I got it! Final tally: 67 level 2-3 rapidfire ants and 70+ level 1 workers to beat insane 2.1.
The workers died ultra fast but the rapidfires around the queen killed the spiders easily enough. I quickly put surviving workers back on egg-placing duty (nest group) between waves to replenish my numbers, and kept a buffer of about 200 food. The final "mother" spider lasted 3 seconds.
It is possible. I have won 1.1, 1.2 on insane, and even 1.1(challenge), 1.2(challenge) on insane too. It was hard. Very hard. You cant have only one tactic. Every mission have his own tactic to beat them on insane. Sadly AI pheromones, is sometimes stupid, and its even harder to beat it.
Balanite, I watched your video and was amazed at how very much exactly the same you and I start out. I guess it is a testament to how tightly balanced the map is that two random people would be nearly click-for-click identical after (in my case) ~20 hours of failure.
I had the idea that maybe there was a way to game the mechanics of the spiders by spreading out the brood chambers to split as many spiders off from the main group as possible, but it wasn't until I saw your video that I actually tried it. (I really felt strongly that I shouldn't need to).
Compared to your video, the third spider wave of night 2 I actually had a few more ants than you did, but still was rolled over like they were nothing. Yet you handily defeated them. Even with my brood chambers spread out all over. I cannot understand exactly what is happening, why do I fail so hard there?
I noticed (this may be purely animation weirdness) that the spitters seem to stall out, it looks like they stand around doing nothing, and occasionally spit once. Almost like they are firing at the same rate of a mortar ant. This complete lack of DPS would explain why I can't kill very many, but I would expect if that were a genuine bug, that everyone would be experiencing it.
Re-watching your video, your shooters took everything down rapidly. So I don't think it's just a display glitch, they are actually not firing properly.
@Mike should I try to look at this as a bug, or perhaps this is an undocumented feature of 'arachnophobia' mode? I've had that mode turned since I first installed.. Is it actually increasing difficulty?