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Tibor Bukovinszky Antonie M. Verschoor Nico R. Helmsing T. Martijn Bezemer Elisabeth S. Bakker Matthijs Vos Lisette N. de Senerpont Domis 《PloS one》2012,7(9)
Effects of food quality and quantity on consumers are neither independent nor interchangeable. Although consumer growth and reproduction show strong variation in relation to both food quality and quantity, the effects of food quality or food quantity have usually been studied in isolation. In two experiments, we studied the growth and reproduction in three filter-feeding freshwater zooplankton species, i.e. Daphnia galeata x hyalina, D. pulicaria and D. magna, on their algal food (Scenedesmus obliquus), varying in carbon to phosphorus (C∶P) ratios and quantities (concentrations). In the first experiment, we found a strong positive effect of the phosphorus content of food on growth of Daphnia, both in their early and late juvenile development. Variation in the relationship between the P-content of animals and their growth rate reflected interspecific differences in nutrient requirements. Although growth rates typically decreased as development neared maturation, this did not affect these species-specific couplings between growth rate and Daphnia P-content. In the second experiment, we examined the effects of food quality on Daphnia growth at different levels of food quantity. With the same decrease in P-content of food, species with higher estimated P-content at zero growth showed a larger increase in threshold food concentrations (i.e. food concentration sufficient to meet metabolic requirements but not growth). These results suggest that physiological processes such as maintenance and growth may in combination explain effects of food quality and quantity on consumers. Our study shows that differences in response to variation in food quality and quantity exist between species. As a consequence, species-specific effects of food quality on consumer growth will also determine how species deal with varying food levels, which has implications for resource-consumer interactions. 相似文献
3.
ROBERT STERNER 《Freshwater Biology》1997,38(3):473-481
1. Boundaries between growth limitation by carbon (C) and phosphorus (P) in homeostatic heterotrophic consumers such as zooplankton will vary as demands on these two elements vary, as they should at different food quantities. At very low food quantity when production is close to zero, metabolic requirements (for carbon) become more important than growth requirements (for carbon and phosphorus in fixed proportion). Thus, the boundary separating C-and P-limited growth should be at a higher C : P ratio at low food quantity than at high food quantity.
2. A model including both metabolism and growth indicates that consumer growth should differ between foods of high vs. low phosphorus concentration only when food quantity is above a certain level. Thus, two foods might give identical consumer growth rates at low food quantity but give different consumer growth at higher quantity.
3. Solution of the model using parameters based on 2 mm Daphnia compared with a survey of C and P in seston of marine and freshwater sites supports earlier conclusions of the potential importance of food quality constraints on Daphnia growth. 相似文献
2. A model including both metabolism and growth indicates that consumer growth should differ between foods of high vs. low phosphorus concentration only when food quantity is above a certain level. Thus, two foods might give identical consumer growth rates at low food quantity but give different consumer growth at higher quantity.
3. Solution of the model using parameters based on 2 mm Daphnia compared with a survey of C and P in seston of marine and freshwater sites supports earlier conclusions of the potential importance of food quality constraints on Daphnia growth. 相似文献
4.
Seston quality controls zebra mussel (Dreissena polymorpha ) energetics in turbid rivers 总被引:3,自引:1,他引:2
Daniel W. Schneider Sharook P. Madon James A. Stoeckel Richard E. Sparks 《Oecologia》1998,117(3):331-341
Feeding processes and energetic balance of zebra mussels were both related to the quantity and quality of natural seston.
Filtration rate and pseudofeces production increased while clearance rate remained constant with increasing seston concentration.
Ingestion rate, assimilation efficiency, and assimilation rate all increased with increasing food quality, measured as the
ratio of organic to inorganic material in the seston. Respiration rate did not change with either food quantity or quality.
As a result, scope for growth declined with decreasing food quality, and fell below 0 cal mg−1 h−1 at an organic:inorganic ratio of 0.5. The association between feeding processes and food quality appears related to a breakdown
in the ability of zebra mussels to selectively ingest high-quality organic particles when the organic content of the seston
is low. Ingestion, assimilation efficiency, assimilation rate and scope for growth were all higher when seston was amended
with an addition of a natural assemblage of algae. Food quality may be a better indicator of environmental conditions suitable
for growth than food quantity. These results suggest that the conditions of high suspended inorganic sediment concentrations
in large turbid rivers represent a difficult growth environment for the zebra mussel.
