scholarly journals Diet of Dinocras cephalotes and Perla marginata (Plecoptera: Perlidae) in an Apennine stream (northwestern Italy)

2007 ◽  
Vol 139 (3) ◽  
pp. 358-364 ◽  
Author(s):  
Tiziano Bo ◽  
Stefano Fenoglio ◽  
Giorgio Malacarne
Keyword(s):  
Trophic Structure ◽  
Prey Selection ◽  
Feeding Habits ◽  
Gut Contents ◽  
Freshwater Invertebrates ◽  
Trophic Preferences ◽  
Prey Items

AbstractThe feeding habits of nymphs of Perla marginata (Panzer) and Dinocras cephalotes (Curtis) were investigated in the Rio Orbarina (northwestern Italy). These species are among the largest European carnivorous freshwater invertebrates and they play an important role in the trophic structure of small, fishless Apennine streams. We examined the gut contents of 60 P. marginata and 60 D. cephalotes nymphs to characterize the diets and evaluate possible feeding differences between the species. In both of these predaceous stoneflies, the diet included vegetable detritus, mainly in the smaller instars. Both species showed trophic preferences, since only a few taxa constituted most of the ingested prey items, independently of their availability in the substratum. Interestingly, there were no clear differences in prey selection between nymphs of the two species.

Diet, prey selection and cannibalism in the hunter opisthobranch Roboastra europaea

2003 ◽  
Vol 83 (3) ◽  
pp. 489-495 ◽  
Author(s):  
César Megina ◽  
Juan Lucas Cervera
Keyword(s):  
Prey Selection ◽  
Mating Behaviour ◽  
Gut Contents ◽  
Potential Prey ◽  
Strait Of Gibraltar ◽  
Natural Diet ◽  
Predatory Behaviour ◽  
Specialist Predator ◽  
Cannibalistic Behaviour ◽  
Prey Items

The diet and predatory behaviour of the nudibranch Roboastra europaea (Mollusca) is described and compared with other nudibranch-hunting opisthobranchs. The natural diet in the Strait of Gibraltar was studied by the analysis of gut contents. Roboastra europaea is a specialist predator of nudibranchs, and the diet is comprised essentially of the polycerids Polycera sp., Polycerella emertoni, Limacia clavigera and conspecific R. europaea. One or several Polycera species appeared as the most dominant prey.  The complete assemblage of potential prey of this predator—the fundamental diet—was assessed in laboratory trials that included all likely prey groups. This predator consistently rejected both non-nudibranch species and non-polycerid nudibranchs. Roboastra europaea is exclusively a predator of polycerids and previously unencountered polycerids are also potential prey items.  As most of the hunter opisthobranchs, R. europaea exhibited cannibalistic behaviour, to the extent that aggressiveness prevailed over mating in intraspecific encounters. Roboastra europaea as prey showed a complex result in laboratory trials: (a) if one individual was small enough complete ingestion proceeded; (b) if there was not enough difference in size, a cannibal attack proceeded, but if ingestion was not possible, it could result in mating behaviour.

scholarly journals Preimaginal feeding habits of Dictyogenus fontium (Plecoptera, Perlodidae) in an alpine brook in NW Italy

2007 ◽  
Vol 18 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Stefano Fenoglio ◽  
Tiziano Bo ◽  
Giorgio Malacarne
Keyword(s):  
Feeding Habits ◽  
Gut Contents ◽  
Plant Detritus ◽  
Trophic Preferences ◽  
Nw Italy

The feeding habits of Dictyogenus fontium nymphs were investigated in the Rio Olen, an alpine brook in NW Italy. In an analysis of the gut contents of 84 nymphs, we detected evident trophic preferences: Chironomidae (Diptera) were the major component of the prey ingested, independently of their availability in the substratum. Plant detritus and algae were also an important part of the diet of this carnivorous stonefly. The findings are discussed on the basis of ecological considerations.

scholarly journals Rainy Season Food Availability for Anurans of Kimboza Forest Reserve, Tanzania

