XVI International Botanical Congess

We examined the effect of simulated slug herbivory on photosynthesis and leaf growth, birth and death rates of variegated and non-variegated Hedera helix (ivy). Juvenile and adult slugs of the species Lehmannia poirieri both feed on ivy, but cause different leaf damage patterns. We simulated adult and juvenile (or no) slug herbivory on mature ivy by removing or damaging 10% of the total leaf area per plant on each of three herbivory events within a one week period. Photosynthetic rates increased and leaf death rates decreased in response to herbivory, suggesting that Hedera helix may actively compensate for tissue removal or damage through increased carbon gain. Adult slug damage resulted in significantly greater increases in photosynthesis and leaf longevity than did juvenile slug damage. Plastochron index is currently being measured to determine leaf growth rates.