scholarly journals Diet of the Bobolink (Dolichonyx oryzivorus) in rice fields on its wintering grounds in Argentina

2019 ◽  
Vol 27 (1) ◽  
pp. 10-16
Author(s):  
Rodrigo E. Lorenzón ◽  
Carolina E. Antoniazzi ◽  
Franco N. Fabre ◽  
Virginia M. Quiroga ◽  
Silvia A. Regner ◽  
...  
Keyword(s):  
Stomach Contents ◽  
Rice Fields ◽  
Cultivated Plants ◽  
Relative Importance ◽  
Santa Fe ◽  
Wintering Grounds ◽  
Dolichonyx Oryzivorus ◽  
Winter Diet ◽  
Number Of Seeds ◽  
Plant Components

AbstractWinter diet of Bobolinks (Dolichonyx oryzivorus), a bird considered a pest of rice fields, is known to consist primarily of seeds. However, it is not yet possible to establish the extent to which non-rice plants and animal components contribute to its diet. To contribute to these issues, we studied the diet of the Bobolink found in rice fields on its wintering grounds in Santa Fe, Argentina, to provide information on (i) the composition of the diet and (ii) the relative importance of plant and animal components in the diet and of the different prey categories. We captured Bobolinks with mist nets and obtained samples of stomach contents by warm water and emetic-based regurgitation to determine the composition of the diet (n = 46 samples) and the importance of the different prey (n = 25 samples), mainly during March, just prior to northbound migration. We confirmed that the Bobolink’s diet in this region during this period is predominantly herbivorous (97%) and rice-based (55%), although it also consumes a large number of seeds of non-cultivated plants that represented 42% of the diet. Invertebrates, although of less importance than plant components (3%), had been consumed by 97% of captured individuais. Our results document the importance of non-cultivated plants and animal prey in the diet of Bobolinks in addition to rice.

scholarly journals Seasonal variation on diet of juvenile Elops saurus Linnaeus, 1766 (Ladyfish) in the Parnaiba River Delta

2020 ◽  
Vol 32 ◽  
Author(s):  
Tatiane Araujo Santos ◽  
Thamires Souza Gonçalves ◽  
Patricia Silva do Nascimento ◽  
Cézar Augusto Freire Fernandes ◽  
Francisca Edna de Andrade Cunha
Keyword(s):  
High Frequency ◽  
Rainy Season ◽  
Stomach Contents ◽  
Dry Season ◽  
River Delta ◽  
Frequency Of Occurrence ◽  
Relative Importance ◽  
Dry Period ◽  
Food Items ◽  
Importance Index

Abstract: Aim Identify seasonal variations in the diet of juvenile living in the estuary of the Parnaíba River Delta. Methods Food items were identified through analysis of stomach contents, and later submitted to analysis by regular methods for Frequency of Occurrence (FO), Frequency Numerical (FN), Gravimetric Frequency (FW) and Relative Importance Index (IRI). Results Juvenile diet of Elops saurus that inhabit the lagoons in the Parnaíba delta was composed in order decreasing of importance by Osteichthyes (Teleostei), Insecta and Crustacea in addition to Polychaeta and Nematoda. It was also observed a high frequency of occurrence of fragments of plastics in the diet. In the rainy season, 17 items were recorded in the diet, whereas in the dry season only 7 items were present. Relative Importance Index showed high presence of the Teleostei fish (69.93%) on diet of E. saurus during the rainy season, whereas during the dry period the insects of the families Corixidae (43.25%) and Dysticidae (39.16%). Conclusions With the study it was possible to identify that juvenile are piscivorous in the rainy season when there is a higher availability of prey in the environment and insectivores in the dry season when it reduces the supply of food, indicating feeding flexibility to environmental alterations.

Invasive bullfrogs as predators in a Neotropical assemblage: What frog species do they eat?

