scholarly journals Gluttonous predators: how to estimate prey size when there are too many prey

2008 ◽  
Vol 68 (2) ◽  
pp. 315-320 ◽  
Author(s):  
MS. Araújo ◽  
A. Pinheiro ◽  
SF. Reis
Keyword(s):  
Prey Size ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Sampling Effort ◽  
High Intake ◽  
Precision Error ◽  
Bootstrap Procedure ◽  
Future Studies ◽  
Large Numbers ◽  
Prey Items

Prey size is an important factor in food consumption. In studies of feeding ecology, prey items are usually measured individually using calipers or ocular micrometers. Among amphibians and reptiles, there are species that feed on large numbers of small prey items (e.g. ants, termites). This high intake makes it difficult to estimate prey size consumed by these animals. We addressed this problem by developing and evaluating a procedure for subsampling the stomach contents of such predators in order to estimate prey size. Specifically, we developed a protocol based on a bootstrap procedure to obtain a subsample with a precision error of at the most 5%, with a confidence level of at least 95%. This guideline should reduce the sampling effort and facilitate future studies on the feeding habits of amphibians and reptiles, and also provide a means of obtaining precise estimates of prey size.

Feeding habits of the velvet belly lanternshark Etmopterus spinax (Chondrichthyes: Etmopteridae) off the Algarve, southern Portugal

2006 ◽  
Vol 86 (4) ◽  
pp. 835-841 ◽  
Author(s):  
João Neiva ◽  
Rui Coelho ◽  
Karim Erzini
Keyword(s):  
Deep Water ◽  
Foraging Behaviour ◽  
Prey Size ◽  
Feeding Habits ◽  
Feeding Strategy ◽  
Stomach Contents ◽  
Prey Composition ◽  
Southern Portugal ◽  
Meganyctiphanes Norvegica ◽  
Diet Shifts

Etmopterus spinax is one of the most abundant predators of the upper continental slope off the Algarve (southern Portugal), where it is captured in large quantities in deep-water fisheries. The feeding habits of E. spinax off the Algarve were investigated through the analysis of stomach contents of 376 individuals. Prey composition was described and maturity, sex and size related variations in the diet analysed. The overall diet of E. spinax suggested a fairly generalized benthopelagic foraging behaviour primarily tuned to pelagic macroplankton/microneckton, teleost fish and cephalopods. Sex and maturity related differences in the diet were not significant. Two main ontogenic diet shifts were observed at about 17 and 28 cm total length. Small and medium sized immature sharks had a diet dominated by eurybathic crustaceans, chiefly Meganyctiphanes norvegica and Pasiphaea sivado. Larger individuals consumed more teleosts and cephalopods, in part associated with scavenging as a new feeding strategy. With increasing shark size the diet diversified both in terms of resources exploited and prey size.

scholarly journals Food Habits of the Endemic Long Legged Wood Frog, Rana Pseudodalmatina (Amphibia, Ranidae), in Northern Iran

2016 ◽  
Vol 50 (4) ◽  
pp. 363-368
Author(s):  
M. Najibzadeh ◽  
A. Gharzi ◽  
N. Rastegar-Pouyani ◽  
E. Rastegar-Pouyani ◽  
A. Pesarakloo
Keyword(s):  
Stomach Content ◽  
Food Habits ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Food Habit ◽  
Wood Frog ◽  
Hyrcanian Forest ◽  
Northern Iran ◽  
Frog Species ◽  
Prey Items

Abstract Iranian long legged wood frog, Rana pseudodalmatina Eiselt & Schmidtler, 1971 is a brown frog species endemic to the Hyrcanian forest. The objective of the present study is to collect detailed information on the feeding habits of 44 specimens of this species (24 ♂, 20 ♀) by analyzing the stomach contents of individuals from 10 populations inhabiting range. The food habit of R. pseudodalmatina generally varies by the availability of surrounding prey items, and it is a foraging predator, the food of which consists largely of Coleoptera (mainly Carabidae, Dytiscidae and Haliplidae), Diptera (Muscidae) and Hymenoptera (Formicidae), and no difference was found between females and males in the stomach content.

