Vigilance against predators induced by eavesdropping on heterospecific alarm calls in a non-vocal lizard Oplurus cuvieri cuvieri (Reptilia: Iguania)

Prey animals can reduce their risk of predation by detecting potential predators before encounters occur. Some animals gain information about nearby predators by eavesdropping on heterospecific alarm calls. Despite having well-developed ears, most lizards do not use vocal information for intraspecific communication, and few studies have shown practical use of the ears in wild lizards. Here, we show that the Madagascan spiny-tailed iguana (Oplurus cuvieri cuvieri) obtains auditory signals for predator detection. The Madagascan spiny-tailed iguana and the Madagascar paradise flycatcher (Terpsiphone mutata) are syntopic inhabitants of the Ampijoroa dry deciduous forest of Madagascar. The iguana and the flycatcher have neither a predator–prey relationship nor resource competition, but they have shared predators such as raptors and snakes. Using playback experiments, we demonstrated that the iguana discriminates mobbing alarm calls of the flycatcher from its songs and then enhances its vigilance behaviour. Our results demonstrate the occurrence of an asymmetrical ecological relationship between the Madagascan spiny-tailed iguana and the paradise flycatcher through eavesdropping on information about the presence of predators. This implies that indirect interspecific interactions through information recognition may be more common than generally thought in an animal community.     

Aegean wall lizards switch foraging modes,diet, and morphology in a human‐built environment

Foraging mode is a functional trait with cascading impacts on ecological communities. The foraging syndrome hypothesis posits a suite of concurrent traits that vary with foraging mode; however, comparative studies testing this hypothesis are typically interspecific. While foraging modes are often considered typological for a species when predicting foraging‐related traits or mode‐specific cascading impacts, intraspecific mode switching has been documented in some lizards. Mode‐switching lizards provide an opportunity to test foraging syndromes and explore how intraspecific variability in foraging mode might affect local ecological communities.Because lizard natural history is intimately tied to habitat use and structure, I tested for mode switching between populations of the Aegean wall lizard, Podarcis erhardii, inhabiting undisturbed habitat and human‐built rock walls on the Greek island of Naxos. I observed foraging behavior among 10 populations and tested lizard morphological and performance predictions at each site. Furthermore, I investigated the diet of lizards at each site relative to the available invertebrate community.I found that lizards living on rock walls were significantly more sedentary—sit and wait—than lizards at nonwall sites. I also found that head width increased in females and the ratio of hindlimbs to forelimbs in both sexes increased as predicted. Diet also changed, with nonwall lizards consuming a higher proportion of sedentary prey. Lizard bite force also varied significantly between sites; however, the pattern observed was opposite to that predicted, suggesting that bite force in these lizards may more closely relate to intraspecific competition than to diet.This study demonstrates microgeographic variability in lizard foraging mode as a result of human land use. In addition, these results demonstrate that foraging mode syndromes can shift intraspecifically with potential cascading effects on local ecological communities.     

Study of closely related species within the Physalaemus cuvieri group (Anura): contribution of microsatellite markers

Various species of the Physalaemus cuvieri group of frogs are difficult to distinguish morphologically, making molecular analysis an attractive alternative for indentifying members of this group, which is considered to be at risk because of loss of habitat. The genetic structure of natural populations of P. ephippifer and P. albonotatus species was investigated and analyzed, together with that of five previously studied populations of P. cuvieri. Nine microsatellite loci were used in the analyses. The overall G(ST) value (0.46) revealed high genetic variation among the populations, as expected for different species. Bayesian analysis implemented by the STRUCTURE software clustered the seven populations into seven groups (K = 7). All the P. albonotatus and P. ephippifer specimens were grouped into a single cluster, both species showing clear differentiation from P. cuvieri. The different grouping based on these microsatellites of some P. cuvieri individuals from Porto Nacional and from Passo Fundo suggests that they could be a new species, indicating a necessity for taxonomic reevaluation. Despite the intrinsic difficulties in analyzing closely related species, the nine microsatellite loci were found to be adequate for distinguishing these three species of the P. cuvieri group and their populations.     