2012 ◽  
Vol 62 (4) ◽  
pp. 397-408 ◽  
Author(s):  
Ruben A. Boelter ◽  
Igor L. Kaefer ◽  
Camila Both ◽  
Sonia Cechin
Keyword(s):  
South America ◽  
Stomach Contents ◽  
Relative Importance ◽  
Feeding Preferences ◽  
Prey Category ◽  
American Bullfrog ◽  
Important Prey ◽  
Prey Composition ◽  
Frog Species

Anurans are important prey for the American bullfrog Lithobates catesbeianus, but field assessments of its diet in the context of a local prey assemblage are lacking. We aimed to identify the frog species consumed by an invasive bullfrog population in subtropical South America, and to assess their relative importance among other types of prey. Characterization of the frog assemblage in the study area also allowed us to calculate the degree of electivity of the recorded anuran prey, in order to gain insight regarding bullfrog feeding preferences and to test if the bullfrog prey composition differed from a random sample of the assemblage. A total of 32.6% of the bullfrogs had at least one anuran in the stomach contents, and post-metamorphic anurans represented 49.1% of the relative prey importance for adult bullfrogs. Anurans were preyed on by all size classes, and constituted the volumetrically most important prey category in the diet of individuals heavier than 100 g. Cycloramphidae, Hylidae and Leiuperidae were positively selected, and Hypsiboas pulchellus and Physalaemus cuvieri were the species most often taken. We found a low occurrence of cannibalism, despite the high density of bullfrogs at the study site. Our results showed that the degree of electivity differed among bullfrog prey types, suggesting that some frog species may be preyed on in a higher proportion than their relative abundance in the assemblage. Testing the clues provided by this assemblage-level approach may lead to a better assessment of the interactions between bullfrogs and the native frog fauna.

Hard prey specialists or opportunistic generalists? An examination of the diet of the cownose ray, Rhinoptera bonasus

2007 ◽  
Vol 58 (1) ◽  
pp. 135 ◽  
Author(s):  
A. B. Collins ◽  
M. R. Heupel ◽  
R. E. Hueter ◽  
P. J. Motta
Keyword(s):  
Feeding Behaviour ◽  
Stomach Contents ◽  
Relative Importance ◽  
Charlotte Harbor ◽  
Severe Damage ◽  
Important Prey ◽  
Cownose Ray ◽  
Rhinoptera Bonasus ◽  
Group Feeding ◽  
Index Of Relative Importance

Atlantic cownose rays (Rhinoptera bonasus) are benthic, suction feeders whose foraging activities have been implicated in severe damage to commercial shellfish industries. With jaws highly modified for durophagy, it has been assumed that R. bonasus are crushing specialists that feed primarily upon hard molluscan prey. Stomach contents from R. bonasus caught within Florida’s Charlotte Harbor estuary between July 2003 and July 2004 were analysed using the index of relative importance (IRI) to determine most important prey types. Prey items were identified from 38 families and fell into nine distinctive groups. The three most dominant prey groups were crustaceans (%IRI = 55.31), polychaetes (%IRI = 25.20) and bivalves (%IRI = 12.58). Shoalmates had more similar diets than non-shoalmates, suggesting group feeding. Most small or softer-bodied prey consumed were relatively intact, indicating lack of prey processing and capture through suction feeding. All larger, harder-bodied prey showed evidence of crushing (fractured and broken shells). Although R. bonasus has been characterised as a hard prey specialist, these results suggest it may behave as an opportunistic generalist, modifying feeding behaviour to consume readily available prey.

scholarly journals IDENTIFIKASI GULMA TANAMAN PADI (Oryza sativa L. var. Ciherang) SUMATARA SELATAN

2018 ◽  
Vol 1 (1) ◽  
pp. 40-44
Author(s):  
Syarifah Syarifah ◽  
Ike Apriani ◽  
Ra Hoetary Tirta Amallia
Keyword(s):  
Critical Period ◽  
Research Method ◽  
Cynodon Dactylon ◽  
Oryza Sativa L ◽  
Rice Fields ◽  
Cultivated Plants ◽  
Ageratum Conyzoides ◽  
Poaceae Family ◽  
Eleocharis Palustris ◽  
Descriptive Method

