Energy Values of Ecological Materials

Golley, Frank B.

doi:10.2307/1932247

Cited by 363 publications

(148 citation statements)

References 9 publications

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“…This was not done in this study. However, using the value of 0.89 found by Avery (1971) for L. vivipara (similar values have been reported for other insectivorous lizards (Pough 1973;Bennett and Dawson 1976)), and assuming an energy content of insects of 23.0 J (mg dry weight) -1 (Golley 1961), reasonable estimates can be made. This yields values of 0.20, 0.01, 0.19 and 0.28 kJ day -1 for autumn, winter, spring and summer respectively: The values for the three active seasons are not significantly different from the predicted value (t-tests; autumn: t=1.43, spring: t-1.55, summer: t=0.47; df=13, P>0.05); but the value for the nonactive winter lizards is significantly lower (t= 3.69, df=13, 0.002 < P < 0.005).…”

Section: Comparison With Alternative Techniquessupporting

confidence: 72%

Validation and use of 22Na turnover to measure food intake in free-ranging lizards

et al. 1983

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Summary.As the food intake of free-ranging animals has proved to be difficult to measure by traditional means, the feasibility of using radioactive Na to measure food consumption in a small scincid lizard (Lampropholis guichenoti) was assessed. This technique has previously been used only for several species of mammal. A significant relationship between food intake and Na turnover was found in the laboratory, with Na turnover underestimating intake by 7.6%. The food intake of free-ranging members of a field population was estimated by 22 Na turnover to be 9.55, 0.65, 9.39 and 13.75 mg dry weight (day) -1 during autumn, winter, spring and summer respectively. Estimates of assimilated and expended energy from these food intake values agree closely with data reported for other lizards using alternative techniques. This study also describes the technical innovations which were necessary to study lizards weighing less than 1 g; and it suggests that 22 Na can provide an easy, reliable and inexpensive means of studying the energetics of many free-living animals.

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Section: Comparison With Alternative Techniquessupporting

confidence: 72%

Validation and use of 22Na turnover to measure food intake in free-ranging lizards

et al. 1983

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“…Currently, the 'energy assimilation hypothesis' best explains fruit consumption by migrating passerines, with an energetic advantage and more rapid increase in body mass thanks to omnivory rather than strict insectivory, though a large quantity of fruits needs to be consumed (Parrish 1997, Eggers 2000, Berthold 2001, Bairlein 2003, Newton 2008. Some fruit species frequently consumed by migrating flycatchers in Iberia, such as Dogwood in the present study, have a high energy content, only slightly lower than that of insects (c. 5 kcal g À1 dry pulp for Dogwood as previously indicated, in comparison with 5.2-6.8 kcal g À1 dry weight for insects, according to Golley 1961, Avery 1971, Jordano 1981. Fruits are obtained more easily than insects because they are an immobile and predictable food source, concentrated in space and conspicuous.…”

Section: Concluding Remarks: Migrating Flycatchers Fruits and Consersupporting

confidence: 64%

Summer-autumn feeding ecology of Pied Flycatchers Ficedula hypolueca and Spotted Flycatchers Muscicapa striata: the importance of frugivory in a stopover area in north-west Iberia

Hernández¹

2009

Bird Con. Int.

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Summer-autumn feeding ecology of Pied Flycatchers Ficedula hypolueca and Spotted Flycatchers Muscicapa striata: the importance of frugivory in a stopover area in north-west Iberia Á NGEL HERNÁ NDEZ SummaryNorth-west Iberia is a crucial stopover region for European populations of Pied Flycatchers Ficedula hypoleuca and Spotted Flycatchers Muscicapa striata during their summer-autumn migration. Both species are almost completely insectivorous during breeding in Europe and wintering in sub-Saharan Africa, but are known to consume fleshy fruits during summerautumn migration, though no detailed investigations have been carried out over long periods of time. In this study, the summer-autumn feeding ecology of Pied and Spotted Flycatchers in a stopover area in north-west Spain, with a landscape of hedgerows and irrigated meadows, was studied for five consecutive years (2002)(2003)(2004)(2005)(2006). In general, the passage of both flycatcher species was noticeable from mid-August to the end of September, with a peak in the first ten days of September. The two flycatcher species consumed fruits throughout the stopover period in all years, with constant intensity of frugivory in time, though the importance of fruits was almost three times greater in the diet of Pied Flycatchers (c. 30% of feeding acts) than in that of Spotted Flycatchers (c. 10% of feeding acts). Both species preferred Dogwood Cornus sanguinea fruits, but also ate Elder Sambucus nigra berries and Bramble Rubus spp. drupelets. The high level of selection of Dogwood fruits was probably linked to their high lipid content, an essential nutrient for fattening in long-distance migrant passerines. Hedgerows and wood edges in north-west Iberia are rich in fleshy fruits but threatened by intensive farming. Their conservation and restoration are proposed because they seem to be high-quality stopover habitats for partially frugivorous passerines during summer-autumn migration.

