Published by the Communications
and Development Department
1 December 2003
Dr Raphael Didham, a senior lecturer in the School of Biological
Sciences at the University of Canterbury, has just returned from five
weeks in Panama where he participated in a massive international collaborative
research project on insects of the tropical rainforest.
Dr Didham and his wife, Laura Fagan, who is an entomologist at Landcare
Research, received funding for the project from the Royal Society
of New Zealand’s International Science and Technology Linkages
Fund.
The goal of project IBISCA – Investigating the Biodiversity
of Soil and Canopy Arthropods – is to study the vertical stratification
of insects in tropical rainforests and to estimate how many species
live in the tropical forest canopy. The project is funded by the US
Smithsonian Tropical Research Institute in Panama, the international
companies SolVin and Solvay, and by a host of other international
funding agencies including the Global Canopy Programme, UK. The total
cost of the project is estimated at upwards of 1 million Euro.
Dr Didham said that during the study, new discoveries were made every
day, and it was expected that more than 70% of some groups of insect
species collected would be new to science. Although Dr Didham has
worked in other tropical countries in the past, he said he was amazed
by the “staggering diversity of insects” in Panama.
Ultimately, the IBSCA project will help scientists estimate “ballpark"
figures for insect diversity in tropical forests.
Current estimates depend on the assumption that the number of insect
species in the canopy represents almost two-thirds of all insect species.
This assumption led researchers in the 1980s to suggest that as many
as 30 million insect species might exist, but later work has challenged
this estimate, suggesting that only 10% of insects live in the canopy.
Dr Didham says that researchers have been “nipping at the edges”
of this topic for some time, but previous studies have not been robust
enough to be widely generalised to all insect species.
To achieve a more acceptable sample size, IBSCA invited 33 entomologists
from 15 countries (over half of all tropical canopy entomologists
in the world) to participate. They also chose a range of new technologies
developed in the last five years to study the forest canopy including
fixed canopy cranes, a giant helium balloon and a giant canopy raft.
The raft, constructed of plastic beams and netting and weighing more
than three-quarters of a tonne, was flown into place by helicopter
and fixed by professional climbers.
He and Ms Fagan also had a memorable night sleeping in hammocks 35m
above the ground in a fixed tree house called the “Icos”.
The pair spent the night fighting off swarms of biting insects attracted
to the tree house by the light trap attached to its roof.
Dr Didham said the hundreds of bites they received were a small sacrifice
however, as the best moth sample of the entire study was caught that
night.
After collection, all the samples were pooled and separated into 40
focal groups. Each group was then assigned to a pair of researchers
with expertise in that taxonomic group for identification and analysis.
Dr Didham and Ms Fagan are responsible for the Order Diptera, or
the flies. The collection includes the largest fly Dr Didham has ever
seen stretching as long as his palm and more than 2.5cm wide.
This project complements Dr Didham’s current research programme
in New Zealand, which focuses on fly species in the forest canopy.
Dr Didham and Ms Fagan plan to return to Panama in May 2004 and again
in 2005 to continue with the project. Phase II in 2004 will investigate
seasonal variation in the vertical stratification of insects, and
in 2005 a workshop will be held to discuss the results.
Also in 2005, the principal scientist for IBSCA, Yves Basset, will
visit the University of Canterbury to share his knowledge of worldwide
forest canopy research and technology, which Dr Didham believes will
help inspire scientists here to co-ordinate various canopy research
already under way in NZ.
"There is a growing awareness of the importance of forest canopies
in NZ, and the University of Canterbury has more researchers on aspects
of the forest canopy than any other university in the country,"
Dr Didham said.
For more information contact:
Dr Raphael Didham
School of Biological Sciences
University of Canterbury
Ph 03 364 2059
Email raphael.didham@canterbury.ac.nz
