ORIGINAL PAPER Discrimination of conspecific faecal chemicals and spatial decisions in juvenile Iberian rock lizards (Lacerta monticola) (original) (raw)
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acta ethologica, 2008
Faeces play a role in intraspecific chemical communication in many vertebrates, including lizards. Here, we hypothesised that juvenile Iberian rock lizards (Lacerta (=Iberolacerta) monticola) use substrate-borne conspecific faecal chemicals to assess the social environment and base their spatial decisions. To test this hypothesis, we prepared chemical stimuli by dissolving faeces in an organic solvent (dichloromethane, DCM) and conducted chemosensory trials where we quantified latency to the first tongue flick (TF) and TF rates when young captive-borne juveniles were placed in an arena compartment whose substrate was labelled by (1) a control (DCM), (2) their own faecal chemicals, (3) faecal chemicals of another juvenile, (4) faecal chemicals of an adult female or (5) faecal chemicals of an adult male. Following TF observations, we removed a partition that separated the labelled compartment from a chemically unlabelled one, and recorded for 5 min when juveniles first crossed to the unlabelled compartment and total time spent in the labelled compartment. Each juvenile was tested with all stimuli in a randomised order. In addition, juveniles belonged to different families and were unrelated to and unfamiliar with faeces donors. Taken together, TF and spatial responses toward stimuli indicate that juveniles discriminated between faecal chemicals of conspecific juveniles, adult females and males, and that they avoided remaining in substrates labelled by adult male faecal chemicals. We suggest that juveniles assess the social environment based on conspecific faecal chemicals thus avoiding aggression and cannibalistic risks undertaken from encounters with adult males.
Intraspecific chemical recognition in the lizard Liolaemus tenuis
Journal of chemical ecology, 1999
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.
Herpetological Conservation & Biology, 2024
Intraspecific communication via chemosignals has been linked to important natural history aspects in lizards, including honest signaling tied to reproductive success and conspecific displays of sociality. Chemosignals can be used over significant spatial and temporal parameters, allowing for inconspicuous interaction by some species. This type of cryptic communication is not easily detected, but researchers can obtain baseline lizard signaling capabilities by quantifying tongue-flick (TF) rate toward conspecific scents. We tested chemosignaling behavior in endangered Guatemalan Beaded Lizards (Heloderma charlesbogerti) by evaluating TF response toward same-sex and opposite-sex conspecific stimuli and control treatments. Our suspected sources of pheromones for determining conspecific scent recognition were shed skin and used substrate. Age and reproductive cycle of trial subjects had no discernable effect on TF rate, but sex was a significant factor. Both males and females displayed differential TFs between treatments from opposite-sex and same-sex donor individuals. Male lizard TF response was significantly different between all treatments, including controls. Females had lower and less pronounced differential TFs towards treatments than males, as female TF response was only significantly different between opposite-sex stimuli towards control and same-sex stimuli treatments. We conclude that nonvolatile chemosignals are present in H. charlesbogerti biomaterials, with the degree of behavioral response varying depending on sex and presented stimuli. Our study not only adds to our understanding of intraspecific chemosignaling in helodermatid lizards, but also provides information that could lead to more comprehensive conservation programs for H. charlesbogerti.
Journal of Ethology, 2009
Iguanid lizards are known for visual acuity and a diminished vomeronasal organ, which has led to mixed conclusions on whether iguanids use chemical cues. The collared lizard, Crotaphytus collaris, is a territorial iguanid that lives in open rocky habitats. Fecal pellets placed prominently on open rocky perches may provide an ideal mechanism for intraspecific chemical signaling. In order to determine whether collared lizards can discriminate between chemical stimuli found in conspecific fecal pellets, we collected 24 males and 25 females to analyze sexspecific behavioral responses via tongue-flicks and a newly observed behavior for the species, gular pumps, to cotton swabs containing water, cologne, chemical stimuli from conspecific male and female fecal pellets, and the lizard's own fecal pellet. Both sexes were able to discriminate chemical stimuli from water via at least one behavior. Male collared lizards exhibited greater rates of response (tongueflick and gular pumps) toward male fecal pellets when compared to the negative water control. Our results also suggest individuals may be able to discriminate between fecal pellets, as indicated by generally greater (but nonsignificant) counts of male tongue-flick responses to male fecal pellets when compared to their own. Collared lizard chemical discrimination appears to utilize tongue-flick and gular pump behaviors, possibly associated with distinct chemosensory modes (vomerolfaction and olfaction). Based on this study, we suggest that chemical signals may play a greater role in intraspecific communication than previously thought in this highly visual lizard.
Animal Behaviour, 2007
Recent studies have stressed the role of scent marks as signals potentially mediating competitor assessment. According to this view, receivers may use scent marks to derive information about the costs of exploiting a given area, but few studies have directly addressed this hypothesis. One of its main predictions is that scent marks should reflect a signaller's competitive ability. We simulated the situation faced by an intruding male when entering the scent-marked territories of rival males of varying competitive ability to test predictions about the role of scent marks in a lizard, Podarcis hispanica. We report that males were attracted to areas marked by males of similar or higher competitive ability (i.e. larger size), but not to areas scent marked by males of lower competitive ability, and that this preference disappeared towards the end of the breeding season. Our results show that (1) male lizards can assess rival competitive ability (i.e. rival size) on the basis of scent marks alone, (2) scent marks do not function as chemical barriers to deter intruders, and (3) male response to marked areas varies throughout the breeding season, suggesting a shift in the cost-to-benefit balance of entering a scent-marked area. We propose that male assessment of rival competitive ability may function as an indirect assessment mechanism of territory resource quality in this species, and thus that scent marks may convey information not only about costs but also about the benefits of exploiting a scent-marked area.