Natural colonization or introduction? Phylogeographical relationships and morphological differentiation of house geckos (Hemidactylus) from Madagascar

Several house gecko species of the genus Hemidactylus are almost cosmopolitan lizards, with distributions that have probably been shaped by natural transoceanic dispersal as well as by more recent human introductions. Here we revise the Hemidactylus populations of Madagascar and compare them genetically with populations from other sites in the Indian Ocean region. Morphological data strongly confirm the occurrence of three Hemidactylus species on Madagascar: Hemidactylus frenatus , distributed along the western coast of Madagascar; H. platycephalus , restricted to the north-west and the widespread H. mercatorius that occurs throughout the island, including coastal areas at sea level as well as big cities (Antananarivo, Fianarantsoa) at altitudes of 1200–1300 m above sea level. Analyses of partial sequences of the 16S rRNA gene in 46 Hemidactylus specimens from Madagascar, East Africa, South Asia, and the Comoro and Mascarene archipelagos demonstrated the presence of a fourth species, H. brooki, on the Mascarenes (Réunion, Rodrigues, and Mauritius) and Comoros (Moheli). The Malagasy populations of H. platycephalus were genetically uniform and differentiated from the African and Comoroan specimens studied. H. frenatus had a relatively low genetic differentiation over the whole region with no recognizable phylogeographical structure, indicating more recent colonizations or introductions. In contrast, H. mercatorius showed a strong phylogeographical structure of haplotypes, with two distinctly different lineages in Madagascar. Moreover, all Malagasy specimens differed strongly from the single African specimen included. This indicates that populations of H. mercatorius in Madagascar have a long history that predates human settlement.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 115–130.     

Polystoma cuvieri n. sp. (Monogenea: Polystomatidae), a parasite of the urinary bladder of the leptodactylid frog Physalaemus cuvieri in Paraguay

A new species of polystomatid monogenean, Polystoma cuvieri, is described from the urinary bladder of the leptodactylid frog Physalaemus cuvieri Fitzinger in Paraguay. This new species possesses a reticulated intestine and hamuli of about 350 microns long. The closest species is Polystoma napoensis Vaucher, 1987, described from Osteocephalus spp. in Ecuador. The Paraguayan material is distinguished by the blade size of the hamuli. The hamuli blades appear to be useful in Polystoma systematics.     

Metabolic rate and endurance capacity in Australian varanid lizards (Squamata: Varanidae: Varanus)

In ecomorphological and ecophysiological studies, locomotor performance is often considered to be an intermediate step between the form of an organism and its environment. We examined this premise by measuring morphology, physiology and circular track endurance in the closely related group of Australian varanid lizards. Body size, body mass and relative body proportions were poor indicators of endurance. Body mass was not correlated with endurance and size-free lower forelimb length had only a weak relationship with endurance. Instead, maximal metabolic rate was positively correlated with endurance capacity in varanids. A comparison of varanids with other groups of lizards supported this result as varanids showed both elevated maximal metabolic rate and elevated endurance scores when compared with similar sized non-varanid lizards. There was support for a strong association between endurance with foraging mode and climate. Varanid species with higher endurance tended to be widely foraging and from xeric climates, while sit-and-wait and mesic species showed reduced endurance.   © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 664–676.     

An ancient African radiation of corvoid birds (Aves: Passeriformes) detected by mitochondrial and nuclear sequence data

The Malaconotidae, Platysteiridae and Vangidae represent an African and Malagasy assemblage of closely related corvoid taxa with distinctive morphology. Their relationships with their putative Asian closest relatives, and thus their biogeographic history, have not hitherto been thoroughly evaluated. We present evidence that the African and Malagasy groups originated through a single African colonization event c. 37.7 ± 4.6 Myr BP. Three main groups that differ in their foraging behaviour diverged c. 35.8 ± 4.5 Myr BP, suggesting that an African radiation occurred around that time. Several disperal events out of Africa to Madagascar (Vangidae) and Indo-Malaya ( Philentoma , Hemipus and Tephrodornis ) took place about 28.9 ± 4.0 Myr BP (Oligocene), a period when faunistic exchanges between Eurasia and Africa seem to have been common. Our estimation of the colonization of Madagascar by the Vangidae is 28.9 ± 4.0 Myr BP, in congruence with the estimated colonization of Madagascar by several African vertebrate groups (carnivorous mammals, snakes, sylvioid passerines, treefrogs, turtles).     

The relationship between skull morphology, biting performance and foraging mode in Kalahari lacertid lizards

Lizards are a diverse clade in which one radiation consists entirely of sit-and-wait foragers and another consists of wide foragers. Lizards utilizing these two foraging modes are known to differ in diet, but little is known about how feeding morphology relates to diet and/or foraging mode. This study tested the hypothesis that skull morphology and biting performance are related to diet preference, and consequently, coevolve with foraging mode. Four species of lacertid lizard were studied because they vary in foraging mode, their phylogenetic relationships are known and they are well studied ecologically. Using an 'ecomorphological' approach, skull morphology and biting performance were quantified and mapped on to the phylogeny for the species. The results indicate that sit-and-wait species have shorter, wider skulls than the wide foraging species, and that all are significantly different in overall head shape. The sit-and-wait species had similar values for biting performance; however, clear phylogenetic patterns of covariation were not present between sit-and-wait and wide foraging species for either biting performance or skull morphology. Thus, skull morphology and performance have little influence on diet and foraging mode in these species. Instead it is likely that other factors such as seasonal prey availability and/or life history strategy shape foraging mode decisions.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 140 , 403–416.     

