Malesian Butterflies
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Malesian Butterflies
Ornithoptera aesacus Ney, 1903

CONSERVATION

IUCN Redlist category
Vulnerable (IUCN 2020)

Rationale for redlist categorization
Ornithoptera aesacus has been assessed as Vulnerable. The species occurs in an estimated extent of occurrence of around 2,900 km?, with a maximum estimate of area of occupancy of 1,045 km?; within this area there are threats such as forest loss which appear to be highest in western Obira, while central areas still retain much forest cover. However, given the species altitudinal distribution, it primarily occurs away from the central highlands. Another threat is gold mining which has notably affected other species (Cottee-Jones et al. 2013, Birdlife International 2016), and has been reported to have continued for years (Collins and Morris 1985), suggesting a continuing decline in quality and extent of habitat for this and other forest species on Obira. At present there is very little information available on the abundance, life history or habitat requirements of this species, so that additional research is recommended. Given that both gold mining and logging are likely to be relatively localised, the number of locations is likely to be more than five. However, given the lack of precise distribution data for his species, it is difficult to estimate number of locations in more detail. Using precaution, we tend towards a number of ten locations for the purpose of this assessment, reflecting that other species of Ornithoptera are often rather localised. If improved data suggested that the number of locations was more than ten, the species would require a reassessment of Near Threatened. There is a need for more data on this species, specifically with regard to the status of its population and the impact that threats may have on the species. Improvements in environmental mining regulations are needed to safeguard habitat for this and other species on the island. (IUCN 2020)

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

Cause of stress
Mining & quarrying,Intentional use (species is the target) (IUCN 2020)

Described Threats
Habitat loss is likely to be the most acute threat to this species. The Maluku Islands have experienced extensive logging, with deforestation rates on nearby Halmahera predicted as high as 88% by Lambert (1993). Forest loss maps provided by Global Forest Watch (Hansen et al. 2013) suggest that forest loss was highest in western Obira, while central and eastern areas still retain much forest cover. Logging, especially of lowland forest, and illegal gold mining has been reported to occur across Obira island, notably affecting other species (Cottee-Jones et al. 2013, Birdlife International 2016), and has been reported to have continued for years (Collins and Morris 1985).
This species features in the species trade. 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). As a result, all Ornithoptera are listed on CITES Appendix II, with the exception of Ornithoptera alexandrae which is listed on CITES Appendix I. According to CITES databases, most trade in O. aesacus comes from ranched individuals (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). 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. (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). This species is listed with all other birdwings on CITES Appendix II ( Ornithoptera, Trogonoptera and Troides , with the exception of O. alexandrae which is listed on Appendix I). Most specimens exported from Indonesia are traded from ranched populations, with overall ca. 7,800 of the reported ca. 8,100 specimens exported from Indonesia between 2000 and 2015 originating from ranched individuals (CITES 2015). Wild-caught specimens are rarely documented in trade (CITES 2015). This is in agreement with previous trends from the country between 1987 and 2005, where ranched individuals were the most common source of traded individuals (UNEP-WCMC 2007). (IUCN 2020)

Kind of conservation needed
Private sector standards & codes,Resource & habitat protection (IUCN 2020)

Applied conservation actions
The species is also included in CITES Appendix II, together with all other Ornithoptera species (with the exception of Ornithoptera alexandrae , which is listed on Appendix I). Pulau Obi Nature Reserve covers 12.5 km? of the central range on Obira and was established in 1995 (WDPA 2015), but this is in the centre of the island and covering elevations higher than 200 m Asl. Surveys are needed to establish if the species occurs in the reserve. There is a need for more data on this species, specifically with regard to the status of its population and the impact that threats may have on the species. As has been suggested for other species on the island, improvements in environmental mining regulations are needed to safeguard habitat for this and other species on the island. (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.
  • Cottee-Jones, H. E., Mittermeier, J. C. and Redding, D. W. 2013. The Moluccan Woodcock Scolopax rochussenii on Obi Island, North Moluccas, Indonesia: a 'lost' species is less endangered than expected. Forktail 29: 88-93.
  • 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.
  • 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.
  • 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. 2007. Review of trade in ranched birdwing butterflies. UNEP-WCMC, Cambridge.
  • Wambi, D. 1996. Birds, bugs and butterflies. New Guinea Insight 6: 5-9.
  • WDPA. 2015. World Database of Protected Areas. Cambridge Available at: www.protectedplanet.net.

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