2021 ◽  
pp. 15-25
Author(s):  
Nsajigwa Emmanuel Mbije ◽  
Asha Kamungu
Keyword(s):  
Food Availability ◽  
Rainy Season ◽  
Diet Composition ◽  
Feeding Habits ◽  
Gut Contents ◽  
Generalist Predators ◽  
Forest Reserve ◽  
Significant Difference ◽  
To Come ◽  
Prey Items

Amphibians are mostly considered to be generalist predators. Some species have a narrow diet or even specialize on certain prey categories. An assessment of the feeding habits of anuran species of Kimboza forest reserve, Tanzania was conducted during rainy season between March 2017 and June 2017. Through a visual encounter survey, 93 species were captured and analyzed for gut contents. About 462 prey items were identified the most abundant component being Isoptera and Hymenoptera. There was no significant difference (P > 0.05) in the anurans’ diet (composition or diversity or preferences) among different habitats of the forest (along boundaries and within the forest) but significant difference (P < 0.05) was found between the upper Stratum and the lower Stratum of the forest. The study provides a preliminary estimation of the actual diet of anurans and establishes a general feeding pattern for these species for the management of the Kimboza forest reserve. The study recommends the intensification of similar assessments in the nearby forest areas to come up with a complete description of the feeding habits for management purposes.

scholarly journals The trophic structure of fish in seaweed farms, and adjacent seagrass and coral habitats in Zanzibar, Tanzania

2021 ◽  
Vol 19 (2) ◽  
pp. 17-27
Author(s):  
Batuli M. Yahya ◽  
Saleh A. Yahya ◽  
Aviti J. Mmochi ◽  
Narriman S. Jiddawi
Keyword(s):  
Coral Reefs ◽  
Trophic Structure ◽  
Relative Proportion ◽  
Predatory Fish ◽  
Gut Contents ◽  
Fish Diet ◽  
Diet Specialization ◽  
Floating Seaweed ◽  
Significant Difference ◽  
Prey Items

Coral reefs, seagrasses and seaweed farms (Eucheuma denticulatum) are characteristic habitats in many parts of the coast of Zanzibar, Tanzania. However, information on trophic interactions, movements of fish, and variation in fish diet specialization between these habitats are scarce. The present study determined the trophic structure and the variation in diet composition of fish caught in (floating) seaweed farms, and in adjacent seagrass and coral reef habitats in Pongwe, Zanzibar. Fish were caught using traditional basket traps (dema) and gut contents of 392 fish were analyzed. A one-way Analysis of Similarities (ANOSIM) showed that there was a significant difference in the composition of prey items eaten by invertivores in different habitats (Global R = 0.109, p = 0.002.). There was no significant difference in the composition of prey items eaten by herbivores, invertivore-piscivores and omnivores (p > 0.05), likely due to movement of fish between these habitats for foraging. There was no significant difference in the relative proportion of trophic groups between the habitats (p > 0.05) except for herbivores (p < 0.05). Floating seaweed farms attract invertebrates and smaller fish, thus providing feeding grounds for predatory fish, and should be considered as ecologically important habitats as are coral reefs and seagrass beds.

scholarly journals Diets and Trophic Structure of Fish Assemblages in a Large and Unexplored Subtropical River: The Uruguay River

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1374 ◽  
Author(s):  
Anahí López-Rodríguez ◽  
Ivana Silva ◽  
Sunshine de Ávila-Simas ◽  
Samanta Stebniki ◽  
Rodrigo Bastian ◽  
...  
Keyword(s):  
Trophic Structure ◽  
Environmental Changes ◽  
Fish Assemblages ◽  
Feeding Habits ◽  
Gut Contents ◽  
Ecological Knowledge ◽  
Freshwater Biodiversity ◽  
Flood Pulse Concept ◽  
Vast Number ◽  
Uruguay River

