Effects of rainfall and geography on the comparative diets of eight rainbow lizard populations across Togo, Benin and Nigeria (West Africa) (original) (raw)
Related papers
2018
Feeding ecology is directly linked to survival and fitness and consequently shapes the life history of organisms. The choice of prey can influence interactions among species, prey composition and abundance, and ultimately the transfer of energy and matter within ecosystems (de Ruiter et al., 2005). Consequently, knowledge of the dietary niche and trophic patterns of organisms is important for understanding their ecological interactions and the factors that promote coexistence of species at the community level (e.g., Pianka, 1974; Brown and Gillooly, 2003). Although many reptiles and most amphibians are generalized insectivores (e.g., Parmelee, 1999; Van Damme, 1999), recent studies suggest that species living within human habitations are opportunistic feeders and include non-insect food in their diets. For example, Weterings (2017) reported that the insectivorous gecko Hemidactylus platyurus fed on rice, cucumber, and egg in garbage bins. Additionally, the anthropophilic and insectivorous gecko Gehyra mutilata has been reported to feed on nectar from flowers (Tanalgo and Hughes, 2017), while the insectivorous Gekko monarchus was observed feeding on white bread on a kitchen table (Weterings and Weterings, 2018). The West African rainbow lizard Agama picticauda Peters, 1877 is now considered as distinct from A. agama (Linnaeus, 1758) and recognized as a common and widespread lizard in sub-Saharan West Africa
Dietary ObservatiOns Of fOur sOuthern african agamiD LizarDs (agamiDae
Analysis of stomach contents can provide insights into foraging mode, habitat use, and dietary specialization of animals. In this paper, we make observations on the poorly known diet of four southern African agamid species, Agama aculeata distanti (Eastern Ground Agama), Agama armata (Peter's Ground Agama), Agama atra (Southern Rock Agama), and Acanthocercus atricollis (Southern Tree Agama). We examined the diet of 67 individuals by identifying and weighing prey items after stomach flushing lizards in the field. We found that these agama species fed on a broad spectrum of arthropods (11 orders). A high relative importance of ants was present for all agama species examined here, which suggests that ants are a major food source in the arid ecosystem. We found that active prey such as ants, beetles, and highly mobile flying insects like wasps and flies to be major components of the diet, indicating that these lizards are ambush predators. We also found that 43% of the stomachs contained herbaceous material and 39% contained sand particles. Agama atra had the most diverse dietary niche, eating fewer ants and more beetles, hemipterans, and dipterans than other species, whereas A. armata had a narrower dietary niche consisting mainly of ants. Lastly, although low in sample size, we found that juveniles qualitatively had a diet of functionally similar prey items, albeit with a narrower niche breadth, when compared to adults. We discuss how diet corresponds with differences in foraging behavior and habitat specialization.
Amphibia-Reptilia, 2018
Food habits of the Moroccan Spiny-tailed lizard, Uromastyx nigriventris, from three localities along an aridity gradient from north-east (Mediterranean) to southwest (Atlantic pre-Saharan) of the Atlas range, Morocco, were investigated in spring and autumn 2015 using fecal microhistological analysis. The obtained results showed that these lizards are predominantly herbivorous feeding on 4 to 13 different plant species depending on locality and season, but some insects, namely coleopterans and ants (Formicidae) (up to 6%) are also consumed. They heavily ingested annual and perennial herbaceous plants through a single season. There were significant differences among seasons and localities in terms of species richness and Shannon-Wiener diversity indexes. These indexes increased significantly, respectively for the spring and autumnal diets, and correlatively with the species richness in the habitat along the aridity gradient. The Stress-Gradient Hypothesis could explain this increase. ...
