Peter Zani

Few field studies have tested for geographic variation in escape behavior and even fewer have examined responses of prey to multiple predators despite most prey occurring in multipredator environments. We performed 458 escape trials on Side-blotched Lizards (Uta stansburiana Baird and Girard, 1852) from 10 populations that differed in predator abun...

Temperate ectotherms, especially those at higher latitudes, are expected to benefit from climate warming, but few data yet exist to verify this prediction. Furthermore, most previous studies on the effects of climate change utilized a model of uniform annual change, which assumes that temperature increases are symmetric on diurnal or seasonal time...

Climate change is causing winters to become milder (less cold and shorter). Recent studies of overwintering ectotherms have suggested that warmer winters increase metabolism and decrease winter survival and subsequent fecundity. Energetic constraints (insufficient energy stores) have been hypothesized as the cause of winter mortality but have not b...

The effects of climate change on environments are increasingly obvious and are leading to stronger and more varied biological responses as organisms compensate. To understand better the responses of terrestrial ectotherms to climate oscillations we created a biophysical model based on the degree-days concept to predict relevant life-history events....

Many previous studies on competition focused on outcomes of competition and less on behavioral changes during or immediately following intra- or interspecific interactions. I performed 300 h of observation of three lizard species (Side-blotched Lizards, Uta stansburiana; Sagebrush Lizards, Sceloporus graciosus; Western Fence Lizards, Sceloporus occ...

In 1929, August Krogh reviewed the state of physiology (Krogh 1929) and pointed out that “for a large number of problems, there will be some animal or choice of a few such animals on which it can be conveniently studied.” Krogh's principle focused animal physiology on appropriate models to study relevant questions in an attempt to unify the field....

The standard paradigm of organismal biology views lower-level traits (e.g., aspects of physiology) as determining organismal performance abilities (e.g., maximal sprint speed), which in turn constrain behavior (e.g., social interactions). However, few studies have simultaneously examined all three levels of organization. We used focal observations...

Several areas of the vertebrate brain are involved in facilitating and inhibiting the production of sexual behaviors and displays. In the laboratory, a higher rate of sexual displays is correlated with a larger ventral posterior amygdala (VPA), an area of the brain involved in the expression of sexual display behaviors, as well as larger VPA neuron...

• Life‐history strategies are known to shift with latitude in many species. While life‐history variation related to body size, reproductive investment, and behavior has been studied for years, another crucial life‐history component is the immune system, which can influence an animal's survival. • We measured selected life‐history traits in side‐blo...

Question: Do populations of side-blotched lizards (Uta stansburiana) have longer hind limbs when exposed to greater potential predation? If so, is the pattern due to evolved responses among populations? Methods: We measured hind-limb lengths of male side-blotched lizards as well as abundance and composition of several predator types (other lizards,...

Abstract Self-amputation (autotomy) of the tail is essential for the survival of many lizards. Accordingly, it has garnered the attention of scientists for more than 200 years. Several factors can influence the release of the tail, such as the size, sex, and age of the lizard; type of predator; ecology; and evolutionary history of the lineage. Once...

Animals in high predation environments tend to react to predators more quickly and effectively compared to animals in low predation environments. Because antipredator behavior can be increased by predator introductions and decreased by predator losses, we examined whether populations occurring outside of a predator's range are associated with behav...

We studied the spatial ecology of Common Side-blotched Lizards (Uta stansburiana) in the northern Great Basin desert of eastern Oregon. Over 3 yr (2007–2009) we collected 3675 coordinates from 51 males and 60 females during the breeding season (mid-May to early July). We found significant variation among years and between the sexes in home-range si...

Diapause in insects typically results in metabolic adjustments that may include the levels of feeding and activity, metabolic rate, and the accumulation and utilization of reserves. The objective of this study was to characterize and quantify the various neutral lipid classes in the pitcher-plant mosquito (Wyeomyia smithii) that are associated with...

The polychrotid lizard Anolis fuscoauratus was studied at six localities in the Ecuadorian and Brazilian Amazon from 1994 to 1999. Throughout the Amazon, A. fuscoauratus occurs in forested habitats, is arboreal on tree trunks, limbs, and branches as well as vines, has a body temperature (Tb) of 28.7 ± 0.2°C (mean ± SE) while active, maintains Tb sl...

