Malesian Butterflies
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Malesian Butterflies
Troides brookiana Wallace, 1855

CONSERVATION

IUCN Redlist category
Least Concern (IUCN 2020)

Rationale for redlist categorization
Trogonoptera brookiana has been assessed as Least Concern, because of its large extent of occurrence, it being locally common, and occurring in a number of protected areas throughout its range. However, this species is likely to be affected by habitat loss, being generally confined to primary forests, so that continuing loss of habitat could have detrimental effects on local populations of this species. The species is also widely traded, although under the auspices of CITES. Careful trade monitoring is required to maintain populations of this species. (IUCN 2020)

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

Cause of stress
Intentional use (species is the target),Increase in fire frequency/intensity,Shifting agriculture (IUCN 2020)

Described Threats
There are pressures acting on this species, although it is unknown to what extent this impacts the population and distribution of this species. Habitat loss is a common threat to a large number of - if not all - birdwing butterflies (Collins and Morris 1985). Similarly, it has been shown that fire can have a dramatic impact on this species: in a study in lowland forest in East Kalimantan, Trogonoptera brookiana was reported before the fire, but not in the two years immediately after the fire (Hirowatari et al. 2007). However, other studies showed that this species can return to areas previously affected by fire and was suggested as an indicator of forest recovery in Kutai National Park (following fires in 1983; MacKinnon et al. 1996).

This species features in the species trade. The species is listed on CITES Appendix II together with the genera Ornithoptera and Troides , with the exception of O. alexandrae which is listed on Appendix I. Recently traded individuals appear to come to a large degree from 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. (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 on Appendix II of CITES. According to the CITES Trade Database, the species is predominantly commercially ranched (CITES 2015). Overall, between 2000 and 2015, around 4,300 of the around 8,500 individuals recorded as exported from Papua New Guinea and 6,500 of the approximately 7,500 individuals exported from the Solomon Islands were from ranched populations (CITES 2015). Only 300 were exported from Singapore and around 200 from Thailand during the same time span (CITES 2015). This is in agreement with previous trends from the range countries between 1987 and 2005, where ranched and captive individuals were the most common source of traded individuals (UNEP-WCMC 2007). In 1985, it was reported that despite legal protection in Malaysia and Indonesia, likely as many as 125,000 specimen were exported annually (Barlow 1983, in Collins and Morris 1985). (IUCN 2020)

Applied conservation actions
The species was not considered to be threatened in an IUCN Red List assessment in 1985 (Collins and Morris 1985). This species, together with its congeneric T. trojana and all species of the genera Ornithoptera and Troides , is listed on CITES Appendix II (with the exception of O. alexandrae which is an Appendix I species; CITES 2008); this means that trade in these species is controlled in order to avoid utilization which may be incompatible with the species' survival. Given the potential impact of trade and the limited quantitative information available for this species, monitoring and evaluation of population status of understudied subspecies would vastly improve our knowledge of this species and our ability to address any population declines where they may occur, as would detail on the southeast Asian mainland distribution of this species. The species is listed as a protected species in Indonesia (Rusman et al. 2016).
There are a number of protected areas within the range of the butterfly, but it is unknown whether the species occurs within them (WDPA 2013). We know that the species occurs in Kutai National Park (MacKinnon et al. 1996) and Mount Sago Nature Reserve, West Sumatra (Rusman et al. 2016) as well as in Sungai Imbak Forest Reserve, Sabah, Malaysia (Jalil et al. 2008). Given the potential impact of trade and the limited quantitative information available for this species, monitoring and evaluation of population status of understudied subspecies would vastly improve our knowledge of this species and our ability to address any population declines where they may occur. (IUCN 2020)

REFERENCES

  • CITES. 2008. Appendices I, II and II. (Accessed: 23 September 2008).
  • 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.
  • Hirowatari, T., Makihara, H. and Sugiartaro. 2007. Effects of fires on butterfly assemblages in lowland dipterocarp forest in East Kalimantan. Entomological Science 10: 113-127.
  • IUCN. 2020. The IUCN Red List of Threatened Species. Version 2020-3. Available at: www.iucnredlist.org. (Accessed: 10 December 2020).
  • Jalil, M.F., Mahsol, H.H., Wahid, N. and Ahmad, A.H. 2008. A preliminary survey on the butterfly fauna of Sungai Imbak Forest Reserve, a remote area at the centre of Sabah, Malaysia. Journal of Tropical Biology and Conservation 4(1): 115-120.
  • MacKinnon, K.; Hatta, G.; Halim, H.; Mangalik, A. 1996. The ecology of Kalimantan: Indonesian Borneo. Periplus Editions, Singapore.
  • 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.
  • Rusman, R., Atmowidi, T. and Peggie, D. 2016. Butterflies (Lepidoptera: Papilionoidea) of Mount Sago, West Sumatra: Diversity and Flower Preference. HAYATI Journal of Biosciences 23: 132-137.
  • 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. 2013. World database of Protected Areas. Available at: www.protectedplanet.net.

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