The Ecological Significance of Sexual Dimorphism in Size in the Lizard Anolis conspersus.
27 Jan 1967-Science (American Association for the Advancement of Science)-Vol. 155, Iss: 3761, pp 474-477
TL;DR: Anolis conspersus selects prey from a wide range of taxa and shows no obvious intraspecific specialization not connected to differences in microhabitat and prey size.
Abstract: Adult males of Anolis conspersus capture prey of significantly larger size and occupy perches of significantly greater diameter and height than do adult females; similarly, these three dimensions of the niche are significantly larger for adult females than for juveniles. Adult males on the average eat a smaller number of prey, and the range in size of prey is larger. The relationship between the average length of the prey and that of the predator is linear when the predator size is above 36 millimeters, but becomes asymptotic when it is below that value. Subadult males as long as adult females eat significantly larger food than do the latter, but only in the larger lizards is this correlated with a relatively larger head. Anolis conspersus selects prey from a wide range of taxa and shows no obvious intraspecific specialization not connected to differences in microhabitat and prey size. The efficiency of this system for solitary species is pointed out.
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01 Jan 2012
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01 Jan 1979
TL;DR: Detailed analysis of habitats reveals important differences in Yellow-throated and Solitary Vireos, although both require relatively mature stands of trees, and comments on the evolution of foraging behaviour are discussed.
Abstract: In southern Ontario Yellow-throated Vireos usually occupy a very open deciduous forest, hut with mature trees. Solitary Vireos breed in relatively mature and dense mixed forest, allopatric to Yellow-throated Vireos. In western Pennsylvania, however, these vireos may he found sympatrically occupying deciduous forest. But detailed analysis of habitats reveals important differences, although both require relatively mature stands of trees. The two species exhibit foraging behaviour which is very similar in several respects and there appears to be less divergence where the two species are sympatric. Both take food largely from branches in the interior of trees, but the Solitary Vireo secures a greater portion of its food by hovering. Yellowthroated Vireos are not restricted to crown layer foraging, but the presence of Red-eyed Vireos appears to influence the depth of their foraging activity, Male and female Yellow-throated Vireos exhibit divergence in foraging strategies. Comments on the evolution of foraging behaviour are discussed.
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21 Jun 2019
TL;DR: La biologia de the lagartija cola de latigo Aurivela tergolaevigata es poco conocida, y se encontro que hay diferencias in the dieta entre sexos y estaciones, por distintas categorias presas.
Abstract: La biologia de la lagartija cola de latigo Aurivela tergolaevigata es poco conocida. Aunque su status de conservacion es no amenazado, el deterioro del bioma desertico donde habita es muy importante a causa principalmente de la desertificacion. El objetivo de este trabajo fue comparar entre machos y hembras rasgos objetos de la seleccion sexual y/o por fecundidad, y analizar la dieta en relacion a algunas fuentes de variacion. Se registraron medidas del cuerpo, cabeza y abdomen. Se analizaron contenidos estomacales, las dimensiones de las presas se asociaron al tamano de la cabeza del predador. Se encontro que hay diferencias en la dieta entre sexos y estaciones, por distintas categorias presas. Las diferencias intersexuales en el tamano relativo de la cabeza no afecta el tamano de las presas, si bien machos con cabezas mas altas y anchas pueden consumir presas mas largas. La diferencia entre machos y hembras en el tamano relativo del abdomen se explica en terminos de la fecundidad.
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Cites background from "The Ecological Significance of Sexu..."
...…incrementan el éxito reproductivo. también la competencia por el alimento puede conducir a divergencias en el tipo y tamaño de presa que prefieren y por lo tanto conduciría a divergencias intersexuales en el tamaño de la cabeza (Schoener, 1967; Shine, 1989; Preest, 1994; Verwaij en et al. 2002)....
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TL;DR: 1 Florida Museum of Natural History, Division of Herpetology, P.O. Box 117800, University of Florida, Gainesville, Florida 32611, USA.
Abstract: 1 Florida Museum of Natural History, Division of Herpetology, P.O. Box 117800, University of Florida, Gainesville, Florida 32611, USA 2 Centro del Cambio Global y la Sustentabilidad en el Sureste, A.C., Calle Centenario del Instituto Juarez s/n, C.P. 086080, Villahermosa, Tabasco, Mexico. 3 Instituto de Ecologia y Sistematica. Carretera de Varona, km 3.5, Boyeros. A.P.8029, C.P. 10800, La Habana, Cuba. 4 Centro de Aplicaciones Tecnologicas para el Desarrollo Sostenible (CATEDES/CITMA). Agramonte E/ Prado y Aguilera, No. 848, C.P. 99100, Guantanamo, Cuba. * Corresponding author: charruau_pierre@yahoo.fr
2 citations
Cites background from "The Ecological Significance of Sexu..."
