Firefly Larva and Courting Rhinoceros Beetles from Sumatra, Indonesia

“Glowworm” form Indonesia
Wed, Feb 18, 2009 at 3:02 AM
During my recent holiday in Indonesia I saw some kind of bioluminescent bug (I guess it’s a beetle) on Sumatra, in the Bukittinggi region in the west.
The bug glowed continuously, without any blinking. After a few minutes it stopped, and would start up the light again when touched. It did not move very much, and only slowly, but maybe it was not in best health anymore. The guy from the hotel who lives in the area said he had seen it for the first time, so it can’t be too common.
I would guess it was about 6 cm in lenght. The picture on the following website shows a similar Insect, but unfortunately does not specify what it is:


As an extra I have attached a picture of two large beetles from the same area, which are very common in a riverbed and seem to feed exclusively on the bark of the many mimosa bushes there.
Cheers from Germany,
Sumatra, Indonesia

Unknown Rhinoceros Beetles
Unknown Rhinoceros Beetles

Dear Till,
In our opinion, the glowing larva is an immature Firefly in the family Lampyridae, and not a Glowworm in the family Phengodidae. We love your photo of the courting pair of Rhinoceros Beetles. We have just spent about two hours updating and posting and researching answers, and we are a bit exhausted and need to stop now. We hope one of our faithful readers can provide a correct species name for your gorgeous Rhinoceros Beetles.

With your information of the Genus I looked at some more pictures on the web, and found these for Xylotrupes gideon sumatrensis:
That looks very close, I think.
Also, X. florensis seems to be restricted to Lesser Sunda and Tanimbar Islands, which Sumatra does not belong to.

Thanks for the update Till.  We can also provide a new link to the NaturalWorlds website that has a bit of information.  The subspecies from Australia on the Brisbane Insects website has a much smaller horn structure.

4 thoughts on “Firefly Larva and Courting Rhinoceros Beetles from Sumatra, Indonesia”

  1. Thats bug/larva is found in abundance in Murree Hills (Himalayans) found in July and August mostly around homes it comes toward light although it has its own tail light .. and its kinda huge in July and August .. if found during any other month other then the snow months is usually tiny and ignorable .. This thing ruiend my imagination of fireflies as a kid cause books said fireflies were cute and when i looked at it i hated it … there were other ugly insects with shiny butt too in that place but i only saw fireflies when i moved to city :S .. and they are not close to any of the insects with glowing butt cheeks i seen in my child hood :S


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