scholarly journals What does a Pacman eat? Macrophagy and necrophagy in a generalist predator (Ceratophrys stolzmanni)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6406 ◽  
Author(s):  
Diana Székely ◽  
Fernando P. Gaona ◽  
Paul Székely ◽  
Dan Cogălniceanu
Keyword(s):  
Content Analysis ◽  
Gastrointestinal Tract ◽  
Prey Size ◽  
Feeding Habits ◽  
Natural Habitat ◽  
Generalist Predator ◽  
Direct Observations ◽  
The Pacific ◽  
First Time ◽  
Prey Items

We describe for the first time the feeding ecology of the Pacific horned frog (Ceratophrys stolzmanni), as inferred through gastrointestinal tract content analysis and behavioural observations in its natural habitat. Ingested prey in adults ranged from mites and various insects to frogs and snakes. Prey items predominantly consisted of gastropods, non-formicid hymenopterans, and centipedes. We found no relationship between the size of the predator and the prey ingested, in terms of prey size, volume or number of items ingested. Additional direct observations indicate that all post-metamorphic stages are voracious, preying on vertebrates and engaging in anurophagy, cannibalism, and even necrophagy. Our study sheds light on the feeding habits of one of the least known species of horned frog.

scholarly journals Feeding habits of the american crocodile, crocodylus acutus (cuvier, 1807) (reptilia: crocodylidae) in the Southern Coast of Quintana Roo, México

2008 ◽  
Vol 24 (3) ◽  
Author(s):  
Alejandro Villegas ◽  
Juan Jacobo Schmitter-Soto
Keyword(s):  
Body Size ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Quintana Roo ◽  
Southern Coast ◽  
Crocodylus Acutus ◽  
American Crocodile ◽  
Volume Method ◽  
Prey Items

Between January and September 2006, 21 crocodiles (Crocodylus acutus) were captured and six were recaptured in four lagoons located in the southern coast of Quintana Roo. Stomach contents were obtained in order to identify prey items, which were analyzed by the frequency and volume method. In decreasing order of importance, prey items were fish, crustaceans, birds, mammals and insects. Diet of crocodiles changed considerably according to their body size. Adult crocodiles added larger preys (birds and mammals) to their diet; fish and crustaceans were present in the diet at all sizes, thus showing theimportance of these prey in the diet of American crocodiles.

scholarly journals Diet and feeding habits of Saurida tumbil (Bloch, 1795) from northern Kerala, South-west coast of India

2016 ◽  
Vol 63 (4) ◽  
Author(s):  
P. P. Manojkumar ◽  
P. P. Pavithran
Keyword(s):  
West Coast ◽  
Prey Size ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Relative Importance ◽  
West Coast Of India ◽  
South West ◽  
South West Coast ◽  
Index Of Relative Importance ◽  
Maximum Similarity

Composition of the diet of greater lizardfish Saurida tumbil (Bloch, 1795), caught from northern Kerala, south-west coast of India was studied and described. The stomachs of 1981 specimens were collected between January, 2012 and June, 2014. Analysis of stomach contents based on index of relative importance (IRI) revealed that this species is exclusively piscivorous. Contrary to other benthic predators of the study area, it mainly feeds on pelagic and demersal fishes(IRI = 63.2), molluscs (IRI = 17.86), crustaceans (IRI = 18.33) and other miscellaneous items (IRI = 2.54). The diet of S. tumbil were found to be related to the seasonal availability of resources, occurrence of juveniles of certain species and on the migration of fishes from nearby places to the study area. Significant changes in prey items were observed between predator length groups, but a positive, significant relationship was recorded between prey size and predator size (p<0.05). Statistical analysis indicated a uniform representation of different diets in the stomach. Maximum similarity in diet between different food items was found in April and November.

scholarly journals Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae), off Uruguay and northern Argentina

2016 ◽  
Vol 14 (3) ◽  
Author(s):  
Santiago A. Barbini ◽  
Luis O. Lucifora
Keyword(s):  
Body Size ◽  
Diet Composition ◽  
Prey Size ◽  
Prey Availability ◽  
Feeding Habits ◽  
Warm Season ◽  
Cold Season ◽  
The North ◽  
Multiple Hypothesis ◽  
Modelling Approach