Predatory lizards perceive plant‐derived volatile odorants

Many lizards are olfactory foragers and prey upon herbivorous arthropods, yet their responses to common herbivore‐associated plant volatiles remain unknown. As such, their role in mediating plant indirect defenses also remains largely obscured. In this paper, we use a cotton‐swab odor presentation assay to ask whether lizards respond to two arthropod‐associated plant‐derived volatile compounds: 2‐(E)‐hexenal and hexanoic acid. We studied the response of two lizard species, Sceloporus virgatusand Aspidoscelis exsanguis, because they differ substantially in their foraging behavior. We found that the actively foraging A. exsanguisresponded strongly to hexanoic acid, whereas the ambush foraging S. virgatus responded to 2‐(E)‐hexenal—an herbivore‐associated plant volatile involved in indirect defense against herbivores. These findings indicate that S. virgatus may contribute to plant indirect defense and that a species' response to specific odorants is linked with foraging mode. Future studies can elucidate how lizards use various compounds to locate prey and how these responses impact plant‐herbivore interactions.     

Foraging mode of the chameleon,Bradypodion pumilum: a challenge to the sit‐and‐wait versus active forager paradigm?

Foraging mode is an important aspect of life history, often associated with traits such as locomotor mode, energy budget, risk of predation and reproductive effort. Because of these life-history associations, classification of foraging mode can be conceptually useful. Lizards figured prominently in the historical development of foraging mode concepts, yet our current understanding is dominated by only two lizard families which are good examples of the two extreme modes, sit-and-wait vs. active foraging. A great deal of lizard phylogenetic diversity remains unrepresented. Chameleons are a highly derived lizard taxon for which we have very little behavioural or ecological data, and no foraging mode data. Because chameleons are so unusual, it is not possible to predict where they will fit within the bimodal paradigm. I studied time budget and foraging mode in the Cape dwarf chameleon, Bradypodion pumilum , in Stellenbosch, South Africa. Several approaches were taken to assess foraging behaviour. First, lag-sequential analysis was applied to compare rates behaviours associated with observed eating events, which did not support a sit-and-wait foraging mode. Second, the number of moves per minute (MPM) and per cent time moving (%TM) were compared with those of other lizard taxa from the literature. Foraging in B. pumilum was found to be most consistent with an active foraging mode, although the MPM is unusually low. Thus I propose classification of B. pumilum as a cruise forager. Sufficient data are available to define a discriminant function for active vs. sit-and-wait modes among lizard speries, which classifys B. pumilum as active and additionally lends statistical support for good separation between foraging modes. These findings are discussed in relation to the evolution of foraging modes in chameleons and other lizard families.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 797–808.     

Wide home ranges for widely foraging lizards

Space usage by animals may be influenced by a range of factors. In this study we investigate whether foraging behaviour affects the home range size of lizards. Two distinct tactics of foraging have been recognized in predators: sit-and-wait foraging (SW) and active foraging (AF). Foraging activity level of a data set of lizard species, mainly compiled from literature, is compared with their home range sizes. Two opposite predictions can be made about foraging in connection with home range area: on the one hand, SW species may exhibit larger home ranges due to their mating system; on the other hand, AF species have higher metabolic energy and thus food requirements and can be expected to have larger home ranges that have to yield this food. This study shows that percentage of the time moving (as an index of foraging mode) correlates positively with home range, even after correcting for body mass, and these patterns remain when phylogenetic relationships are taken into account. We thus conclude that home range areas parallel activity levels in lizards.     

The comparative aspects of spatial ecology of lizards exemplified by the toad-headed lizards (Reptilia, Agamidae, Phrynocephalus)

The possibility of analysis of phylogenetic parameters of the spatial distribution of populations is discussed by an example of the agamid toad-headed lizards (Phrynocephalus). Summarizing both original and published data on the individual home ranges and the relocation of individuals of 30 populations from 12 species showed that differentiation of the type of spatial distribution is weak in toad-headed lizards. This observation confirms the idea that this clade of agamids is phylogenetically young and relatively recently radiated. At the interspecific level, positive correlation between home range size and body size was observed in the studied group. Such spatial parameters, shared by all toad-headed lizards, as relatively large size and weakly structured individual home ranges can be explained by the peculiarities of their reproduction features and their foraging mode. The individual type of space-usage in toad-headed does not fit the traditional scheme dividing all the lizards into the territorial Iguania and the nonterritorial Autarchoglossa.     

