Seasonality of a Diverse Beetle Assemblage Inhabiting Lowland Tropical Rain Forest in Australia
Version of Record online: 10 DEC 2008
© 2008 The Author(s) Journal compilation © 2008 by The Association for Tropical Biology and Conservation
Volume 41, Issue 3, pages 328–337, May 2009
How to Cite
Grimbacher, P. S. and Stork, N. E. (2009), Seasonality of a Diverse Beetle Assemblage Inhabiting Lowland Tropical Rain Forest in Australia. Biotropica, 41: 328–337. doi: 10.1111/j.1744-7429.2008.00477.x
- Issue online: 22 APR 2009
- Version of Record online: 10 DEC 2008
- Received 6 March 2008; revision accepted 25 Augugst 2008.
- feeding guild;
- spatiotemporal dynamics;
- temporal partitioning;
- vertical stratification;
- Wet Tropics
One of the least understood aspects of insect diversity in tropical rain forests is the temporal structuring, or seasonality, of communities. We collected 29,986 beetles of 1473 species over a 4-yr period (45 monthly samples), with the aim to document the temporal dynamics of a trophically diverse beetle assemblage from lowland tropical rain forest at Cape Tribulation, Australia. Malaise and flight interception traps were used to sample adult beetles at five locations at both ground and canopy levels. Beetles were caught throughout the year, but individual species were patchy in their temporal distribution, with the 124 more abundant species on average being present only 56 percent of the time. Climatic variables (precipitation, temperature, and solar radiation) were poorly correlated with adult beetle abundance, possibly because: (1) seasonality of total beetle abundance was slight; (2) the peak activity period (September–November) did not correspond to any climatic maxima or minima; or (3) responses were nonlinear owing to the existence of thresholds or developmental time-lags. Our results do not concur with the majority of tropical insect seasonality studies suggesting a wet season peak of insect activity, perhaps because there is no uniform pattern of insect seasonally for the humid tropics. Herbivores showed low seasonality and individual species’ peaks were less temporally aggregated compared to nonherbivores. Canopy-caught and larger beetles (> 5 mm) showed greater seasonality and peaked later in the year compared to smaller or ground-caught beetles. Thus seasonality of adult beetles varied according to the traits of feeding ecology, body size, and habitat strata.