Animal Behaviour, 2008
True individual recognition (TIR), the ability to recognize conspecific individuals on the basis of identity cues, is required for the evolution of several social traits (e.g. the maintenance of dominance hierarchies). However, knowledge about the distribution and functional significance of TIR is scant in some vertebrate groups, such as reptiles. In this study we used a functional modification of a habituationedishabituation paradigm to investigate the existence and adaptive significance of TIR in a territorial lizard (Podarcis hispanica, Lacertidae). Males discriminated between individual rivals of similar characteristics (e.g. size, weight, familiarity) solely on the basis of their scent marks. Males also remembered the spatial location of scent marks and subsequently behaved more aggressively towards rival males that consistently marked in the core than on the periphery of their experimental terrarium. Together, these results suggest that, in this species, scent marks function to identify the potential threat posed by each individual neighbour, allowing resident males to allocate their aggressive behaviour accordingly. Our findings challenge the simplistic and commonly held view that 'dear enemy' phenomena in lizards are exclusively based on familiarity asymmetries, and support an alternative threat level hypothesis in which TIR may be more important than previously acknowledged.
2007
Recent studies have stressed the role of scent marks as signals potentially mediating competitor assessment. According to this view, receivers may use scent marks to derive information about the costs of exploiting a given area, but few studies have directly addressed this hypothesis. One of its main predictions is that scent marks should reflect a signaller's competitive ability. We simulated the situation faced by an intruding male when entering the scent-marked territories of rival males of varying competitive ability to test predictions about the role of scent marks in a lizard, Podarcis hispanica. We report that males were attracted to areas marked by males of similar or higher competitive ability (i.e. larger size), but not to areas scent marked by males of lower competitive ability, and that this preference disappeared towards the end of the breeding season. Our results show that (1) male lizards can assess rival competitive ability (i.e. rival size) on the basis of scent marks alone, (2) scent marks do not function as chemical barriers to deter intruders, and (3) male response to marked areas varies throughout the breeding season, suggesting a shift in the cost-to-benefit balance of entering a scent-marked area. We propose that male assessment of rival competitive ability may function as an indirect assessment mechanism of territory resource quality in this species, and thus that scent marks may convey information not only about costs but also about the benefits of exploiting a scent-marked area.
Behavioral ecology and sociobiology, 2020
Signal divergence and sensory preferences may lead to sexual isolation and eventually promote speciation between animal populations. However, few studies have quantified the degree of chemical signal divergence and scent-mediated sexual isolation in lizard populations. Geographic and ecological variations among populations of the whiptail lizard Aspidoscelis lineattissimus suggest that there might be chemical signal divergence among these populations. Here, we used gas chromatography-mass spectrometry to characterize and compare the chemical composition of the femoral gland secretions of male whiptail lizards of four populations from a western region of Mexico and, through behavioral experiments, explored the effects of lizard scents on precopulatory behaviors and intrasexual male-male chemical recognition among populations. Our results showed that males of each population contain a divergent mixture of compounds in their femoral gland secretions. Differential chemosensory behavior indicated that male and female lizards discriminated and were more attracted to scents of lizards from their same population. Although females also seem to discriminate male scents between populations, their associated preference to territories scent-marked by males of their own population is different between regions (eastern vs western) and not between populations. We suggest that between some populations of A. lineattissimus there may be partial premating isolation mediated by chemical signals and behavioral divergence
The Journal of experimental zoology, 2001
Actively foraging lizards are capable of identifying prey using only chemical cues sampled by tongue-flicking, and the relatively few omnivorous and herbivorous lizards tested similarly can identify both animal and plant foods from chemical cues. Whether lizards that eat plants respond to cues specific to preferred plant types and whether there is geographic variability in responses to cues from various plants correlated with the importance of those plants in local diets is unknown. In three populations of an omnivorous lacertid, the Balearic lizard Podarcis lilfordi, we studied chemosensory sampling and feeding responses to chemical cues from plant and animal foods presented on cotton swabs. Each lizard population is endemic to one islet off the coast of Menorca, Balearic Islands, Spain. Lizards in all three populations discriminated chemical cues from plant and animal foods from control substances. Our results extend findings of prey chemical discrimination and plant chemical disc...
Animal Behaviour, 1986
Behavioural cues were used to assay the capacity of common lizards to detect chemical deposits of snakes. The lizards were observed in cages that had been previously inhabited either by one of two species of snake that feed on lizards (the viper Vipera berus and the smooth snake Coronella austriaca), or the grass snake (Natrix natrix), which does not feed on lizards. As a control, the lizards were tested both in a clean cage and in one sprayed with a pungent odorant. The lizards responded to the snakes' chemicals by increased tongue-flick rates, with the highest rates being given in response to the deposits of their predators. The chemosensory examination of the snakes' odours induced a shift in general behaviour in response to the predator, but not to the non-predator chemical cues. This behavioural response consisted mainly of a disruption of the locomotor patterns. Our findings strongly suggest that lizards detected and distinguished between the chemicals deposited by three species of snake. Behavioural performances were highly variable among individual lizards in all trials, but the relative scores of individuals tended to be similar in response to different stimuli.