Papua New Guinea plants

There is fairly little readily available information for the native flora of the South Pacific. Thankfully, this has started to change with the advent of the PNGPlants Project. This excellent website brings together descriptions, factsheets and photos of herbarium specimens (such as the specimen of Nothofagus pullei above) to provide a very accessible introduction to the plants of one of the most biodiverse regions in the world.

Featured insect: Pantorhytes plutus (Coleoptera: Curculionidae)

The weevil genus Pantorhytes is a large genus placed in the tribe Pachyrhynchini in the subfamily Entiminae. It consists of over 74 species found primarily in New Guinea, but also being found in the Solomon Islands and Queensland. The species pictured here, P. plutus is found in the Bismarck Archipelago. A map showing the distribution of specimens in the Australian National Insect Collection (see here also) can be found here

Pantorhytes plutus and a number of other species in the genus have become major pests of cacao trees, particularly in PNG. All the species have fairly limited ranges, such that P. szentivanyi, P. albopunctulatus and P. healyi are pests in the Northern Province of PNG, P. torricellianus is a problem in the Sepik region, P. plutus through the Bismarcks, and P. biplagiatus through Bougainville and the Solomon Islands. The genus has had a surprisingly large amount of study done on their biology, including egg development, and control. A couple of studies have looked at their dispersal, including one study that used a radioactive isotope tracing technique, which provided theoretical insight into mathematical models of insect dispersal. A parasitic wasp, Pristocera rufa is known to parasitize P. szentivanyi, though not to such an extent as to be a reliable biological control agent.


They are such a threat, they have made it onto a page detailing the world's worst cocoa problems (though I cannot find any other evidence that Pantorhytes are in Tuvalu), and accordingly there's been a number of studies dealing to their control (such as this one and this one).Biopesticides, including Beauveria bassiana have also proved to be of use in their control. A photo of an infected beetle is shown above.

A circular detailing their control in the Solomon Islands recommends using ants as a form of biological control. Unfortunately, two of the species they recommend for this control are the yellow crazy ant (Anopolepis gracilipes) and the little fire ant (Wasmannia auropunctata). Both these species are highly invasive generalist predators and scavengers which have adverse effects on more than just Pantorhytes weevils in cacao plantations. Should they already be present in the area, their use as a control agent may be encouraged, but they should NOT be introduced anywhere for that purpose if they aren't already there.

References:
Gressitt JL. 1966. The weevil genus Pantorhytes (Coleoptera) involving cacao pests and epizoic symbiosis with cryptogamic plants and microfauna. Pacific Insects 8(4):915-965.
Setliff GP. 2007. Annotated checklist of weevils from the Papuan region (Coleoptera: Curculionoidea). Zootaxa 1536. 296pp.
Stibick JNL. 1978. The genus Pantorhytes (Coleoptera: Curculionidae) Division A. I Addistions and changes to the common and major cacao species. Pacific Insects 18(3&4):115-136.

PNG Entomology Textbook

Michael Schneider was a lecturer at the Bulolo University College in Morobe Provence, PNG from 1994 to 1999. As a result, he has produced both a key to the Insect Pects of PNG, and an entomology textbook for students and forestry. This last work is a particularly impressive effort, being a clear, informative and thorough textbook with a strong emphasis on the insect fauna of Papua New Guinea. For anyone with a developing interest in insects, it's well worth checking out. For those of us who are particularly fascinated with the insects of Melanesia though, it's a must-see.

Agriculture in the Pacific

Agriculture in developing countries is an area where a lot of international assistance and aid money goes. A lot of hard work, interesting information and useful resources are the fruits of these activities. Unfortunately though, this information can get easily lost in the morass of information that is the internet. The following is my humble attempt to promote a few of the sites I know that are relevant to Agriculture in the South Pacific, in addition to the ACIAR and SPC Forestry pamphlets I've talked about before.

Terracircle is an NGO that works primarily in Melanesia promoting sustainable agriculture through technical training, publications, consultancy and the provision of small grants for communities.

Working in close association with Terracircle is the Kastom Gaden Association (another website is under construction here) and the Planting Material Network, both based in the Solomon Islands. Both these organisations operate much more on the grass-roots level, connecting farmers within the Solomons to each other and encouraging communication at that level.

