The taxonomy of the shoot borer, Hypsipyla robusta and allied species in the Asian/Australian region

Bangladesh, India, Indonesia, Lao PDR, Malaysia, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam

Dr Marianne Horak
Phone: 02 6246 4259
Fax: 02 6246 4264
Email: m.horak@ento.csiro.au

• Forest Science Institute of Vietnam, Vietnam
• University of Paradeniya, Sri Lanka
• Papua New Guinea Forest Research Institute, Papua New Guinea
• Forest Research Institute of Malaysia, Malaysia
• Kerala Forest Research Institute, India
• Forest Research Centre, Malaysia
• Royal Forest Department, Thailand
• Department of Environment and Natural Resources, Philippines
• Department of Forestry, Laos
• Bangladesh Forest Research Institute, Bangladesh
• Forestry Research Institute of Ghana, Ghana
• Museum Zoologicum Bogoriense, Indonesia

$153,484

01/07/1999 - 30/06/2001

Dr John Fryer

Damage from Hypsipyla robusta, a phycitine shoot borer, has severely limited plantation development using some high-value timber trees from Family Meliaceae, including Australian red cedar (Toona ciliata), Chukrasia tabularis, mahoganies (Swietenia sp. and Khaya sp.) and West Indian cedar (Cedrela odorata). But prior to any attempts to control the borer, scientists need to resolve whether H. robusta is actually more than one species.
This project surveyed H. robusta and allied species, in the first instance using traditional methods to examine museum specimens and fresh material contributed by groups in Australia, Sri Lanka, India, PNG and Ghana. Once tentative classifications were established, those that appeared closely related were subjected to molecular studies to make finer distinctions at genetic level. The results were published in an illustrated guide.

Researchers aimed to clarify the identity of H. robusta and possible other congeneric species throughout its range. The work took place in conjunction with another ACIAR-funded study (FST/1997/024), 'The management and ecology of the shoot borer, Hypsipyla robusta, feeding on species of Meliaceae in the Asia-Pacific region'.

The scientists combined morphological studies with sequence data to obtain conclusive results on the taxonomy of this difficult group, in order to:
establish the identity of the putative H. robusta throughout its range;
confirm that the populations of Hypsipyla on T. ciliata and Xylocarpus spp. in Australia are conspecific and not genetically separated;
establish whether the population of H. robusta in Ghana is conspecific with that from Asia to Australia and simply the end point of a cline, or whether it is a distinct species;
establish whether the species attacking shoots in eastern Africa is the same species as so-called H. robusta in western Africa;
establish the identity of the second species in Ghana, found in fruit and bark but apparently not in shoots;
establish the identity of H. scabrusculella Ragonot from Madagascar, considered a synonym of H. robusta;
establish the identity of the five Indo-Australian species presently referred to as Hypsipyla;
survey Indo-Australian tree species of Subfamily Swietenioideae for further phycitine borers.

Preliminary results from Africa indicated the presence of more than one species of Hypsipyla in Khaya fruit in one plantation, and during the second year more emphasis was given to elucidating this situation, including a field trip to Ghana. Material collected in Ghana necessitated study of fresh Hypsipyla material from Madagascar after researchers confirmed the species in West Africa differed from H. scabrusculella.
Now that material from Madagascar has become available, a comprehensive taxonomic revision of the genus Hypsipyla in the old world will be published, with a user-friendly key to enable identification by non-specialists.
The surprising results fully justify a taxonomic revision of so-called Hypsipyla robusta in the Old World, and they confirm that this task could only be done in collaboration with field scientists providing reared material. They also underlined the paucity of taxonomically useful characters in Hypsipyla, explaining the taxonomic uncertainties in such an important group despite earlier attempts at resolving their identity. Taxonomic decisions were all initially based on genitalia morphology in both sexes and then corroborated at the molecular level.
Summary of taxonomic results:
1. H. robusta was confirmed as the same species from Sri Lanka throughout India and Southeast Asia to the Philippines, New Guinea, Australia and Vanuatu.
2. In Australia the populations of H. robusta on Toona ciliata and Xylocarpus spp. are not genetically separated.
3. The population of the pest Hypsipyla near robusta in Ghana is morphologically and genetically distinct from H. robusta and is currently being described as a new species.
4. A second Hypsipyla species in Ghana, reared from fruit and bark but so far not from shoots of Khaya, has been confirmed and identified as Hypsipyla albipartalis (Hampson), described from the Congo.
5. The female type of H. scabrusculella Ragonot gave insufficient information to establish whether the species was different from both H. robusta and the pest Hypsipyla in Ghana. A sustained effort to obtain material from Madagascar has only recently been successful, with molecular studies confirming that H. scabrusculella is a distinct species and enabling description of the new species from Ghana.
6. The types of H. elachistalis Hampson, H. rotundipex Hampson, H. debilis Caradja, H. swezeyi Tams and a paratype of H. ereboneura Meyrick have been examined and now confirmed that all five species do not belong to the genus Hypsipyla.
7. Larvae of two unknown species of Catopyla Bradley, a genus close to Hypsipyla initially described from Nigeria, have been found in fruit of Khaya anthotheca in Malawi and in fruit of Chukrasia tabularis in Thailand. Both species have conspicuous, black and white ringed larvae, very different from Hypsipyla, and seem to be restricted to feeding in meliaceous fruit.
With reliable taxonomic information about the Hypsipyla species in Africa and Asia finally available, successful biological and integrated pest control will now be possible. Knowledge about species identity will allow well-informed evaluation and comparison of research results and transfer of parasites and pathogens.