Troides plateni Staudinger, 1888

CONSERVATION

IUCN Redlist category
Least Concern (IUCN 2020)

Rationale for redlist categorization
Troides plateni has been assessed as Least Concern. The species has a potentially large extent of occurrence of around 41,000 km?, is commonly reported from urban areas and occurs in secondary forest. Although forest loss may have affected especially coastal areas of Palawan over recent years, it is unlikely that this will have had a significant impact on this robust species. (IUCN 2020)

Threat category
Ecosystem conversion|Ecosystem degradation,Species mortality (IUCN 2020)

Cause of stress
Intentional use (species is the target),Unintentional effects: (large scale) [harvest] (IUCN 2020)

Described Threats
The species is listed on CITES Appendix II together with the genera Ornithoptera and Trogonoptera , with the exception of O. alexandrae which is listed on Appendix I. Recently traded individuals appear to come mostly from captive or ranched populations (CITES 2015). Butterfly ranching is generally thought of as a sound, economically viable and sustainable rural industry (Wambi 1996, Hanscom 1993, Burrows 2003 in Small 2007). However, there are concerns that butterfly ranching may not be as sustainable in some countries as it is often perceived to be (e.g., Papua New Guinea; Small 2007). This is based on a lack of data and species monitoring to assess the status of butterfly populations, and for many species, such monitoring is fraught with difficulty due to inaccessibility of their habitat (Small 2007). New and Collins (1991) noted that trade is extremely difficult to monitor because transportation of unpinned specimens is easy, especially of comparatively low value species which may instead be traded at high volumes. It has been stated that overcollecting seldom becomes a threat to butterflies, due to the reproductive capacity of insects and the difficulty in capturing significant numbers of the population (Pyle and Hughes 1978, in Parsons 1992). However, where birdwing butterflies are highly specific to host plants and where density of these hosts plants limits population size, collection in conjunction with habitat loss could have significant impacts on the species or subpopulations.

For most birdwing butterflies, habitat loss is by far the most important threat; commerical logging was thought to be of low economic value in the past, due to a poor representation of dipterocarp trees on the island (Quinnell and Balmford 1988). However, large-scale logging has become viable following depletion of forests in other parts of the Philippines (Quinnell and Balmford 1988). Data from Global Forest Watch shows highest forest loss since 2001 on Palawan island in coastal areas (Hansen et al. 2013). Assuming an altitudinal distribution similar to T. rhadamantus , this would put the species above some of these impacts. However, the species has also been commonly observed in Puerto Princesa, suggesting that the species occurs in lowland areas and is adaptable to more urban environments as long as food plants are available; in fact it has been reported as common in secondary forest (Collins and Morris 1985). This suggests some robustness of this species in the face of habitat disturbance and loss. (IUCN 2020)

Commercial use
Butterflies are mostly traded dead for the curio market (Collins and Morris 1985, New and Collins 1991). Between 1998 to 2007, 306,000 butterflies were traded from Southeast Asia, with 13,000 of these being wild-caught (Nijman 2010). There is a distinct shift towards ranched and captive-bred individuals in trade from 2003 onwards; in 1985, it was reported that globally less than 10% of trade was in ranched individuals (Collins and Morris 1985). Altogether at least 34 different species were recorded in trade, most of which belonged to the birdwing butterflies ( Troides and Ornithoptera ; Nijman 2010). It should be noted that trade in butterflies may be underreported, because of difficulties monitoring. New and Collins (1991) noted that trade is extremely difficult to monitor because transportation of unpinned specimens is easy, especially of comparatively low value species which may instead be traded at high volumes.
Birdwings can fetch high prices on the market. For example, butterfly collectors have paid high prices for birdwing butterflies of this genus: a pair of Ornithoptera meridionalis was reported to have fetched USD 3,400 in Germany (Melisch and Schutz 2000). Reported prices for Troides are however much lower. For example, a more recent pricing was around $85 per pair of T. hypolitus , around $15 per individual of T. helena and between $43 and $85 per pair of T. haliphron (Putri 2016). This species is listed on Appendix II of CITES, where it is treated as a subspecies of T. rhadamantus . Recent data from the CITES Trade database show, that since 2000 and 2015 close to 529,000 individuals were exported from the Philippines, primarily as live specimen (around 509,000 live individuals; CITES 2015); of those, 98% are captive-bred (CITES 2015) as the species is overall considered to be easily reared (Collins and Morris 1985). In fact, it has been suggested it is more easily reared than Trogonoptera brookiana (UNEP-WCMC 2012). However, from the CITES data, it is difficult to attribute how many of these are T. plateni . In 1988, Quinnell and Balmford (1988) suggested that at least 2,000 individuals are traded each year from Palawan. (IUCN 2020)