The Melanesian Farmer First Network is broader in scope than the two above, supporting farmers throughout PNG, the Solomons and Vanuatu. I liked the Innovations page on their site, though unfortunately it is only very infrequently updated.

OISAT (or the "Online Information Service for Non-Chemical Pest Management in the Tropics" in full) aims to detail control methods for tropical crops and pests. It seems to have more of a focus on Asia, but the information that is here will be of worth in most places with these crops and pests. It is currently fairly incomplete, with few of the insects in the Pest Management strategy having any information beyond a picture. However, there was a note saying the page had been updated in some form a day ago, so there is hope that this will change in the future.

Conservation Biology papers with a Pacific focus

The most recent (April 2010) issue of Conservation Biology has a number of papers which focus on the fauna, flora and environment of the South Pacific.

The issue starts off with an editorial by David Melick on economic schemes to negate carbon emissions. In particular he deals with the scheme to compensate landowners for NOT cutting down forests on their land (REDD) and the way this has played out thus far in the Papua New Guinea scene. He ends with this very pertinent statement:

... REDD will come to nothing if the system is not supported by the people who own and live in the forests. If the process is not rushed (it may take years, not months) and the PNG government is willing to accept international scrutiny and advice, forest governance and communitybenefits for the rural poor may finally be improved significantly...

Highly relevant for all who work in the South Pacific, particularly those of us with a western, productivity-based mindset. As the Mainland cheese ads say---Good things take time.

William Laurance and others discuss the impact of Oil Palm cultivation and some of the issues and opportunities surrounding it. In particular, they discuss the Roundtable on Sustainable Palm Oil (RSPO) a nonprofit organisation that hopes to promote and market sustainably grown palm oil. Unfortunately, its track record appears to be fairly poor. The seeming blind eye the organisation has taken toward the destruction caused by growing oil palm in peat swamps is singled out as being a major failing of the RSPO. however Laurance et al. refuse to be pessimistic about the situation and make some recommendations, most of which involve fairly major restructuring of the RSPO and developments in its monitoring and enforcement policies. However, the real problem in the situation is the lack of market demand for sustainably grown palm oil, meaning that the RSPO has little clout.

Alison Boyer revisits the very high extinction rate of Pacific Island birds, this time investigating what ecological traits seem to have an influence on extinction rate. She concludes that differences in endemism, body size and diet influence the potential for extinction and gives a list of bird species that may be worthy of a higher threat category than currently given.

Shankar Aswani and Armagan Sabetian look at the impact that urbanisation has had on the parrotfish population around Gizo and Munda, in the Western Province of the Solomon Islands. Not surprisingly, they found that over the period 2004--2005 parrotfish numbers decreased around Gizo. However, they did find that some customary management systems were effectively preserving larger and greater numbers of parrotfish. The most effective systems were those that prevented all fishing in certain areas.

Mayeul Dalleau and team looked at shallow marine habitats around Wallis Island and used digital imagery and habitat maps as surrogates for biodiversity in the proposal of marine protected areas. While they promote this method as being an effective and efficient of surveying large areas, they do recognise that it is very desirable to do some actual field work to complement the habitat data, particularly in regions such as the Red Sea which has a very different environment from the oceanic Pacific islands.

It's a good issue. Well worth a read, certainly if any of the above issues pique your interest.

References:

Aswani S, Sabetian A. 2010. Implications of Urbanization for Artisanal Parrotfish Fisheries in the Western Solomon Islands. Conservation Biology 24(2): 520-530

Boyer AG. 2010. Consistent Ecological Selectivity through Time in Pacific Island Avian Extinctions Conservation Biology 24(2): 511-519

Dalleau M, Andréfouët S, Wabnitz CCC, Payri C, Wantiez L, Pichon M, Friedman K, Vigliola L, Benzoni F. 2010. Use of Habitats as Surrogates of Biodiversity for Efficient Coral Reef Conservation Planning in Pacific Ocean Islands. Conservation Biology 24(2): 541-552