How phylogeny and foraging ecology drive the level of chemosensory exploration in lizards and snakes

The chemical senses are crucial for squamates (lizards and snakes). The extent to which squamates utilize their chemosensory system, however, varies greatly among taxa and species’ foraging strategies, and played an influential role in squamate evolution. In lizards, ‘Scleroglossa’ evolved a state where species use chemical cues to search for food (active foragers), whereas ‘Iguania’ retained the use of vision to hunt prey (ambush foragers). However, such strict dichotomy is flawed as shifts in foraging modes have occurred in all clades. Here, we attempted to disentangle effects of foraging ecology from phylogenetic trait conservatism as leading cause of the disparity in chemosensory investment among squamates. To do so, we used species’ tongue‐flick rate (TFR) in the absence of ecological relevant chemical stimuli as a proxy for its fundamental level of chemosensory investigation, that is baseline TFR. Based on literature data of nearly 100 species and using phylogenetic comparative methods, we tested whether and how foraging mode and diet affect baseline TFR. Our results show that baseline TFR is higher in active than ambush foragers. Although baseline TFRs appear phylogenetically stable in some lizard taxa, that is a consequence of concordant stability of foraging mode: when foraging mode shifts within taxa, so does baseline TFR. Also, baseline TFR is a good predictor of prey chemical discriminatory ability, as we established a strong positive relationship between baseline TFR and TFR in response to prey. Baseline TFR is unrelated to diet. Essentially, foraging mode, not phylogenetic relatedness, drives convergent evolution of similar levels of squamate chemosensory investigation.     

Does foraging mode mould morphology in lacertid lizards?

Evolutionary changes in foraging style are often believed to require concurrent changes in a complex suite of morphological, physiological, behavioural and life-history traits. In lizards, species from families with a predominantly sit-and-wait foraging style tend to be more stocky and robust, with larger heads and mouths than species belonging to actively foraging families. Here, we test whether morphology and foraging behaviour show similar patterns of association within the family Lacertidae. We also examine the association of bite force abilities with morphology and foraging behaviour. Lacertid lizards exhibit considerable interspecific variation in foraging indices, and we found some evidence for a covariation between foraging style and body shape. However, the observed relationships are not always in line with the predictions. Also, the significance of the relationships varies with the evolutionary model used. Our results challenge the idea that foraging style is evolutionarily conservative and invariably associated with particular morphologies. It appears that the flexibility of foraging mode and its morphological correlates varies among lizard taxa.     

The Relationship Between Foraging Ecology and Lizard Chemoreception: Can a Snake Analogue (Burton’s Legless Lizard,Lialis burtonis) Detect Prey Scent?

In lizards and snakes, foraging mode (active vs. ambush) is highly correlated with the ability to detect prey chemical cues, and the way in which such cues are utilized. Ambush-foraging lizards tend not to recognize prey scent, whereas active foragers do. Prey scent often elicits strikes in actively-foraging snakes, while ambushers use it to select profitable foraging sites. We tested the influence of foraging ecology on the evolution of squamate chemoreception by gauging the response of Burton's legless lizard ( Lialis burtonis Gray, Pygopodidae) to prey chemical cues. Lialis burtonis is the ecological equivalent of an ambush-foraging snake, feeding at infrequent intervals on relatively large prey, which are swallowed whole. Captive L. burtonis did not respond to prey odour in any manner: prey chemical cues did not elicit elevated tongue-flick rates or feeding strikes, nor were they utilized in the selection of ambush sites. Like other ambushing lizards, L. burtonis appears to be a visually oriented predator. In contrast, an active forager in the same family, the common scaly-foot ( Pygopus lepidopodus ), did tongue-flick in response to odours of its preferred prey. These results extend the correlation between lizard foraging mode and chemosensory abilities to a heretofore-unstudied family, the Pygopodidae.     

