Epsilon Open Archive

Abstract

This study investigated the effects of airborne
interaction between different barley cultivars on the
behaviour of bird cherry-oat aphid Rhopalosiphum padi, the
ladybird Coccinella septempunctata and the parasitoid
Aphidius colemani. In certain cultivar combinations,
exposure of one cultivar to air passed over a different cultivar
caused barley to have reduced aphid acceptance and
increased attraction of ladybirds and parasitoids. Parasitoids
attacked aphids that had developed on plants under exposure
more often than those from unexposed plants, leading
to a higher parasitisation rate. Ladybirds, but not parasitoids,
were more attracted to combined odours from certain
barley cultivars than either cultivar alone. The results show
that airborne interactions between undamaged plants can
affect higher trophic levels, and that odour differences
between different genotypes of the same plant species may
be sufficient to affect natural enemy behaviour.