Some aspects of the feeding biology of benthic herbivores

Moore, James W.

doi:10.1007/bf00029292

Cited by 21 publications

(11 citation statements)

References 31 publications

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“…Moore suggested that Cocconeis species were not grazed because they are adnate, lying very close to the algal filaments. These diatoms were also apparently selected against by G. lacustris in a subarctic stream (Moore, 1977a) but also see Moore (1977b) for comments on the difficulties of studying selective grazing.…”

Section: Discussionmentioning

confidence: 99%

Feeding and growth of Asellus aquaticus (Isopoda) on food items from the littoral of Windermere, including green leaves of Elodea canadensis

1978

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In the laboratory, Asellus aquaticus .devoured intact green leaves from growing shoots of the aquatic macrophyte Elodea canadensis. in four collections of A. aquaticus on Elodea in a lake (Windermere), c. 20% of the specimens contained in their guts fragments of green Elodea leaves; this material and pieces of oak (Quercus) were identified from characteristic leaf hairs. Some specimens had also eaten the filamentous alga Oedogonium. Fluorescence microscopy is a useful aid for screening Invertebrates that may have eaten living plant tissues.Immature A. aquaticus, with an initial mean body length of c. 3 mm, wet weight c. 1 mg, were grown through sexual maturity over a 49-day period at 15°C in a series of twenty-two experiments (six to twelve isolated specimens in each experiment) comparing growth rates on different foods, including instances where no food was given. Animals were fed on a variety of items collected from the littoral of Windermere, plus some laboratory cultures of algae and bacteria. The highest mean specific growth rate (5.8% day"') was obtained on young Elodea leaves mechanically shaken to remove epiphytes. Other diets yielding fast growth rates (3.7-5.3%day"') were young growing leaves oi Elodea with few epiphytes and older green and brown living leaves covered with a thick growth of epiphytic algae, epiphytic algae removed from Elodea., plastic imitation Elodea immersed in the lake until covered with attached algae, epilithic algae on stones, Oedogonium, and decaying oak leaves. Slower growth (l.3-2.2%day"') and poorer survival was obtained on the following: a pure culture of the bacterium Sphaerotilus natans; cultured bacteria from lakewater; the filamentous algae Gadophora and Stigeoclonium both with and without epiphytes; faecal matter from Asellus; freshly killed Asellus; lake sediment. Some growth (mean = 0.7% day"') and 50% survival for 21 days occurred in 'starved' animals kept in filtered, sterilized lakewater. Better survival and slightly faster growth (1.0-1.5%day"') occurred in 'starved' animals kept in filtered and unfiltered lakewater.Growth of A. aquaticus was also experimentally determined from birth in animals fed on young green Elodea leaves and on decaying oak leaves. On both diets, growth was curvilinear and approximately exponential from birth to sexual maturity reached at c. 2mg wet weight in 46-60 days at \5°C. In older specimens the relative growth rate gradually fell over a period of 50 days, representing a more linear phase of growth during sexual maturity.

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Section: Discussionmentioning

confidence: 99%

Feeding and growth of Asellus aquaticus (Isopoda) on food items from the littoral of Windermere, including green leaves of Elodea canadensis

1978

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“…Of course, such considerations would be no less important later at night. However, since many nonpredaceous stream invertebrates feed more or less continuously (e.g., Moore 1977, McCullough eta!. 1979a, b, Marchant and Hynes 1981, it is unlikely that individual feeding patterns are sufficiently synchronized to account for drift peaks after the post-sunset peak, although Bishop (1969) suggested such a hypothesis.…”

Section: Die/ Periodicitiesmentioning

confidence: 99%

Identification of Stream Drift Mechanisms: An Experimental and Observational Approach

Kohler¹

1985

Ecology

156

118

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Laboratory experiments were conducted with the periphyton—grazing mayfly Baetis tricaudatus to test the hypothesis that stream drift results from the passive removal of individuals from substrates. This hypothesis accounts for entry into the water column and diel drift periodicities, based on changes in the positioning of individuals on substrates and changes in their activity rates. A factorial design that incorporated food abundance (low or high), food distribution (low, intermediate, or high degree of patchiness), and forager hunger level (starved or well fed) was used to produce contrasting diel behavioral patterns necessary to test the hypothesis. Nymph behavior was monitored during the day and night using time—lapse cinematography and direct visual observations. Nymphs fed ad libitum had greater proportions of individuals on top surfaces at night that during the day. Starved nymphs showed little day—night variation in activity or positioning behavior, and their behavior during the day was similar to that of fed nymphs at night. Therefore, if drift—entry was passive, diurnal drift of starved nymphs should have been greater than or equal to nocturnal drift of fed nymphs in comparisons made within food levels. In all cases this prediction was not supported. These results refute the passive drift—entry hypothesis and support the alternative hypothesis of active entry into the water column. Drift patterns and foraging behaviors in these experiments and in an additional set of experiments were analyzed to identify proximate factors responsible for active drift—entry by Baetis. Drift was greatest at night and at the low food level. Periphyton patchiness and nymph hunger level did not significantly affect drift in the factorial experiments. In additional experiments, over a wide range of food abundance (2.5 x 105 to 107 diatom cells/cm2), the proportion drifting at night was significantly greater than zero when food was patchily distributed on substrates, but not when food was uniformly distributed. Based on these results and behavioral observations suggesting that food patches were less readily encountered with increasin degree of patchiness, I suggest that active drift is a component of Baetis food searching behavior and that individuals abandon habitats by enterin the water column when their estimate of habitat quality falls to some threshold level.

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“…Apart from Nilsson's (1974) of food (leaves) eaten was measured directly, other studies have been based on measuring either the time taken to empty the gut when the amphipod is starved (Moore. 1975(Moore. , 1977 or the time taken for a visible tracer to pass along the gut (Monk.…”

Section: Introductionmentioning

confidence: 99%

Field estimates of feeding rate for Gammarus pseudolimnaeus (Crustacea: Amphipoda) in the Credit River, Ontario

Marchant

Hynes

1981

Freshwater Biology

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The feeding rate of G. pseudolimnaeus was measured monthly for 7 months in the field by monitoring the decline in weight of gut contents when the amphipod was starved. This decline was modelled by an exponential regression of weight on time. As the amphipods appeared to be continuous feeders, feeding rate was calculated by multiplying the dry weight of a full gut by the specific rate of emptying, i.e., the slope of the exponential regression. Specific rate of emptying was independent of animal size, but increased with temperature. Therefore, food has a longer period in which to be digested at low temperatures, which suggests that assimilation efficiency may increase.However, the assimilation efficiency of amphipods feeding on decaying maple leaves in the laboratory was only 10% and did not vary with temperature. Ingestion and egestion rates were measured in the laboratory by weighing amounts eaten and defecated. The turnover time of the contents of a full gut in the laboratory often agreed very well with turnover time measured in the field, i.e., the reciprocal of the specific rate of emptying, thus confirming the use of an exponential regression.

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Some aspects of the feeding biology of benthic herbivores

Cited by 21 publications

References 31 publications

Feeding and growth of Asellus aquaticus (Isopoda) on food items from the littoral of Windermere, including green leaves of Elodea canadensis

Feeding and growth of Asellus aquaticus (Isopoda) on food items from the littoral of Windermere, including green leaves of Elodea canadensis

Identification of Stream Drift Mechanisms: An Experimental and Observational Approach

Field estimates of feeding rate for Gammarus pseudolimnaeus (Crustacea: Amphipoda) in the Credit River, Ontario

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