The gymnophthalmid lizard Prionodactylus oshaughnessyi was studied at two Amazonian rain-forest sites. These lizards live at the interface of the terrestrial habitat and arboreal habitat, are active throughout the day at relatively low body temperatures, and maintain body temperatures (29.0 ± 0.34°C) slightly higher than ambient temperatures. Grass...

The whiptail lizard Cnemidophorus deppii was studied during late dry season on a tropical beach on the Pacific coast of Nicaragua. Most aspects of the ecology of this species are similar to those of other active foraging lizard species studied. Individual C. deppii spend most of a typical daily activity period on sand moving from vegetation patch t...

The lizard Norops oxylophus used a variety of microhabitats distributed linearly along streams in southeastern Nicaragua. Body temperatures averaged 27.8 °C and lizards typically were in shade. Lizards spent 98.16% of their time stationary and 1.84% moving. The rate of movement was low (0.001 m∙s−1) even when corrected for time not moving (0.071 m∙...

Of 22 lizard species studied in eastern Ecuador, 21 were diurnal. Ten were active foragers and 12 were sit-and-wait foragers. Considerable variation existed in habitat and microhabitat distribution and body temperatures among species. Body size varied over an order of magnitude (20–270 mm snout–vent length). Most morphological (size-free) variation...

Ectotherms from high latitudes experience a reduction in the length of their seasonal activity period, which may have consequences for life-history strategies. I studied winter survivorship and spring reproduction of a population of Common Side-Blotched Lizards, Uta stansburiana, in eastern Oregon. Results suggest that winter survivorship is much h...

Reproduction can impose “costs” associated with the burden of carrying developing embryos or eggs. Numerous studies using squamate reptiles have documented a reduction in locomotor performance related to reproduction. Recently several experimental studies have attempted to determine whether the reduction in locomotor performance is physical or phys...

We studied the squamate fauna from four sites in southern Amazonia of Brazil. We also summarized data on lizard faunas for nine other well-studied areas in Amazonia to make pairwise comparisons among sites. The Biogeographic Similarity Coefficient for each pair of sites was calculated and plotted against the geographic distance between the sites. A...

Side-blotched lizards (Uta stansburiana Baird and Girard, 1852) use sagebrush desert habitat above cliffs and typically flee over and down the nearest cliff when disturbed. We tested antipredator escape tactics of lizards to a common local snake, the western yellowbelly racer (Coluber mormon Baird and Girard, 1852). Our goal was to determine if liz...

Silica gel high-performance thin-layer chromatography (HPTLC) with chloroform-methanol-water (65:25:4) mobile phase and cupric sulfate-phosphoric acid detection reagent was used to characterize and quantify various polar lipid classes in organs (livers, abdominal fat bodies, and tails) of 6 male and 6 female side-blotched lizards (Uta stansburiana)...

Evolution has produced a wide range of body plans, but for a given body mass, the energetic cost of transport (COT) of terrestrial animals falls in a relatively narrow range. Previous research indicates that the COT depends on the proficiency of minimizing mechanical work performed, efficiency of performing that work, and cost of generating force t...

An expanding body of literature has demonstrated that global climate change continues to adversely affect many populations, species, and ecosystems. However, life-history theory also predicts possible benefits from longer growing seasons and less severe winters, particularly for ectotherms. To test the idea that climate change will have benefits as...

We performed high-performance thin-layer chromatography (HPTLC) to characterize and quantify the various neutral lipid classes in organs (livers, abdominal fat bodies, and tails) of 6 male and 6 female northern side-blotched lizards (Uta stansburiana stansburiana) with a range of body sizes (from young-of-the-year to adult). We determined the perce...

We studied the ecology of Alopoglossus angulatus and A. atriventris in western Amazonia. Both species are found in leaf litter of lowlandtropical forest, but A. angulatus tends to be found near water whereas A. atriventris is found in terra firme forest. Both tend to be active in shade on sunny and cloudy days. Body size of adults differs (A. angul...

We studied the ecology of four species of closely related leaf litter geckos, Coleodactylus amazonicus, C. septentrionalis, Lepidoblepharis xanthostigma, and Pseudogonatodes guianensis in tropical rainforests of Brazil and Nicaragua. All are found in leaf litter of undisturbed tropical forest where mean hourly surface temperatures vary from 23.5-29...

