Abstract
To understand insect herbivory in the subtropical rainforest of Fushan, northeastern Taiwan,
we investigated seasonal patterns of insect folivory (quantified by leaf area loss) and leaf traits
(toughness, total phenols, N, and P) of 7 common hardwood species from March to November
2006. We also examined the relationships between the leaf area loss and the 4 leaf traits.
The leaf area loss (rate of insect folivory) significantly differed among sampled months and
species. Folivory mostly occurred in leaves before maturation. The area loss in young leaves,
which accumulated until July, was the highest in Pasania hancei var. ternaticupula f. ternaticupula
(13.00%), while the lowest was in Meliosma squamulata (2.96%), and ranged 4.25~7.02% in the
other 5 species.
All 4 leaf traits significantly differed among sampled months. Young leaves sampled in April
were tender, low in total phenols, and high in N and P. The leaf toughness and concentrations of total
phenols and N also differed among species. The area loss in young leaves was significantly positively
correlated with the N and P concentrations in young leaves (sampled in April). The greatest
leaf area loss occurred in P. hancei with the highest N and P concentrations in its young leaves.
The results suggest that even in the same habitat, hardwood species face different pressures of
insect folivory in the subtropical rainforest of Fushan. Higher folivory appeared to occur in species
with higher foliar concentrations of N and P. It was also clear that insect folivores favored young,
tender leaves rich in N and P and low in total phenols.