Ontogenic changes in prey consumption by the stonefly Paragnetina media in relation to temporal variation in prey nutrient content

2000 ◽  
Vol 78 (5) ◽  
pp. 748-763 ◽  
Author(s):  
Catherine J Duvall ◽  
D Dudley Williams

In Duffin Creek, Ontario, nymphs of the predatory stonefly Paragnetina media (Perlidae) commonly feed on detritus and three prey types: hydropsychid larvae (Hydropsyche sparna and Hydropsyche slossonae), nymphs of the mayfly Baetis tricaudatus, and chironomid larvae belonging to subfamilies Tanypodinae and Orthocladiinae. This study examined temporal changes in the nutrient (lipid and protein) content of these prey to determine if the predator tracks food resources by selecting prey on the basis of nutrient requirements at different stages in its own development. All three common prey types exhibited temporal variation in lipid levels, with peaks occurring at different times: June for the hydropsychids, August for the chironomids, and October for B. tricaudatus. Prey protein levels were less variable. The proportions of the prey types that were eaten varied throughout the year and according to predator size. For example, while small P. media ate mostly detritus, they also consumed early-instar hydropsychids during the larval recruitment period of the latter; mid-sized nymphs included more animal matter in their diet, primarily chironomid larvae; and larger nymphs primarily ate B. tricaudatus. Paragnetina media nymphs in all size categories showed an increase in body lipid level in the autumn, suggesting a general accumulation of lipid reserves in readiness for the winter, although dietary adjustment to accomplish this was detectable only in small P. media. There was no evidence to suggest that P. media selected prey on the basis of the latter's protein content. Male P. media nymphs preyed predominantly on chironomid larvae and included mites in their diet, whereas female nymphs preferred B. tricaudatus and hydropsychids. On a per milligram body mass basis, male nymphs had the higher nutrient gain, since, for both lipid and protein, intake by males was between two and three times that by females. However, male and female bodies had similar lipid contents. We conclude that whereas there is temporal variation both in the nutritional (lipid and protein) content of the common prey of P. media and in this predator's diet, there is only weak evidence for nutrient-resource tracking.

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Katalin Hubai ◽  
Nora Kováts ◽  
Gábor Teke

AbstractAtmospheric particulate matter (PM) is one of the major environmental concerns in Europe. A wide range of studies has proved the ecotoxic potential of atmospheric particles. PM exerts chemical stress on vegetation by its potentially toxic constituents; however, relatively few studies are available on assessing phytotoxic effects under laboratory conditions. In our study, aqueous extract of particulate matter was prepared and used for treatment. Experiment was following the procedure defined by the No. 227 OECD Guideline for the Testing of Chemicals: Terrestrial Plant Test. Tomato (Lycopersicon esculentum Mill.) plants were used; elucidated toxicity was assessed based on morphological and biochemical endpoints such as biomass, chlorophyll-a and chlorophyll-b, carotenoids, and protein content. Biomass reduction and protein content showed a clear dose–effect relationship; the biomass decreased in comparison with the control (100%) in all test groups (TG) at a steady rate (TG1: 87.73%; TG2: 71.77%; TG3: 67.01%; TG4: 63.63%). The tendency in protein concentrations compared to the control was TG1: 113.61%; TG2: 148.21% TG3: 160.52%; TG4: 157.31%. However, pigments showed a ‘Janus-faced’ effect: nutrient content of the sample caused slight increase at lower doses; actual toxicity became apparent only at higher doses (chlorophyll-a concentration decrease was 84.47% in TG4, chlorophyll-b was 77.17%, and finally, carotene showed 83.60% decrease in TG4).


