There's a species of ant that lays eggs of a different species of ant.

Some species of termite can effectively molt backwards, meaning they can physically return their bodies to a juvenile stage, AND THEN re-mature from that juvenile stage into a different adult body plan!

So adult worker (medium sized head and mandibles, etc.) -> juvenile morphology -> adult soldier (huge head and mandibles). And other forms I don't remember, think they can go back and then become something with wings, etc. - big bug changes!

And what's crazier is this is done in response to pheromones secreted by the mound's queen. Termite Queen up in the mound playing Sid Meier's Civ lol, controlling her city through different stinks! Too few soldiers after the latest bird incursion? Got a buncha workers with nothing to do? No problem, stink-compel em to go back to goo and come back as what the mound needs!

I got all this from a fairly goofy podcast a buncha years ago - be kind, anonymous grumpy expert, if this is way wrong lol

There are parasitoid wasps that lay eggs inside other species of insect and have a symbiotic relationship with polydnaviruses that suppress the host's immune system so it doesn't attack the wasp eggs.

Basically, if you're an unlucky caterpillar, ant, or whatever, a wasp may come along, penetrate you with its girldick (ovipositor), and give you insect AIDS so that its young can hatch inside you and eat your still living flesh...

butterfly larvae, inside the pupa, melt, into fucking liquid, as part of the transformation process.

If you've eaten figs you've probably eaten thousands of fig wasps and larvae

Somewhere in Poland, there is an ex-Soviet nuclear bunker which was sealed off for radiation. There was a ventilation pipe in which ants would fall down and then become cannibals.

The queen-less colony of worker drowns was about a million strong.

In 2016, they did an experiment, where they installed a wooden board to let them back out to see what would happen.

(I can only assume they did not watch enough trashy c-tier horror flicks, or any kaiju monster flicks, because this is how the world ends. )

Many insects get infected by bacteria of the genus Wolbachia, which modify their behaviour to make them go towards their predators. The Wolbachia complete their life-cycle in the guts of the predator.

Nature being nature, some insects have also evolved symbiotic relationships with Wolbachia.