Ecology of southeastern Arizona whiptail lizards (Cnemidophorus: Teiidae): population densities, resource partitioning, and niche overlap

1979 ◽  
Vol 57 (7) ◽  
pp. 1487-1499 ◽  
Author(s):  
Joseph C. Mitchell

Four species of whiptail lizards, two bisexual (Cnemidophorus inornatus and C. tigris) and two unisexual (C. sonorae and C. uniparens), were examined for ecological differences during the 1975 activity season in the desert–grassland of southeastern Arizona.Density estimates indicate the decreasing order of abundance was C. uniparens, C. inornatus, C. tigris, and C. sonorae. Daily activity was generally bimodal. Most active lizards were encountered away from plant cover and utilization of shade patches differed among species, Termites, coleopterans, orthopterans, and various larvae dominated whiptail diets and a wide variety of other prey types were consumed in small quantities. Monthly variations of arthropod biomass and prey diversities between years are presented and discussed.Niche breadths and two measures of niche overlap were calculated and compared for temporal, spatial, and trophic niche components for syntopic species pairs. Ecological differences between bisexual and unisexual species were determined to be minimal.Comparisons of data and niche overlaps indicate the order of importance in separating southeastern Arizona whiptail niches is macrohabitat, microhabitat, time, and food. However, due to higher than average niche overlap and noted similarities among these four species, it is concluded that southeastern Arizona whiptails form a guild of similar lizards.

1982 ◽  
Vol 3 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Robert W. Henderson

AbstractTrophic relationships and foraging strategies are examined in two New World arboreal, diurnal, snake communities: Leptophis mexicanus, Oxybelis aeneus, and O.fulgidus from Mexico's Yucatán Peninsula, and Uromacer catesbyi and U. oxyrhynchus from Isla Saona, República Dominicana. Active foragers (L. mexicanus and U. catesbyi) have similar body proportions and feed primarily on diurnally quiescent prey (hylid frogs, bird eggs). Sit-and-wait strategists (O. aeneus, O.fulgidus and U. oxyrhynchus) have similar body proportions and feed on diurnally active prey (primarily lizards). Active foragers take prey that is, on the average, larger than the prey of sit-and-wait foragers, but presumably, active foragers expend more energy in locating prey. Trophic niche breadth is widest among the active foragers and narrowest for the slender vine snakes (O. aeneus and U. oxyrhynchus). Trophic niche overlap values are low for species pairs that occur sympatrically (or syntopically) with the exception of O. aeneus-O. fulgidus, but O. fufgidus preys on a wider variety of lizard taxa, preys on birds (which are absent from the diet of O. aeneus), and takes prey items that are significantly larger in size. It seems likely that, among arboreal colubrids, the sit-and-wait foraging strategy is derived from one of active foraging.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Parimuchová ◽  
Lenka Petráková Dušátková ◽  
Ľubomír Kováč ◽  
Táňa Macháčková ◽  
Ondřej Slabý ◽  
...  

AbstractTrophic interactions of cave arthropods have been understudied. We used molecular methods (NGS) to decipher the food web in the subterranean ecosystem of the Ardovská Cave (Western Carpathians, Slovakia). We collected five arthropod predators of the species Parasitus loricatus (gamasid mites), Eukoenenia spelaea (palpigrades), Quedius mesomelinus (beetles), and Porrhomma profundum and Centromerus cavernarum (both spiders) and prey belonging to several orders. Various arthropod orders were exploited as prey, and trophic interactions differed among the predators. Linear models were used to compare absolute and relative prey body sizes among the predators. Quedius exploited relatively small prey, while Eukoenenia and Parasitus fed on relatively large prey. Exploitation of eggs or cadavers is discussed. In contrast to previous studies, Eukoenenia was found to be carnivorous. A high proportion of intraguild predation was found in all predators. Intraspecific consumption (most likely cannibalism) was detected only in mites and beetles. Using Pianka’s index, the highest trophic niche overlaps were found between Porrhomma and Parasitus and between Centromerus and Eukoenenia, while the lowest niche overlap was found between Parasitus and Quedius. Contrary to what we expected, the high availability of Diptera and Isopoda as a potential prey in the studied system was not corroborated. Our work demonstrates that intraguild diet plays an important role in predators occupying subterranean ecosystems.


Author(s):  
Vanessa Modesto ◽  
Ester Dias ◽  
Martina Ilarri ◽  
Manuel Lopes‐Lima ◽  
Amílcar Teixeira ◽  
...  

2005 ◽  
Vol 95 (3) ◽  
pp. 233-240 ◽  
Author(s):  
Norma Machado da Silva ◽  
Carina da Conceição Fantinel ◽  
Vera Lucia da Silva Valente ◽  
Vitor Hugo Valiati

Ecological parameters such as trophic niche overlap and niche breadth were computed from the frequency of all drosophilid species collected in 2001 and 2002, in the urban area of Porto Alegre city, Brazil. Independently of place, drosophilids community composition and components breeding or feeding sites, the highest frequencies of Zaprionus indianus (Gupta, 1970) were obtained during seasons with higher average temperatures, especially during summer. From a total of the 19,146 individuals of Z. indianus sampled, 80% were found in this season. The data of trophic niche breadth suggest a higher opportunism of adult flies in feeding substrate use, but the females are still selective in oviposition substrate choice. For the values of niche overlap, only for some species, did we find any correlation between these and species richness and/or number of resources, and the most of the correlation values considering breeding and feeding sites were positive. The colonization of Z. indianus in Porto Alegre could be leading to adjustments in the survival strategies of the resident species, but it is possible that many species have conditions for coexisting with the invader.


