Population diet variation and individual specialization in the poison toad, Melanophryniscus rubriventris (Vellard, 1947)

2011 ◽  
Vol 32 (2) ◽  
pp. 261-265 ◽  
Author(s):  
María Fernanda Quiroga ◽  
Marcos Vaira ◽  
Maria Ines Bonansea
Keyword(s):  
Entire Range ◽  
Diet Composition ◽  
Foraging Strategies ◽  
Future Research ◽  
Individual Specialization ◽  
Generalist Species ◽  
Defensive Strategies ◽  
Important Prey ◽  
Diet Variation ◽  
Prey Items

AbstractFew studies have investigated the level of individual variation in diet composition of poisonous frogs and toads. We compare the diet composition of three populations of a poisonous toad, Melanophryniscus rubriventris, and predicted that toads within a population might be constrained to forage on particular types of alkaloid-containing prey and consequently diets among populations might not diverge from each other. Most important prey categories in the diets of the three populations consisted of the same ground-dwelling arthropods. We found evidence for individuals consuming different arrays of prey types in all populations implying that this “generalist” species is actually comprised of individuals eating different sets of the available range of prey. Formicidae, Acari, and Coleoptera were all important alkaloid-containing prey items in the diets of all populations and individuals, although there were differences in their order of importance among populations and individuals use different sets of the entire range of alkaloid-containing preys. Future research should evaluate individual diet variation in other poisonous anurans taxa given that shifts in diet composition might have important implications for understanding the consequences of alternate foraging strategies in the evolution of defensive strategies among species.

scholarly journals Trophic ecology and foraging behavior of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata, Tropiduridae) in a caatinga area of northeastern Brazil

2011 ◽  
Vol 101 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Leonardo B. Ribeiro ◽  
Eliza M. X. Freire
Keyword(s):  
Foraging Behavior ◽  
Diet Composition ◽  
Trophic Ecology ◽  
Dry Season ◽  
Northeastern Brazil ◽  
Wet Season ◽  
Lizard Species ◽  
Important Prey ◽  
Lepidopteran Larvae ◽  
Prey Items

This study aimed to analyze the seasonal variation in diet composition and foraging behavior of Tropidurus hispidus (Spix, 1825) and T. semitaeniatus (Spix, 1825), as well as measurement of the foraging intensity (number of moves, time spent stationary, distance traveled and number of attacks on prey items) in a caatinga patch on the state of Rio Grande do Norte, Brazil. Hymenoptera/Formicidae and Isoptera predominated in the diet of both species during the dry season. Opportunistic predation on lepidopteran larvae, coleopteran larvae and adults, and orthopteran nymphs and adults occurred in the wet season; however, hymenopterans/Formicidae were the most important prey items. The number of food items was similar between lizard species in both seasons; however the overlap for number of prey was smaller in the wet season. Preys ingested by T. hispidus during the wet season were also larger than those consumed by T. semitaeniatus. Seasonal comparisons of foraging intensity between the two species differed, mainly in the wet season, when T. hispidus exhibited less movement and fewer attacks on prey, and more time spent stationary if compared to T. semitaeniatus. Although both lizards are sit-and-wait foragers, T. semitaeniatus is more active than T. hispidus. The diet and foraging behavior of T. hispidus and T. semitaeniatus overlap under limiting conditions during the dry season, and are segregative factors that may contribute to the coexistence of these species in the wet season.

scholarly journals Diet composition of the Pharaoh Eagle Owl, Bubo ascalaphus (Strigiformes, Strigidae) in a Steppe region of Algeria

2021 ◽  
Vol 29 (2) ◽  
pp. 177-182
Author(s):  
Naceur Benamor ◽  
Toufik Guetouache ◽  
Farid Bounaceur
Keyword(s):  
Diet Composition ◽  
Bird Species ◽  
Total Biomass ◽  
Food Items ◽  
Important Prey ◽  
Steppe Region ◽  
Eagle Owl ◽  
Western Algeria ◽  
North Western ◽  
Prey Items