Received: 12 May 1997 / Accepted: 7 July 1998 相似文献
5.
Filtration and digestion responses of an elementally homeostatic consumer to changes in food quality: a predictive model 总被引:1,自引:0,他引:1
François Darchambeau 《Oikos》2005,111(2):322-336
In the study of the stoichiometric relationship between autotrophs and herbivores, attention has been largely focused on effects of the encountered mismatch between needs and supplies of an element on herbivore growth and ecosystem processes. Herbivore adaptation to poor food quality has rarely been investigated. This study presents a predictive model of feeding, assimilation, digestion and excretion of Daphnia facing a dietary deficiency in phosphorus. Biochemical compounds in the food were divided into phosphorous and non-phosphorus compounds. It was assumed that Daphnia is able to differently assimilate both types of compounds by regulation of target specific digestive enzymes. Feeding rate was regulated by optimal gut residence time of food particles, and assimilation efficiency by gut residence time and optimal secretion of both classes of gut enzymes. The model predicted the optimal strategy for a consumer facing an elementally imbalanced diet: (1) increase the ingestion rate, and (2) increase the secretion rate of both classes of gut enzymes. It resulted in decreased C and nutrient assimilation efficiencies, increased C feeding costs, and reduced growth rate. Sensitivity analysis showed that these predictions were qualitatively not influenced by parameter values. An alternative model was tested that includes an additive term allowing the direct excretion of C assimilated in excess. Results showed that this strategy is not optimal for the consumer growth rate. In conclusion, the model supports the hypothesis that carbon ingested in excess may generate energy that can be used to obtain more nutrients by increased feeding rate. 相似文献
6.
植物蛋白酶抑制剂在植物抗虫与抗病中的作用 总被引:13,自引:0,他引:13
综述了植物蛋白酶抑制剂抗虫与抗病作用的研究进展.蛋白酶抑制剂广泛存在于植物体内,与植物抗虫抗病密切相关.植物蛋白酶抑制剂能抑制昆虫肠道蛋白酶,使昆虫生长发育缓慢,甚至死亡.但取食蛋白酶抑制剂后,昆虫能迅速分泌对抑制剂不敏感的蛋白酶,而使蛋白酶抑制剂无效.食物蛋白的含量和质量也影响植物蛋白酶抑制剂的抗虫效果.病原菌的感染能诱导植物产生蛋白酶抑制剂,诱导产生的蛋白酶抑制剂能抑制病原菌的生长. 相似文献
7.
Mismatches in the elemental composition of herbivores and their resources can impact herbivore growth and reproduction. In
aquatic systems, the ratio of elements, such as C, P, and N, is used to characterize the food quality of algal prey. For example,
large increases in the C:P ratio of edible algae can decrease rates of growth and reproduction in Daphnia. Current theory emphasizes that Daphnia utilize only assimilation and respiration processes to maintain an optimal elemental composition, yet studies of terrestrial
herbivores implicate behavioral processes in coping with local variation in food quality. We tested the ability of juvenile
and adult Daphnia to locate regions of high-quality food within a spatial gradient of algal prey differing in C:P ratio, while holding food
density constant over space. Both juveniles and adults demonstrated similar behavior by quickly locating (i.e., <10 min) the
region of high food quality. Foraging paths were centred on regions of high food quality and these differed significantly
from paths of individuals exposed to a homogeneous environment of both food density and food quality. Ingestion rate experiments
on algal prey of differing stoichiometric ratio show that individuals can adjust their intake rate over fast behavioral time-scales,
and we use these data to examine how individuals choose foraging locations when presented with a spatial gradient that trades
off food quality and food quantity. Daphnia reared under low food quality conditions chose to forage in regions of high food quality even though they could attain the
same C ingestion rate elsewhere along a spatial gradient. We argue that these aspects of foraging behavior by Daphnia have important implications for how these herbivores manage their elemental composition and our understanding of the dynamics
of these herbivore–plant systems in lakes and ponds where spatial variation in food quality is present.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
Nancy B. Grimm 《Environmental Biology of Fishes》1988,21(2):143-152
Synopsis Feeding habits, diel periodicity and total daily ingestion, and nitrogen budgets of longfin dace (Agosia chrysogaster) were examined on two occasions when food quality, but not quantity, differed. Agosia chrysogaster was found to be an opportunistic omnivore, consuming primarily insects when the preferred taxon (baetid mayflies) was abundant
