Low beta diversity of herbivorous insects in tropical forests.
Recent advances in understanding insect communities in tropical forests have contributed little to our knowledge of large-scale patterns of insect diversity, because incomplete taxonomic knowledge of many tropical species hinders the mapping of their distribution records. This impedes an understanding of global biodiversity patterns and explains why tropical insects are under-represented in conservation biology. Our study of approximately 500 species from three herbivorous guilds feeding on foliage (caterpillars, Lepidoptera), wood (ambrosia beetles, Coleoptera) and fruit (fruitflies, Diptera) found a low rate of change in species composition (beta diversity) across 75,000 square kilometres of contiguous lowland rainforest in Papua New Guinea, as most species were widely distributed. For caterpillars feeding on large plant genera, most species fed on multiple host species, so that even locally restricted plant species did not support endemic herbivores. Large plant genera represented a continuously distributed resource easily colonized by moths and butterflies over hundreds of kilometres. Low beta diversity was also documented in groups with differing host specificity (fruitflies and ambrosia beetles), suggesting that dispersal limitation does not have a substantial role in shaping the distribution of insect species in New Guinea lowland rainforests. Similar patterns of low beta diversity can be expected in other tropical lowland rainforests, as they are typically situated in the extensive low basins of major tropical rivers similar to the Sepik-Ramu region of New Guinea studied here.
Novotny
Vojtech
V
Biology Center of the Czech Academy of Sciences and School of Biological Sciences, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic. novotny@entu.cas.cz
Miller
Scott E
SE
Hulcr
Jiri
J
Drew
Richard A I
RA
Basset
Yves
Y
Janda
Milan
M
Setliff
Gregory P
GP
Darrow
Karolyn
K
Stewart
Alan J A
AJ
Auga
John
J
Isua
Brus
B
Molem
Kenneth
K
Manumbor
Markus
M
Tamtiai
Elvis
E
Mogia
Martin
M
Weiblen
George D
GD
D000818:Animals; D044822:Biodiversity; D004032:Diet; D005843:Geography; D007313:Insecta / Q000502:physiology*; D010219:Papua New Guinea; D014197:Trees; D014329:Tropical Climate