The growth of weeds in the rice fields can reduce production. Weed is a disrupting plant that grows and spreads rapidly so it becomes a nutritional competitor for cultivated plants. This study aims to identify rice weeds in the fields of Rimau District, Banyuasin, South Sumatra. The research method used was descriptive method with purposive sampling on wetland rice fields of the Ciherang variety. Sampling was carried out in a critical period (3-6 weeks after planting) in rice fields. The results of weed identification obtained 6 families consisting of 15 species, namely Ageratum conyzoides L., Crassocephalum crepidioides, Cleome rutidisprema DC., Cyperusroduntus L. Cyperus compressus, Eleocharis palustris L., Frimbristylis miliacea L. Vahl, Phylanthus naruri L., Eurphobia hirta, Cynodon dactylon (L.) Press., Digitaria ciliaris (Retz.) Koel., Echinochola colona (L.) Link., Eleusinindica (L.) Gaertn., Paspalum scrobiculatum L., Ludwigia octovalvis (Jacq.) Raven. The Poaceae family is most commonly found as a rice weed in Rimau District, South Sumatra.

scholarly journals Feeding habits of Lithobates megapoda (Anura: Ranidae), a threatened leopard frog used for human consumption, in Lake Chapala, Mexico

2021 ◽  
Vol 20 (1) ◽  
pp. 75-88
Author(s):  
José Luis Barragán-Ramírez ◽  
Benjamín Hernández ◽  
María Guadalupe Velarde-Aguilar ◽  
Oscar Pérez-Flores ◽  
José Luis Navarrete-Heredia ◽  
...  
Keyword(s):  
Trophic Ecology ◽  
Dietary Diversity ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Prey Type ◽  
Leopard Frog ◽  
Human Consumption ◽  
Relative Importance ◽  
Prey Category ◽  
Lake Chapala

The Big-footed Leopard Frog (Lithobates megapoda) is a threatened and endemic species from western Mexico. This species has aquatic habits and it is distinguished by its large size, particularly by the length of its legs, reason for which it is captured for human consumption. Also, knowledge about its natural history is scarce and incomplete. In this study, we analyzed the composition of the diet of L. megapoda on the shore of Lake Chapala, the largest lake in Mexico. A total of 69 adult individuals were collected lifeless in fishing nets, during the rainy season (June-October), of which 48 had stomach contents. A total of 96 prey items were identified, which correspond to 13 prey categories. Fish constituted the most dominant prey category in the diet in terms of number, volume, frequency of occurrence, and relative importance. No significant differences were found in the consumption by prey type (aquatic or terrestrial). However, the aquatic preys had a greater relative importance and were more voluminous than the terrestrial ones. The diversity of prey categories, in terms of prey volume, indicates males may have a higher dietary diversity than females, but we not evaluated possible bias. In addition, a significant effect was found in the interaction of size (SVL) of frogs with the average of prey volume. Females (that are larger than males) consumed prey within a wide volume range and, the larger they are, more voluminous are prey. In this way it is possible that intraspecific competition for trophic resources in the environment is reduced. This study helps us understand the trophic ecology of L. megapoda, a frog species that plays an important role in the food web where it lives, as a predator feeding on aquatic and terrestrial organisms.

scholarly journals Feeding habits of Aspitrigla cuculus (L., 1758) (red gurnard), Lepidotrigla cavillone (Lac., 1802) (large scale gurnard) and Trigloporus lastoviza (Brunn., 1768) (rock gurnard) around Cyclades and Dodecanese Islands (E. Mediterranean)

2000 ◽  
Vol 1 (1) ◽  
pp. 91 ◽  
Author(s):  
A. TERRATS ◽  
G. PETRAKIS ◽  
C. PAPACONSTANTINOU
Keyword(s):  
Large Scale ◽  
Eastern Mediterranean ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Frequency Of Occurrence ◽  
Relative Importance ◽  
Bottom Trawling ◽  
Percentage Frequency ◽  
Index Of Relative Importance

