Insects and Spiders

Abstract

Arthropods (e.g., insects, spiders, mites, crustaceans) are the most diverse group of organisms in the biosphere. Several families of insects (e.g., staphylinid beetles, ichneumonid wasps) contain more species than all vertebrates combined. Most arthropods do not yet have scientific names. Little is known about the life histories of most species. The insects of Costa Rica and neighboring Panama have received more attention than any other tropical region of comparable size, but it is mainly limited to species descriptions and distribution records. I and colleagues who have contributed subsections throughout this chapter draw upon the published studies from Monteverde, but no attempt has been made to list all insect species reported from Monteverde. This chapter differs from others in that some contributors focus on tropical cloud forests in general rather than on only Monteverde. The justification is that for most insects, altitude is the single most important factor determining distribution. Most species show widespread geographic distributions but restricted altitudinal distributions. One intensively sampled cloud forest in Costa Rica is Zurqui de Moravia (1600 m), from which considerable information is drawn for this chapter. We have included most of the insect groups that have been studied in Monteverde: spittlebugs, treehoppers, rove beetles, scarab beetles, longhorn beetles, butterflies, social wasps, ants, and bees. Major orders of insects not included from this chapter are mayflies, cockroaches, termites, earwigs, barklice, thrips, and lacewings. Termites and other social insects are less prominent in cloud forests than in lowland forests. Spiders are the only noninsect arthropods included; the information is from a cloud forest at a similar elevation in Colombia. Cloud forests are defined here as forests higher than 1200 m. Our knowledge of cloud forest arthropods is so fragmentary that generalizations are premature. This chapter provides preliminary information on natural history to stimulate entomologists to consider cloud forests as distinct from lowland rain forests. We include practical information on the conservation of cloud forest arthropods, many of which are vital components of the ecosystem.