuos fueron recolectados en invierno en la Peninsula de Hualpen, que corresponde al punto medio del rango latitudinal de distribucion de P. thaul. En terreno y en laboratorio se registro la temperatura corporal y las temperaturas de sustrato y el aire. Los datos indican que P. thaul es una especie termoconforme, ya que su temperatura corporal varia durante el dia segun varia la temperatura del substrato y del aire. Pleurodema thaul no parece utilizar las propiedades morfologicas del cuerpo para facilitar la termorregulacion, ya que la temperatura del cuerpo no se relaciona con el tamano corporal o el peso de los individuos. El hecho de que durante el invierno P. thaul no termorregule activamente constituye un claro antecedentes que el calentamiento global puede ocasionar graves efectos sobre esta especie.

Interspecific chemical variation of precloacal pore secretions of Liolaemus lizards was characterized in 20 species, and intraspecific chemical variation was characterized using nine individuals of L. bellii. The latitude (Chile, 18 degrees to 33 degrees South latitude) and altitude (100 to 4350 m.a.s.l.) of the capture sites were recorded, as well as the number of precloacal pores of each lizard. Secretions were analyzed by GC-MS. A total of 49 compounds were found distributed among the 20 species of Liolaemus. Different chemical patterns occurred at intra- and interspecific levels. Compounds belonged to three main families: n-alkanes, long chain carboxylic acids, and steroids. Cholesterol and five carboxylic acids (tetradecanoic, hexadecanoic, hexadecenoic, octadecanoic, and Z-9-octadecenoic) appeared in all species. The number of precloacal pores correlated positively with altitude and negatively with latitude, suggesting that lizards produce more secretions under harsh environments.

Experimental tests were conducted to determine whether females and males of the tree-dwelling lizard Liolaemus tenuis (Tropiduridae) show intraspecific chemical recognition during breeding and postreproductive seasons. Animals were individually maintained in plastic enclosures for one week. Thereafter, the number of tongue-flicks that a lizard performed in the enclosure of a male, a female, its own home enclosure, and a control (unused) enclosure were recorded. In both seasons, males and females made fewer tongue-flicks in their home enclosures than in any other one, indicating a recognition of a familiar place, probably a chemical self-recognition. Conspecific chemical recognition was season dependent. During the post-reproductive season, lizards tongue-flicked at similar rates in conspecific and control enclosures, while during the breeding season enclosures of females elicited more tongue-flicks by both sexes, and the overall tongue-flick rates were higher than in the postreproductive season. Results are discussed within the context of the social system of the species.

The study of acoustic communication in lizards has been restricted and mainly focused on Gekkota. The rest of the lizards, Unidentata, are generally considered voiceless, although there are sparse reports on vocal sound production in members of different families. We analyzed the spectro-temporal characteristics of the distress calls emitted by the Unidentata lizard, Liolaemus chiliensis (the weeping lizard; Liolaemidae), the only species of this highly diverse genus (>220 species) that vocalizes. We also explored the relationships of the call characteristics with the sex and size of the individuals. The vocalizations of L. chiliensis are highly diverse and complex compared to any known call produced by Unidentata lizards. They exhibit pronounced frequency modulations, various nonlinear phenomena, and harmonics that extend into the ultrasonic range. Fundamental frequency and call duration are correlated with body size, and males emit louder but simpler calls (i.e., with less nonlinear phenomena) than fema...

