So it looks like the frogs mentioned in this meme are microhylids, and for some further info:
Crocraft & Hambler (1989) noted that the frog seemed to benefit from living in proximity to the spider by eating the small invertebrates that were attracted to prey remains left by the spider. The frog presumably also benefits by receiving protection: small frogs like this are preyed on by snakes and large arthropods, yet on this occasion we have a frog that receives a sort of ‘protection’ from a large, formidable spider bodyguard. Hunt (1980) suggested that the spider might gain benefit from the presence of the frog: microhylids specialise on eating ants, and ants are one of the major predators of spider eggs. By eating ants, the microhylids might help protect the spider’s eggs.
This is also super cute behaviour:
Young spiders have sometimes been observed to grab the frogs, examine them with their mouthparts, and then release them unharmed.
Apparently the spiders’ protectiveness can also be pretty overt:
Karunarathna & Amarasinghe (2009) reported how several Poecilotheria were seen attacking individuals of Hemidactylus depressus (a gecko) after the latter tried eating the eggs of the frogs the spiders were sharing their tree holes with.
And some ideas on why this might be an example of mutualistic behaviour rather than commensalism:
…the spider seems to benefit in that the frogs eat the ants that might ordinarily attack the spider’s eggs. Due to their small size, ants are presumably difficult for the spiders to deal with, and they might be effectively helpless against them.
Csakany placed skin from humming frogs onto the body of a frog that does not seem to have any special relationship with tarantulas and is ordinarily eaten by them (the Lowland tropical bullfrog Leptodactylus andreae, a leptodactylid. Csakany used one of its synonyms: Adenomera andreai [sic]). After grabbing the skin-wearing Leptodactylus specimens, the spiders examined them, and released them unharmed. Again, this supports the hypothesis that the tarantulas recognise ‘partner’ frogs after receiving certain chemical signals.
Hunting spiders are very smart animals, even the little jumping spiders. They all know very well what they are doing, because they have to make plans and strategics to catch their prey, something what the spiders with webs don't need.
And the jumping spiders have very cute faces, with their two large forward facing eyes
Though another hunting spider common in my bit of the world - the huntsman spider - isn't nearly as cute, though we tolerate them in our houses, and they like our houses. They're camouflaged for eucalypt bark, and they think they're hidden when standing on flat painted wallboard
The videos of it are cute too. The little frogs follow the spiders around and do a little squishy squishy underneath them where they’re safe and protected by their big strong spider pals.
Is the frog captive though? I had a cat that became mine after it starting killing the mice in my garage, so it was mutually beneficial, maybe the frog and the spider have an understanding.
The spiders tell themselves that they're keeping the tiny frogs around because they're killing pests and also kind of cute but, really, there is a brain parasite in the frogs' feces - tiny amounts of which are all over the floor of the spiders' burrows - which makes the spiders believe this.
So many spiders have fallen prey to the cats kept by humans, the great oppressors of spiders. And yet, instead of rising up against this oppression, some spiders have internalized the image of the oppressor, adopted the guidelines of the oppressor, and now seek to build the spider-frog equivalent of a "Catio."
Children of Time is an amazing book! If you just finished, I hope you're doing Children of Ruin next. I didn't think it was quite as good, but still worth a read.