in the environment, but consuming primarily algae when mayfly abundance was low. Ingestion provided a better measure of diel
feeding periodicity than gut fullness; feeding was diurnal on both sample dates, but more markedly so when the primary food
was algae. Mean nitrogen content of algal foods was low, and A. chrysogaster apparently compensated for this by increasing its daily ingestion rate when algae were the major food. A reduction in nitrogen
content of food during digestion from 4–6% (of dry mass) to less than 1% (in feces) suggested a high assimilation efficiency
for nitrogen (nitrogen assimilated/nitrogen consumed = 72–78%). Populations of this abundant and successful cyprinid in Sonoran
Desert streams may play an important role in ecosystem nitrogen dynamics. Nitrogen stored in fish biomass comprised 3–6% of
the total nitrogen stored in Sycamore Creek, and excretion of ammonia by the fish represented 5–10% of total nitrogen uptake
by algae. Such rapid recycling of usable nitrogen to primary producers is significant in this nitrogen limited stream ecosystem. 相似文献
9.
Jeschke JM Kopp M Tollrian R 《Biological reviews of the Cambridge Philosophical Society》2004,79(2):337-349
The functional response of a consumer is the relationship between its consumption rate and the abundance of its food. A functional response is said to be of type I if consumption rate increases linearly with food abundance up to a threshold level at which it remains constant. According to conventional wisdom, such type I responses are more frequent among filter feeders than among other consumers. However, the validity of this claim has never been tested. We review 814 functional responses from 235 studies, thereby showing that type I responses are not only exceptionally frequent among filter feeders but that they have only been reported from these consumers. These findings can be understood by considering the conditions that a consumer must fulfil in order to show a type I response. First, the handling condition: the consumer must have a negligibly small handling time (i.e. the time needed for capturing and eating a food item), or it must be able to search for and to capture food while handling other food. Second, the satiation condition: unless its gut is completely filled and gut passage time is minimal, the consumer must search for food at a maximal rate with maximal effort. It thus has to spend much time on foraging (i.e. searching for food and handling it). Our functional response review suggests that only filter feeders sometimes meet both of these conditions. This suggestion is reasonable because filter feeders typically fulfil the handling condition and can meet the satiation condition without losing time, for they are, by contrast to non-filter feeders, able simultaneously to perform foraging and non-foraging activities, such as migration or reproduction. 相似文献
10.
McWilliams SR Karasov WH 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2001,128(3):579-593
Birds during migration must satisfy the high energy and nutrient demands associated with repeated, intensive flight while often experiencing unpredictable variation in food supply and food quality. Solutions to such different challenges may often be physiologically incompatible. For example, increased food intake and gut size are primarily responsible for satisfying the high energy and nutrient demands associated with migration in birds. However, short-term fasting or food restriction during flight may cause partial atrophy of the gut that may limit utilization of ingested food energy and nutrients. We review the evidence available on the effects of long- and short-term changes in food quality and quantity on digestive performance in migratory birds, and the importance of digestive constraints in limiting the tempo of migration in birds. Another important physiological consequence of feeding in birds is the effect of diet on body composition dynamics during migration. Recent evidence suggests that birds utilize and replenish both protein and fat reserves during migration, and diet quality influences the rate of replenishment of both these reserves. We conclude that diet and phenotypic flexibility in both body composition and the digestive system of migratory birds are important in allowing birds to successfully overcome the often-conflicting physiological challenges of migration. 相似文献
11.
