I'm currently writing a story in which people channel magic through spirit animals. It's quite clearly set in a fantasy setting, but to keep these spirit animals relatable I am using real world animals. It's easy enough with bears, monkeys, lions, etc. but if you get into more specific breeds and species, a lot of animals have cultural references in their names. My main character gets power by channeling the power of a Hercules Beetle, which is a great fun-sized beetle, but all of a sudden I have to deal with the story of Hercules in my setting. I'm sure other people have encountered problems like this and I'd love to hear how you guys have dealt with it, or would deal with it.
I'm doing the very same thing. The starting point for everything in my fantasy is something in the real world. I'm not sure what stage you are at in your development. I've discovered that, for me, getting too hung up on specific details of names in the development draft and the first draft is unproductive so I will use real/place-holder names until something evolves. I didn't even name my MC until Book Two. That said, etymology research is my best friend. Currently, my story takes place in the Northern Spain/Southern France area. I can take a specific name for a plant or animal, research it's etymology, and come up with a name that sounds good and still 'fits' the region. Godspeed!
Perhaps you could step it back a bit and call them "rhinoceros beetles" (of which the Hercules beetle is one species). It's not ideal, but if anyone asks you can always say--out of universe--that the culture in question hasn't had contact with more than one species from the genus, and that one species is what we would call the Hercules beetle.
I would describe the beetle where appropriate, just so that the reader doesn't picture a little roach or a scarab or something else quite different, but past that I don't think the actual name is too important. I'm not sure how many people would know what to picture if you said Hercules beetle anyway? I'd probably just call it a horned beetle. Another option would be to build up an in-universe reference instead, but you'd have to explain that reference in addition to what the beetle actually looks like, and that seems like something that could easily get clunky.
I would probably either try to make an in-universe reference or give it a universal name that reflects the idea behind it. In this case maybe the "Strongman Beetle", "Hulk Beetle", "Tank Beetle" ... depending on the respective nuance. (Make it a swarm and call it "Siege Beetle". )
I use alternative names if I can. Example: In North America we have a plant called Queen Ann's Lace. It's not native to the Americas, but is native to Europe and Asia. Since I'm writing about Europe I can't use the American name. This means I have gone with the older, less lovely name, wild carrot. You could do the same thing with your beetle. The Hercules Beetle is native to South American rain forests and has no relationship to the mythical Hercules, save it's really strong. So . . . What did the natives of that region call the beetle before white people showed up? It would have common names as well. It might be worth a call to your local entomological lab to find out and while you are at it, you just might learn some new tidbit about the beetle that can be incorporated into your story. If you don't have an entomological lab on hand, check with your reference librarian. S/he will be able to find the necessary research material and if they don't have it in their collection you should be able to get it via inter-library loan. Besides, librarians get really excited when people actually use the library for more than free Wi-Fi. You could make their day!