The effects of condensed tannins on behaviour and performance of a
specialist aphid on Aspen
Abstract
The plant defence syndromes (PDSs) concept predicts host plants should
develop diverse resistance profiles against their herbivores. We used
Electrical Penetration Graphs (EPG) to investigate complex and
genotype-specific penetration-barriers to Chaitophorous tremulae aphid
feeding on Aspen (Populus tremula). Leaf condensed tannins were
associated with enhanced probing activity and increased ingestion of
xylem sap. Aphids probed less on Aspen genotypes low in tannins,
suggesting other defence traits might be elicited. Our results support
the idea of multi-layered PDS defence traits, and provide evidence of
high plasticity in tannin profiles across temporal and spatial scales.
We conclude that tannin plasticity may form a dynamically unpredictable
aspect of the PDS defence arsenal that protects Aspen against
piercing-sucking aphids.