Applied conservation actions
This species was not considered to be threatened during a global status assessment of the world's swallowtails in 1985 (Collins and Morris 1985). This species is listed, together with all other Troides , on CITES Appendix II. The species may occur in a number of protected areas within its range, specifically in the eastern parts of the island where Malampaya Sound Protected Landscape and Seascape covers a large area of Palawan's northeastern headland (WDPA 2016); however data on species occurrence within the area are lacking, so this cannot be verified. (IUCN 2020)

REFERENCES

• CITES. 2015. CITES Trade Data Base. Available at: http://trade.cites.org/.
• Collins, N.M. and Morris, M.G. 1985. Threatened Swallowtail Butterflies of the World. The IUCN Red Data Book. IUCN, Gland and Cambridge.
• Hanscom, T. 1993. Setting hearts aflutter: little butterflies take wing as big business. The Rotarian 163: 16-19.
• Hansen, M.C., Potapov, P.V., Moore, R., Hancher, M., Turubanova, S.A., Tyukavina, A., Thau, D., Stehman, S.V., Goetz, S.J., Loveland, T.R., Kommareddy, A,. Egorov, A., Chini, L., Justice, C.O. and Townshend, J.R.G. 2013. High-resolution global maps of 21st-century forest cover change. Science 342: 850-853.
• IUCN. 2020. The IUCN Red List of Threatened Species. Version 2020-3. Available at: www.iucnredlist.org. (Accessed: 10 December 2020).
• Melisch, R. and Schutz, P. 2000. Butterflies and beetles in Germany. Traffic Bulletin 18: 91-93.
• New, T.R. and Collins, N.M. 1991. Swallowtail butterflies: an action plan for their conservation. International Union for Conservation of Nature and Natural Resources/Species Survival Commission Lepidoptera Specialist Group, Gland, Switzerland.
• Nijman, V. 2010. An overview of international wildlife trade from Southeast Asia. Biodiversity and Conservation 19(1101-1114).
• Parsons, M.J. 1992. The butterfly farming and trading industry in the Indo-Australian region and its role in tropical forest conservation. Tropical Lepidoptera 3(Suppl. 1): 1-31.
• Putri, I.A.S.L.P. 2016. Handicraft of butterflies and moths (Insecta: Lepidoptera) in Bantimurung Nature Recreation Park and its implications on conservation. Biodiversitas 17(2): 823-831.
• Pyle, R.M. and Hughes, S.A. 1978. Conservation and Utilization of the Insect Resources of Papua New Guinea. Wildlife Branch, Department of Natural Resources, Port Moresby.
• Quinnell, R. and Balmford, A. 1988. A future for Palawan's forests? Oryx 22: 30-35.
• Small, R.D.S. 2007. Becoming unsustainable? Recent trends in the formal sector of insect trading in Papua New Guinea. Oryx 41(3): 386-389.
• UNEP-WCMC. 2012. Review of butterflies from Asia and Oceania subject to long-standing positive opinions. Prepared for the European Commission Directorate General E - Environment ENV.E.2. ? Development and Environment. UNEP-WCMC, Cambridge.
• Wambi, D. 1996. Birds, bugs and butterflies. New Guinea Insight 6: 5-9.
• WDPA. 2016. Database on Protected Areas. A database online managed by UNEP-WCMC/IUCN World Commission on Protected Areas (WCPA). Available at: http://www.unep-wcmc.org/wdpa/index.htm.