Abstract The diet composition of Pharaoh Eagle Owl (Bubo ascalaphus) was investigated in a semiarid area of North-western Algeria. A total of 65 pellets regurgitated by the B. ascalaphus were analysed, 288 food items were composed primarily of mammal remains (4 rodents, 1 bat and insectivore, 93.7%), and 1 bird species (passerine, 6.3%). The most frequent prey among the mammals were rodents (83.3%), which included Mus musculus (59.7%), Meriones shawi (11.1%), Meriones libycus (11.1%) and Jaculus jaculus (1.4%). The rodents were the most important prey items in biomass (91.4%), M. shawi made up to 41.9% of the total biomass. We may conclude that the Pharaoh Eagle Owl relies, in its feeding, very broadly on small mammals, completed by other groups.

scholarly journals Feeding habits of oriental sole (Brachirus orientalis) on the Bushehr coast of the Persian Gulf

2020 ◽  
Vol 28 (3) ◽  
pp. 175-185
Author(s):  
Dima Alghada ◽  
Yazdan Keivany ◽  
Fatemeh Paykan-Heyrati
Keyword(s):  
Coastal Waters ◽  
Persian Gulf ◽  
Diet Composition ◽  
Prey Species ◽  
Feeding Habits ◽  
Male And Female ◽  
Important Prey ◽  
Males And Females ◽  
The Persian Gulf ◽  
Prey Items

AbstractThe feeding habits of oriental sole, Brachirus orientalis (Bloch & Schneider) were investigated using 300 male and female specimens collected from coastal waters of Bushehr Province (Persian Gulf) between June 2015 and July 2016. The total length of females and males ranged from 16.2 to 38.5 cm and 14.1 to 29.1 cm, respectively. Of the total number of stomachs examined, 225 were empty (vacuity index = 77%). This index varied significantly over the year (P < 0.05), with maximum values in April and September and minimum in October and May. The B. orientalis diet was composed of nine prey species belonging to five classes. The most important prey items were Crustacea and Mollusca (Bivalvia and Gastropoda). Diet composition showed little seasonal variation, and Crustacea, Bivalvia, and Gastropoda were the most important prey items in all seasons. Sex did not appear to have any significant effects on dietary composition, and the main prey items were consumed by both males and females (P > 0.05).

scholarly journals Foraging niche partitioning in sympatric seabird populations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christina Petalas ◽  
Thomas Lazarus ◽  
Raphael A. Lavoie ◽  
Kyle H. Elliott ◽  
Mélanie F. Guigueno
Keyword(s):  
Interspecific Competition ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Sympatric Species ◽  
Foraging Strategies ◽  
Gps Tracking ◽  
Seabird Species ◽  
Foraging Range ◽  
Common Murre ◽  
Prey Items

AbstractSympatric species must sufficiently differentiate aspects of their ecological niche to alleviate complete interspecific competition and stably coexist within the same area. Seabirds provide a unique opportunity to understand patterns of niche segregation among coexisting species because they form large multi-species colonies of breeding aggregations with seemingly overlapping diets and foraging areas. Recent biologging tools have revealed that colonial seabirds can differentiate components of their foraging strategies. Specifically, small, diving birds with high wing-loading may have small foraging radii compared with larger or non-diving birds. In the Gulf of St-Lawrence in Canada, we investigated whether and how niche differentiation occurs in four incubating seabird species breeding sympatrically using GPS-tracking and direct field observations of prey items carried by adults to chicks: the Atlantic puffin (Fratercula arctica), razorbill (Alca torda), common murre (Uria aalge), and black-legged kittiwake (Rissa tridactyla). Although there was overlap at foraging hotspots, all species differentiated in either diet (prey species, size and number) or foraging range. Whereas puffins and razorbills consumed multiple smaller prey items that were readily available closer to the colony, murres selected larger more diverse prey that were accessible due to their deeper diving capability. Kittiwakes compensated for their surface foraging by having a large foraging range, including foraging largely at a specific distant hotspot. These foraging habitat specialisations may alleviate high interspecific competition allowing for their coexistence, providing insight on multispecies colonial living.

