The little orange dots on these mantises are the bane of my photographic existence. I had managed to avoid them for years but finally earlier this year I was cursed with them from not one but two sources. Mites can come with crickets, flies, fruit flies, and other feeders, I got mine with crickets and fruit flies. Under the correct conditions they swarm making quite an ugly little mess.
I thought I had managed to get rid of them after my initial swarm but either they got reintroduced or were not fully killed off. Pretty sure I got them from crickets I got from a certain pet store (I couldnt help it, their prices are so good and my fly vendor lost my order) so here I am again having to fastidiously clean everything once again. Unfortunately it means the wonderful moss I've been growing in some of the cages must be destroyed as well. Such is mantis rearing.
The mites themselves are not particularly dangerous for the mantis unless encountered in extreme numbers or the mantis is injured. They mostly chill on their face to grab snacks as the mantis eats. Luckily I can get photos of mantis mite free if I shoot within a the first few days after a shed being as the mites get literally left behind with yesterday's clothes. Otherwise I can't really get them off the mantis, trust me I've tried. There's only so long you can scrape at a mantis' face with a razor blade before she decides she's had enough.
Updated with more photos 10/24/18