The feeding habits of the three most abundant gurnard species, red gurnard (Aspitrigla cuculus), large scale gurnard (Lepidotrigla cavillone) and rock gurnard (Trigloporus lastoviza) in the eastern Mediterranean (Dodecanese and Cyclades, Greece) are examined. The stomach contents of the gurnard specimens collected in April and September 1996 by bottom trawling were analyzed. The % frequency of occurrence, % number and % weight of prey types in the stomach contents were evaluated. By weight, Mysidacea and Decapoda dominated in the diet of the three species in both seasons, however the Index of Relative Importance, as well as the percentage frequency of occurrence varied. Rock gurnard presented the most diverse diet whereas the diet of large scale and red gurnard were more specialized. High overlap in terms of number was found between rock and large scale gurnard in May. Rock gurnard had the most divers diet in both seasons.

scholarly journals Polymorphism of morphometric parameters of the flower and fruit of the Sargent apple tree (Malus sargentii Rehl)

2021 ◽  
Vol 6 (48) ◽  
pp. 18-18
Author(s):  
Vitaly Donskih ◽  
Tatiana Aniskina ◽  
Victоria Kryuchkova
Keyword(s):  
Apple Tree ◽  
Inverse Correlation ◽  
Botanical Garden ◽  
Fruit Weight ◽  
Cultivated Plants ◽  
Morphometric Traits ◽  
Fruit Length ◽  
Flower Diameter ◽  
Number Of Seeds ◽  
Fruit Diameter

The Sargent apple tree is highly valued for its decorative qualities, it is used in breeding work when developing new ornamental varieties. To assess the breeding potential, as well as planning crosses, information is needed on the variability of the morphometric traits of the apple flower and fruit, as well as the presence of a relationship between these traits. The research was carried out in the laboratory of cultivated plants of the Tsytsin Main Botanical Garden on 12 quantitative traits of flower and fruit. It was found that almost all traits are characterized by a low level of polymorphism of 7-15% (flower diameter - 13.2%, pedicel thickness - 14.9%, peduncle length - 8.3%, fruit length - 4.7%, fruit diameter - 5.7%) or an average level (16-25%), except for the mass of seeds (40%) and the number of seeds in the fruit (33.9%). An inverse correlation was found between the length of the anther and the number of seeds inside the fruit (r = -0.46), as well as strong direct relationships between the diameter of the fruit and the weight of the fruit (r = 0.79) and the diameter of the fruit and the length of the fruit (r = 0, 78). A reliable direct relationship between the group was also revealed: flower length, filament length, pedicel thickness, fruit length, fruit diameter, fruit weight. Keywords: POLYMORPHISM, FLOWERS, CRABAPPLES, SORBOMALUS, MALUS SARGENTII, SARGENT APPLE TREE

Swordfish Xiphias gladius diet in the Florida Straits

2020 ◽  
Vol 96 (4) ◽  
pp. 695-706
Author(s):  
Amy M Heemsoth ◽  
Amy C Hirons ◽  
Caroline M Collatos ◽  
David W Kerstetter
Keyword(s):  
Diet Composition ◽  
Stomach Contents ◽  
Relative Importance ◽  
Crustacean Species ◽  
Index Of Relative Importance ◽  
Xiphias Gladius ◽  
Florida Straits ◽  
Prey Length ◽  
Positive Significant Correlation

