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Direct and indirect interactions involving ants, insect herbivores, parasitoids, and the host plant Baccharis dracunculifolia (Asteraceae)
Author(s) -
Fagundes Marcílio,
Neves Frederico S.,
Fernandes G. Wilson
Publication year - 2005
Publication title -
ecological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.865
H-Index - 81
eISSN - 1365-2311
pISSN - 0307-6946
DOI - 10.1111/j.0307-6946.2005.00668.x
Subject(s) - biology , gall , herbivore , parasitoid , homoptera , insect , biological pest control , host (biology) , galling , botany , ecology , pest analysis , materials science , metallurgy
. 1. The relative importance of direct and indirect interactions in controlling organism abundance is still an unresolved question. This study investigated the role of the direct and indirect interactions involving ants, aphids, parasitoids, and the host plant Baccharis dracunculifolia (Asteraceae) on a galling herbivore Baccharopelma dracunculifoliae (Homoptera: Psyllidae). 2. The effects of these interactions on the galling herbivore's performance were evaluated by an exclusion experiment during two consecutive generations of the galling insect. 3. Ants had a direct negative effect on the performance of the galling herbivore by reducing the number of nymphs per gall. In contrast, ants had no indirect effects on gall mortality through the associated parasitoids. 4. Aphids negatively affected gall development, suggesting that galls and aphids might be partitioning photoassimilates and nutrients moving throughout host‐plant tissues. 5. In addition, galls that developed during the rainy season were heavier, indicating that variation in the host plant, due to weather changes, can affect the development of B. dracunculifoliae galls. However, variation in the development of B. dracunculifoliae galls due to presence of aphids or the weather changes did not affect parasitoid attack. 6. These results suggest that direct interactions between ants and galls influenced galling insect abundance, whereas numerical indirect effects involving galling insects, ants, aphids, and host plants were less conspicuous.