Wednesday, 7 March 2012

Trigonopterus diversity in New Guinea

Examples of Trigonopterus weevils
The weevil genus Trigonopterus is found in the islands of Indonesia, eastwards to Fiji and Samoa. There are around 90 described species, but thanks to the work of Alexander Riedel, the true diversity of the genus is becoming apparent. One of the latest works of Riedel and coauthors was published earlier this year in PLoS ONE, and describes how a DNA barcoding approach is helping to make sense of the group.

In this study, over 1000 specimens were collected from five broad regions of New Guinea. Initial sorting suggested that there were 270 species represented in this group with each area possessing an average of 41 species. After sorting, these specimens had their COI gene sequenced and analysed using a number of different methods. These analyses slightly increased the total number of species to 279, due to the presence of very similar-looking species being present in the sample.

The authors argue that when facing sorting through groups of greater than 50 species, it becomes inefficient to circumscribe them using traditional means. In these situations, DNA barcoding approaches can make the task more tractable and form a solid base for ongoing taxonomic research. In addition, they recommend that Trigonopterus form a key group for use in biodiversity assessment surveys within Melanesia.

This study shows how much there is to learn about the biota of Melanesia. Unfortunately though, the are resources available for researchers interested are relatively scarce. Additionally, most of the research done is by researchers based in places such as Europe and the States, with involvement by Pacific Islanders generally being limited to providing technical assistance. This paper is a case in point. While a 'man blo niu guinea' is a coauthor, he was not involved in the experimental design or in the writing of the paper; both valuable skills for success in science. Locally based scientists in the Pacific will continue to struggle until more funding becomes available from their governments, and they take opportunity to be involved in all parts of the scientific process from design to publication.

Tanzler R, Sagata K, Surbakti S, Balke M, Riedel A (2012) DNA barcoding for community ecology—How to tackle a hyperdiverse, mostly undescribed Melanesian fauna. PLoS ONE 7(1): e28832.

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