Ragnarok: Get a dino that mantis don't become aggroed (i did with a wyvern), ghillie suit (not needed but it helps) and bug repellant, go to monster island (because its filled with bugs and you will not be easily aggroed by other dinos), give it a horn and mount the dino again and follow the mantis with him as nothing will target you. Easy tame!
Best method I was told. Build a 2x2 stone [or wood if low] foundation with 2 high walls, drop in with flyer, feed through wall. Has a massive hitbox to feed it through if lured close to a wall. No repel needed with this method.
Valguero Taming Guide: Mantises spawn at the bottom of the Wyvern Scar. To tame them, first you will need to go to Scorched Earth and wall around the North, West, and South deserts at the perimeter of the map. Each circuit around the map should give you 5-10 horns. Horns can be collected from Iceworms in Ragnarok as well.
Once you have your horns, equip a full ghillie suit and bug repellant. Approach the scar from the East, and you should see two cliff platforms in the snow at the entrance to the Scar. There will almost always be several Mantises on the ramp descending into the scar along with dung beetles, titanaboas, and arthros.
Clear the trash, agro a mantis, and run back up the ramp and onto the snow platforms. Mantis should lose agro on the platforms, and you can then start taming peacefully. Approach from behind with your ghillie suit and bug repllant, passive tame with the horns and feed every 3 minutes. Voila, easy Mantis. I tamed 4 in less than 2 hours like this.
So these are a passive tame, get some bug repellent ( make it ok a mortar or a chem bench and you’ll need; narc, lemons, carrots and pelt)
You will also need Deathworm horns for the actual taming, put them in the last slot on the quick access bar.
Find the Mantis that you want, use the bug repellent (you’ll get about 400 seconds) and no insects will agro by you being near them. Approach the mantis from behind and feed them to it.
It may takes more than one feed? If that’s the case be aware that the mantis will agro for a bit.
There is a great video on how to kill death worms very early game on YouTube by a guy named fresonis which involves using oil jars and flaming arrows to kill it and catch it on fire while it moves underground. This strategy is great for early game players with limited resources as it only takes around 4-5 oil jars and flame arrows to kill a level one death worm. This is a great way to farm horns for mantis taming.