Biodiversity: Insects get tropical
The biodiversity of plant-eating insects across the lowland tropical rainforests of Papua New Guinea may be high, but species tend to be widely distributed. The finding
Vojtech Novotny and colleagues studied around 500 species of butterfly caterpillars, beetles and fruitflies over 75,000 square kilometres of contiguous rainforest. Although species richness was high, as would be expected for the tropics, the species found did not alter much even over hundreds of kilometres, despite a range of different geological terrains.
Host plant specificity of caterpillars, on the other hand, decreases as distance from the equator increases, according to a second paper by Lee A. Dyer and colleagues. So the number of specialist species decreases with increasing latitude. The finding is timely, as biologists have discussed the latitudinal gradient in ecological specialization since the time of Darwin and Wallace, yet quantitative evidence for its existence has been hard to find.

CONTACT

Vojtech Novotny (New Guinea Binatang Research Center, Madang, Papua New Guinea)
Author paper [3]
Tel: +675 853 3258; Email: binatangi@datec.net.pg or novotny@entu.cas.cz

Scott E. Miller (Smithsonian Institution, Washington, DC, USA) Co-author paper [3]
Tel: +1 202 633 5135; E- mail: millers@si.edu

Lee A. Dyer (Tulane University, New Orleans, LA, USA) Author paper [4]
Tel: +1 504 862 8288; E-mail: ldyer@tulane.edu

Nigel E. Stork (University of Melbourne, Australia) N&V author
Tel: +61 3 9250 6806; E-mail: nstork@unimelb.edu.au