We consider a stoichiometric population model of two producers and one consumer. Stoichiometry can be thought of as the tracking of food quality in addition to food quantity. Our model assumes a reduced rate of conversion of biomass from producer to consumer when food quality is low. The model is open for carbon but closed for nutrient. The introduction of the second producer, which competes with the first, leads to new equilibria, new limit cycles, and new bifurcations. The focus of this paper is on the bifurcations which are the result of enrichment. The primary parameters we vary are the growth rates of both producers. Secondary variable parameters are the total nutrients in the system, and the producer nutrient uptake rates. The possible equilibria are: no-life, one-producer, coexistence of both producers, the consumer coexisting with either producer, and the consumer coexisting with both producers. We observe limit cycles in the latter three coexistence combinations. Bifurcation diagrams along with corresponding representative time series summarize the behaviours observed for this model. 相似文献
12.
Offspring size–number tradeoffs and food quality feedbacks impact population dynamics in a Daphnia–algae system
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Population fluctuations can be affected by both extrinsic (e.g. weather patterns, food availability) and intrinsic (e.g. life‐history) factors. A key life‐history tradeoff is the production of offspring size versus number, ranging from many small offspring to few large offspring. Models show that this life‐history tradeoff in offspring size and number, through maturation time, can have significant impacts on population dynamics. However, few manipulative experiments have been conducted that can isolate life‐history effects from impacts of extrinsic factors in consumer–resource systems. We experimentally tested the effect of an offspring size–number tradeoff on population stability and food availability in a consumer–resource system. Using Daphnia pulex, we created a shift from many, small offspring being produced to fewer, larger offspring. Two sets of experiments were performed to examine the interaction of an extrinsic factor (light levels) and intrinsic population structure on dynamics, and we controlled for the ingestion pressure on algal prey at the time of the manipulation. We predicted that the tradeoff would impact internal consumer population characteristics, including biasing the stage structure towards adults, increasing adult size, and increasing average population‐level reproduction. This adult‐dominated stage structure was predicted to then lead to instability and a low quantity–high quality food state. Under all light levels, the manipulated populations became dominated by large adults. Contrary to predictions, the amplitudes of fluctuations in Daphnia biomass were lower in populations shifted to few–large offspring, representing higher stability in these populations. Furthermore, in high light conditions, a stable low Daphnia – high algae biomass (low food quality) state was observed in few–large offspring treatments but not in control (many–small offspring) treatments. Our results show a strong link between light levels as an extrinsic factor and the life‐history tradeoff of consumer offspring size versus number that impacts consumer–resource population dynamics through feedbacks with resource quality. 相似文献
13.
《Journal of biological dynamics》2013,7(2):97-116
We consider a stoichiometric population model of two producers and one consumer. Stoichiometry can be thought of as the tracking of food quality in addition to food quantity. Our model assumes a reduced rate of conversion of biomass from producer to consumer when food quality is low. The model is open for carbon but closed for nutrient. The introduction of the second producer, which competes with the first, leads to new equilibria, new limit cycles, and new bifurcations. The focus of this paper is on the bifurcations which are the result of enrichment. The primary parameters we vary are the growth rates of both producers. Secondary variable parameters are the total nutrients in the system, and the producer nutrient uptake rates. The possible equilibria are: no-life, one-producer, coexistence of both producers, the consumer coexisting with either producer, and the consumer coexisting with both producers. We observe limit cycles in the latter three coexistence combinations. Bifurcation diagrams along with corresponding representative time series summarize the behaviours observed for this model. 相似文献
14.
Summary The aim of this study was to assess the effects of developmental events, occurring in fish during the first weeks after hatching, on the quantity and quality of the ingested food and on growth. The investigation was carried out with the larvae and juveniles of Rutilus rutilus, the single cyprinid species occurring in an oligotrophic subalpine lake in Tirol, Austria. Comparison between availability of prey in the water and gut contents suggests that the selection of food by the young fish is strongly influenced by developmental processes. For example, the prevalence of indigestible phytoplankton in the gut of young larvae can be taken as a sign of the not yet fully developed sensory and locomotory capacities of the young fish (El-Fiky et al. 1987). Furthermore, quantitative and qualitative changes in the gut contents correlate strongly with changes in the form and relative length of the gut, but reflect only weakly the availability of prey in the water. In the Seefelder See population of R. rutilus the switch from a phytoplankton to a cladoceran dominated diet is accompanied by an increase in relative growth rate by nearly one order of magnitude (Wieser et al. 1988). 相似文献
15.
