Species for Sale: Rhinoceros Beetles
By: Wwf Hk
Tags: Biodiversity, Endangered Species, Beetle, Hong Kong, Conservation

by Thomas Gomersall

Rhinoceros beetles (Subfamily: Dynastinae) are a group of beetles named for the large nose horn found in the males. Despite their intimidating appearance, they are actually harmless insects that feed mainly on sap and males mostly use their horns for jousting with each other over females (Fang, 2006, p. 60–p.61; Ferguson, 2019).

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Large beetles like rhinoceros and stag beetles are very popular as pets and collectibles in Asia. Males are particularly sought after in some countries for the spectator sport of ‘beetle-wrestling’, in which they are made to fight each other. Most of the rhinoceros beetles traded are collected from Central and South America, where their species diversity is highest, but they may also be collected from Southeast Asia and Oceania, including from within protected areas (Leung, 2020; New, 2005; Brock, 2006).

Within Hong Kong, the beetle trade (which caters primarily to local customers) and interest in collecting rhinoceros beetles peaked around a decade ago, thanks to a then-popular Japanese video cum card game, Mushi King, that heavily featured them. Since then, the game has lost popularity and the fad of pet beetles in Hong Kong has largely faded with it. However, rhinoceros beetles can still be bought as pets and for beetle wrestling in places like Mong Kok and Kwun Tong, with pet shops selling both exotic and, to a lesser extent, native species. Depending on their rarity and size, prices can range from HK$100 per pair to HK$1,000 per individual (Leung, 2020; Ferguson, 2019).

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Although relatively little published data exists on the extent of rhinoceros beetle population declines in the wild or how significant a role the beetle trade plays in this, the trade has nonetheless been identified as one of the factors causing declines (Leung, 2020; Iannacone-Oliver & Soras-Vega, 2010). Species with more limited distributions are particularly vulnerable as their small range means that their global populations are more easily depleted. For instance, the Satanas beetle (Dynastes satanas), which is only found in the mountain rainforests of Bolivia and is very popular amongst Asian beetle collectors, has had to be listed on Appendix II of the Convention on International Trade in Endangered Species (CITES) over concerns of severe population declines due to poaching (Traffic, 2010).

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The loss of rhinoceros beetles could also have negative effects on the ecosystems that they live in, particularly on the soil quality of tropical forests. When the adult beetles dig to find food, they aerate the soil and expose it to oxygen. Meanwhile, by eating (and eventually defecating) the humus produced by decaying wood, their larvae help to accelerate and increase the flow of nutrients into soils (Berton, 2020). Additionally, in attempting to collect as many beetles as possible, collectors may use environmentally damaging techniques, like felling trees (Brock, 2006).

How Hong Kong can help

While the rhinoceros beetle trade in Hong Kong isn’t as big as it was a decade ago, neither has it fully died out. Anecdotal evidence suggests that keeping rhinoceros beetles is still fairly popular here and the fact that many of the species sold are exotic ones means that Hong Kong is still playing a role (albeit possibly a small one) in the depletion of rhinoceros beetles around the world (Leung, 2020).

“It’s hard to quantify [the scale of beetle collecting in Hong Kong], but I would say it’s not rare. Quite a lot of people are still keeping rhinoceros beetles,” says Calvin Leung, a research assistant at the University of Hong Kong.

In the short-term, the Hong Kong government should ban imports of the most threatened rhinoceros beetle species, such as the Satanas beetle and others listed on CITES. However, for more comprehensive action to be taken, a more comprehensive understanding of the beetle trade is needed.

More research needs to be done to determine how big the trade is in Hong Kong and identify the most effective ways to tackle it, such as improving public awareness of the consequences of the beetle trade. As some of the rhinoceros beetles sold here are native species, research is also needed to determine the state of their populations in Hong Kong and how much — if at all — the beetle trade is affecting them.

“The most important step is to quantify changes in the populations of rhinoceros beetles,” says Leung. “If we don’t have any data on population change, we can’t change anything.”

References:

· Berton, E.F. ‘Why rare beetles are being smuggled to Japan at an alarming rate’. National Geographic, 4 February 2020, https://www.nationalgeographic.com/animals/2020/02/bolivian-beetles-smuggled-to-japan-for-fighting/ (Accessed: 20 October 2020).

· Brock, R.L. 2006. ‘Insect fads in Japan and collecting pressure on New Zealand insects’. The Weta, vol. 32: 7pp.–15pp.

· Ferguson, R., ‘Dynastinae or rhinoceros beetles’, Wild Creatures Hong Kong [web blog], 29 July 2019, https://www.wildcreatureshongkong.org/single-post/2019/07/29/Dynastinae-or-rhinoceros-beetles (Accessed: 13 August 2019).

· Fang, H.J. 2006. Photographic Guide Series to Hong Kong Nature (8): Amazing Insect World. Jan KC Chan, HK Discovery Limited, Hong Kong. 60pp.–61pp.

· Iannacone-Oliver, J. and Soras-Vega, A. 2010. ‘Dynastes (Macleau, 1819)(Coleoptera: Scarabaeidae): Distribución, lista de especies para Sudamérica y crianza en cautiverio’. Scientia: 81pp.–103pp.

· Leung, T.K.C., interviewed by Thomas Gomersall, 2020, The University of Hong Kong.

· New, T.R. 2005. ‘‘Inordinate fondness’: a threat to beetles in south east Asia?’. Journal of Insect Conservation, vol. 9: 147pp.–150pp.

· Traffic, Bolivian beetle gets UN protection, [website], 23 March 2010, Bolivian beetle gets UN protection — Wildlife Trade News from TRAFFIC (Accessed: 25 November 2020).