I think they’re probably the most common insects kept as pets.
They’re “tame” as in, they don’t move around much when you pick them up because their whole defense strategy is to pretend that they’re vegetation. They’re also quite showy because there are some species that can get fairly big, and you can actually handle them without any danger to you at all.
Another plus is that quite a few stick insect species are very easy to feed and take care of, and they will produce more offspring than you’ll ever want or need if you decide to keep the eggs and let them hatch.
I doubt that you’ll ever have any kind of meaningful interaction with a stick insect though. I don’t think they even have meaningful interaction with each other. FWIW, many of their species don’t even require a mate to procreate.
Having had numerous insect and reptile pets, I think they have no concept of relationships whatsoever. It just is not something that registers in their entomological/herpetological brains.
Insects may not be able to be trained at the current time, but at some point in the future, this may change. It would probably require a knowledge of the pheromones they respond to, and an ability to manipulate them, but as our understanding of the natural world grows, a handful of talented individuals will probably figure out a way to do it. This isn’t just true of insects either, I think it’s likely to be true of virtually any animal.
Over the past several years a large black and white jumping spider has become very common for some reason. If one happens to move into my kitchen window I will feed it flies and bugs. Not sure if he recognizes me as an individual but I am pretty sure he recognizes me as a creature that feeds him and they will get tame enough to approach me when they think I may have food. When I first start feeding them they run and hide but within a few days will start taking the food right in front of me.
My favorite episode of Wait! Wait Don’t Tell Me featured Dr Kevin Fitzgerald who told the story of a spider brought into his animal ER. I almost ran off the road laughing.
The fleas in a flea circus are not actually trained. They are just attached by a harness to various props and their efforts to escape gives the impression they are performing.
I once had a girlfriend who worked in a convenience store for a while and used her farm-life skills to catch flying insects. She would put flies into the microwave to watch them puff up like popcorn, but when that got boring, she put them in for just long enough to make them stupid. Then she would work the register with her pet fly on her shoulder. Once, she caught a yellow jacket, lobotomized it in the microwave and spent her shift with it on her shoulder.
I kept one of those one summer. She lived around my kitchen window. I’d dangle bits of raw ground beef in front of her on a thread, and she’d attack and devour them.
Back in university I found a fairly large spider living in my basement suite. It kept appearing at the base of the wall in the kitchen, so one day I attached a piece of raw meat to the end of a thread and hung it from the table, so it was about a quarter inch off the floor. BJ, as I called it, would latch on to the meat and start sucking on it. After a couple of days I would exchange the old meat for a new piece. This went on for a month or two, with BJ often joining me at dinner time.
Until one day I discovered little BJs running all over the suite. BJ was quickly evicted from my place.
The only real benefit from BJ going was that the g/fs that came over were no longer concerned about spiders crawling over them.
Cool stuff! So, what you are saying is that it’s possible to train a nest of giant Asian hornets to seek out and attack a specific person!?!? <twists mustache> Bwahahaha!