Laurance WF, Koh LP, Butler R, Sodhi NS, Bradshaw CJA, Neidel JD, Consunji H, Vega JM. 2010. Improving the Performance of the Roundtable on Sustainable Palm Oil for Nature Conservation. Conservation Biology 24(2): p 377-381

Melick, D. 2010. Credibility of REDD and Experiences from Papua New Guinea. Conservation Biology 24(2): 359-361

Molecular identification of New Guinea mammal poo

The use of environmental DNA samples for identification and monitoring of animals has been increasingly widely used over the past five years or so. This essentially involves extracting DNA from non-tissue materials and analysing it in such a way as to discover the creatures that produced/lived in/ate/passed by the material. For example, pond water has been analysed to discover what frog species were present in the area and faecal matter has been analysed to figure out both what was eaten and who was the eater.

This last scenario has been played out on the Huon Peninsula in Papua New Guinea. Research has begun on the endangered Matschie's tree kangaroo (Dendrolagus matschiei) looking into its population structure and genetics. This research has applications to help direct the future conservation of the species by giving an indication as to how many individuals there are and how much they move around. However, the capture and collection of tissues from a rare, endangered animal that spends the majority of its time in montane rainforest canopies present both logistic and ethical concerns which are alleviated by the collection of DNA from their faeces. Finding poo is sometimes a lot easier than the beast itself!

Unfortunately, poo from one marsupial often looks the same as poo from another and so faeces were mistakenly collected from an additional two species the New Guinea pademelon (Thylogale browni) and the small dorcopsis (Dorcopsulus vanheurni). A recent paper published in Molecular Ecology Resources by Thomas McGreevy and coauthors give a method for determining which species of marsupial produced the poo of interest. The primer set they've developed amplifies a portion of DNA that is a different length in each species---making it easy to distinguish which came from what and making sure that time is not spent looking at the wrong ones.

References:
McGreevy TJ Jr, Dabek L, Husband TP. (2010). A multiplex PCR assay to distinguish among three sympatric marsupial taxa from Huon Peninsula, Papua New Guinea, using the mitochondrial control region. Molecular Ecology Resources. 10(2): 397-400.

Highly diverse weevils in northern New Guinea

New Guinea is an amazing place. It is one of the final frontiers of exploration, particularly in the biological realm with highly diverse rainforest that cover huge areas and a nearly unbelievable range of habitats from hot, humid mangrove swamp forests to 4,000 m high mountains and glaciers. The diversity of the island astounds everyone who works there and the amount remaining to be discovered absolutely boggles the mind.

A case in point was published late last year, when research on Trigonopterus weevils from the Cyclops Mountains was published. This research was headed up by Alexander Riedel and they looked at the congruence between clades revealed by cytochrome c oxidase 1 (COI) DNA sequences and morphological variation. They found 51 morphospecies which were all congruent with COI data. What is incredible though is the genetic distances within this group. Uncorrected distances between species were incredibly high, the lowest being 16.5% and a mean of 20.5%. Within species variation ranged from 0% (not too surprising), to a whopping 8.8%. To put this in context, a 2% genetic distance is usually bandied about as being the point at which you're thinking that you've got two different species.

This diversity is particuarly impressive when one considers that these results are derived from a single transect in a relatively low area in one mountain range. The authors justifiably expect that more extensive sampling will produce many more species.

Not only are they incredibly diverse, these weevils are also tough. Being cryptorhynchine weevils, their rostrum can fold up into a groove in their thorax when they're disturbed. Unlike most other cryptorhynchines though their elytra are fused together and to the thorax, making them able to withstand extremely high pressure and ensuring that they are very difficult to dissect. This is a problem when dissections are necessary to fully characterise and identify these beetles.

It's a very interesting paper on a really cool group of weevils. Check out the supporting information for habitus photos of the morphospecies and get an idea of the morphological variation in the group.


References:

Riedel A, Daawia D, Balke M. 2010. Deep cox1 divergence and hyperdiversity of Trigonopterus weevils in a New Guinea mountain range (Coleoptera, Curculionidae). Zoologica Scripta 39(1): 63--74.

