Caterpillar Seasonality in a Costa Rican Dry Forest

Abstract

Calcrpillars---taken here to mean the larvae of Lepidoptera-are nOI uniformly or randomly present in spe<:ics or abundance in tropical lowland habitats. Instead, it is evident (0 any field natu.ra1ist that tropica1 C4leIpillar species and biomass are frequently oorrelated with seasonal phenomena. either directly or through their relationships with other organisms displaying seasonality. Indeed. other tropical insects are highly seasonal (e.g., Wolda 1988: Tauber el aI. 1986; NummeJin 1989; Janzen 1973. 1983a.h, 1987a,c: Tanaka et al. 1987: Paannan and Stork 1987; Winston 1980) and there is no reason to expect catcrpillan to be any different. Caterpillar seasonality is particularly evident in lTOpical dry forest. This vegeta_ tion type once covered at least half of the terrestrial tropics (e.g .• Murphy and Lugo 1986). However. it has been largely altered or replaced by agriculture, forestry, and anima] husbandry (e.g .• Uhl and Buschbacher 1985; Janzen 1988a.b). lronicaJly. the tropical dry forest caterpillar fauna is not of recent interest because ponions of it are in danger of extinction (which it is), but rather because as tropical dryland agroforestry ecosystems begin to reacquire diverse cropping systems and even regenerate wildland vegetation. the caterpillar fauna becomes conspicuous as pests. hosts for parasitoids. food for valued vertebrates . and even as a source of genetic and chemical biodiversity for commerciaJ exploitation .