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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TL;DR: Findings indicate that animal prey plays a role in niche differentiation between C. cupreus and S. fuscicollis/S.
Abstract: We compared the prey capture strategies of red titi monkeys, Callicebus cupreus, with those of sympatric mustached, Saguinus mystax, and saddleback tamarins, Saguinus fuscicollis, to examine whether animal prey is important in niche differentiation between these Neotropical primates We collected data on strata and substrate use during foraging, on prey searching and capturing, and on prey type of two C cupreus groups and one group each of S mystax and S fuscicollis during a 5-month field study in northeastern Peruvian Amazonia Our results showed that C cupreus differed both from S mystax and S fuscicollis in prey capture strategies: (1) C cupreus used lower forest strata for prey search and capture than S mystax and higher forest strata than S fuscicollis (2) C cupreus captured prey on a higher variety of substrates than S mystax and more often on open microhabitats compared to S fuscicollis (3) C cupreus captured prey more often directly than S mystax and rarely by manual search, in contrast to S fuscicollis (4) C cupreus fed exclusively on arthropods and focused on Hymenoptera, in contrast to both tamarin species that focused on Orthoptera and included vertebrates in their diet These findings indicate that animal prey plays a role in niche differentiation between C cupreus and S fuscicollis/S mystax and might facilitate the coexistence of these three sympatric species
49 citations
TL;DR: It is suggested that differential food particle size allocation can be a mechanism for reducing interspecific competition in heteromyid rodents.
Abstract: Laboratory experiments were designed to determine if heteromyid rodents of different body sizes select seeds of an average size which is correlated with the body size of the granivore. Eight types of commercial seeds were used and 6 heteromyid species were tested. Although there was no correlation of average seed size selected and the body size of the individual granivore, there was a highly significant positive correlation (r = .95) of average seed size selected versus average body size of each group of rodents of a particular species. Thus small animals of a species select seeds of the same average size as large animals of that same species. There was a tendency for individuals of larger species to take a greater variety of seeds. We suggest that differential food particle size allocation can be a mechanism for reducing interspecific competition.
49 citations
TL;DR: The first such evidence for lizards is reported, this in Anolis sagrei on Great Abaco Island, Bahamas, where the polymorphism occurs only in females, a restriction usual for insects but very rare in vertebrates.
Abstract: Polymorphism in body color and pattern occurs in an enormous diversity of animals, from crustaceans to mammals (Mayr, 1963). Its adaptive significance is often interpreted in terms of differential resemblance, protective or otherwise, to the animal's typical background. Yet substantial field evidence for this explanation exists only for a small fraction of species [for example, butterflies (Clarke and Sheppard, 1962; Curio, 1965); snails (Cain and Sheppard, 1954; Clarke, 1968; Owen, 1969; Arnold, 1969); frogs (Nevo, 1973); salamanders (Williams et al., 1968); snakes (Camin and Ehrlich, 1958); birds (Hall et al., 1966); and mammals (Gershenson, 1945) ]. Here we report the first such evidence for lizards, this in Anolis sagrei on Great Abaco Island, Bahamas. The polymorphism occurs only in females, a restriction usual for insects (Richards, 1961) but very rare in vertebrates; in fact, to our knowledge it occurs only in a handful of other Anolis and the partridge Lyrurus tetrix (Stegmann, 1932, cited by Huxley, 1955). In some vertebrates, however, polymorphism is more clearly expressed in females than males: e.g., the lizard Uta stansburiana (Ballinger and McKinney, 1967). We discuss possible reasons for this polymorphism's rarity after presenting the data.
48 citations
TL;DR: A formal test of the sociality hypothesis is provided alongside alternative explanations for the evolution of communicative complexity among closely related species and used new phylogenetic methods to investigate the factors underlying communication evolution.
Abstract: Complex social communication is expected to evolve whenever animals engage in many and varied social interactions; that is, sociality should promote communicative complexity. Yet, informal comparisons among phylogenetically independent taxonomic groups seem to cast doubt on the putative role of social factors in the evolution of complex communication. Here, we provide a formal test of the sociality hypothesis alongside alternative explanations for the evolution of communicative complexity. We compiled data documenting variations in signal complexity among closely related species for several case study groups—ants, frogs, lizards and birds—and used new phylogenetic methods to investigate the factors underlying communication evolution. Social factors were only implicated in the evolution of complex visual signals in lizards. Ecology, and to some degree allometry, were most likely explanations for complexity in the vocal signals of frogs (ecology) and birds (ecology and allometry). There was some evidence for adaptive evolution in the pheromone complexity of ants, although no compelling selection pressure was identified. For most taxa, phylogenetic null models were consistently ranked above adaptive models and, for some taxa, signal complexity seems to have accumulated in species via incremental or random changes over long periods of evolutionary time. Becoming social presumably leads to the origin of social communication in animals, but its subsequent influence on the trajectory of signal evolution has been neither clear-cut nor general among taxonomic groups.
48 citations
TL;DR: The results indicate that bacterial communities are only weakly shaped by the diversification of their lizard hosts due to the strikingly high levels of bacterial diversity and variation observed within Anolis species.
Abstract: Adaptive radiations provide unique opportunities to test whether and how recent ecological and evolutionary diversification of host species structures the composition of entire bacterial communities. We used 16S rRNA gene sequencing of faecal samples to test for differences in the gut microbiota of six species of Puerto Rican Anolis lizards characterized by the evolution of distinct ‘ecomorphs’ related to differences in habitat use. We found substantial variation in the composition of the microbiota within each species and ecomorph (trunk-crown, trunk-ground, grass-bush), but no differences in bacterial alpha diversity among species or ecomorphs. Beta diversity analyses revealed subtle but significant differences in bacterial composition related to host phylogeny and species, but these differences were not consistently associated with Anolis ecomorph. Comparison of a trunk-ground species from this clade (A. cristatellus) with a distantly related member of the same ecomorph class (A. sagrei) where the two species have been introduced and are now sympatric in Florida revealed pronounced differences in the alpha diversity and beta diversity of their microbiota despite their ecological similarity. Comparisons of these populations with allopatric conspecifics also revealed geographic differences in bacterial alpha diversity and beta diversity within each species. Finally, we observed high intraindividual variation over time and strong effects of a simplified laboratory diet on the microbiota of A. sagrei. Collectively, our results indicate that bacterial communities are only weakly shaped by the diversification of their lizard hosts due to the strikingly high levels of bacterial diversity and variation observed within Anolis species.
48 citations
Cites background from "The Ecological Significance of Sexu..."
...Although most anoles are insectivorous dietary generalists, ecomorphs may differ in foraging mode (Losos 2009), and partitioning of trophic resources has been observed both within and among sympatric Anolis species (Schoener 1967, 1968; Stamps et al. 1997)....
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References
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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.
218 citations
129 citations
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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
119 citations
"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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