Predation Risk and Opportunity Cost of Fleeing While Foraging on Plants Influence Escape Decisions of an Insular Lizard

Cost‐benefit models of escape behaviour predict how close a prey allows a predator to approach [flight initiation distance (FID)] based on cost of not fleeing (predation risk) and cost of fleeing (loss of opportunities). Models for FID have been used with some success to predict distance fled (DF). We studied effects of foraging opportunity cost of fleeing and examined differences between age‐sex groups in the omnivorous Balearic Lizard, Podarcis lilfordi. Balearic lizards forage on the ground for invertebrate prey and climb the thistle Carlina corymbosa to forage on its inflorescences. We studied escape behaviour in three experimental groups, with human beings as simulated predators: lizard foraging above ground on C. corymbosa, foraging on the ground away from thistles and on the ground with cut inflorescences. Flight initiation distance was shorter for lizards with cut inflorescences than for (1) lizards above ground due to the greater risk above ground due to conspicuousness of black lizards on yellow flowers; and (2) lizards on ground away from flowers due to the cost of leaving while feeding. The only age‐sex difference was slightly greater FID for adult males than subadults, presumably because larger adult males are more likely to be attacked by predators. Other potential factors affecting this difference are discussed. Experimental group and age‐sex group did not interact for FID or DF. Because lizards foraging on inflorescences above ground fled to the base of the plants to refuge provided by spiny thistle leaves, their DF was shorter than in the other groups, which fled across the ground, usually without entering refuge. DF did not differ between groups on the ground or among age‐sex groups. The predicted shorter DF for lizards with cut inflorescences than on ground without inflorescences did not occur. We hypothesize that the opportunity cost was small due to the abundance of blooming thistles and that DF may be less sensitive to opportunity cost than FID.     

Karyological analysis of Proechimys cuvieri and Proechimys guyannensis (Rodentia, Echimyidae) from central Amazon

The aim was to characterize the karyotype of rodents of the genus Proechimys from three localities in the central Brazilian Amazon, in the search for new markers that might shed light on our understanding of the taxonomy and evolutionary history of this taxon. Two karyotypes were found, viz., 2n = 28, FN = 46 in individuals from the NRSP (Cuieiras River) and REMAN (Manaus), and 2n = 46, FN = 50 in individuals from the Balbina Hydroelectric Plant. While individuals with the karyotype with 2n = 28 chromosomes were morphologically associated with Proechimys cuvieri, their karyotype shared similarities with those of the same diploid number in two other regions. Although three karyotypes are described for Proechimys cuvieri, no geographic distribution pattern that defined a cline could be identified. Based on the morphological examination of voucher specimens and additional results from molecular analysis, the karyotype with 2n = 46 and FN = 50 could be associated with P. guyannensis.     

Notes on the ecology of a suburban population of Rainbow lizards in coastal Kenya

Aspects of the ecology of a suburban population of rainbow lizards, Agama agama Linnaeus 1758, have been studied in Malindi, a coastal locality of SE Kenya. Four different family groups were monitored on a wall transect 120 m long. Each group constituted a dominant male (i.e. a brightly coloured and aggressive individual) and three to four adult females, but in one of the studied groups a subordinate male was also seen. Both sexes were active in the morning, and peak activity fell between 10.00 and 11.30 hours. Dominant males used elevated perches significantly more often than subordinate males and females. The diet consisted of terrestrial arthropods, and most of the prey eaten were beetles (6–8 mm long). The foraging strategy used by rainbow lizards was to eat small insects at very short time intervals. The lizards used sit-and-wait foraging, remaining motionless until the prey was <5 cm away. The rainbow lizards studied did not feed upon plant material.     

Feeding time strategies of the fringe-toed lizard,Uma inornata,during breeding and non-breeding seasons

Summary I examined the foraging behavior during the breeding and non-breeding seasons, May and July 1986, of the fringe-toed lizard Uma inornata (Iguanidae). During the breeding season males differ from females in their diet and in their foraging time strategy, males exhibiting time minimization and females energy maximization. In May, plant associated foods were selectively eaten. Males concentrated on flowers, a readily available quick energy food, which reduced foraging time and increased time for reproductive activities. Time budgets indicate that males spend over twice as much time in the open and in movement in May than do females. Females at this time restrict their activities to the cover of perennial bushes, and feed primarily on plant foods (flowers and arthropods). Energy maximization appears to be maintained by both sexes in the non-breeding season when food resources diminished to one-half of those in the breeding season. The lizards were less selective in their July feeding habits, broadening their diets to include ground-dwelling arthropods and foliage. Predation by these lizards follows a wait-ambush mode of foraging.     

Abscessed bony areas on Acanthopagrus cuvieri (Day) as a substrate for epiphytic algae

Enteromorpha compressa (L.) Greville and E. clathrata (J. Agardh), widely distributed green algae in Arabian Gulf, were observed growing on Acanthopagrus cuvieri (Day). Abscessed areas on the operculum provided suitable sites for attachment of both species of algae; broken spine tips were preferred by E. compressa . This study showed that these algae preferred hard substrata, with no scales for attachment. E. compressa appeared earlier and grew faster. The condition of the fish was normal.