The Neotropics represent a hotspot for freshwater biodiversity with vast number of fish species of scarce ecological knowledge. This hold true for the Uruguay River, where fish assemblages and their diets remain unexplored. Fish assemblages were surveyed in 14 sites along its main course, from headwaters to mouth (approximately 1800 km), with the aim to identify the trophic roles of fish and to describe trophic structure of these assemblages. Following standardized samplings, diet was determined to perform a trophic classification of species. One hundred species (2309 gut contents) were analysed and classified into four trophic groups subdivided into eight lower-level groups: Piscivore, piscivore-invertivore, detritivore, omnivore-detritivore, omnivore-invertivore, omnivore-planktivore and omnivore-herbivore. The trophic structure of the assemblages varied along the river, with the relative species richness of fish consuming terrestrial invertebrates increasing towards the middle river section, probably driven by the large floodplains in that areas, supporting global theories such as flood pulse concept. This study describes the feeding habits of fish along the Uruguay River, being the first dietary description for 29 species. This knowledge is essential for management and conservation, serving as baseline in the context of future environmental changes and generates novel evidence about the functioning of ecosystems in this scarcely studied climatic region.

Active prey selection in developing larvae of Atlantic bluefin tuna (Thunnus thynnus) in spawning grounds of the Gulf of Mexico

2021 ◽  
Author(s):  
Akihiro Shiroza ◽  
Estrella Malca ◽  
John T Lamkin ◽  
Trika Gerard ◽  
Michael R Landry ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Prey Selection ◽  
Bluefin Tuna ◽  
Gut Contents ◽  
Physical Factors ◽  
Larval Rearing ◽  
Thunnus Thynnus ◽  
Small Copepod ◽  
Atlantic Bluefin Tuna ◽  
Larval Stages

Abstract Bluefin tuna spawn in restricted areas of subtropical oligotrophic seas. Here, we investigate the zooplankton prey and feeding selectivity of early larval stages of Atlantic bluefin tuna (ABT, Thunnus thynnus) in larval rearing habitat of the Gulf of Mexico. Larvae and zooplankton were collected during two multi-day Lagrangian experiments during peak spawning in May 2017 and 2018. Larvae were categorized by flexion stage and standard length. We identified, enumerated and sized zooplankton from larval gut contents and in the ambient community. Ciliates were quantitatively important (up to 9%) in carbon-based diets of early larvae. As larvae grew, diet composition and prey selection shifted from small copepod nauplii and calanoid copepodites to larger podonid cladocerans, which accounted for up to 70% of ingested carbon. Even when cladoceran abundances were &lt;0.2 m−3, they comprised 23% of postflexion stage diet. Feeding behaviors of larvae at different development stages were more specialized, and prey selection narrowed to appendicularians and primarily cladocerans when these taxa were more abundant. Our findings suggest that ABT larvae have the capacity to switch from passive selection, regulated by physical factors, to active selection of presumably energetically optimal prey.

Feeding ecology of Symbolophorus californiensis larvae (Teleostei: Myctophidae) in the southern transition region of the western North Pacific

2009 ◽  
Vol 90 (6) ◽  
pp. 1249-1256 ◽  
Author(s):  
Chiyuki Sassa
Keyword(s):  
Transition Region ◽  
North Pacific ◽  
Western North Pacific ◽  
Developmental Stages ◽  
Feeding Habits ◽  
Larval Growth ◽  
Trophic Niche ◽  
Size Class ◽  
Gut Contents ◽  
Wide Range

The feeding habits of myctophid larvae of Symbolophorus californiensis were examined in the southern transition region of the western North Pacific where the main spawning and nursery grounds of S. californiensis are formed. This species is a key component of the pelagic ecosystems of this region, and their larvae attain one of the largest sizes among myctophids. To analyse gut contents larvae, including most life history stages after yolk-sac absorption (3.7 to 22.2 mm body length (BL)), were collected in the upper 100 m layer in 1997 and 1998. Feeding incidence was higher during the day than at night (53.1–92.3% versus 0–5.6%), and daytime feeding incidence increased gradually with larval growth. Larvae fed mainly on copepods of various developmental stages. Larvae of S. californiensis showed an ontogenetic change in their diet: larvae ≤7.9 mm BL (i.e. preflexion stage) fed mainly on copepod eggs and nauplii, while the larvae ≥8 mm BL consumed mainly calanoid copepodites such as Pseudocalanus and Paracalanus spp. In the largest size-class (16–22.2 mm BL), the furcilia stage of euphausiids was also an important prey item. There was an increase in the average prey size with growth in larvae ≤11.9 mm BL, while the number of prey eaten positively correlated with growth in larvae ≥12 mm BL. The trophic niche breadth also increased with larval growth, which would ensure a wide range of available food resources for the larger size-class larvae.