2015 ◽  
Vol 44 (2) ◽  
pp. 113-119
Author(s):  
MR Alam ◽  
MM Haque ◽  
KR Sumi ◽  
MM Ali

An experiment was conducted to evaluate the effects of Pangasius pond sediment on the nutrient uptake by para-grass (Brachiaria mutica) during the period from March to October, 2011 in a Pangasius farm, Dhanikhola, Trishal, Mymensingh. Initially soil chemistry of Pangasius pond sediment and para-grass producing virgin soil was analyzed at the laboratory. The fodder was cultivated at various level of inorganic fertilizer with Pangasius pond sediment having three replications in each treatment. The size of each replication was 25 m2 (5m×5m). The fodder was harvested at the pre-flowering stage (45 days after transplantation). After first cutting, experimental plot was irrigated, and again after 45 days of first cutting second cutting was done. After proper collection and preparation the para-grass samples and rice straw, their proximate composition analysis was done. The nutrient content of para-grass was also compared with rice-straw being used as dairy feed. The analytical results indicated that the nutrients content of Pangasius pond sediment was higher than the virgin soil which was the stimulating factor for para-grass growth and production. The basic nutrients such as crude lipid and protein content of para-grass were found increasing from first to second sampling. However, crude lipid and protein of para-grass at second sampling was found much higher than those of rice straw. Application of Pangasius pond sediment as alternative source of fertilizer enriched nutrient content of para-grass much higher than those of rice straw. Therefore, it could be argued that higher level of lipid and protein content of para-grass is the stimulating factor to dairy cattle production under integrated aquaculture–fodder grass production using Pangasius pond sediment.Bang. J. Anim. Sci. 2015. 44(2): 113-119


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7890 ◽  
Author(s):  
Hideyuki Doi ◽  
Eisuke Kikuchi ◽  
Shigeto Takagi ◽  
Shuichi Shikano

Analysis of aquatic food webs is typically undertaken using carbon and nitrogen stable isotope composition of consumer and producer species. However, the trophic consequences of spatio-temporal variation in the isotope composition of consumers have not been well evaluated. Lake Katanuma, Japan, is highly acidic and has only one dominant species of benthic alga and one planktonic microalga, making it a prime system for studying trophic relationships between primary consumers and producers. In this simple lake food web, we conducted a field survey to evaluate spatial and temporal variation in the carbon and nitrogen stable isotope composition of a chironomid larvae in association with a single benthic and planktonic alga. We found a significant correlation between carbon stable isotope ratios of the chironomid larvae and the benthic diatom species in the lake. Thus, chironomid larvae may represent a reliable isotopic baseline for estimating isotope values in benthic diatoms. However, although the correlation held in shallow water, at four m depths, there was no significant relationship between the isotope ratios of chironomids and benthic diatoms, probably because deep-water larvae spend part of their life cycle migrating from the lake shore to deeper water. The differing isotope ratios of deeper chironomid tissues likely reflect the feeding history of individuals during this migration.


2011 ◽  
Vol 108 (1) ◽  
pp. 140-147 ◽  
Author(s):  
Mirre Viskaal van Dongen ◽  
Marjolijn C. van den Berg ◽  
Nicole Vink ◽  
Frans J. Kok ◽  
Cees de Graaf

Taste is expected to represent a food's nutrient content. The objective was to investigate whether taste acts as nutrient-sensor, within the context of the current diet, which is high in processed foods. Intensities of the five basic tastes of fifty commonly consumed foods were rated by nineteen subjects (aged 21·0 (sd 1·7) years, BMI 21·5 (sd 2·0) kg/m2). Linear regression was used to test associations between taste and nutrient contents. Food groups based on taste were identified using cluster analysis; nutrient content was compared between food groups, using ANOVA. Sweetness was associated with mono- and disaccharides (R2 0·45, P < 0·01). Saltiness and savouriness were correlated, with r 0·92 (P < 0·01) and both were associated with Na (both: R2 0·33, P < 0·01) and protein (R2 0·27, P < 0·01 and R2 0·33, P < 0·01, respectively). Cluster analysis indicated four food groups: neutral, salty and savoury, sweet–sour and sweet foods. Mono- and disaccharide content was highest in sweet foods (P < 0·01). In salty and savoury foods, protein content (P = 0·01 with sweet–sour foods, not significant with neutral or sweet foods) and Na content (P < 0·05) were the highest. Associations were more pronounced in raw and moderately processed foods, than in highly processed foods. The findings suggest that sweetness, saltiness and savouriness signal nutrient content, particularly for simple sugars, protein and Na. In highly processed foods, however, the ability to sense nutrient content based on taste seems limited.