Spatial stoichiometry: cross‐ecosystem material flows and their impact on recipient ecosystems and organisms
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Judith Sitters Carla L. Atkinson Nils Guelzow Patrick Kelly Lauren L. Sullivan 《Oikos》2015,124(7):920-930
Cross‐ecosystem material flows, in the form of inorganic nutrients, detritus and organisms, spatially connect ecosystems and impact food web dynamics. To date research on material flows has focused on the impact of the quantity of these flows and largely ignored their elemental composition, or quality. However, the ratios of elements like carbon, nitrogen and phosphorus can influence the impact material flows have on food web interactions through stoichiometric mismatches between resources and consumers. The type and movement of materials likely vary in their ability to change stoichiometric constraints within the recipient ecosystem and materials may undergo changes in their own stoichiometry during transport. In this literature review we evaluate the importance of cross‐ecosystem material flows within the framework of ecological stoichiometry. We explore how movement in space and time impacts the stoichiometry of material flow, as these transformations are essential to consider when assessing the ability of these flows to impact food web productivity and ecosystem functioning. Our review suggests that stoichiometry of cross‐ecosystem material flows are highly dynamic and undergo changes during transport across the landscape or from human influence. These material flows can impact recipient organisms if they change stoichiometry of the abiotic medium, or provide resources that have a different stoichiometry to in situ resources. They might also alter consumer excretion rates, in turn altering the availability of nutrients in the recipient ecosystem. These alterations in stoichiometric constraints of recipient organisms can have cascading trophic effects and shape food web dynamics. We highlight significant gaps in the literature and suggest new avenues for research that explore how cross‐ecosystem material flows impact recipient ecosystems when considering differences in stoichiometric quality, their movement through the landscape and across ecosystem boundaries, and the nutritional constraints of the recipient organisms. 相似文献
16.
Insect-based dog and cat food: A short investigative review on market,claims and consumer perception
《Journal of Asia》2023,26(1):102020
The interest in use of insects for human food has also resulted in the appearance of insect-based dog and cat food products in the market. Insect-based pet food producers are using several health and sustainability claims for marketing purposes, which are expected to be the main drivers of market growth in the near future.In this paper, we systematically synthesize information about the insect-based pet food market, investigating the type of products commercially available, providing a geographical overview and type of insect species being commonly used in these products. We then try to synthesize information about health and sustainability claims currently being used by insect-based pet food companies in different geographies. Finally, we review information about consumer perception of: (1). these products in general; and (2). claims being used to market these products.The insect-based pet food market is growing rapidly in Europe. Recent regulatory approval in the USA will push this growth in the North American market too. It appears that consumers have connected very well with sustainability, hypoallergenicity and the overall gut health claims. Finally, insect-based pet food producers should: (1). adopt systematic marketing; (2). produce more scientific evidence; and (3). actively communicate and partner with veterinarians to improve the consumer perception of claims used on insect-based pet foods. 相似文献
17.
Rodents, plants, and precipitation: spatial and temporal dynamics of consumers and resources 总被引:5,自引:0,他引:5
Resource/consumer dynamics are potentially mediated by both limiting resources and biotic interactions. We examined temporal correlations between precipitation, plant cover, and rodent density, with varying time lags using long-term data from two sites in the Chihuahuan desert of North America: the Sevilleta Long-term Ecological Research site (LTER), New Mexico, USA and a site near Portal, Arizona, USA. We also calculated the spatial correlations in precipitation, plant cover, and rodent dynamics among six sites, five at Sevilleta and one at Portal. At Sevilleta, all three variables were temporally correlated, with plant cover responding to precipitation during the same growing season and rodent populations lagging at least one season behind. At Portal, plant stem count was also correlated with precipitation during the same growing season, but there was no significant correlation between rodents and either precipitation or plant growth. Spatial correlations in plant cover and rodent populations between sites reflected the localized nature of summer rainfall, so that sites with highly correlated summer precipitation exhibited higher correlations in plant cover and rodent populations. In general, our results indicate that limiting resources influence consumer dynamics, but these dynamics also depend crucially on the biotic interactions in the system. 相似文献
18.
