Ecology of the lizard Norops oxylophus (Polychrotidae) in lowland forest of southeastern Nicaragua

1995 ◽  
Vol 73 (10) ◽  
pp. 1918-1927 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani ◽  
Richard D. Durtsche
Keyword(s):  
Sexual Maturity ◽  
Sexual Difference ◽  
Prey Size ◽  
Body Temperatures ◽  
Lowland Forest ◽  
Rapid Succession ◽  
Ecological Characteristics ◽  
Ecological Success ◽  
Rate Of Movement

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∙s−1). Caterpillars, spiders, ants, and various orthopterans composed most of the diet. Prey size was only weakly correlated with lizard snout–vent length (SVL) and there was no sexual difference in prey size independent of SVL. Lizards averaged 0.01 prey attacks/min and most lizards spent less than 0.15% of their time feeding. Males were larger than females, but females had a relatively larger body and greater mass. Females reach sexual maturity at 49 mm SVL and produce clutches of a single egg in rapid succession. Males reach sexual maturity at 53 mm SVL. Many ecological characteristics of N. oxylophus reflect a set of characteristics evolving early in the N. fuscoauratus series of the anoline lineage that has contributed to their ecological success in stream habitats of Caribbean lowland forest.

Ecology of the arboreal tropidurid lizard Tropidurus (=Plica) umbra in the Amazon region

1997 ◽  
Vol 75 (11) ◽  
pp. 1876-1882 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani ◽  
Teresa Cristina S. Avila-Pires
Keyword(s):  
Sexual Dimorphism ◽  
Tropical Forest ◽  
Clutch Size ◽  
Sexual Maturity ◽  
Prey Size ◽  
Amazon Region ◽  
Body Temperatures ◽  
Dietary Specialization ◽  
Lowland Tropical Forest

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 °C. The diet consists nearly exclusively of ants and there is no relationship between prey size and lizard size. Females reach sexual maturity at 79 mm snout–vent length (SVL) and males at 78 mm SVL. Although there appears to be no sexual dimorphism in SVL, males have relatively larger heads than females. Clutch size is usually two eggs and females appear to produce more than one clutch per season. Comparisons with other studied tropidurid lizards suggest that dietary specialization on ants, reduced sexual dimorphism, and reduced clutch size are derived characters.

Body size, diet and reproductive ecology of Coluber hippocrepis in the Rif (Northern Morocco)

2004 ◽  
Vol 25 (3) ◽  
pp. 287-302 ◽  
Author(s):  
Juan Pleguezuelos ◽  
Soumia Fahd
Keyword(s):  
Body Size ◽  
Sexual Maturity ◽  
Prey Size ◽  
Reproductive Ecology ◽  
Size Difference ◽  
Southern Europe ◽  
Strait Of Gibraltar ◽  
Dietary Shift ◽  
Intersexual Difference ◽  
Whip Snake

AbstractAlthough it is generally assumed that the Horseshoe Whip Snake (Coluber hippocrepis) originated in northern Africa, its biology and ecology has been studied mainly in southern Europe. In this paper we report on morphology, feeding, and reproductive ecology of Coluber hippocrepis in the Rif region (northern Morocco). Males attained larger sizes than did females, but there was no body-size difference between populations separated by the Strait of Gibraltar. The species feeds exclusively on vertebrates: mammals (45%), reptiles (28%), birds (17%), and amphibians (10%). There was an ontogenetic dietary shift in terms of frequency of prey consumed and in terms of prey size; moreover, an intersexual difference in prey frequency was found. Sexual maturity was attained at 540 mm snout-vent length (SVL) in males, and 720 mm SVL in females. Males showed a vernal spermatogenic cycle. Oviposition occurred at the beginning of summer, and offspring were observed in the field during September.

Organization of a taxonomically diverse lizard assemblage in Amazonian Ecuador

1996 ◽  
Vol 74 (7) ◽  
pp. 1313-1335 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani
Keyword(s):  
Related Species ◽  
Prey Size ◽  
Principal Component ◽  
Prey Type ◽  
Lizard Species ◽  
Lowland Forest ◽  
Closely Related Species ◽  
Use Patterns ◽  
Microhabitat Distribution ◽  
Order Of Magnitude

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 among species (77%) was accounted for by two principal component axes and appears tied to phylogeny. Prey size was correlated with lizard size and species were separated by prey size. Low overlaps in microhabitat, habitat, and prey type also separated species. Pseudocommunity analysis indicated structure in the consumer–resource matrix. In some comparisons, prey overlaps among species were greater within than between higher taxa, and closely related species tended to be found in similar habitat patches and microhabitats, suggesting that resource-use patterns are determined to some extent by phylogeny. Ecology, morphology, and phylogeny appear tied together in a complex manner, with resource partitioning contributing to maintenance of structure. Historical interactions among closely related species may have been important in determining which species within particular clades invaded and persisted within local assemblages in lowland forest.