The evolution and functions of avian and mammalian antipredator callsare well understood, which contrasts with a lack of progress in reptiles.Here, we present the first investigation of the functions of a distress call ina lizard. We studied Liolaemus chiliensis, which emits a short and complexhigh-pitched scream when it is subdued. We determined the behavioralresponses of two potential targets to these calls, conspecifics, and a snakepredator. Additionally, we tested whether the chemical environment(presence of chemical scents from conspecifics) modulates the lizards’responses to calls. Both the conspecifics and the predator responded to thedistress calls, which triggered a longer period of immobility in the lizardsand a reduction in exploratory behavior in the snake, as compared to awhite noise. In addition, the lizards in the arena with scents of conspecif-ics responded to distress calls and noise with more movements and escapeattempts. These results suggest that distress calls may enhance the survivalof L. chiliensis individuals.IntroductionMany birds and mammals emit calls when they areunder the risk of predation. These vocalizationsinclude alarm calls emitted when prey detect preda-tors and distress calls emitted when they are seized bypredators (Caro 2005). The distress calls may induce avariety of behavioral changes in conspecifics and/orpredators, which can enhance the survival probabili-ties of the prey and/or its conspecifics (H€ogstedt 1983;Neudorf & Sealy 2002; Caro 2005). These calls can becries for help, attracting conspecifics which may helpby attacking the predator (Branch & Freeberg 2012),or they may be warnings that help kin to escape frompredation (Rohwer et al. 1976). In addition, predatorscan be startled by distress calls (Wise et al. 1999;Neudorf & Sealy 2002), among other reasons, becausecalls may convey honest information about the defen-sive capabilities of the prey (Laiolo et al. 2004).Distress calls can also attract secondary predators,whose presence, or potential presence, may lead theprimary predator to release its prey in order to protectitself (H€ogstedt 1983; Koenig et al. 1991). Clearly,distress calls can have different functions that are notmutually exclusive (Rohwer et al. 1976; Perrone1980; Conover 1994; Branch & Freeberg 2012).The research on different types of antipredator callsdone on birds and mammals has allowed progress inthe understanding of the proximate and ultimatecauses involved in their evolution (e.g., Caro 2005;Zuberb€uhler 2009; Moller & Nielsen 2010; Gill & Bier-ema 2013). This contrasts with the lack of studies inother taxa that exhibit antipredator vocalizations,such as amphibians (Hodl & Gollmann 1986; Toledo &€Haddad 2009) and reptiles (Greene 1988). For lizards,there are no studies on the role of these vocalizationseven if many species vocalize under predation risk(see Labra et al. 2013). It is probable that lizards useconspecific calls to reduce their predation risk,because many species respond to the sounds associ-ated with predation even if they do not use sounds insocial interactions. For example, some species eaves-drop on the alarm calls of birds, which can trigger, ascompared to their songs, higher vigilance (Vitouseket al. 2007; Ito & Mori 2010) or increased camouflage(Ito et al. 2013). Other lizard species discriminatebetween vocalizations from predator and non-preda-tor bird species (Cantwell 2010) or modulate their

La variacion interespecifica en las tasas de calentamiento de Liolaemus pareciera ser un mecanismo fisiologico adaptativo que permitiria a los lagartos enfrentar restricciones termicas ambientales impuestas a la termorregulacion conductual. Esta tendencia ha sido raramente analizada a nivel intraespecifico y en este estudio exploramos si existe variacion intraespecifica en las tasas de calentamiento de Liolaemus tenuis, una especie con rango de distribucion relativamente amplio en Chile central. Probamos la hipotesis de que las tasas de calentamiento estan relacionadas con la condicion termica ambiental, a traves de comparaciones de las tasas de calentamiento de tres poblaciones (a lo largo de un rango latitudinal), que habitan en ambientes termicos diferentes. Ademas, exploramos si el factor intrinseco, sexo, modula estas tasas de calentamiento. Las tasas de calentamiento tienen una variacion intraespecifica significativa a nivel poblacional y sexual. Sin embargo, estas tasas estan solo parcialmente relacionadas a las condiciones ambientales a la que estan sometidas las poblaciones. La poblacion nortena, que habita a mas altas temperaturas, se calienta mas lento, lo que podria reducir el riesgo de sobrecalentamiento. Por otra parte, independiente de la poblacion, las hembras se calientan mas lento que los machos. El significado de esta variacion sexual no es claro, pero podria ser consecuencia de las significativas diferencias en las conductas sociales de ambos sexos. Debido a que los machos defienden un territorio con un haren, un calentamiento mas rapido les permitiria asignar mayor tiempo a las conductas asociadas a la defensa y mantencion del territorio.

Squamata reptiles are often divided in two major groups based on the main sensory modality that they use: the chemical/visual and the visual taxa. Although Liolaemus lizards belong to the visual taxon Iguania, I show that they may depend heavily on chemosignals in many different aspects of their life. The combined information from Liolaemus and other “visual genera” that use chemosignals, urges us to reconsider the classical dichotomous segregation of Squamata in terms of sensory modality. In addition, further work is also necessary to understand the role of chemical signals in “visual” lizards.

Se estudio la variacion sexual y geografica de los patrones de coloracion en Liolaemus tenuis. Se conto el numero de escamas con diferentes colores en dos regiones del cuerpo, en individuos de ambos sexos y provenientes de tres grupos de poblaciones a lo largo de un gradiente latitudinal. Los patrones de coloracion mostraron variaciones sexuales y geograficas; las hembras y el grupo mas nortino fueron mas oscuros. Las presiones selectivas que determinan estas variaciones de los patrones de coloracion no son claras. Sin embargo, considerando que los machos de L. tenuis son territoriales y poligamos, se postula que la variacion sexual del color seria una consecuencia de la seleccion sexual que involucra eleccion de machos por parte de las hembras y las interacciones macho-macho (e.g. despliegues agonisticos entre machos). La variacion geografica estaria determinada por presiones de depredacion, dada la tendencia a la presencia de coloraciones similares a las predominantes en el ambiente (i.e. predominio de colores oscuros hacia las zonas de matorral).