...Sexual dimorphism could permit each sex to utilize different resources, thus decreasing intraspecific competition, whereby the greater length and mass in males allows them to ingest larger prey items than females (Schoener 1967; Shine 1989; Herrel et al. 1996)....
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TL;DR: It was found that the Psammophilus blanfordanus regularly bask in the morning to maintain elevated body temperatures and the observed sexual dimorphism in body size, head size and body colouration in males to hold more number of females in their territory.
Abstract: Behavioral ecology, breeding period, sexual dimorphism and ovipositional behavior were investigated in the lizard, Psammophilus blanfordanus in Mayurbhanj of Odisha. It was found that they regularly bask in the morning to maintain elevated body temperatures. However, the maximum number of adult males and the gravid females of Psammophilus blanfordanus are usually found from May through July months of the year. Males acquired larger body sizes than females during breeding season. Eggs are laid in clutches of up to eight in numbers. The observed sexual dimorphism in body size, head size and body colouration in males to hold more number of females in their territory. This is the first described observation of the ovipositional behavior of Psammophilus blanfordanus. The ovipositional behavior consisted of digging a hole to lay eggs, laying the eggs, burrying the eggs, emergence of hatchlings from the burrow. INTRODUCTION Blanford’s Rock Agama (Psammophilus blanfordanus) is an agamid lizard found in Peninsular India and is named after William Thomas Blanford (1832–1905), member of the Geological Survey of India. In reptiles, patterns of daily activity range from nocturnal to diurnal with various intermediate conditions and in some cases activity rhythms are not encountered (Heatwole and Taylor, 1987; Zug et al., 2001; Winne and Keck, 2004). Many lizard species have distinct preferences for particular substrates, perch shape, vegetation densities or other aspects of habitat structure (Heatwole, 1977; Arnold, 1987; Hussein, 1994; 2000). Population dynamics, microhabitat use and activity pattern are the important components of animal ecology. The time of day when animals emerge from refuge and engage in activities such as basking, foraging, searching for mates and so on may be restricted to certain periods of the day or year. Indeed, most reptiles exhibit high activity during discrete times of the day/ year and the factors controlling such periodicity interact in a complex manner (Schoener, 1977; Heatwole and Taylor, 1987; Underwood, 1992; Zug et al., 2001). Lizard communities may achieve resource partitioning by spatial or temporal separation in their activity patterns depending upon the habitat, prey availability and thermal ecology (Schoener, 1977; Heatwole and Taylor, 1987; Davis and Verbeek, 1972; Zucker, 1986; Martin and Salvador, 1997; Howard and Hailey, 1999; Melville and Schulte, 2001; Leal and Fleishman, 2002). Growth pattern is a key aspect in the life history of any species (Andrews, 1982; Sinervo and Aldoph, 1989; Roff, 1992; Arendt, 1997) and reproduction is the most costly event in an animal’s life. Body size and growth rate are particularly important life history traits because of their relation to reproductive output, longevity, age at first reproduction, and so on (Andrews, 1982; Bauwens and Verheyen, 1985; Ferguson and Talent, 1993; Clobert et al., 1998; Lorenzon et. al., 1999; Bronikowski, 2000). Reproduction is an important event in the life history of all organisms. Female body size, clutch/egg and offspring body sizes are the basic components of life-history traits. Oviparous reptiles show complex interrelationships among maternal body size, clutch and egg sizes. In lizards, clutch size varies with proximate climatic factors, food availability and fat body reserves (Vitt, 1992; Dunham, 1994; Schwarzkopf, 1994; Shanbhag, 2002; 2003). Even if sexual selection is responsible for the initial morphological divergence in body and head sizes, ecological factors may act either to constram or amplify this initial sexually selected difference (Shine, 1989; 1991). Unlike the other species, the male in breeding season has a brilliant red head and crest with black coloration dorso-laterally and ventrally. They are found mainly on rocks. The male displays with head nodding (Smith, 1941). From snout to vent they are about 10 cm long and the tail is about 20 cm. Females are slightly smaller than the males. Most studies on growth rates in lizards are mainly based on mark and recapture surveys (Bellairs, 1969; Jenssen and Andrews, 1984; Shine, 1988; James, 1991; Sugg et al., 1995; Allan et al., 2006) or on frequency distribution of individuals in a population collected at different points of time in a year (Andrews, 1976; Ferguson and Brockman, 1980; Bishop and Echternacht, 2003). The information on the ecology and natural history of this species is limited. Though the peak breeding months seems to be June through August, the breeding behavior or ovipositional behavior has not been clearly documented. No information is available about its clutch size, incubation