DIVERSITY AND FAUNISTICS OF SMALL MOTHS (MICROLEPIDOPTERA) IN BORNEAN RAIN-FOREST

1. Samples of Microlepidoptera (including Pyraloidea) collected at light in mangrove forest, lowland mixed dipterocarp forest, and montane oak-laurel forest in Borneo are compared. 2. Diversity (Williams' alpha) is very high in lowland forest, with a value of 414; it is lower, 226, in montane forest and Very much lower, 47, at the edge of mangrove forest. 3. There is some evidence that apparent diversity increases with accumulation of samples. 4. Samples from the three forest types have very few species in common and come from separate assemblages. 5. Pyraloidea in samples taken 1 km apart in lowland forest represent an assemblage common to the two sites but Microlepidoptera samples appear to represent slightly different assemblages. 6. There are no abundant species in lowland or montane forest: species with more than ten individuals comprised less than 4% of the samples. Four common species in mangrove forest accounted for 34% of the sample. 7. The proportion of Tineoidea, Gelechioidea and Pyraloidea is lower in montane forest than in lowland forest, while that of Yponomeutoidea and Tortricoidea is higher. 8. Just eight families of Microlepidoptera account for 90% of the species in samples from all three forest types. 9. The number of species of moths in Borneo is suggested to be in excess of 8500.