PARENT SESSION
Poster Session # 9: Herbivory.
Tuesday, August 5 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Attraction of parasitoid enemies to a constitutively odorous plant.
Lincoln, David1, 1 University of South Carolina, Columbia, SC
ABSTRACT- Volatile emissions from leaves has been implicated in plant defense via the attraction of herbivore enemies by induced emissions following foliar herbivory. Emissions from constitutively odorous plants, however, have received little attention. I examined the attraction of parasitoid wasps to an odorous shrub, wax myrtle (Myrica cerifera), in two adjacent habitats. M. cerifera is a common shrub in the zonal vegetation bordering coastal marshes in the southeastern USA and as an understory shrub in inland forests. The leaves constitutively produce a mixture of volatile compounds, dominated by mono- and sesqui-terpenoids. Ten pairs of plants were selected along a marsh edge and one plant had 25 leaves mechanically wounded while the other remained unwounded. Four yellow sticky traps (7.5 X 10 cm) were attached to each plant. The same design was performed approximately 100 m away in a mixed oak/pine forest adjoining the marsh. The sticky traps were collected 24 h later and the abundance of parasitoid wasps was determined. In both habitats, mechanically wounded plants attracted more parasitoid hymenopterans over the 24 h time period than did unwounded plants (P>0.01). More parasitoids were captured in the forest understory than at the marsh edge, despite greater volatile production among plants in the high light prevalent at the marsh edge habitat. In a separate experiment, groups (N=5) of three plants were unwounded, 25 leaves wounded, or 50 leaves wounded. Increased wounding (50 vs 25 leaves) had a marginally significant attractive effect (P=0.06). These results suggest that constitutively odorous plants may attract herbivore enemies via their emissions, but the effect may differ among habitats.
Key words: herbivore enemies, induced, volatile emission, constitutive