1986 ◽  
Vol 2 (1) ◽  
pp. 73-85 ◽  
Author(s):  
David Dudgeon ◽  
Christina Y. M. Wat

ABSTRACTZygonix iris is widespread in tropical Asia, and larvae are sprawlers/clingers on rock surfaces in fast-flowing streams and rivers. In the Lam Tsuen River, Hong Kong, this species is univoltine; emergence occurs prior to the summer monsoon and larval recruitment during the wet season. Studies on larval dietary composition in four habitats indicated that Z. iris is a generalist predator, consuming epibenthic prey taxa in proportion to their abundance in the environment. Larval Chironomidae (Diptera) and Baetis (Ephemeroptera) were the commonest food items at all sites and there was little consistent evidence of preference for individual taxa. Larger Z. iris larvae tended to consume more prey taxa than did smaller larvae, and Baetis prey size was positively correlated with predator size. No size selection of chironomid larvae was apparent. Despite its unusual larval habit, Z. iris is a generalist feeder resembling lotic and lentic temperate-zone Odonata.


2002 ◽  
Vol 62 (4b) ◽  
pp. 807-818 ◽  
Author(s):  
J. HIGUTI ◽  
A. M. TAKEDA

Chironomid larvae were collected and abiotic variables measured at monthly intervals at 21 sampling stations in two lagoons (Guaraná and Patos) and two tributaries (Baía and Ivinheima) of the Upper Paraná River floodplain. The genera Procladius, Chironomus, Goeldichironomus, and Polypedilum were dominant in the lagoons and in the Baía River, while Cryptochironomus and Lopescladius were more dominant in the Ivinheima River. The similarity in the generic composition of the chironomids of the lagoons and the Baía River is probably due to the fact that this river presents hydrodynamic characteristics similar to those of the lagoons. The results obtained suggest that the hydrodynamics of these environments are the main factor determining spatial variation in the chironomid fauna. This is intuitively clear, as this factor itself determines sediment type, quantity of organic matter and presence or absence of aquatic macrophytes. However, on a seasonal scale, the flood pulse seems to be the main controlling factor of the temporal variation in densities and dominance of chironomid larvae. Given that this factor has a large influence on the temporal dynamics of several limnological variables, this is again a logical correlation. Our results suggest a strong relationship between the variations in the chironomid community and fluctuations in limnological characteristics.


Author(s):  
Piyush Vadodariya ◽  
Bhagyashree Abuj ◽  
Nilima Karmakar ◽  
Nitin Gudadhe ◽  
Priti Faldu ◽  
...  

Background: Lablab Bean had been considered as an excellent source of protein (20-25%) with it’s two different groups, like Wal (highly fibrous) and Papdi (less fibrous). Cooking alters the level of nutrient content and as well as the antinutrient content and based on this concept the following experiment had been carried out. Methods: The study was carried out in Navsari Agricultural University, Gujarat, India, in 2016-17. Two different groups of Indian bean (Lablab purpureus L.) including Wal group (Guj.W.1, Guj.W.2, 125-36, NIBD-15-05, NIBD-15-10) and Papdi group (GNIB-21, NIBD-15-09, NIBD-15-10, NIBD-14-01, NIBD-14-04) were analyzed for their nutrients and anti-nutritional contents for raw and cooked (boiling) vegetables. Result: Papdi group was proved to be comparatively rich in some nutrient contents like ascorbic acid, flavonoid, Fe, Mn whereas Wal was found to be rich in the other nutrient contents like crude fibre, carbohydrate, S, Zn, Cu, â carotene etc. Both groups performed well for antioxidant activities and protein content. Hence, it was difficult to detect the particular group distinctly and reported that Wal was found to be comparatively nutritionally rich after cooking.


