HOW MOTHS PASS THE DRY SEASON IN A COSTA RICAN DRY FOREST

Abstract

The dry and largely deciduous forests in Santa Rosa National Park in northwestern lowland Guanacaste Province, Costa Rica, Central America, have a moth fauna of about 2800 species. These moths pass the six month rain-free dry season, and some other portions of the year. by: (a) remaining dormant in the egg stage (I species only), (b) remaining dormant in the pupa] or prepupa] stage (many species), (c) undergoing larval development (a few species of particular life forms) (d) remaining in the Park as a potentially active but non-reproductive adult (many species). and (e) migra ting out of the Park after one to two generations and then returning at the beginning of the following rainy season (a few species of particular life forms). The migrating moths constitute a strong link between the dry forest and the rainforests to the east of the dry fores!. The seasonal patterns of donnancy of immatures. reproductively dormant adults, and rnigmtion are nOI well correlated with the simple presence or absencc of foliage on host plants. or with climate changes (except thaI the temperature drop that occurs at the beginning of the rainy season appears to be a widely used cue for pupal ce]osion). The pattern of habitat use by leaf-eating caterpillars is probably determined more by the seasonal abundance of carnivores (parasitoids and predators) than by the mere presence of leaves; this process is very strongly evident in the failure of many moths to have more than one generat ion per yea r, even when their host plants are leafy throughout the six month rainy season or are even evergreen. Key