PATTERNS OF INSECT HERBIVORY, GROWTH, AND SURVIVORSHIP IN JUVENILES OF A NEOTROPICAL LIANA

Percent damage to young leaves of the shade-tolerant liana Connarus turczaninowii in Panama ranged from 2.9% in 1981 to 7.5% in the census following an El Nino event (January 1984). Although the median leaflet lifetime was 2.5 yr, c33% of the lifetime damage by herbivores occurred during the first 2 mo. Annual rates of insect damage to mature leaves varied from 2.8% in 1982 to 6.0% in 1984. The most common herbivore observed on mature leaves was the beetle Demotispa sp.nov. The proportion and actual quantity of damage by this species was minimal on young leaves, but increased with leaf age. Leaves from plants in extremely high light had lower concentrations of water and N, and more condensed tannins; such leaves were also tougher. No difference in rates of insect damage, however, were detected among plants that occurred across a continuum of light environments. Plant growth increased with canopy openness and, in one year, decreased with an increase in insect herbivory. Even though damage rates were high following El Nino, growth was high. Juvenile growth probably responded positively to the duration of the previous dry season because of increased light in the understory and a decrease in water loss from the soil due to the increased level of deciduousness of large canopy trees. -from Author