Featured insect: Gymnopholus weiskei Heller 1901 (Coleoptera: Curculionidae)

Today is the first of what I hope will become a relatively regular thing - a feature on various South Pacific insects. The lucky candidate, by virtue of being able to source a cool picture, and having found a paper on the genus Gynmopholus....

Gymnopholus weiskei is a large beetle, around 3cm long. It is found in the Morobe province of Papua New Guinea, and feeds on a range of host plants including yams (Dioscorea spp.), brambles (Rubus archboldianus) and chinaberry (Melia azedarach)

Gymnopholus weiskei was first described by Dr K. M. Heller in 1901 and is the type species for the genus. This means that for a weevil to be named in the genus Gymnopholus, it must have several key similarities with G. weiskei.

There is another very cool photo of G. weiskei here.

References:

Marshall, GAK. (1959). Curculionid genus Gymnopholus (Coleoptera).

Occasional papers of the Bernice P Bishop Museum. 22(7):71-81

Szent-Ivany, JJH. (1970).
Ethological and ecological observations on Gymnopholus spp. mainly G. (S.) lichenifer Gress. (March-April 1967).

Pacific Insects 12(4): 763-768

Photo courtesy of bugsbynature.com

Homona mermerodes eats a lot.

With the advent of cheap and effective DNA amplification and sequencing methods, there has been an increased appreciation of biological diversity. In particular, a field that has particularly benefited from the techniques has been the detection of cryptic species. These are groups of organisms that appear the same, but a look into the DNA of the creatures reveal that they are complexes of genetically different populations. Frequently, these cryptic species are found to be host specific to certain food types, while the former "superspecies" was thought to have a range of hosts.

There has been a lot of work done recently on the northern coast of Papua New Guinea by the Binatang Research Centre. Their research has a focus on rainforest invertebrate dynamics and ecology, and they have done a sterling job in encouraging science in the country. They've trained several PNG citizens as parataxonomists, and a look at their publication list is rather impressive. As part of this research, they have investigated the population structure of the leafroller moth Homona mermerodes (Lepidoptera: Tortricidae). They used the fabled cytochrome oxidase gene (commonly abbreviated to cox1 or COI) to investigate whether the species is a widespread polyphagous species, or whether it is made up of a lot of cryptic species that are specific to certain plants. The COI gene is found in the mitochondrial DNA, and is famous as the gene of choice for what has become known as barcoding. This is an ambitious scheme to sequence the COI gene region for every organism on the planet to allow it to be quickly and easily identified.

Hulcr et al published the results of the work on Homona in Molecular Ecology Notes in July this year. Their analysis shows that the use of COI made some very nice distinct groups (clades), with big differences between the different clades. The interspecific genetic distances are larger than the intraspecific distances, forming a bimodal (twin-peaked) distribution with very marginal overlap. There were certainly no genetic differences between H. mermerodes reared on different plants, nor were there major differences between PNG and Australian (Queensland) populations.

One of the things that impressed me by this paper was the incorporation of pictures of the moth including both adult, larvae, and genitalia. It has been a concern of mine that much of the rhetoric surrounding barcoding seems to neglect other taxonomic evidence, whether it's morphological or other genes. I believe this is from the enthusiasm surrounding the power of the techniques as opposed to deliberately believing that barcoding is the ONLY way. Single-character taxonomy will always provide misleading results, whether it's in a morphological sense, or if it's only single gene region being looked at. I have experienced this myself when trying to identify things and getting involved with single things rather than looking at the organism as a whole. Good taxonomy takes a lot of information into account in order to try and infer species limits.

It is also good to have an example where a wide ranging, generalist and morphologically variable species has a well-defined genetic structure. Frequently it seems that the genetics of creatures that display these traits suggests that there are a number of cryptic species. It is gratifying (to me at least) to know that these cryptic species groups aren't a given. Further research that attempts to deduce the factors that influence the formation of cryptic species groups will be highly interesting.

Hulcr J, Miller SE, Setliff GP, Darrow KA, Mueller ND, Hebert PDN, Weiblen GD. 2007
DNA Barcoding confirms polyphagy in a generalist moth, Homona mermerodes (Lepidoptera: Tortricidae).
Molecular Ecology Notes 7: 549-557