The evolution of ecosystem processes: growth rate and elemental stoichiometry of a key herbivore in temperate and arctic habitats 总被引:1,自引:0,他引:1
Understanding the reciprocal interactions between the evolved characteristics of species and the environment in which each species is embedded is a major priority for evolutionary ecology. Here we use the perspective of ecological stoichiometry to test the hypothesis that natural selection on body growth rate affects consumer body stoichiometry. As body elemental composition (nitrogen, phosphorus) of consumers influences nutrient cycling and trophic dynamics in food webs, such differences should also affect biogeochemical processes and trophic dynamics. Consistent with the growth rate hypothesis, body growth rate and phosphorus content of individuals of the Daphnia pulex species complex were lower in Wisconsin compared to Alaska, where the brevity of the growing season places a premium on growth rate. Consistent with stoichiometric theory, we also show that, relative to animals sampled in Wisconsin, animals sampled in Alaska were poor recyclers of P and suffered greater declines in growth when fed low‐quality, P‐deficient food. These results highlight the importance of evolutionary context in establishing the reciprocal relationships between single species and ecosystem processes such as trophic dynamics and consumer‐driven nutrient recycling. 相似文献
19.
J N Crawley 《Peptides》1983,4(4):405-410
Cholecystokinin induces a reduction in exploratory behaviors which could reflect an underlying behavioral state of either satiety or malaise. To investigate these alternative hypotheses, the effects of CCK were compared to the effects of (a) consumption of an extra quantity of palatable food, of (b) bombesin at doses known to inhibit food consumption, and of (c) lithium chloride, at doses known to produce taste aversion. Parameters of exploration of a novel arena surface and investigation of a novel object placed in the center of the arena were analyzed by an automated video-tracking computer-assisted animal behavior monitor. Cholecystokinin reduced all parameters of exploration. Ingestion of at least one gram of chocolate chip cookie also reduced all exploratory parameters. Bombesin reduced only parameters of approach to the novel object and the center of the arena. Lithium chloride reduced only parameters of approach to the novel object and the center of the arena. CCK may influence exploratory behaviors through mechanisms similar to those produced by ingestion of palatable food, but somewhat different from those produced by lithium and bombesin. 相似文献
20.
The transfer of energy and nutrients from plants to animals is a key process in all ecosystems. In lakes, inefficient transfer of primary producer derived energy can result in low animal growth rates, accumulation of nuisance phytoplankton blooms and dissipation of energy from the ecosystem. Most research on carbon transfer efficiency in pelagic food webs has focused on either food quantity or food quality, with the latter considered separately as either elemental stoichiometry or biochemical composition. The natural occurrence and magnitude of these types of growth limitations and their combined effects on Daphnia , a keystone grazer in pelagic freshwater ecosystems, are largely unknown. Our empirical models predict that the strength and nature of food quantity and quality limitation varies greatly with lake trophic state (total phosphorus, TP) and that Daphnia growth rates and thus energy and nutrient transfer efficiency are highest in lakes with intermediate trophic status (TP 10–25 μg l−1 ). We predict that food availability place the greatest constraint on Daphnia growth in nutrient poor lakes (TP≤4 μg l−1 ). Phosphorus limitation of Daphnia growth increased with decreasing TP, but the overall effect was never predicted to be the dominant constraining factor. Eicosapentaenoic acid (EPA, 20:5ω3) limitation was predicted to occur in both nutrient poor and nutrient rich lakes and placed the primary constraint on food quality in the most productive lakes. Two contrasting EPA-models gave different results on the magnitude of EPA-limitation, implying that additional food quality factors decrease Daphnia growth at high TP. In conclusion, the model predicts that Daphnia growth should peak in mesotrophic lakes, food quantity will place the greatest constraint on growth in oligotrophic lakes and EPA will primarily limit growth in eutrophic lakes. 相似文献