Environmental temperature can modify not only rates of ectotherm growth, development, and reproduction, but also, at the extremes, temperature can limit survivorship and ultimately fitness. We studied ectotherm populations from a latitudinal gradient to understand how alterations in the thermal environment (e.g., rapid climate change) may affect th...

Animals must perform mechanical work during walking, but most conserve substantial mechanical energy via an inverted-pendulum-like mechanism of energy recovery in which fluctuations of kinetic energy (KE) and gravitational potential energy (GPE) are of similar magnitude and 180 degrees out of phase. The greatest energy recovery typically occurs at...

We studied the ecology of Anolis capito in the rain forest of southeastern Nicaragua during late dry season of 1993. These cryptic anoles live low on trunks in shaded rain forest and are active throughout the day but appear to spend most of their time in shade. Body temperatures averaged 28.8 ± 0.5°C, which is 1.3°C higher than substrate temperatur...

Because mortality accumulates with age, Fisher proposed that the strength of selection acting on survival should increase from birth up to the age of first reproduction. Hamilton later theorized that the strength of selection acting on survival should not change from birth to age at first reproduction. As organisms in nature do not live in uniform...

Only model organisms live in a world of endless summer. Fitness at temperate latitudes reflects the ability of organisms in nature to exploit the favorable season, to mitigate the effects of the unfavorable season, and to make the timely switch from one life style to the other. Herein, we define fitness as Ry, the year-long cohort replacement rate...

We studied the ecology of Anolis punctatus and Anolis transversalis at six localities in the Amazon region of Ecuador and Brazil from 1994-1999. Both lizards are arboreal, about the same size (A. punctatus slightly larger) but differ in some body proportions. Anolis transversalis is restricted to undisturbed primary forest more so than A. punctatus...

The Amazonian lizard Anolis trachyderma was studied at three sites stretching from eastern Ecuador to the central Amazon of Brazil. These lizards occupy low vegetation and leaf litter microhabitats in well-shaded, damp rain forest. Their body temperatures are low (27.8 C on average) and only slightly higher than corresponding substrate and air. The...

Whereas measures of maximal performance are important for defining the functional operating space of organisms, it is not clear what determines the levels of submaximal performance used in nature. In this study, I address the following two questions. What influence does the habitat have in determining performance levels in nature? Why do animals no...

In this study, I utilize the expected functional relationships between claw and toe morphology and clinging performance as a basis for examining evolutionary trends across 85 lizard taxa from 13 families. After controlling for body size and phylogeny, multivariate comparisons indicate that several aspects of claw and toe morphology are correlated w...

Nineteen species of lizards simultaneously studied at the Curuá-Una in the central Amazon of Brazil separate on the basis of microhabitat use and prey types. There is no relationship between microhabitat niche breadths and dietary niche breadths, species using the greatest diversity of microhabitats do not necessarily use the greatest diversity of...

Lizards in four distantly separated populations of the gymnophthalmid lizard Neusticurus ecpleopus in the Amazon region of South America were strikingly specific in habitat and microhabitat use, being restricted to streams and swamps and living between the water line and the bank-forest interface. They were as likely to be active during cloudy peri...

The diets of 17 lizard species (seven families) studied simultaneously in a Caribbean lowland forest of Nicaragua were compared. Lizards varied in body size over nearly one order of magnitude. Twelve species for which there were adequate samples separated by prey types and most diet overlaps were low. A pseudocommunity analysis on volumetric diet d...

Sympatric lizards in a transitional forest of Roraima, Brazil, dividing Amazon rain forest from savanna, contained a lizard assemblage of 16 species representing six families. Lizards varied in size, activity (diurnal versus nocturnal), microhabitats used, exposure to various conditions of light availability, prey types, and prey sizes. Overlaps in...

We compared microhabitat use, morphology, diets, and reproduction in three populations of Cnemidophorus lemniscatus (Alter do Chao, Curua-Una, and Roraima) and one population of C. cryptus (Rio Xingu) in the Amazon region of Brazil. Cnemidophorus lemniscatus were most common in grasslands or other open areas, but C. cryptus was restricted to sandy...