Life in the trees: the ecology and life history of Kentropyx striatus (Teiidae) in the lavrado area of Roraima, Brazil, with comments on the life histories of tropical teiid lizards

1992 ◽  
Vol 70 (10) ◽  
pp. 1995-2006 ◽  
Author(s):  
Laurie J. Vitt ◽  
Celso Morato de Carvalho
Keyword(s):  
Life History ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Prey Size ◽  
Annual Rainfall ◽  
Activity Period ◽  
Body Temperatures ◽  
Wet Season ◽  
Reproductive Characteristics ◽  
History Of

The ecology and life history of the tropical teiid lizard Kentropyx striatus were studied in a grassland of northern Brazil, the lavrado area. The area, located nearly at the equator, experiences a prolonged dry season with a wet season extending from May to September. Total annual rainfall averages 1750 mm. Lizards were nonrandomly distributed among habitat patches and microhabitats. Most individuals were in trees and shrubs surrounding temporary and permanent water. Most individuals were observed active during late morning, the time period during which feeding and social interactions were observed. Lizards bask to achieve active body temperatures averaging 35.7 ± 0.23 °C. Body temperature is correlated with both substrate and air temperatures; foraging lizards maintained higher temperatures than basking lizards regardless of whether they were in sun, and lizards sampled when there was cloud cover had lower body temperatures than those sampled when sun was available. Females reach sexual maturity at 74 mm snout–vent length (SVL), produce 3–9 eggs per clutch, reproduce more than once per season, and commence reproduction during the wet season. Lizards hatch from eggs at 31 mm SVL. Maturity appears to be reached in 1 year or less. Overall, female reproductive characteristics are similar to those of other tropical teiid lizards that have been studied, with body size explaining much of the variance in reproductive characteristics across species. There is pronounced sexual dimorphism, with males larger in body size as well as certain other characteristics independent of body size. Sexual dimorphism appears to be a consequence of sexual selection. The diet is varied, but is dominated volumetrically by frogs, eruciform larvae, and spiders. Lizard body size accounted for only 5.5% of the variance in prey size and there was no difference in prey size due to sex. The occurrence of frogs and lizards in K. striatus stomachs suggests that teiid lizards may influence the structure of lizard and frog assemblages. The similarity of K. striatus to other studied tropical teiids in reproductive characteristics, morphology, activity period, activity temperatures, and diet underscore the conservative nature of the ecology of teiid lizards, presumably a consequence of their mode of prey acquisition.

Comparative feeding strategies and dietary plasticity of the sympatric cobras Naja melanoleuca and Naja nigricollis in three diverging Afrotropical habitats

2002 ◽  
Vol 80 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Luca Luiselli ◽  
Francesco M Angelici ◽  
Godfrey C Akani
Keyword(s):  
Prey Size ◽  
Prey Type ◽  
The Other ◽  
Feeding Strategies ◽  
Habitat Types ◽  
Suburban Areas ◽  
Dietary Flexibility ◽  
Prey Composition ◽  
Ecological Success ◽  
The One

Two cobra species are found in the forest block of southern Nigeria (West Africa). However, whereas the one species, the spitting cobra (Naja nigricollis), is often found in strongly altered habitats (including suburban areas), the other, the black forest cobra (Naja melanoleuca), is a typical forest species that is currently subject to a rapid decrease in population abundance because of intensive forest alteration and landscape modification in this part of Africa. We studied whether the body sizes, diets, and feeding strategies of these two species changed in relation to habitat type, and whether the ecological success of the one species versus the other in altered habitats depends upon greater dietary flexibility in prey type or prey size. Therefore, we divided our cobra records into three habitat categories: (1) suburbia, (2) plantation–forest mosaic, and (3) mature forest. We observed that sexual size dimorphism was minor in both species and in all habitat types, and that intersexual differences in prey composition and prey size were also minor. Nevertheless, there was a remarkable ontogenetic change in taxonomic composition of the diet for one species (N. nigricollis, with juveniles taking almost exclusively lizards and adults taking small mammals, birds, and lizards) but not the other. Remarkably, the species that is less adapted to life in suburban areas showed a reduction in mean body size from the forest to suburbia, which may also indicate suboptimal adaptation to strongly altered habitats. Prey size was similar for the two species and in the three habitat types, and the relationships between prey size and predator size were similar. Thus, it seems unlikely that flexibility in prey-size patterns explains the greater colonizing success of N. nigricollis. Nevertheless, and although both species exhibited remarkable dietary flexibility, leading them to prey upon homeotherms as well as heterotherms and upon terrestrial as well as arboreal and even aquatic prey, there were important interspecific differences in prey composition that may explain the ecological success of N. nigricollis. The success of N. nigricollis likely lies not in dietary flexibility but in the consistency with which its juveniles prey upon a single prey type (lizards, mainly Agama agama) that is so abundant in nearly every altered habitat in Nigeria and is a virtually unlimited food resource for young N. nigricollis. However, adults of this species also forage frequently upon commensal rodents and poultry, which may also help it to colonize man-made habitats.

