Fungi as food for the aquatic invertebrate Asellus aquaticus

Marcus, J. H.; Willoughby, L. G.

doi:10.1016/s0007-1536(78)80186-7

Cited by 22 publications

(14 citation statements)

References 4 publications

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“…Reports of freshwater invertebrates eating the living green leaves of vascular aquatic plants, in their natural habitats, are briefly summarized by Marcus et al (1978). In the laboratory, the amphipods studied by Embody (1911) ate the epidermis of leaves and stems of Elodea, Uiricularia.…”

Section: Discussionmentioning

confidence: 99%

“…and/or (7) E. callitrichoides (Rich.) Casp (see Marcusef a/., 1978, p. 510); (b) floating: pondweed, Pofamogeton sp.. Sprigs of Elodea leaves with few epiphytes were chosen; also used as food were Elodea leaves with epiphytic algae removed by mechanical vibration, and the epiphytes themselves (details in Marcus et al, 1978). Roots were obtained from: V. beccabunga; R. nasturtium-aquaticum; water mint, Mentha aquatica L.; floatgrass, Glyceria fluitans (L.) R. Br.. Fine roots were selected and washed free from detritus, taking care to remove small particles of decaying leaves adhering to the roots.…”

Section: Materials Used For Growth Experimentsmentioning

confidence: 99%

“…Geometric means and 95% CL for specific growth rates (C,, % body wet wt day"') af 15°C in juvenile and early adult G. pulex fed on fallen tree leaves, green growing leaves or roots of aquatic macrophytes, detritus, and pellets of the aquatic Hyphomycete fungus, Lemonniera aquatica. W (mg) is the mean of geomefHc mean body weights of individuals during each growlh period {D, days); other symbols as in Table 7 Dief •Dried leaves soaked in water for 2-3 days, tA, sprigs of leaves from growing shoot tips; B, leaves cleaned In a stomacher'; C, algal epiphytes from the leaves (see Marcus et al. 1978).…”

Section: Oak and Sycamore Leavesmentioning

confidence: 99%

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Effects of diet, body size, age and temperature on growth rates in the amphipod Gammarus pulex

Sutcliffe¹,

Carrick²,

Willoughby³

1981

Freshwater Biology

169

113

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Increase in body wet weight of Gammarus pulex fed on decaying elm leaves was followed to senescence and death. Growth in juveniles was approximately exponential; from birth to death it conformed to a logistic growth curve, with maximum absolute increments in weight about half-way through a life span of 350-450 days at 15''C. Some individuals lived longer, for up to 640-700 days. The instantaneous or specific growth rate was maximal near birth, at c. 5-6% wet wt day ', and declined exponentially with increasing size and age. Over the range 4.7-14.8°C there was a log-log relationship between temperature and specific growth rate. Growth was maximal at 20°C in newborn animals and at 15°C in 6-9-mg animals.The specific growth rate of young individuals was fastest on decaying leaves of elm with a well developed flora of fungi and other microorganisms. Leached elm leaves without this flora supported growth at a lower rate. The latter diet was sufficient for survival and growth of newborn individuals; detritus, faeces or other food items were not needed. Isolated specimens grew as fast as those kept in groups. Growth was generally slower on leached leaves of oak and sycamore. In newborn animals fed on the fine roots of aquatic plants {Veronica, Rorippa and Glyceria), growth was as fast as on decaying elm leaves; growth on the green living leaves of the plants was slower, as on detritus from two streams and on a pure culture of an aquatic fungus.Consumption of leached elm leaves was related to leaf thickness. In a full gut the wet weight (1.34-1.37 mg) and volume (3.8-4.1 mm^) (for 20-mg animals) was independent of leaf thickness but dependent on animal size, increasing 4-fold over the range 2-50 mg body wt. Daily consumption (dry wt) was approximately equivalent to 50% body dry wt at 5 mg and 20% at 50 mg body wet wt. Individuals fed on thick leaves ingested 50% more dry weight per day and absorbed more in the gut than when fed on thin leaves, but the relative efficiency of absorption was the same at 36-59% for 10-20-mg animals. Weight-specific absorption in the gut was highest in juveniles and decreased with increasing body weight; relative efficiency of absorption was generally lower in the larger individuals. Assuming an energy value of 5 cal mg^' dry wt for elm leaves, daily mean energy intake by absorption in thegutof G. pu/ex was2.2 calmg"' animaldry wt (9.2 Jmg"') in individuals of 0.4 mgdry wt (2 mg wet wt), decreasing to 0.3 cal mg"' (1.3 J mg~') at 10 mg dry wt (50 mg wet wt).Growth in Gammarus is briefly reviewed in the hght of work on other animals and it is emphasized that all aspects of feeding, growth and metabolism should be specifically related to size and age of the individuals, using well defined diets.

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Section: Discussionmentioning

confidence: 99%

Section: Materials Used For Growth Experimentsmentioning

confidence: 99%

Section: Oak and Sycamore Leavesmentioning

confidence: 99%

See 1 more Smart Citation

Effects of diet, body size, age and temperature on growth rates in the amphipod Gammarus pulex

Sutcliffe¹,

Carrick²,

Willoughby³

1981

Freshwater Biology

169

113

View full text Add to dashboard Cite

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“…However, one must also consider the method of presenting the microbes to the animals. Whereas the two fungi were given as relatively large, solid pellets (Marcus & Willoughby, 1978) on which the animals could sit and graze, the bacterium was presented as a more diffuse growth which the animals may have found difficult to eat. It would be very interesting to compare growth of Asellus fed on a procaryotic microbe, such as the aquatic actinomycete Actinoplanes, which also forms solid pellets in liquid culture for subsequent presentation to the animals.…”

Section: Discussionmentioning

confidence: 99%

“…Plots of mean body length against time were curvilinear on arithmetic scales and approximately rectilinear on semi-logarithmic scales (see Fig lb, and Marcus & Willoughby, 1978).…”

Section: Growth Rates On 'Diets'1-22mentioning

confidence: 92%

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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Advances in the Study of So‐called Aquatic Hyphomycetes

Ingold

1979

American J of Botany

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Progress in the study of the freshwater aquatic fungal flora (mainly hyphomycetes) of submerged decaying leaves of dicotyledonous trees and shrubs, since the discovery of the flora in 1942, is reviewed. The abundant occurrence of liberated conidia, which tend to be of distinctive form, in persistent foam on a stream is noted and illustrated by an example from Scotland. Developments in the taxonomy of these fungi since 1942 are noted. About 60 genera and around 120 species are now recorded. In a number the perfect stage has been discovered. In most cases it has proved to be an ascomycete, but it is sometimes a basidiomycete. Conidium development in aquatic hyphomycetes is discussed in the light of recent views on the classification of conidial types. It is argued that the most valid distinction is between phialoconidia and other types, rather than between those of blastic and those of thallic development. Dispersal is discussed with special reference to upstream spread and the problem of dispersal from one isolated water system to another. Finally, attention is given to the ecology and general physiology of these fungi. Their possible importance in processing decaying leaves for subsequent consumption by small aquatic animals is considered. The terrestrial occurrence of many “aquatic hyphomycetes” is noted and it is suggested that “amphibious hyphomycetes” might be a better term.

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Fungi as food for the aquatic invertebrate Asellus aquaticus

Cited by 22 publications

References 4 publications

Effects of diet, body size, age and temperature on growth rates in the amphipod Gammarus pulex

Effects of diet, body size, age and temperature on growth rates in the amphipod Gammarus pulex

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

Advances in the Study of So‐called Aquatic Hyphomycetes

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