scholarly journals Feeding Ecology of Short-Toed Snake-Eagle (Circaetus gallicus [Gmelin, 1788]) in the Montados of Iberian Peninsula

2020 ◽  
Vol 28 (2) ◽  
pp. 155-179
Author(s):  
Nuno Onofre ◽  
Luís Sampaio
Keyword(s):  
Relative Abundance ◽  
Diet Composition ◽  
Prey Species ◽  
Prey Selection ◽  
Prey Type ◽  
Generalist Predator ◽  
Important Prey ◽  
Psammodromus Algirus ◽  
Circaetus Gallicus ◽  
Water Snakes

The diet of Short-toed Snake-eagle (Circaetus gallicus) during the breeding season in an area dominated by cork and holm oak parkland forests (Montados) was analyzed in this study. As expected, results showed that snakes are the dominant prey in the diet of this eagle, comprising up to 92.5% of the identified items, if potential secondary prey species were excluded. The Montpellier Snake (Malpolon monspessulanus) was the most consumed one (42.2%), followed by the Ladder Snake (Zamenis scalaris) (28.0%), and the water snakes (Natrix spp.) (14.2%). According to the same criteria, lizards (mainly Psammodromus algirus) and mammals represent between 4.8 and 2.2%, respectively. Other animals such as pond turtle and amphibians are irregular prey (<1%), and no bird remains were found at all. Short-toed Snake-eagle is usually referred as a stenophagic predator where snakes are by far its most important prey type, and where within this taxonomic group it behaves as a generalist predator. In this study this premise was then tested comparing the relative abundance of the snake species with their proportion in the diet composition of the eagle in order to know whether or not prey selection exists with regard to the species of snakes in this region. Results point to a quite plausible "preference" for the Ladder Snake and an "avoidance" for the smooth snakes group (Macroprotodon brevis/Coronella girondica), and possibly for the Horseshoe Whip (Hemorrhois hippocrepis). The avoidance to the Horseshoe Whip must be indirect and habitat related, while in relation to the two smooth snakes it may be due in large extend to its small size, in particular.

Foraging modes of carnivorous plants

2019 ◽  
Vol 66 (1-2) ◽  
pp. 101-112 ◽  
Author(s):  
Aaron M. Ellison
Keyword(s):  
Prey Availability ◽  
Soil Nutrient ◽  
Optimal Foraging Theory ◽  
Foraging Theory ◽  
Carnivorous Plants ◽  
Foraging Strategies ◽  
Nutrient Concentrations ◽  
Future Research ◽  
Single Location ◽  
Foraging Modes

Abstract Carnivorous plants are pure sit-and-wait predators: they remain rooted to a single location and depend on the abundance and movement of their prey to obtain nutrients required for growth and reproduction. Yet carnivorous plants exhibit phenotypically plastic responses to prey availability that parallel those of non-carnivorous plants to changes in light levels or soil-nutrient concentrations. The latter have been considered to be foraging behaviors, but the former have not. Here, I review aspects of foraging theory that can be profitably applied to carnivorous plants considered as sit-and-wait predators. A discussion of different strategies by which carnivorous plants attract, capture, kill, and digest prey, and subsequently acquire nutrients from them suggests that optimal foraging theory can be applied to carnivorous plants as easily as it has been applied to animals. Carnivorous plants can vary their production, placement, and types of traps; switch between capturing nutrients from leaf-derived traps and roots; temporarily activate traps in response to external cues; or cease trap production altogether. Future research on foraging strategies by carnivorous plants will yield new insights into the physiology and ecology of what Darwin called “the most wonderful plants in the world”. At the same time, inclusion of carnivorous plants into models of animal foraging behavior could lead to the development of a more general and taxonomically inclusive foraging theory.

