Ecology of the lizard Kentropyx pelviceps (Sauria: Teiidae) in lowland rain forest of Ecuador

1995 ◽  
Vol 73 (4) ◽  
pp. 691-703 ◽  
Author(s):  
Laurie J. Vitt ◽  
Peter A. Zani ◽  
Janalee P. Caldwell ◽  
Edwin O. Carrillo
Keyword(s):  
Clutch Size ◽  
Morphological Characteristics ◽  
Maximum Size ◽  
Female Size ◽  
Body Temperatures ◽  
Lowland Rain Forest ◽  
Lowland Tropical Forest ◽  
Treefall Gaps ◽  
Direct Exposure ◽  
Males And Females

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 temperatures of active lizards averaged 34.1 ± 0.4 °C. Lizards active when sun was available had higher body temperatures than lizards active when sun was not available. When sun was available, lizards spent more time moving and moved farther than when sun was not available. When sun was hidden behind clouds, lizards typically ceased foraging, pressed their bodies against the substrate, and basked, receiving direct exposure. Most time active was allocated to basking, presumably as a result of limited availability of sunlight. Prey consisted primarily of roaches, orthopterans, and spiders, and prey size was determined to a large extent (69.6% of variation) by lizard body size. Males and females reached sexual maturity at 80 mm snout–vent length. Males reached a larger maximum size than females, and sexual dimorphism was apparent in nearly all morphological characteristics of adults when the effect of size was removed. Clutch size averaged 6.5 ± 0.3 eggs, and there was no relationship between clutch size and female size. Evidence suggests that the breeding season is extended. Comparisons with other studied species of Kentropyx suggest that many aspects of the ecology of K. pelviceps in eastern Ecuador are affected by the reduced time available for activity resulting from reduced sun availability.

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.

Reproduction and sexual dimorphism of Lepidophyma sylvaticum (Squamata: Xantusiidae), a tropical night lizard from Tlanchinol, Hidalgo, Mexico

2008 ◽  
Vol 29 (2) ◽  
pp. 207-216 ◽  
Author(s):  
Aurelio Ramírez-Bautista ◽  
Laurie Vitt ◽  
Alejandra Ramírez-Hernández ◽  
Fernando Mendoza Quijano ◽  
Geoffrey Smith
Keyword(s):  
Sexual Maturity ◽  
Cloud Forest ◽  
Maximum Size ◽  
Female Size ◽  
Sexually Dimorphic ◽  
Maximum Rainfall ◽  
Tropical Night ◽  
Reproductive Characteristics ◽  
Historical Origin ◽  
Males And Females

Abstract We studied reproductive characteristics of the night lizard, Lepidophyma sylvaticum (Xantusiidae) from cloud forest in Tlanchinol, Hidalgo, Mexico. Males reached sexual maturity at a snout-vent length (SVL) of 55 mm, and females reached sexual maturity at a SVL of 56 mm. Males and females were not sexually dimorphic in SVL, but males had significantly larger heads and limbs than females. Reproduction in males and females was seasonal. Testicular mass increased in July and August, reaching maximum size in September. Minimum testes size occurred in March. Follicles of females began to increase in size in September when vitellogenesis was observed. Follicles in some females increased in mass during January-March, whereas other females ovulated during that period. Late embryonic stages (35-40) were observed in July with parturition likely occurring in July and August, coincident with maximum rainfall. Litter size averaged 4.7 ± 0 .4 neonates, and was not correlated with female size. Similarities in reproductive characteristics between L. sylvaticum and other xantusiids (viviparity, long gestation period) suggest that some reproductive characteristics have a historical origin.

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.

scholarly journals Effect of nutrition on the body temperature and relative organ weights of broilers

2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4575
Author(s):  
Julyana Machado da Silva Martins ◽  
Evandro De Abreu Fernandes ◽  
João Paulo Rodrigues Bueno ◽  
Carolina Magalhães Caires Carvalho ◽  
Fernanda Heloisa Litz ◽  
...  
Keyword(s):  
Small Intestine ◽  
Body Temperature ◽  
Energy Levels ◽  
Liver Weight ◽  
The Body ◽  
Body Temperatures ◽  
Average Surface ◽  
Randomized Design ◽  
Males And Females ◽  
Completely Randomized Design