Heliotherms in tropical rain forest: the ecology of Kentropyx calcarata (Teiidae) and Mabuya nigropunctata (Scincidae) in the Curuá-Una of Brazil

1997 ◽  
Vol 13 (2) ◽  
pp. 199-220 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani ◽  
A. Claudia Marinho Lima
Keyword(s):  
Body Size ◽  
Body Length ◽  
Prey Size ◽  
Forest Edge ◽  
South American ◽  
Wet Season ◽  
Lowland Forest ◽  
Lowland Tropical Forest ◽  
Activity Temperature ◽  
Ecological Differences

ABSTRACTKentropyx 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 heliothermic, basking to gain heat. Their association with open patches results from high activity temperature requirements in an environment where sun availability is low. Null temperature distributions from forest and treefalls showed that forest does not offer opportunities for heat gain similar to treefalls. Moreover, the large proportion of time spent basking by both species indicates the importance of these patches for thermoregulation. K. calcarata is slightly larger in body length and heavier at a given body length than M. nigropunctata. Both species are active foragers that seek out prey while moving through the habitat, feeding on orthopterans, roaches and spiders. M. nigropunctata also eat significant numbers of insects that occur on vegetation, such as hemipterans. Prey size is larger in K. calcarata and associated with lizard body size. Prey size does not vary with body size in M. nigropunctata and prey are typically relatively small.Many of the ecological differences between these two lowland forest species appear to be historical: the ecology of K. calcarata is very similar to that of other species of Kentropyx and teiids in general and the ecology of M. nigropunctata is most similar to that of other studied species of south American Mabuya.

Geographical ecology of the gymnophthalmid lizard Neusticurus ecpleopus in the Amazon rain forest

1998 ◽  
Vol 76 (9) ◽  
pp. 1671-1680 ◽  
Author(s):  
Laurie J Vitt ◽  
Peter A Zani ◽  
Teresa Cristina Avila-Pires ◽  
Maria Cristina Espósito
Keyword(s):  
Prey Size ◽  
Size Variation ◽  
Morphological Characteristics ◽  
Prey Type ◽  
Morphological Characters ◽  
Microhabitat Use ◽  
Body Temperatures ◽  
Lowland Tropical Forest ◽  
Amazon Rain Forest ◽  
Substrate Temperatures

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 periods as during sunny periods, but most individuals were not exposed to direct insolation while active. Activity occurred through much of the day, with most activity at two sites during between 11:00 and 14:30. Body temperatures were 27.0 ± 0.02°C and were correlated with substrate temperatures. Body temperatures were higher than substrate temperatures, indicating behavioral or possibly physiological thermoregulation. These lizards ate a variety of prey, but eight prey categories accounted for a major proportion of the total diet at all sites. There were differences among sites in prey type, prey size, relative prey size, and total stomach fullness. Even though there was some size variation among sites, variation in other morphological characters was more striking. Even withstanding the differences among populations in ecological and morphological characteristics, it appears that much of the ecology of N. ecpleopus is constrained by fidelity to specific habitat patches (stream banks) distributed linearly through lowland tropical forest.

Prey use among sympatric lizard species in lowland rain forest of Nicaragua

1998 ◽  
Vol 14 (4) ◽  
pp. 537-559 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani
Keyword(s):  
Body Size ◽  
Species Interactions ◽  
Prey Size ◽  
Lizard Species ◽  
Lowland Forest ◽  
Closely Related Species ◽  
Lowland Rain Forest ◽  
Order Of Magnitude ◽  
Key Resources ◽  
Consumer Resource

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 data revealed significant guild structure in the assemblage. At each nearest neighbour rank in niche space, observed overlaps were higher than expected based on chance alone when all values in the consumer-resource matrix were randomized. There was no difference between observed and pseudocommunity overlaps with zero positions in the consumer-resource matrix retained (conserved-zero overlaps) indicating that the zero structure of the community matrix was important in maintaining structure and that lizards were converging on key resources. Individual prey size varied among species and mean prey size was significantly correlated with body size of lizard species. A phylogenetic analysis revealed no relationship between similarity in prey use (dietary overlap) and evolutionary relationships — more closely related species did not eat more similar prey types. Based on this analysis of Nicaraguan lizard diets and comparisons with other New World tropical lizard assemblages, it is suggested that factors contributing to the organization of tropical lizard assemblages are complex including historical differences in morphology (size), prey types and sizes, habitat structure and species interactions.

The Succession of Orthodoxies About Sexual Difference

2004 ◽  
Vol 49 (3) ◽  
pp. 327-329
Author(s):  
Howard S. Schwartz
Keyword(s):  
Sexual Difference
Sign in / Sign up

Export Citation Format

Share Document