Swordfish Xiphias gladius inhabit the Florida Straits year-round and provide a significant role in the food web as top-level predators. However, little is known about the diet composition and thus ecological role of swordfish in Florida. This study investigated swordfish diet by analyzing stomach contents of 131 swordfish in the Florida Straits from April 2007 to December 2008. Identifiable species included 13 teleost species, 3 cephalopod species, and 1 crustacean species. Cephalopods dominated the swordfish diet by weight (72.4%) and number (69.9%), and ranked highest in importance in the diet by the index of relative importance (IRI; 81.5%). Teleosts occurred the most (99.1%) but represented the second highest importance in diet by weight (25.2%), number (26.3%), and IRI (17.6%). Illex sp. was the prey with the greatest dietary importance, followed by unidentifiable ommastrephid squids. Stomach fullness index values ranged from 0 (empty) to 8.98 (mean = 0.37). A positive significant correlation between swordfish length and prey length was found (r2 = 0.104, P = 0.037), and no significant correlations were found between swordfish weight and prey weight (r2 = –0.075, P = 0.065). This is the first study to report a comprehensive diet of swordfish inhabiting waters in the Florida Straits region and suggests swordfish may be opportunistic feeders, altering their diet when abundance or presence of prey changes.

The winter diet of thick-billed murres, Uria lomvia, in western Greenland, 1988–1989

1993 ◽  
Vol 71 (2) ◽  
pp. 264-272 ◽  
Author(s):  
Knud Falk ◽  
Jan Durinck
Keyword(s):  
Body Condition ◽  
Prey Species ◽  
Stomach Contents ◽  
Uria Lomvia ◽  
Winter Diet ◽  
Southern Area ◽  
Good Body Condition ◽  
Capelin Mallotus Villosus ◽  
Wet Weight ◽  
Prey Remains

The diet of thick-billed murres (Uria lomvia) wintering in coastal western Greenland was studied by analyzing the stomach contents of 202 birds supplied by local hunters in four regions, from October 1988 to March 1989. Fish and crustaceans were present in 68 and 71% (frequency of occurrence), respectively, of all stomachs containing prey remains (n = 195). Fish made up 81% wet weight, and crustaceans most of the remaining 19%, except for < 1% squid (Gonatus sp.) and polychaetes (Nereis sp.). Capelin (Mallotus villosus) was the dominant prey species (61% wet weight), followed by Thysanoessa spp. (17%), Parathemisto spp. (1%), and Meganyctiphanes norvegica (1%). Euphausiids were the most abundant crustaceans (95% wet weight of all crustaceans), except in October, when hyperid amphipods were dominant (89%). Crustaceans were important in the murres' diet only in the northern part of the survey area; birds in the southern part preyed almost exclusively upon capelin. Most birds were in good body condition (based on the amount of body fat), but murres from the southern area had a slightly higher mean fat index than those from the northern area (7.19 vs. 5.35). We suggest that differences in body condition may be related to the higher proportion of fish, which is of higher caloric value, in the diet of murres in the southern area.

Feeding ecology of the piked spurdog Squalus megalops (Chondrichthyes: Squalidae) in the Gulf of Gabès (central Mediterranean Sea)

2018 ◽  
Vol 69 (1) ◽  
pp. 48
Author(s):  
Sondes Marouani ◽  
Hasna Kadri ◽  
Sami Karaa ◽  
Mohamed Nejmeddine Bradai
Keyword(s):  
Feeding Ecology ◽  
Trophic Position ◽  
Stomach Contents ◽  
Size Class ◽  
Relative Importance ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Index Of Relative Importance ◽  
Three Factor

The present study investigated the feeding ecology of the piked spurdog (Squalus megalops) in the Gulf of Gabès (Tunisia) with regard to sex, size class and season. A study of stomach contents from the 630 individuals examined showed that the species consumed teleosts (percentage index of relative importance (%IRI)=80.32), cephalopods (%IRI=11.96) and crustaceans (%IRI=7.68). A three-factor multivariate analysis of variance (MANOVA) demonstrated significant differences in diet related to size, season and sex. Trophic position analysis revealed that S. megalops is a secondary consumer throughout its life. Quantitative analysis indicated that the species is a generalist feeder with an ontogenetic change in preferred prey from crustaceans to teleosts. The niche breadths of S. megalops in both sexes were broad.

Sign in / Sign up

Export Citation Format

Share Document