Long-term dynamics of insect populations in Indonesia

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This project aims to clarify long term dynamics of insect populations in Java and Sumatra, Indonesia. We established three major study sites under different climate conditions, (1) Padang, central Sumatra, has a typical humid tropical climate without a distinct alternation of wet and dry seasons. Annual rainfall exceeds 5000mm, (2) Bogor, west Java, located at the eastern fringe of the humid tropical climate, has an annual rainfall of 4075mm with more seasonality than Padang, (3) Purwodadi, east Java, has a distinctly seasonal climate. Annual rainfall is > 2000mm with 2-6 consecutive months of < 100mm rainfall. Major study species included phytophagous lady beetles (Coleoptera : Coccinellidae : Epilachninae), tortoise beetles (Coleoptera : Chrysomelidae : Cassidinae), and the banana skipper Erionota thrax (Lepidoptera : Hesperiidae). Seasonal fluctuation in abundance and mortality factors of these insect populations has been documented in detail in relation to the changes in climatic conditions and the action of natural enemies. Regular field census, including mark-recapture of adults and construction of life tables, was carried on the lady beetles (Epilachna emarginata in Bogor, E.vigintioctopunctata in Bogor, Padang and Purwodadi), and on the tortoise beetles (Aspidomorpha miliaris and A.sanctaecrucis in both Bogor and Purwodadi). The census periods for these studies have covered from 2 to 4 years, and some of them are still going on. Eggs, larvae, and pupae of the banana skipper were collected at a regular interval from the field and reared in the laboratory to examine faunal diversity and intensity of actions of parasitic wasps and flies. Laboratory rearings were also executed to clarify the survivorship and reproductive schedules of E.vigintioctopunctata collected from Bogor, Wonogiri (central Java), Sukarami (central Sumatra).