<p>The objective of this study was to evaluate the effect of different nutritional plans on the body temperature and organ biometrics in male and female broilers, of two ages. Here, 1,700 birds were used (850 males and 850 females) in a completely randomized design composed of five treatments (- 3%, - 1.5%, reference, + 1.5% and + 3%), with 10 repetitions, totaling 50 experimental units; the reference treatment based on nutritional and energy levels indicated in previous studies was calculated from this. At 35 and 42 d, the temperatures of the wing, head, shin, back, and cloaca in males and females were measured separately, and the average surface and body temperature were calculated. At 42 d, relative weights of the gizzard, liver, heart, and small intestine were calculated. The temperatures of the wings, back, and cloaca, and consequently the average surface temperature and body temperatures, were not affected by nutritional plans. Effects of increasing the nutritional and energy levels were observed on liver weights, the gizzard, and the small intestine. We conclude that the nutritional plans did not affect body temperature. Males had higher body temperatures than females. Body temperature increased with increase in age, and the increase in the nutritional plans increased liver weight and reduced the gizzard weights.</p>

scholarly journals Nocturnal mating behaviour and dynamic male investment of copulation time in the southern blue-ringed octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)

Behaviour ◽  
2015 ◽  
Vol 152 (14) ◽  
pp. 1883-1910 ◽  
Author(s):  
Peter Morse ◽  
Kyall R. Zenger ◽  
Mark I. McCormick ◽  
Mark G. Meekan ◽  
Christine L. Huffard
Keyword(s):  
Mating Systems ◽  
Mating Behaviour ◽  
Female Size ◽  
Male Size ◽  
Male Preference ◽  
Video Footage ◽  
Mating History ◽  
Males And Females ◽  
Strategic Allocation ◽  
Do So

The southern blue-ringed octopus,Hapalochlaena maculosaHoyle (1883), is a nocturnal species that exhibits a mating system in which females hold sperm from multiple males over a one to two month breeding window before laying a single egg clutch. Contrary to most studied animal mating systems where anisogamy exists, gamete package production is limited for both males and females of this species (approx. 50 spermatophores/eggs). This presents an animal model for studying aspects of sperm competition and dynamic mate choice behaviours. The present study reports on the mating behaviour ofH. maculosaobserved under laboratory conditions using infrared closed-circuit television video footage. Rates of male copulation attempts increased with male size, while female receptivity to mating attempts increased with female size, resulting in larger animals of both sexes gaining more copulations and spending more time per day in copulation. There was some evidence of female preference of larger males, but no male preference of females based on measured morphological traits. Both sexes terminated copulations in equal frequencies but male-terminated copulations were significantly shorter in duration. Males were more likely to terminate copulation early with females they had previously mated with, however were less likely to do so if the female had recently mated with a different male. Among male-terminated copulations, males mated for longer with females that had previously mated with other males in the trial. Male–male mounts were as common as male–female mounts, suggesting that maleH. maculosaare not able to discriminate the sex of conspecifics. These findings suggest male strategic allocation of spermatophores based female mating history is an important factor influencing mating behaviours of this species.

Evolution of sexual dimorphism in the plateau brown frog fails to obey Rensch’s rule

2022 ◽  
pp. 27-33
Author(s):  
Tong Lei Yu
Keyword(s):  
Body Size ◽  
Large Male ◽  
Large Female ◽  
Female Size ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Males And Females ◽  
Brown Frog ◽  
Using Data

Rensch’s rule describes sexual size dimorphism (SSD) that decreases with increasing body size when females are larger than males and SSD that increases when males are larger than females. The plateau brown frog Rana kukunoris, a species endemic to the eastern Tibetan Plateau, exhibits female-biased size dimorphism. Using data on body size from 26 populations and age from 21 populations, we demonstrated that SSD did not increase with increasing mean female snout-vent length (SVL) when controlling for sex-specific age structure, failing to support the Rensch’s rule. Thus, we suggest that fecundity selection (favouring large female size) balances out sexual selection (favouring large male size), which results in a similar divergence between males and females body size. In addition, sex-specific age differences explained most of the variation of SSD across populations.

Age, Growth, and Sexual Maturity of the Shorthorn Sculpin, Myoxocephalus scorpius, in Newfoundland Waters

1970 ◽  
Vol 27 (12) ◽  
pp. 2155-2158 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Growth Rates ◽  
Sexual Maturity ◽  
Average Length ◽  
Maximum Size ◽  
Age Group ◽  
Younger Age ◽  
Shorthorn Sculpin ◽  
Males And Females ◽  
The Difference ◽  
Myoxocephalus Scorpius

In Newfoundland waters, shorthorn sculpins, Myoxocephalus scorpius (L.), live to age 15 and attain a maximum size of just over 50 cm. The growth rates of males and females are little different below age 4, but above age 4 the females grow faster than the males, and the difference between average length-at-age for males and females gets progressively larger with age. Males mature at a younger age and at a smaller size than females. In any age-group where there are mature and immature individuals the mature ones are larger.

