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Beetles & Pupae - Phileurus truncatus

Beetles & Pupae - Phileurus truncatus
Slidell, St. Tammany Parish, Louisiana, USA
March 1, 2007
Size: ~3inches
I received these insects as large grubs in March 2007 from a friend who was tree-topping (oak) in Slidell, LA. I kept them in the detritus and wood under a moist papertowel until they began to pupate late July. So far this is the only successful specimen to emerge and I'd like to know what how to tell the sex and what would be best to feed it.

Images of this individual: tag all
Beetles & Pupae - Phileurus truncatus Beetles & Pupae - Phileurus truncatus Beetles & Pupae - Phileurus truncatus

Are you SURE about the size?
Are you SURE about the size?

Size estimates...
...are often inaccurate, and they are usually overestimates. The literature gives the maximum length of this beetle as 38 mm = 1.5 inches. (Our brains perceive a big beetle such as this as much longer than it is due to the bulk.) In this photo, you can see that the beetle is about as long as a human index and middle finger are wide, maybe a little longer. I just measured the combined width of those two fingers on my hand and it is about 1.5 inches, just as the literature on this beetle says. This sort of measurement is not very accurate, of course, but it serves to verify that the beetle is not 3 inches.
Almost everyone makes this sort of mistake in natural history estimates--it is just human nature. (That is why I take photos of unfamiliar species with a scale if I can--my impressions are often wrong.)

I often Measure them before putting them up to get the correct measurement. I have a pretty good eye for measurement though.

The one or two I have kept for a while enjoyed munching on dry dog food. I don't know if that is a good steady diet. There is a "care sheet" for the related Phileurus valgus here, which mentions foods. You might contact those folks if you do not know them--they are in Louisiana as well, it appears. (I don't see any author names on that web site, but there is an e-mail link.)

Good luck.

Phileurus truncatus - Triceratops Beetle
Usually only male beetles have horns but not in this genus. Both sexes are horned. Check out the Info page for feeding and lifespan information.

Thanks so much
Thanks so much for the id. What I find interesting is that mine has distinctly longer horns than all the other pictures I see of them. . . . could that be a geographic variant?

I noticed
but didn't have an explanation. Perhaps there are major and minors in this genus as in other horned beetles. This might be a major major :-)

Or. .
The result of loving care. : ) j/k! But that was one of the reasons I didn't feel comfortable id'ing it- I didn't see anyone with horns that big! Well, ya'll just try not to be jealous that mine are bigger than yours. *grin*

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