1986 ◽  
Vol 118 (6) ◽  
pp. 549-558 ◽  
Author(s):  
C.S. Rodrigues ◽  
N.K. Kaushik

AbstractIn laboratory tests conducted under simulated stream conditions treatment with the insect growth regulator diflubenzuron at 1.0 mg/L/30 min at 15°C resulted in 100% mortality of Simulium larvae after 10 days. At 0.5 mg/L/15 min there was 97.6% mortality of S. vittatum larvae after 18 days in water at 10.5°C. Diflubenzuron was less effective when the growth rate of simuliid larvae during the test was slow due to inadequate nutrition, and it was more effective at 25 than at 20°C, but there was no difference in efficacy between 10 and 20°C. Efficacy against simuliid larvae varied inversely with their instar. Diflubenzuron at 1.0 mg/L/30 min was tested in the laboratory against selected nontarget invertebrates. Among the Ephemeroptera tested at 15°C, Baetis pygmaeus, Leptophlebia sp., and Isonychia sp. proved susceptible but not Stenonema fuscum and Ephemerella subvaria. Similarly diflubenzuron had little effect on the perlid stonefly Paragnetina media at 15°C and on the filter-feeding caddisfly Hydropsyche betteni at 20°C. Chironomid larvae (Phaenopsectra sp.) tested at 20°C were affected and the amphipods Gammarus pseudolimnaeus and Hyalella azteca were particularly susceptible at 25 but not at 15°C.


2019 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
Jumiati Jumiati ◽  
Dewi Ratnasari ◽  
Achmad Sudianto

AbstrakKerupuk cumi saat ini cukup banyak diminati masyarakat di semua kalangan karena kandungan gizi cumi yang tinggi terutama kandungan proteinnya yaitu 17,9 g/100 g cumi segar. Penelitian ini bertujuan untuk mengetahui mutu kerupuk cumi (Loligo sp.) yang terbaik dengan penambahankunyit(Curcuma domestica) yang berbeda. Analisis yang dilakukan meliputi: analisa proksimat (kadar : air, abu, lemak, protein, dan karbohidrat), dan uji Total Plate Count (TPC Penelitian ini merupakan penelitian eksperimental menggunakan Rancangan Acak Lengkap (RAL), dengan empat perlakuanyaitu: tanpa pemberian ekstrak kunyit (O) , pemberian dosis 12,5% (A), 15% (B) dan 17,5% (C) masing-masing enam ulangan. Hasil analisa uji proksimat, penggunaan ekstrak kunyit pada pembuatan kerupuk cumi berpengaruh nyata terhadap mutu kerupuk cumi dengan pemakaian ekstrak kunyit terbaik yaitu: dosis kunyit 12,5% (kadar air : 9,622%), dosis kunyit 17,5% ( kadar lemak: 4,765%), dosis kunyit 17,5% (kadar protein : 18,112%), dosis kunyit 12,5% (kadar karbohidrat : 68,253%), dan dosis kunyit 12,5% (kadar abu: 1,278%). Penggunaan ekstrak kunyit berpengaruh sangat nyata terhadap TPC pada kerupuk cumi, perlakuan yang paling baik adalah perlakuan C dengan nilai TPC sebesar 28.350 koloni/ gram. Penggunaan esktrak kunyit sebagai bahan anti bakteri pada proses pembuatan kerupuk cumi mampu menghambat aktivitas bakteri dan mempunyai kandungan gizi yang cukup tinggi. AbstractSquid crackers are currently quite popular with people in all circles because of the high nutritional content of squid, especially the protein content of 17.9 g / 100 g of fresh squid. This study aims to determine the quality of the best squid crackers (Loligo sp.) by adding different turmeric (Curcuma domestica). The analysis carried out included: Proximate analysis (levels: water, ash, fat, protein, and carbohydrates), and Total Plate Count (TPC) tests. This study used an experimental method, completely randomized design (CRD), with 4 treatments without the administration of turmeric extract (O), dosing 12.5% (A), 15% (B) and 17.5% (C) respectively 6 repetitions. The results of the proximate test analysis, the use of turmeric extract on the making of squid crackers had a significant effect on the quality of squid crackers with the use of the best turmeric extract: 12.5% turmeric dose (moisture content: 9.622%), 17.5% turmeric dose ( fat content: 4.765%), turmeric dosage 17.5% (protein content: 18.112%), 12.5% turmeric dose (carbohydrate level: 68.253%), and 12.5% turmeric dose (ash content: 1.278%). The use of turmeric extract has a very significant effect on TPC on squid crackers, the best treatment is treatment C with a TPC value of 28,350 colonies / gram. The use of turmeric extract as an anti-bacterial ingredient in the process of making squid crackers is able to inhibit bacterial activity and has a fairly high nutrient content.


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