scholarly journals Testing the heat dissipation limit theory in a breeding passerine

2018 ◽  
Vol 285 (1878) ◽  
pp. 20180652 ◽  
Author(s):  
Jan-Åke Nilsson ◽  
Andreas Nord
Keyword(s):  
Heat Dissipation ◽  
Work Rate ◽  
Body Temperatures ◽  
Limit Theory ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Thermal Window ◽  
Future Reproduction ◽  
Maximum Work ◽  
Males And Females

The maximum work rate of animals has recently been suggested to be determined by the rate at which excess metabolic heat generated during work can be dissipated (heat dissipation limitation (HDL) theory). As a first step towards testing this theory in wild animals, we experimentally manipulated brood size in breeding marsh tits ( Poecile palustris ) to change their work rate. Parents feeding nestlings generally operated at above-normal body temperatures. Body temperature in both males and females increased with maximum ambient temperature and with manipulated work rate, sometimes even exceeding 45°C, which is close to suggested lethal levels for birds. Such high body temperatures have previously only been described for birds living in hot and arid regions. Thus, reproductive effort in marsh tits may potentially be limited by the rate of heat dissipation. Females had lower body temperatures, a possible consequence of their brood patch serving as a thermal window facilitating heat dissipation. Because increasing body temperatures are connected to somatic costs, we suggest that the HDL theory may constitute a possible mediator of the trade-off between current and future reproduction. It follows that globally increasing, more stochastic, ambient temperatures may restrict the capacity for sustained work of animals in the future.

Reproductive biology and diet of the longtail butterfly ray Gymnura poecilura (Shaw, 1804) along western Bay of Bengal

2020 ◽  
Vol 100 (3) ◽  
pp. 461-470
Author(s):  
Muktha Menon ◽  
G. Maheswarudu ◽  
K. Sree Ramulu ◽  
Shoba Joe Kizhakudan
Keyword(s):  
Reproductive Biology ◽  
Maximum Size ◽  
Female Size ◽  
Feeding Intensity ◽  
Disc Width ◽  
The Mean ◽  
Index Of Relative Importance ◽  
Western Bay Of Bengal ◽  
Gravid Females ◽  
Size At Birth

AbstractThe reproductive biology and diet of the longtail butterfly ray Gymnura poecilura is described based on 630 specimens (N = 377 females and 253 males). The mean disc width (WD) of females and males was 576.7 mm (range = 190–920 mm) and 416.3 mm (230–550 mm), respectively. Sexual dimorphism in size was seen, with the maximum size of males being only 60% of the maximum female size. The disc widths at 50% maturity (WD50) were estimated to be 506.5 mm (females) and 435.9 mm (males). The mean uterine fecundity was 3.3 (range = 1–8). The size at birth was between 190 and 220 mm WD. Year-round reproduction was indicated, due to the presence of mature males and gravid females throughout the year, neonates in multiple months and large variations in embryo size within months. Feeding intensity increased with body size. Fish accounted for 80.9% of the diet (Index of Relative Importance, IRI), followed by crustaceans (18.9%) and molluscs. The species was found to be a specialized feeder.

Body size, age distribution, and reproduction in a northern population of wood turtles (Clemmys insculpta)

1992 ◽  
Vol 70 (3) ◽  
pp. 462-469 ◽  
Author(s):  
Ronald J. Brooks ◽  
Cathy M. Shilton ◽  
Gregory P. Brown ◽  
Norman W. S. Quinn
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Partial Correlation ◽  
Age Distribution ◽  
Egg Mass ◽  
Female Size ◽  
After Effects ◽  
Mean Width ◽  
Wood Turtles ◽  
Provincial Park

A population of the wood turtle (Clemmys insculpta) was studied on the east side of Algonquin Provincial Park, Ontario, from 1987 to 1990. A total of 77 adults (56 females, 21 males) and 13 juveniles were captured, measured, and individually marked. Age at maturity was 17–18 years at a minimum carapace length of 185 mm for females and 199 mm for males. Our data supported the hypothesis that turtles in northern populations are larger and older at maturity than are those in southern populations. For 21 nests, mean clutch size was 8.8 eggs and egg mass was 96 g. Predators destroyed 15 of 17 nests in 1990, and had injured 60% of adult turtles observed. Therefore, our population had low recruitment, few juveniles, and high levels of predation on nests and adults. Comparisons among females refuted two predictions from optimal egg size theory. Mean width and mass, but not length, of eggs correlated positively with female size, and correlated positively with clutch size, even after effects of body size were removed by partial correlation. However, smaller females in the population had relatively longer eggs than did larger females, whereas the Algonquin females have absolutely smaller eggs than do much smaller females in a New Jersey population.

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