ABSTRACT The eyespot skate, Atlantoraja cyclophora, is an endemic species from the southwestern Atlantic, occurring from Rio de Janeiro, Brazil, to northern Patagonia, Argentina. The feeding habits of this species, from off Uruguay and north Argentina, were evaluated using a multiple hypothesis modelling approach. In general, the diet was composed mainly of decapod crustaceans, followed by teleost fishes. Molluscs, mysidaceans, amphipods, isopods, lancelets and elasmobranchs were consumed in lower proportion. The consumption of shrimps drecreased with increasing body size of A. cyclophora. On the other hand, the consumption of teleosts increased with body size. Mature individuals preyed more heavily on crabs than immature individuals. Teleosts were consumed more in the south region (34º - 38ºS) and crabs in the north region (38º - 41ºS). Shrimps were eaten more in the warm season than in the cold season. Prey size increased with increasing body size of A. cyclophora , but large individuals also consumed small teleosts and crabs. Atlantoraja cyclophora has demersal-benthic feeding habits, shifts its diet with increasing body size and in response to seasonal and regional changes in prey availability and distribution.

Stomach contents of the marine tucuxi dolphin (Sotalia guianensis) from Rio de Janeiro, south-eastern Brazil

2007 ◽  
Vol 87 (1) ◽  
pp. 253-254 ◽  
Author(s):  
Ana Paula Madeira Di Beneditto ◽  
Salvatore Siciliano
Keyword(s):  
Rio De Janeiro ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Additional Information ◽  
Sotalia Guianensis ◽  
South Eastern ◽  
Eastern Brazil ◽  
Trichiurus Lepturus ◽  
Cynoscion Guatucupa ◽  
Janeiro State

Along the central coast of Rio de Janeiro State (22°25′S–23°00′S), south-eastern Brazil, the marine tucuxi dolphin (Sotalia guianensis) feeds on neritic prey that are distributed through the water column and are abundant all year round. The most frequently found species were the teleost fish Trichiurus lepturus, Cynoscion guatucupa, Isopisthus parvipinnis and Porichthys porossisimus. Fish species were more important than cephalopod species in the diet of the marine tucuxi. Back calculations of prey sizes indicated that they feed mainly on young specimens. The present study provided additional information on the feeding habits of the marine tucuxi dolphin.

scholarly journals FEEDING HABITS AND HELMINTH PARASITES OF SARDINE (S. PILCHARDUS) AND ANCHOVY (E. ENCRASICOLUS) IN THE ADRIATIC SEA

2015 ◽  
Vol 17 (1) ◽  
pp. 216 ◽  
Author(s):  
B. ZORICA ◽  
V. ČIKES KEČ ◽  
O. VIDJAK ◽  
I. MLADINEO ◽  
D. EZGETA BALIČ
Keyword(s):  
Diet Composition ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Stomach Content Analysis ◽  
Helminth Parasites ◽  
Significant Difference ◽  
Prey Composition ◽  
One Year ◽  
Paratenic Hosts ◽  
Hysterothylacium Aduncum

We examined the stomach contents of two of the most economically and ecologically important small pelagic fish species, the sardine, Sardina pilchardus and the anchovy, Engraulis encrasicolus, obtained monthly from commercial purse-seine catches operating on Croatian fishing grounds during a one-year period (January–December, 2011). Both species generally showed a similar diet, with copepod and decapod larvae as dominant prey groups. The composition of anchovy and sardine stomach contents was not size- or sex-related, but throughout the year, a significant difference in diet composition was observed for each species as well as between species. Two gastrointerstinal helminths; the digenean Parahemiurus merus and nematode Hysterothylacium aduncum, were recorded during the stomach content analysis. Differences in population dynamics between the two parasites are congruent with differences in the prey composition of sardine and anchovy, reflecting fine-tuned interactions in the trophic web between parasites and intermediate or paratenic hosts included in the sardine and anchovy diet.

scholarly journals Trophic habits of the invasive crab Libinia dubia H. Milne Edwards, 1834 from the Gulf of Gabès (Tunisia)

2020 ◽  
Author(s):  
AMANI CHAFFAI ◽  
WAFA RJIBA-BAHRI ◽  
ASMA ABIDI ◽  
FRANҪOISE DENIS ◽  
JAMILA BEN SOUISSI
Keyword(s):  
Feeding Habits ◽  
Carapace Width ◽  
Stomach Contents ◽  
Spider Crab ◽  
Gulf Of Gabes ◽  
Chi Square ◽  
Gulf Of Gabès ◽  
Chi Square Test ◽  
Herbivorous Species ◽  
Stomach Weight