2007 ◽  
Vol 26 (2) ◽  
pp. 219-223 ◽  
Author(s):  
Douglas A. Eifler ◽  
Maria A. Eifler ◽  
Bethany R. Harris

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1578 ◽  
Author(s):  
Nancy Cabanillas-Terán ◽  
Peggy Loor-Andrade ◽  
Ruber Rodríguez-Barreras ◽  
Jorge Cortés

Sea urchins are important grazers and influence reef development in the Eastern Tropical Pacific (ETP).Diadema mexicanumandEucidaris thouarsiiare the most important sea urchins on the Ecuadorian coastal reefs. This study provided a trophic scenario for these two species of echinoids in the coral-rocky reef bottoms of the Ecuadorian coast, using stable isotopes. We evaluated the relative proportion of algal resources assimilated, and trophic niche of the two sea urchins in the most southern coral-rocky reefs of the ETP in two sites with different disturbance level. Bayesian models were used to estimate the contribution of algal sources, niche breadth, and trophic overlap between the two species. The sea urchins behaved as opportunistic feeders, although they showed differential resource assimilation.Eucidaris thouarsiiis the dominant species in disturbed environments; likewise, their niche amplitude was broader than that ofD. mexicanumwhen conditions were not optimal. However, there was no niche overlap between the species. The Stable Isotope Analysis in R (SIAR) indicated that both sea urchins shared limiting resources in the disturbed area, mainlyDictyotaspp. (contributions of up to 85% forD. mexicanumand up to 75% forE. thouarsii). The Stable Isotope Bayesian Ellipses in R (SIBER) analysis results indicated less interspecific competition in the undisturbed site. Our results suggested a trophic niche partitioning between sympatric sea urchin species in coastal areas of the ETP, but the limitation of resources could lead to trophic overlap and stronger habitat degradation.


2019 ◽  
Vol 70 (8) ◽  
pp. 1116 ◽  
Author(s):  
B. C. K. Kliemann ◽  
M. C. Baldasso ◽  
S. F. R. Pini ◽  
M. C. Makrakis ◽  
S. Makrakis ◽  
...  

The diet of Glanidium ribeiroi was investigated in lotic stretches downstream from a cascade of reservoirs to determine how it responds to intraspecific and environmental variations. Monthly sampling was performed from 2013 to 2016 at sites including the main channel of the Iguaçu River and tributaries in preserved basins and agricultural land. The diet of individuals in the preserved tributaries was primarily associated with allochthonous resources, whereas in the non-preserved tributaries and main channel the diets were primarily associated with autochthonous resources. Trophic niche breadth and intraspecific variability differed significantly among sampling areas and size classes. Trophic niche overlap among size classes and sampling areas was low. Positive and negative relationships between the trophic niche breadth and the standard length of individuals were also found in different sampling areas. Intraspecific and ontogenic variations were strongly and consistently associated with forest cover. Individuals responded differently to local environmental variations due to differences in landscape gradients and life cycle changes. Therefore, the effects of spatial heterogeneity on diet composition and intraspecific variations therein appear to be crucial to the success of the populations evaluated. These results may help with the implementation of conservation measures for this and other endemic species.


2018 ◽  
Vol 78 (1) ◽  
Author(s):  
Yesely M. Hurtado ◽  
Cesar E. Tamaris-Turizo ◽  
Manuel J. López Rodriguez ◽  
J. Manuel Tierno de Figueroa

The knowledge of the diet of aquatic insects is important to assess the use of resources and overlap of trophic niche between species, as well as to understand their role in the food web of the freshwater ecosystems they inhabit. This is particularly necessary in tropical areas where information on this topic is scarce. The aim of the present work is to describe the feeding habits of the species Anacroneuria marta Zúñiga and Stark, 2002 and Anacroneuria caraca Stark, 1995 in the middle section of the Gaira River (Sierra Nevada de Santa Marta, Colombia). We performed three samplings during the rainy and dry seasons in the two main different microhabitats of the reach (leaf packs and gravel) in 2014. The diet of a total of 87 and 90 individuals of A. caraca and A. marta, respectively, was studied. With this information, niche breadth for each species and niche overlap between them in terms of trophic resources were calculated. The main trophic resource for both species in the dry and rainy season was the animal matter. In the dry season, FPOM was also important in the diet of A. caraca, and A. marta ingested a great quantity of CPOM in the rainy season. Larvae of Trichoptera, were the most ingested prey in both species, followed by Chironomidae, Coleoptera Hydrophilidae, and Ephemeroptera. No differences in diet between both species were detected, so this could favor the niche overlap in terms of trophic resources and could lead to competition between them. The possible ecological scenarios are discussed.


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