Trophic ecology of large pelagic fish in the Saint Peter and Saint Paul Archipelago, Brazil

2019 ◽  
Vol 70 (10) ◽  
pp. 1402 ◽  
Author(s):  
F. V. Albuquerque ◽  
A. F. Navia ◽  
T. Vaske ◽  
O. Crespo ◽  
F. H. V. Hazin
Keyword(s):  
Trophic Ecology ◽  
Feeding Habits ◽  
Saint Paul ◽  
Pelagic Fish ◽  
Trophic Niche ◽  
Trophic Relationships ◽  
Main Prey ◽  
Important Prey ◽  
Saint Peter ◽  
Prey Items

Trophic relationships of large pelagic predators can determine the structure and dynamics of oceanic food webs. The feeding habits and trophic ecology of five large pelagic fish (Acanthocybium solandri, Coryphaena hippurus, Elagatis bipinnulata, Thunnus albacares and Thunnus atlanticus) in the Saint Peter and Saint Paul Archipelago were evaluated to determine whether there is a trophic-niche overlap or resource partitioning among them. Eighty prey items found in 1528 stomachs were identified and grouped into Cephalopoda, Cnidaria, Crustacea, Gastropoda, Teleostei and Tunicata. Exocoetidae and Scombridae were the main prey in the diet of Acanthocybium solandri. In C. hippurus, Cheilopogon cyanopterus and Exocoetus volitans were the most important prey items, whereas C. cyanopterus was the main prey for T. albacares. Thunnus atlanticus consumed a great proportion of invertebrate species, with shrimps of Sergestidae family being particularly important. The gastropod Cavolinia sp. was the most important prey for E. bipinnulata. The five species had a high trophic specialisation and a high trophic level (&gt;4.4), whereas most dietary overlaps were consistently low. The most important factor for diet dissimilarity was the consumption of Exocoetidade. All species were classified as top predators with varied diets, indicating their structural and functional importance in the food web of the Archipelago.

Feeding habits of the sandskate Psammobatis extenta (Garman, 1913): sources of variation in dietary composition

2005 ◽  
Vol 56 (4) ◽  
pp. 395 ◽  
Author(s):  
J. Matías Braccini ◽  
Jorge E. Perez
Keyword(s):  
Feeding Habits ◽  
Seasonal Pattern ◽  
Seasonal Patterns ◽  
Dietary Composition ◽  
Important Prey ◽  
Eastern Brazil ◽  
Prey Diversity ◽  
Sources Of Variation ◽  
Males And Females ◽  
Prey Items

Understanding the variation in the diet of skates is crucial for determining their roles in marine ecosystems. The diet of 458 sandskates, Psammobatis extenta, from Puerto Quequén, Argentina was quantified to determine whether there was geographical, sexual, ontogenetic, and/or seasonal variation in dietary composition. Cumulative prey-diversity curves reached a stable level at ~30 stomachs and thus the sample size was large enough to describe the overall diet of the sandskate. The diet comprised a variety of small invertebrates, suggesting that the sandskate is a secondary consumer (trophic level of 3.5). The most important prey items were gammarids, shrimps and, to a lesser extent, polychaete worms. A significant correlation was found between the diets of sandskates from south-eastern Brazil and Puerto Quequén, suggesting that in both locations they used similar resources and would have similar ecological roles. No difference was found between the diets of males and females, but ontogenetic and seasonal patterns were detected. Small sandskates preyed largely on gammarids and shrimps but consumed fewer polychaetes and brachyurans than larger individuals. In summer and winter, the most important prey item by number was gammarids, whereas the consumption of shrimps peaked in autumn. This ontogenetic and seasonal pattern indicates that large and small sandskates are versatile predators that can shift their diets in response to prey abundance.

scholarly journals Diets of herring, mackerel, and blue whiting in the Norwegian Sea in relation to Calanus finmarchicus distribution and temperature conditions

2006 ◽  
Vol 63 (1) ◽  
pp. 117-127 ◽  
Author(s):  
Irina Prokopchuk ◽  
Evgeniy Sentyabov
Keyword(s):  
Stomach Content ◽  
Diet Composition ◽  
Pelagic Fish ◽  
Calanus Finmarchicus ◽  
Norwegian Sea ◽  
Main Prey ◽  
Blue Whiting ◽  
Important Prey ◽  
Hydrographic Conditions ◽  
Feeding Area