Diet of a guild of geckos in a fragmented, human‐altered African rainforest
African Journal of Herpetology, 2007
The ecology of gekkonids occurring in African forests is poorly known. In this paper, we analyse the feeding habits of a guild of sympatric geckos at a forest-plantation mosaic area in south-eastern Nigeria. Faeces were collected on handling from Hemidactylus brookii, H. fasciatus, H. intestinalis, H. mabouia, H. echinus, and Lygodactylus conraui. All species proved to be dietary generalists, with diets based almost entirely on arthropods. However, food niche overlap values between pairs of species were relatively low and Monte Carlo simulations (with RA2 and RA3 algorithms) showed that the overlap values between H. fasciatus and H. intestinalis were significantly higher than those observed for other pairs of species. Monte-Carlo simulations on co-occurrence estimators (C-score, V-ratio, and number of species combinations) revealed that the gecko guild was not competitively structured along the trophic niche dimension.
Biological Journal of the Linnean Society
Diversification events in the Sahara-Sahel have mostly been attributed to regional aridification and subsequent arid-humid fluctuations, through vicariance or adaptation. However, no study has attempted to test these contrasting hypotheses. Here, we assess the importance of aridity-induced vicariance (as opposed to adaptation to new conditions) on diversification processes in NorthWest African Agama lizards. To test the hypothesis of vicariance as the main driver of diversification, we assessed the occurrence of the following three patterns expected to occur under the proposed scenario: (1) prevalent allopatric or parapatric distributions; (2) allopatric climatic refugia coincident with current distributions; and (3) niche similarity decreasing with increasing phylogenetic distance. We also reconstructed the centre of origin and range expansion dynamics for the Sahelian species to verify the congruence of the genetic signal with the vicariance scenario. All patterns expected from a neutral, non-adaptive niche divergence scenario were present. The diffusion models for the Sahelian species identified similar points of origin, corresponding to the areas of highest genetic diversity, topographic heterogeneity and climatic stability. Other patterns, such as mountain-isolated lineages, also indicate isolation by aridity. Our results support vicariance as the main driver of diversification in NW African Agama at both large and local scales. The importance of southern Mauritania for the conservation of biodiversity and the evolutionary process is highlighted.
Dietary niche variation and its relationship to lizard population density
Journal of Animal Ecology
1. Insular species are predicted to broaden their niches, in response to having fewer competitors. They can thus exploit a greater proportion of the resource spectrum. In turn, broader niches are hypothesized to facilitate (or be a consequence of) increased population densities. 2. We tested whether insular lizards have broader dietary niches than mainland species, how it relates to competitor and predator richness, and the nature of the relationship between population density and dietary niche breadth. 3. We collected population density and dietary niche breadth data for 36 insular and 59 mainland lizard species, and estimated competitor and predator richness at the localities where diet data were collected. We estimated dietary niche shift by comparing island species to their mainland relatives. We controlled for phylogenetic relatedness, body mass and the size of the plots over which densities were estimated. 4. We found that island and mainland species had similar niche breadths. Dietary niche breadth was unrelated to competitor and predator richness, on both islands and the mainland. Population density was unrelated to dietary niche breadth across island and mainland populations. 5. Our results indicate that dietary generalism is not an effective way of increasing population density nor is it result of lower competitive pressure.
2004
We document populations of the introduced African rainbow lizard (Agama agama africana) in Homestead, Miami-Dade County; Hollywood, Broward County; Palm City, Martin County; Punta Gorda, Charlotte County; and Sanford, Seminole County. The Homestead and Punta Gorda populations have been established for over 10 yr and have expanded at least 0.5 km from the point of introduction. The Palm City population has been established since 1999 and the Sanford population since 2000. All agamas were observed in urban or suburban situations perched on walls, rooftops, bridges, rocks, sidewalks, curbstones, or trees. We collected 33 voucher specimens from five populations 28 March 2002–11 March 2004. Maximum clutch size and maximum snout-vent length (SVL) of male and female A. a. africana in Florida exceeded those in native Nigerian populations. All adult females (> 94 mm SVL) collected May–August contained 5–18 vitellogenic follicles or oviductal eggs, but a female collected on 19 September wa...