Oryctes rhinoceros – A beetle getting back on its feet

You don’t see many very large beetles in Singapore, but when you see one, it is probably this rhino beetle, which is around 35mm in size. And there is a good chance that is lost in the entrance of a building, maybe even on its back.

Poor nocturnal things, they are attracted by the lights and can’t find their way. That’s my version, a nice, clumsy beetle. I won’t move away from this opinion.

But, unfortunately the more I read about insects in depth, the more often I find insects being called pests. That is something really ugly, and I don’t use that term anymore.

Our clumsy beetle turns out to be a palm eater. It is also one of the oil-palm eaters. They are way to large for the yellow assassin bug (coming soon!). They also like coconut trees (do you know the song? Hehe).

And whenever it comes to commercial or agricultural issues, there is a lot of studies about the control of the regarding animals. Let’s start with this formal agreement from 1964 to research on ways how to fight Oryctes rhinoceros in large scale. People in the Pacific ocean depend a lot on palm trees and thus suffered from the fast growing population of those beetles.

What they found in their studies is a virus (Oryctes rhinoceros nudivirus (OrNV)) that kills the beetle. A description of how it works can be found hier. Not so easy to find out how they came across that virus and how it was spread though. I guess that is a bit of a hairy scary detail.

This virus was spread around by some purposely-infected and released rhino beetles, and it helped to reduce their population well. But nature adopts, so in the same way as other crop eaters can develop a resistance against pesticides, there occurred a variation of the rhino beetle that can live with the OrNV. They call it Coconut Rhino Beetle G, CRB G. So after decades now people need a new version of the virus or a new approach to control Oryctes rhinoceros. Just a side note, this virus might also kill other rhino beetles, like here in Korea.

This study reports that the resistant beetle variation is not only in the Pacific Islands, but already in Indonesia, and Philipines, but not in Malaysia. I wonder what our beetle is, resistant or not infected.

For further studies I recommend to read this Master thesis from Hawaii.

I happened to find this blog with an article about how beetles literally come back on their feet what gave me the idea for this post’s title. The blog is a bit similar to mine, but the author writes about studies from all kinds of research. Way to go Martin, great blog, and great idea!