scholarly journals Hábitos alimentarios de quironómidos (Diptera: Chironomidae) en lagos del páramo de Chingaza, Colombia

2017 ◽  
Vol 66 (1) ◽  
pp. 136 ◽  
Author(s):  
Yulibey Caleño Ruiz ◽  
Carlos Alberto Rivera Rondon ◽  
Hernando Ovalle
Keyword(s):  
Dietary Habits ◽  
Feeding Habits ◽  
Diet Overlap ◽  
Gut Contents ◽  
High Mountain ◽  
Trophic Guilds ◽  
Use Of Resources ◽  
Fine Particulate ◽  
Chironomidae Larvae ◽  
Well Differentiated

Tropical high mountain lakes show unique environmental conditions where chironomids play an important role in ecosystem functioning. The characteristics of these environments could favor diet overlap and therefore a high interspecific competition. This study described the dietary habits of chironomid genera, identified whether the dietary habits were specialized or generalist, and analyzed the diet overlap in the genera. Chironomidae larvae were collected from four lakes of the Chingaza paramo during the dry season, between April and May of 2 016. The feeding habits of larvae were evaluated by analyzing gut contents following standard methods. Each genus was assigned to trophic guilds (carnivore, detritivore and algivore) and the diet overlap was estimated using the Pinka's index. A total of 1 003 individuals were collected and nine genera were identified. Larvae consumed mainly fine particulate organic matter (FPOM), algae, macrophyte fragments, macroinvertebrates, and animal tissues. FPOM was the main feeding resource of detritivores. The analysis of diets showed a high affinity of each genus for a single trophic guild and most of the genera were generalist in the use of resources. For all lakes, high levels of diet overlap were observed among genera and trophic guilds, mainly among detritivores. Our results suggested that Chironomidae larvae of these lakes presented well differentiated trophic habits, and showed a moderate diet overlap within detritivores and carnivores.

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.

Proceedings of the First International Snakehead Symposium

2019 ◽  
Keyword(s):  
Management Practices ◽  
Feeding Habits ◽  
Feeding Activity ◽  
Movement Patterns ◽  
Diel Activity ◽  
Gut Contents ◽  
Random Forest Models ◽  
Radio Transmitters ◽  
Diurnal Species ◽  
Tracking Period

<em>Abstract.</em>—Understanding the diel activity of a species can shed light on potential interactions with other species and inform management practices. To understand the diel activity of Northern Snakehead <em>Channa argus</em>, feeding habits and movement patterns were observed. Two hundred seventy-three Northern Snakehead were captured by boat electrofishing during May and June of 2007 and 2008. Their gut contents were extracted and preserved. The level of digestion of each prey item was estimated from fresh (1) to >50% digested (4) or empty (5). Random forest models were used to predict feeding activity based on time of day, tide level, date, water temperature, fish total length, and sex. Diel movement patterns were assessed by implanting Northern Snakehead with radio transmitters and monitoring them every 1.5 h for 24 h in both March and July 2007. Movement rates were compared between March and July and among four daily time periods. Independent variables accounted for only 6% of the variation in feeding activity; however, temporal feeding patterns were apparent. No fresh items were observed in guts between 12:30 and 7:30 am, and the proportion of empty stomachs increased at the end of May coinciding with the onset of spawning. Overall, fish moved greater distances during the July tracking period compared to March. Fish showed a greater propensity to move during daylight hours than at night during the March tracking period. A similar but nonsignificant (<EM>P </EM>> 0.05) pattern was observed in July. Movement and feeding data both indicated greater activity during daylight hours than at night, suggesting that Northern Snakehead is a diurnal species. Based on our preliminary findings, we hypothesize that a) diurnal species are more susceptible than nocturnal species to predation by Northern Snakehead and b) Northern Snakehead are more likely to compete for food with diurnal than nocturnal predators.

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