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“…Even though the energy content of the different kinds of insects and microcrustaceans was not investigated, these results suggest that insects must be superior in relation to microcrustaceans; otherwise, the costs involved in the detection, capture, manipulation, digestion and assimilation of microcrustaceans, especially copepods, could be higher. Golley (1961) evaluated the energetic content of different animal groups and obtained a measure of 4419 g.cal.g -1 dry weight for Daphnia and 5363 g.cal.g -1 dry weight for an insect species. Given this, the tendency of a superior energy balance between microcrustaceans and insects becomes more explicit when, in addition to the drop in nutritional condition with insectivorous to planktivorous changes (April-May), a slight recovery in condition was observed when insects became more relevant in the diet at the end of the study.…”

Section: Discussionmentioning

confidence: 99%

Cage culture with tilapia induces alteration in the diet of natural fish populations: the case of Auchenipterus osteomystax

2010

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Fish rearing in cages installed in reservoirs has developed rapidly in Brazil over the last decade. However, this type of aquaculture induces some changes in the environment because of the high quantity of nutrients released into the surroundings. This study evaluated trophic changes resulting from these nutrient inputs into the diet, feeding activity and nutritional condition of Auchenipterus osteomystax, an insectivore that alternatively feeds on zooplankton. Fish were sampled with gillnets in two tilapia (Oreochromis niloticus) experimental caging aquaculture areas of the Rosana reservoir (Paranapanema River), at different distances from the cages. Samplings were carried out for 90 days (before the cages were installed and 30 and 60 days after installation). Diet analysis was based on 250 stomach contents evaluated with occurrence and volumetric methods, combined into a Feeding Index. The spatial and temporal variations in feeding activity were inferred by the stomach repletion index (stomach weight). The relative condition factor was used to evaluate the individual nutritional condition of the sampled fish. Insects and zooplankton accounted for more than 85% of the diet in any sample. Insects predominated before caging culture started and at the end of the sampling period, whereas zooplankton predominated 30 days after caging began. The repletion index increased at 30 days after caging in both areas when the condition factor was the lowest, with some recovery at the end of this period. The input of nutrients near caging areas caused a short elevation in zooplankton availability, which promoted changes in the diet of this opportunist species, increasing its feeding activity. However, these changes appeared to be unsustainable due to the poor nutritional condition of the individuals.Keywords: eutrophication, reservoir, aquaculture, feeding, condition factor. Cultivo de tilápias em tanques rede induz alterações na dieta de comunidades naturais: o caso de Auchenipterus osteomystaxResumo O cultivo de peixes em tanques rede é uma prática crescente nos últimos anos. Entretanto, este tipo de cultivo pode causar algumas alterações no ambiente, devido à alta quantidade de nutrientes aí liberados. Assim, o objetivo deste trabalho foi avaliar as influências proporcionadas pelo cultivo de tilápias em tanques rede sobre a dieta, a atividade alimentar e a condição nutricional da surumanha Auchenipterus osteomystax, uma espécie insetívora, porém com zooplanctivoria facultativa. Os peixes foram capturados em redes de espera em duas áreas experimentais de cultivo, localizadas em dois braços do reservatório de Rosana, rio Paranapanema -Pr, a diferentes distâncias dos tanques, em intervalos de 30 dias entre as amostragens. Uma captura foi antes do início do cultivo e as demais nos dois meses subsequentes. Para a análise da dieta, foram utilizados 250 estômagos, sendo os seus conteúdos avaliados através dos métodos de ocorrência e volumétrico combinados no Índice Alimentar (IAi%). As variações espaciais e temporais na at...

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Energy Values of Ecological Materials

Cited by 363 publications

References 9 publications

Validation and use of 22Na turnover to measure food intake in free-ranging lizards

Validation and use of 22Na turnover to measure food intake in free-ranging lizards

Summer-autumn feeding ecology of Pied Flycatchers Ficedula hypolueca and Spotted Flycatchers Muscicapa striata: the importance of frugivory in a stopover area in north-west Iberia

Cage culture with tilapia induces alteration in the diet of natural fish populations: the case of Auchenipterus osteomystax

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