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Insectivorous birds disrupt biological control of cereal aphids
Author(s) -
Grass Ingo,
Lehmann Katrin,
Thies Carsten,
Tscharntke Teja
Publication year - 2017
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1002/ecy.1814
Subject(s) - aphid , biology , predation , trophic level , insectivore , sitobion avenae , agroecosystem , ecology , mesopredator release hypothesis , biological pest control , predator , agronomy , pest analysis , aphididae , botany , homoptera , agriculture
Abstract Insect‐feeding birds may interfere with trophic interactions in plant–insect food webs, which may be particularly important in agroecosystems. Here, we studied how Eurasian Tree Sparrows ( Passer montanus ) affect aphids and their predators in cereal fields using bird exclusion experiments. The Tree Sparrows fed their nestlings with aphid antagonists. Hoverflies and ladybird beetles accounted for 77% of the food for the nestlings during peak aphid density. When birds were excluded, densities of hoverfly larvae, which were the most abundant aphid predator group in the cereals, were 4% higher in wheat and 45% higher in oat, while aphid densities were 24% lower in wheat and 26% lower in oat. The demonstrated disruption of biological control by mesopredators through bird predation may be a common phenomenon in cropping systems characterized by small‐sized and abundant pest species. Management of biotic interactions such as biological control needs a broad food‐web perspective, even in simplified agroecosystems.