Population fluctuations of light-attracted chrysomelid beetles in relation to supra-annual environmental changes in a Bornean rainforest

• Published in: Bulletin of entomological research Vol. 99; no. 3; pp. 217 - 227
• Main Authors: Kishimoto-Yamada, K., Itioka, T., Sakai, S., Momose, K., Nagamitsu, T., Kaliang, H., Meleng, P., Chong, L., Hamid Karim, A.A., Yamane, S., Kato, M., Reid, C.A.M., Nakashizuka, T., Inoue, T.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.06.2009
• Subjects: Animal and plant ecology; Animal populations; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Borneo; Chrysomelidae; Coleoptera; Coleoptera - physiology; drought; El Nino; El Niño-Southern Oscillation (ENSO); Entomology; Environment; flowering; Flowers - physiology; forest canopy; forest habitats; Fundamental and applied biological sciences. Psychology; general flowering; insect communities; insect ecology; insect surveys; Insects; light traps; lowland dipterocarp forest; microhabitats; phenology; plant-insect relations; Population Dynamics; Rainforests; Southeast Asian tropics; species differences; Species Specificity; supra-annual events; Synecology; temporal variation; Terrestrial ecosystems; Trees; Tropical Climate; tropical rain forests; Borneo; Asia; Southeast Asian tropics; El Niño-Southern Oscillation (ENSO); general flowering; Coleoptera; drought; lowland dipterocarp forest; Fluctuations; Chrysomelidae; Insecta; Environmental factor; Tropical rain forest; Pollinator; El Niño; Phytophagous; Arthropoda; Flowering; Invertebrata; Drought; Population density
• ISSN: 0007-4853; 1475-2670
• DOI: 10.1017/S000748530800624X

In Southeast Asian tropical rainforests, two events, severe droughts associated with the El Niño-Southern Oscillation and general flowering, a type of community-wide mass flowering, occur at irregular, supra-annual intervals. The relationship between these two supra-annual events and patterns of insect population fluctuations has yet to be clearly elucidated. Leaf beetles (Chrysomelidae) are major herbivores and flower-visitors of canopy trees, affecting their growth and reproduction and, in turn, affected by tree phenology; but their population fluctuations in the Southeast Asian tropics have not been extensively investigated. We examined population fluctuation patterns of the 34 most dominant chrysomelid species in relation to the two supra-annual events by conducting monthly light-trapping over seven years in a lowland dipterocarp forest in Borneo. Our results showed large community variation in population fluctuation patterns and a supra-annual (between-year) variation in abundance for most of the dominant chrysomelids that was significantly larger than the annual (within-year) variation. Specifically, in response to a severe drought in 1998, chrysomelid species exhibited different population responses. These results show that population fluctuations of individual species, rather than the entire assemblage, must be analyzed to determine the effects of changes in environmental conditions on the structure of insect assemblages in the tropics, especially in regions where supra-annual environmental changes are relatively more important than seasonal changes.