Feeding habits of the invasive spider crab Libinia dubia from the Mediterranean Sea were studied in the Gulf of Gabès (Tunisia) using the frequency of occurrence and points methods. The population was sampled at least monthly between November 2015 and October 2016. Stomach contents of 384 specimens were analysed. Results indicate that L. dubia is an herbivorous species exhibiting clear preferences for algae (ALG) and Magnoliophyta (MAG) (62.03%, 7.13 points and 59.36%, 5.3 points respectively) although Echinodermata (ECH), Porifera (POR), Cnidaria (CNI), Mollusca (MOL), Polychaeta (POL), Crustacea (CRU) and fish (FIS) were accidentally consumed along with Bryozoa (BRY), sediment (SED), and unidentifiable materials (UNM). The diversity of ALG ingested was studied in detail: Chlorophyceae were found in 87.93% of stomachs containing ALG and contributed most of points to the stomach contents (4.18 points) followed respectively by Phaeophyceae (81.03%, 2.27 points) and Rhodophyceae (40.95%, 0.68 points).Very low Vacuity Index was recorded (VI = 2.6%). Ingested items varied significantly with regard to the season (Chi-square test, χ2calculated = 87.86 > χ2theoretical = 7.81, df = 3, p < 0.05) and crab size (χ2calculated = 14.25 > χ2theoretical = 5.99, df = 2, p = 0.026). Insignificant differences were registered by studying Carapace Width-Stomach Weight (CW-SW) relationships (T-test, tcalculated < ttheoretical, p > 0.05). Kruskal-Wallis test was applied so that the composition of crab diet among groups could be compared (H = 1.1, df = 3, p = 0.77). 

scholarly journals Cormorant pellets as a tool for the knowledge of parasite-intermediate host associations and nematode diversity in the environment

2019 ◽  
Vol 56 (4) ◽  
pp. 296-302 ◽  
Author(s):  
L. Garbin ◽  
J. I. Diaz ◽  
A. Morgenthaler ◽  
A. Millones ◽  
L. Kuba ◽  
...  
Keyword(s):  
Prey Item ◽  
Feeding Habits ◽  
Paratenic Host ◽  
Intermediate Hosts ◽  
Good Tool ◽  
Larval Stages ◽  
Nematode Diversity ◽  
Bird Colonies ◽  
Prey Items ◽  
Host Associations

SummaryAnisakids are usually acquired through the diet. Cormorant pellets are useful to detect both parasite larval stages, and prey items which could act as intermediate hosts in the environment. The current study provides information about the feeding habits of both birds and mammals, and the diversity of parasites circulating in the environment. The objective of the study was to identify Anisakidae larvae and prey items in pellets from the Imperial shag Phalacrocorax atriceps and the Red-legged cormorant P. gaimardi, suggesting possible parasite–prey associations. A total of 92 P. atriceps’ and 82 P. gaimardi’s pellets were collected from both Punta León, and Isla Elena bird colonies, respectively, during the period from 2006 to 2010. Pellets were preserved in ethanol and hard prey item remnants, and nematode larvae were studied using standard techniques. Prey item occurrence, nematode prevalence, and mean intensity were calculated. A correspondence analysis was performed to evaluate the larvae-prey association. Contracaecum spp., Pseudoterranova spp,, Anisakis spp., Terranova spp., and Hysterothylacium spp. third-stage larvae (L3) were identifi ed in pellets. Pseudoterranova spp. and Anisakis spp. L3 predominated in the environment of Punta León, whereas Contracaecum spp. and Hysterothylacium spp. L3 predominated in the Puerto Deseado area. The highest larvae-prey association was that of Contracaecum spp. L3 with Engraulis anchoita, followed by with Odontestes sp. in P. atriceps’ pellets. Contracaecum spp. L3 were significantly related to both sprats, Sprattus fueguensis and Ramnogaster arcuatta, in P. gaimardi’s pellets. It was verifi ed that E. anchovy is the main gateway of Contracaecum spp. L3 in P. atriceps. Odonthestes sp. might act as an intermediate/paratenic host of Contracaecum spp. L3 in the area. Both sprats might play a role as intermediate/paratenic hosts of C. australe, being the main gateway into P. gaimardi in the area. Thus, pellet analysis can be postulated as a good tool for indicating parasite-host associations between anisakids, and the prey items which act as intermediate hosts.

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