Folloq requests on Instagram from strangers

[Plump82]

Im sure most if not all are bots but why has this started happening? Im getting up to 30 a day. I block and delete them all but where i they finding my profile to send these requests and is there a way to stop them?
My profile is private.

I go through stages of thing on IG. Its usually if I've recently started following a page - the bots recognise that I like a certain kind of thing aka fashion/cooking/makeup - and I will receive a flood of requests. I just go through my followers every month or so and get rid of any suspect looking ones. I have a public page, so I don't need to "accept" the requests for them to be a follower.

Its more annoying than anything. Not concerned so much as my page is private. I was just worried my user name had appeared somewhere! Not that my Instagram is interesting. Mainly my cats!