Feeding ecology of three predacious aquatic insects and two fish in a riffle of the Speed River, Ontario

Abstract

The food habits of two fish (Etheostoma flabellare and Rhinichthys atratulus) and three predacious aquatic insects (Nigronia serricornis, Paragnetina media and Agnetina capitata) were examined for one year in a riffle of the Speed River, Ontario. Adult E. frabellare fed primarily on net-spinning caddisflies whereas juvenile E. flabellare relied heavily on chironomids. Rhinichthys atratulus had a more varied diet composed of chironomids, Antocha larvae (Tipulidae) and net-spinning caddisflies. Two of the aquatic insect predators consumed large numbers of net-spinning caddisflies; however, I? media contained large percentages of Hydropsyche and Cheumatopsyche whereas N. serricornis fed primarily on non-hydropsychid net-spinners. The diet o? A. capitata was composed largely of chironomids and mayflies. Schoener's diet overlap index ((Y) suggested that large E. J'abellare and I? media had similar diets; however, E. flabellare ingested much larger prey than I? media. Adult E. flabellare contained a significantly greater proportion of larger prey items in comparison with benthic samples whereas similar comparisons with other predators showed no selection for larger prey. These data demonstrate that E. flabellare was size selective given the range of prey sizes available whereas the other predators were not. Also, there was little dietary overlap among the fish and invertebrate predators suggesting a partitioning of resources.

The influence of copper exposure on predator‐prey interactions in aquatic insect communities

“…The preference of Paragnetina media for hydropsychid caddisflies has been reported elsewhere (Fuller & Hynes, 1987). Although prey selectivity of these organisms will largely depend on prey availability (Allan, 1982), the similarity of our results to those observed in the field suggests that feeding behaviour of stoneflies in experimental streams reflected natural preferences.…”

Ecology of invertebrate predators in a Coastal Plain stream

“…Diets of the invertebrate predators in Buzzards Branch were composed of a variety of animal spedes and detritus, and were similar to those reported for related taxa in other studies (e.g. Baker & McLachlan, 1979;Allan, 1982;Johnson, 1982;Blois, 1985;Feminella & Stewart, 1986;Fuller & Hynes, 1987;Dudgeon, 1989b,c). Diet was related to the habitat of the predators.…”

“…Baker & McLachlan, 1979;Allan, 1982;Johnson, 1982;Blois, 1985;Feminella & Stewart, 1986;Fuller & Hynes, 1987;Dudgeon, 1989b,c). Diet was related to the habitat of the predators.…”

The importance of omnivory and predator regulation of prey in freshwater fish assemblages of North America

“…Trophic studies of freshwater fish assemblages are not exhaustive food web analyses, but simultaneous gut analyses of freshwater fishes and invertebrates are rare and usually do not encompass entire food webs (e.g., Mackey 1979, Allan 1983a, Fuller & Hynes 1987but see Minshall 1967). Hence, the complete food chains of the 15 freshwater ecosystems could not be established, such that the omnivory found in the present analysis may not all be same-chain in character.…”