Seasonality of insect herbivory on the leaves of Neoboutonia macrocalyx inthe Kibale National Park, Uganda

The seasonality of herbivory on the leaves of Neoboutonia macrocalyx Pax. i n Kibale Forest National Park, Uganda, was studied. A total of 2929 fallen leaves was collected during 15 months under randomly-selected trees in thre e different habitats; natural forest and two selectively cut forest sites. The percentage of leaf area eaten and leaf size were estimated. Leaf herbiv ory was highly seasonal and correlated with rainfall in the previous 2 mont hs, but less than 100 mm monthly rainfall had no effect. There was no corre lation between leaf size and rainfall. Although Kibale Forest has two wet s easons, insect feeding on leaves had only one peak during the major rainy s eason from September to December. Three to four months after peak herbivory , leaves had very low rates of insect damage. Habitat had only a small effe ct on the amount of insect feeding. The sampling time accounted for 71% of variation in leaf herbivory. New leaves were formed continuously year-round . The constant leaf production by Neoboutonia trees may be an adaptation to escape generalist herbivorous insects which might be synchronized with the major wet season when the leaf flush of the most other deciduous species o ccurs. Thus, the availability of fresh leaves is not acting as a regulating factor in seasonality of Neoboutonia herbivory.