| August 2002. Maninita Island is vastly dominated by Pisonia grandis and there was hardly a leaf left on the island thanks to the ‘Pisonia moth’ (Hippontion velox). The second most common tree is Neisosperma oppositifolia which was not affected, the third is Guettarda speciosa which was completely defoliated by this moth.
There was a difference of opinion on the identification of the moth. Was it Agrius convolvuli, the sweet potato hawkmoth as some thought or A cingulata Fabricius, 1775 (Sphingidae)? The latter is known to have a New World distribution, i.e. Canada to Argentina, Galapagos and Sandwich Is., as well as the Caribbean. The species is close to A convolvuli L., a well known pest distributed over the entire Old World.
Making matters even more complicated was the view that the caterpillar illustrated here is a third specie, Cephanodes armatus Rothschild and Jordan, a hummingbird hawkmoth with clear wings. It is known to feed on Guettarda and is known from Tonga. It was asked whether could have been some confusion with the larvae collected being on a creeper on the Guettarda such as morning glory (Ipomoea) or Convolvulus. However, it was said that the caterpillar was definitely feeding on the Guettarda; this was observed many times. Also, a hummingbird moth was observed on the island.
The baseline survey undertaken on Maninita Island can download the preliminary report from www.pacificbirds.com, go to Trip Reports Tab. In June, the rats were taken off the island (hopefully) and a follow up `baseline’ survey will be undertaken in a couple of years time, all being well.
|