Abstract Diets of Norwegian spring-spawning herring, mackerel, and blue whiting in the Norwegian Sea are investigated in relation to the distribution of plankton and hydrographic conditions. Fish stomachs and zooplankton samples were collected during summer (June and July) cruises in 2001 and 2002. Calanus finmarchicus was the principal prey of mackerel, accounting for 53–98% of total stomach content by weight. The diet composition of herring varied depending on feeding area and availability of food under various environmental conditions. C. finmarchicus was important prey for herring only in July 2001 (about 77% by weight) in the central part of the sea and in June 2002 (about 82% by weight) near the Lofotens. In July 2002 appendicularians (Oikopleura spp.), amphipods (mainly Parathemisto abissorum), and euphausiids were important in the diet of herring, and at some stations cannibalism was observed. The main prey of blue whiting were amphipods (10–34% by weight), appendicularians (11–34%), and euphausiids (8–47%), as they usually feed deep in the water column, though C. finmarchicus was important, particularly in June 2002, when blue whiting were caught in the upper layers of the sea. Higher water temperatures indirectly affect pelagic fish through accelerated development of their prey and favourable conditions for migration farther north.

scholarly journals Broad geographic, taxonomic and ecological patterns of interpopulation variation in the dietary habits of snakes

Web Ecology ◽  
2006 ◽  
Vol 6 (1) ◽  
pp. 2-16 ◽  
Author(s):  
L. Luiselli
Keyword(s):  
Dietary Patterns ◽  
Diet Composition ◽  
Dietary Habits ◽  
Similarity Index ◽  
Climatic Region ◽  
Snake Species ◽  
Close Affinity ◽  
Interaction Terms ◽  
Diet Variation ◽  
Hunting Strategy

Abstract. Because of their unique morphological and ecological characteristics (i.e. being obligate carnivorous, solitary, and ingesting their prey whole), snakes are expected to show unusual dietary patterns compared to other ectothermic vertebrates, and the best way to explore this is to analyse the snake dietary patterns globally. Here I review and analyse the peer-reviewed snake diet literature available in order to explore whether there are broad patterns in the interpopulation variability of diet composition in these unique ectothermic predators. I collated data for 181 independent populations belonging to 58 species of snakes from some of the main families (1 Boidae, 2 Pythonidae, 27 Colubridae, 10 Elapidae, and 18 Viperidae) and from all the continents (4 from South and Central America, 13 from North America, 12 from Europe, 18 from Africa, 4 from Asia, and 7 from Australia). All these populations satisfied some precise criteria of inclusion, and were therefore re-analysed in a comparative perspective. I classified each literature entry according to 1) snake species, 2) snake family, 3) geographic position (continent) of the study areas, 4) climatic region (temperate versus tropical), 5) guild (if the species is aquatic, terrestrial, or arboreal), 6) hunting strategy (sit-and-wait versus active forager), and 7) venom (if the species is venomous or not). All these seven factors were analysed by GLM procedures to evaluate their effects on the interpopulation diet variation within snake species, that was assessed by using a univariate similarity index. The various taxonomical categories of snake prey were grouped according to two different levels of taxonomic affinity: a) general affinity, e.g. frogs and toads, salamanders, lizards, birds, etc., and b) close affinity, by grouping prey types belonging to a same genus. My study revealed that, within-species snake populations showed a very low variability in terms of diet composition. As for the general affinity criterion, there was no single factor that produced a significant effect on the interpopulation diet variation but, with regard to the interaction terms between factors, significant effects were determined by 1) continent × climatic region (with Asian, African and South-American tropical populations having significantly lesser similarity values), 2) continent × hunting strategy (diets being less diverse in ambush predators in Africa, Asia and South America), and 3) climatic region × guild (with arboreal tropical snakes showing less interpopulation similarity). As for the close affinity criterion, there was also no effect of single factors on interpopulation diet variability, but the interaction term hunting strategy × venom was significant, with sit-and-wait venomous species being less variable in their diet composition. Snake family was completely un-influent in determining any effect on snake interpopulation diet variation. The broad reasons that may explain these generalized patterns are discussed.

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