View all news

Trouble in paradise

Press release issued: 17 August 2001

Trouble in paradise

Researchers at the University of Bristol report in Science this week [17 August] the results of a study that highlights the potential environmental damage caused by insect pests introduced in the community.

The research was conducted in Hawai'i at the Alaka'i Swamp on Kaua'i Island by Dr Jane Memmott, Lecturer in Terrestrial Ecology, and Dr Laurie Henneman, Research Assistant at Bristol University's School of Biological Sciences.

The aim of the study was to find out how alien insect species, particularly those introduced for biological control, interact with native species within a specific food web.

The researchers collected 2,112 caterpillars from the Alaka'i Swamp and reared them individually in the laboratory to find parasitoid links. Out of the 216 parasitoids reared from the 2,112 caterpillars collected, 83 per cent were biological control, 14 per cent were accidentally immigrants and 3 per cent were native parasitoids.

The study found that while immigrant species are present in the Alaka'i Swamp their current infiltration into the native moth community is much lower than that of the biological control agents.

Also, because all the alien parasitoids reared were introduced to the Hawaiian Islands before 1945, and have more than likely been established in the Alaka'i Swamp for many years, the moth species collected have suffered attack from the parasitoids for decades, and this will continue. However, some of the more vulnerable native species may have disappeared before the study began.

Dr Jane Memmott said: 'Although it is impossible to understand the dynamics of this system after only two years of study, there is little doubt that the community structure has been altered considerably from its original state.

'Increasingly, biological control is being considered for conservation as well as agriculture. There are clearly important environmental benefits to this practice as agents may control invasive alien plants or insects that, unchecked, may cause irreparable damage to native communities.'

Back to archive

Copyright: 2001 The University of Bristol, UK
Updated: Friday, 17-Aug-2001 10:23:53 BST

Edit this page