We explored chemical discrimination of own vs. novel space by different age classes (neonates, juveniles, and adults) of the lizard Liolaemus bellii, during pre- and post-hibernation seasons. We recorded the number of tongue flicks (TF) lizards produced during 10 min in their own or a novel enclosure. Age class and season affected chemical discrimination. Only adults and neonates discriminated their own space, albeit using different strategies: while adults made fewer TF in their own enclosure, neonates made more TF in their own enclosure. This difference was interpreted in terms of different requirements for discrimination of individuals during their lives. Increased chemical exploration by juveniles and adults at the onset of the post-hibernation season was associated with food-searching and reproductive behaviors.

The chemical composition of secretions of precloacal pores from two populations of the lizard Liolaemus fabiani (Puilar and Punta-Brava) were compared. This is an endemic species from the Atacama Salt Flat (26 degrees 46'S 68 degrees 14'W; 2400 m) in northern Chile, restricted to the internal lakes of the salt flat. Interpopulational differences in the chemical composition of the secretions were expected considering that populations have genetic differences and are subject to different thermal conditions. By using GC-MS, a total of 44 compounds were found belonging to three categories: n-alkanes, long-chain carboxylic acids, and steroids. Six compounds were found in all the individuals studied: tetradecanoic, pentadecanoic, hexadecanoic, hexadecenoic, octadecanoic, and octadecenoic acids. The secretions of both populations had similar types and proportions of the different compounds, except for cholesterol and hexanoic acid, which were more abundant in the Puilar population. These differences can be ascribed to the different environmental conditions to which populations are subjected. The adaptive meaning of these differences is discussed.

For territorial organisms, recognition of familiar individuals can reduce the frequency and intensity of aggressive encounters (‘dear enemy’ phenomenon), stabilize social systems, and reduce the cost of territory maintenance. Here, we investigated the behavioural events displayed during contests between familiar and unfamiliar individuals in the lizard Liolaemus tenuis (Liolaemidae), a species in which males are territorial. The behaviours recorded were attack, warning, evasion, and submission, and the latencies to the first aggressive (attack or warning) behaviour. Additionally, we assessed the ability of individuals to remember a familiar conspecific after a period without social interaction. Individual males reduced and delayed aggressive behaviour directed towards socially familiar individuals compared with unfamiliar ones. These results suggest that males distinguished between familiar and unfamiliar conspecific males and are in agreement with the ‘dear enemy’ phenomenon. Other behaviours were similar in the contests between familiar and unfamiliar individuals. Recognition of familiar conspecifics was lost after 20 d without social interactions. This may be relevant for interactions with floater males or with neighbours that lose their territory and subsequently attempt to fight for their ex-neighbour's territory.

In squamate reptiles the effects of pregnancy on physiological thermoregulation, such as thermal tolerances and rates of heat exchange, are practically unknown. This is remarkable since pregnancy i...

Chemical signals produced by lizards are involved in different aspects of their interactions at intra and interspecific levels, including sex recognition, territory marking, and individual self-recognition (Mason, 1992; Cooper, 1994;Font, 1996), and have also been proposed as pre-reproductive barriers for sympatric congeneric species (Cooper and Vitt, 1986). The range of functions of chemical recognition would suggest that lizards should be able to discriminate many different patterns of chemical signals. We postulate that it would be “more economical” for lizards to discriminate only one chemical signal pattern, the one used by individuals in their self-recognition, and that signals not matching with the basic chemical pattern will not be discriminated.

The behavioral and physiological thermoregulation of three Atacama desert-dwelling Liolaemus lizards was studied and compared with previous data on Liolaemus from other ecosystems. The thermoregulatory mechanisms of the desert-dwelling species differed from those of the others, a consequence of differences in the habitat structure of the species. Desert species have higher critical thermal minima and, contrary to expectations, lower selected body temperatures than Liolaemus from Mediterranean environments. Results of the rates of thermal time constants suggest mechanisms to cope with the fast decrease of environmental temperature that occurs in the desert during the mid-afternoons. Finally, the manner in which selection of low body temperatures may allow survival in desert conditions is discussed.