duration and about the hatchling. In this paper, we describe the ovipositional behavior, duration of time taken by a hatchling to emerge out from an egg and hatching success of this species for the first time were described. MATERIALS AND METHODS In the present study, ecology, sexual dimorphism, breeding period and ovipositional behavioral of Psammophilus blanfordanus was observed very closely in residential areas of Mayurbhanj, Odisha and the important events were recorded by the help of camera and also recorded the hatchling success. The behavior of different activities of Psammophilus blanfordanus were observed silently from 2 m away through unaided eye. The animal was not disturbed during observation. The nest soil was loosely packed and consisted of a mixture of sandy and clayey soil. The weather was hot and humid. The atmospheric temperature was noted as 27o C. The study site was surveyed twice a day (at 8:30 am and 4 pm). A female Psammophilus blanfordanus was observed in a residential area on 23 June 2011 between 12:23-12:48 pm digging a hole on a small hip of sands. The lizards were spotted and their day-to-day behavior, during their breeding period, their sexual dimorphism, body colouration, sex recognition, ovipositional behavior and hatching success were also noted. The egg size could not be measured accurately because handling the eggs might have affected their incubation. RESULT AND DISCUSSION (A) Behavioral Ecology Psammophilus blanfordanus are usually diurnal, and are he-
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TL;DR: The eight species of the genus Anolis in Puerto Rico can be divided into four morphological similarities as discussed by the authors : perch height, perch diameter, high-shade preference and low-shading preference.
Abstract: The eight species of lizards of the genus Anolis in Puerto Rico can be divided into four morphological similarities. One, Anolis curvieri, is very different from the rest and has not been discussed here. The other seven species fall into three groups. Each of these groups occupies a different structural habitat which can be defined in terms of perch height and perch diameter. Within each of these three groups the species have very similar but not indential structural habitats but differ very widely in climatic habitat defined in terms of shade. Shade preferences seem to result from the temperature preferences of the species involved. In each group there is one species with high shade preference which is essentially restricted to the mountains. Each group also has a species with a lower shade preference which occurs in the lowlands and extends up into the mountains in exposed or sunny situations. One of the three groups has an additional species which is restricted to the hot and southwest corner of Puerto Rico. When one compares the temperature preferences or eccritic temperatures of the various species, one finds in each group that the highland species has a lower eccritic temperature than does the lowland species. There is little temperature difference between the lowland species and arid southwest species in the group where this additional third species is present. The species within each structural habitat show many morphological similarities which may be the result of their being closely related or may be the result of adaptation to similar environments. The differences in microhabitat between the Puerto Rican anoles separate them spatially though not completely. In species occupying different structural habitats in the same area the overlap may involve part of the home range of most of the individuals in the area. In species occupying the same structural but different climatic habitats the overlap may involve all of the home range of some individuals but of only a small fraction of the individuals in the total population. The spatial separation among Puerto Rican Anolis can be suggested to be of ecological significance because it reduces interspecific competition and because it allows the various species to adapt more precisely to different parts of the available habitat. Thus members of a genus may exploit the habitat more efficiently.
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01 Jan 1964
TL;DR: The life of the rainbow lizard , The life of a rainbow lizard, مرکز فناوری اطلاعات £1,000,000 ($2,000; £1,500,000)
Abstract: The life of the rainbow lizard , The life of the rainbow lizard , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
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"The Ecological Significance of Sexu..." refers background in this paper
...On the basis of essentially the same pattern of staining, other investigators have reached the same conclusion (3, 4), or have attributed staining additionally or alternatively to the processes of the bipolar cells (5, 6), the ganglion cells (4, 5), or centrifugal fibers from the optic nerve (7)....
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...A greater proportion of large insects were found in larger adult males than in adult females of Anolis lineatopus and Agama agama (4, 5); similarly, juveniles take smaller food than adults (5-7)....
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