The tropidurid lizard Tropidurus umbra lives on medium-sized trees in lowland tropical forest of the Amazon region. Individuals may be active on tree trunks in sun or shade, with most activity occurring from 11:00 to 13:00. Body temperatures average 29.1 degrees C. The diet consists nearly exclusively of ants and there is no relationship between pr...

Comparisons between closely related radiations in different environments provide a unique window into understanding how abiotic and biotic factors shape evolutionary pathways. Anolis lizards have radiated extensively in the West Indies, as well as mainland Central and South America. In the Caribbean, similar communities of anole species specialized...

Thecadactyltts rapicauda in the eastern and western Amazon region occurs on large trees within the forest but readily moves into buildings. Thecadactylus in the western Amazon is more common in buildings than in the eastern Amazon where Hemidactylus invades buildings. Body temperatures averaged 26.9 ± 0.3 C and were similar to both air and substrat...

We compared morphology of two geographically close populations of the tropical lizard Tropidurus hispidus to test the hypothesis that habitat structure influences the evolution of morphology and ecology at the population level. T. hispidus isolated on a rock outcrop surrounded by tropical forest use rock crevices for refuge and appear dorsoventrall...

Kentropyx calcarata (Teiidae) and Mabuya nigropunctata (Scincidae) occur together in lowland tropical forest of the Amazon near the Rio Curuá-Una of Brazil. During the wet season of 1995 these lizards were common at forest edge along narrow roads that transect forest, in treefalls and along streams where sun reaches the ground. Both species are hel...

Comparisons of ecological and reproductive data among three well-studied and two lesser-studied populations of Gonatodes humeralis in the Amazon region revealed geographic variation in adult snout-vent length, morphology, habitat distribution, perch height, and prey types. Populations were similar in size of prey, and there was no correlation of li...

Using comparative techniques to account for phylogenetic effects, I examined patterns of evolution of caudal autotomy and foraging in 39 lizard species to test the hypothesis that caudal autotomy has co-evolved with morphology, locomotor performance, and foraging behaviour. There were significant positive associations between evolution of the point...

We studied a population of Tropidurus flaviceps during the wet season in Amazonian lowland rain forest of eastern Ecuador. The lizards were strictly arboreal with activity occurring throughout much of the day on surfaces of trunks and limbs of the tree Macrolobium acaciaefolium within a large lagoon. Lizards retreated into cavities within the limbs...

Norops chrysolepis was studied in two tropical forest habitats in Amazon rain forests of Ecuador (Sucumbios Province) and Brazil (Roraima State). Nearly all individuals occurred in leaf litter of terra firme forest, and most were first observed in shaded microhabitats or those receiving filtered sun. Body temperatures of active individuals averaged...

A population of the tropical lizard Tropidurus hispidus, isolated on a granitic rock outcrop in tropical forest of northern Brazil, was studied during the 1993 wet season. Four types of observational studies revealed that lizards are active throughout most of the day. During 10-minute intervals, individual lizards moved five times for an average of...

Kentropyx pelviceps was studied in lowland tropical forest of eastern Ecuador. Most individuals were first observed in leaf litter of treefall gaps or forest, approximately 30% being first observed above ground on trunks or branches of fallen trees. Activity occurred from 10:00 to 16:00 in microhabitats receiving maximum insolation. Body temperatur...

The voluntary and forced locomotor performances of juvenile and adult painted turtles (Chrysemys picta) from two Ohio populations were examined using a laboratory racetrack with photocell-activated timers and a video recording system. Body size was correlated with many aspects of locomotion, but regardless of animal size, changes in stride frequenc...

Although several vertebrates are freeze tolerant, little is known of the relationship between body size and the kinetics of cooling and freezing. We compared these responses for six hatchling and eight adult Chrysemys picta from an Ohio population. All turtles initially recovered from freezing, and all adults, but only two hatchlings (which experie...

Anolis cristatellus, a common lizard of the Puerto Rican Bank (German et al., 1980b), has been intro-duced into the vicinity of La Romana, Republica Do-minican, and were well established when first noted by Grant (1956). Williams (1977) suggested that these animals may have been introduced when a sugar mill was built by a Puerto Rican based company...