The development and the current state of behavioral studies in Chile was analyzed considering articles on Chilean fauna published between 1984 and 1998 (203 articles). The number of articles on the subject of animal behavior has increased significantly along the period studied, indicating an increasing interest on this research. However, the international impact of Chilean research has been comparatively low. Proposals to stimulate the development of this research area in Chile are: i) that main research universities in Chile recruit well-trained behavioral ecologists. This will have immediate impact by increasing the number of courses in animal behavior, which will attract a new generation of biology students into this area, promoting the persistence and growth of the Chilean Ethological Society, and stimulating research in animal behavior; and ii) that Chilean scientists working in animal behavior establish academic links with foreign colleagues specifically trained in this area. El desarrollo y estado actual de los estudios sobre conducta animal en Chile fueron analizados considerando los artículos sobre fauna de Chile publicados entre 1984 y 1998 (203 artículos). El número de artículos en conducta animal incrementó significativamente a lo largo del período estudiado, lo cual indica un interés creciente en este tipo de investigaciones. Sin embargo, el impacto internacional de la investigación chilena ha sido comparativamente bajo. Las propuestas para estimular el desarrollo de esta disciplina en Chile son: i) que las principales universidades que priorizan la investigación científica contraten a ecólogos del comportamiento bien entrenados. Esto tendrá un impacto inmediato incrementando el número de cursos en comportamiento animal, lo que atraerá a una nueva generación de biólogos hacia este campo, promoverá la persistencia y el crecimiento de la Sociedad Chilena de Etología, y estimulará la investigación en comportamiento animal; y ii) que los científicos chilenos que trabajan en comportamiento animal establezcan vínculos académicos con colegas extranjeros entrenados específicamente en esta área.

This study reports on an experiment designed to quantify potential predation by birds on the lizard Podarcis hispanica atrata in the Columbretes islands (Castellon, Spain). We used plasticine replicas to examine predation risk of replicas as a function of proximity to vegetation and to potential predators, and to investigate the seasonal variation in patterns of predation. Predation on replicas was very high and intensive within only four days, and differed between study areas and seasons. Predation was more intense when replicas were closer to nests of gulls and far from vegetation. The Yellow-legged Gull (Larus cachinnans michaellis) was identified as the major species responsible for predation on lizard replicas.

An experimental study was carried out to determine whether self and conspecific chemical recognition occurs in Liolaemus bellii, a Tropidurid lizard from Central Chile. Experiments were performed during the autumn and the spring. Using the number of tongue flicks as an indicator of discrimination, it was found that L. bellii showed both self and conspecific chemical recognition. Lizards recognized their own territories, and conspecific chemical recognition showed seasonal changes. During autumn, lizards showed higher exploratory behavior (higher numbers of tongue flicks and motion time) than in spring, and female enclosures elicited in males higher numbers of tongue flicks. Similar results were previously found in other Liolaemus species from a different habitat The information available at present for Liolaemus suggests that recognition of own territory is more important than recognition of conspecifics, and the latter seems to be associated mainly to the reproductive season. Therefore, conspecific and self-chemical recog- nition seem to be independent of the habitat used by the species, although habitat could modulate the use of chemical signals.

Indexación: Scopus. Experimental tests were conducted with the lizard Liolaemus tenuis (Tropiduridae), to determine the potential sources of pheromones used in its chemical communication, centered in the phenomenon of self-recognition. During the post-reproductive season, feces of both sexes and secretions of precloacal pores (present only in males) were tested. Stimuli were presented to lizards spread on rocks, and the number of tongue-flicks (TF) to the rocks was used as a bioassay to determine pheromone recognition. Feces contained pheromones involved in self-recognition, since lizards showed less TF confronted to rocks with suspensions of their own feces than with suspensions of feces of conspecifics or with water (control). In order to assess the chemical nature of self-recognition pheromones, feces were submitted to a sequential extraction with three solvents of increasing polarity, thereby obtaining three feces fractions. There were no differences in TF towards rocks with different fractions with own feces. Additionally, lizards showed similar TF to rocks with fractions of own and conspecific feces, suggesting that the separation procedure broke up a complex stimulus into parts that were not active individually as pheromones. Finally, males did not discriminate between precloacal secretions from themselves and from another male. It is possible that these secretions convey information relevant to or detectable by females only. https://www-scielo-cl.recursosbiblioteca.unab.cl/scielo.php?script=sci_arttext&pid=S0716-078X2002000100013&lng=en&nrm=iso&tlng=en

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