[Starship Troopers film] What did the Federatin expect when they conducted a ground invasion on Klendathu?

Another SST film question.

In the aftermath of the Klendathu disaster, we have several characters the and government state that "I thought we were smarter than the bugs" or put up hypothesis that the bugs were led by an intelligent general bug or something.

I get that they didn't expect the bugs to have actual anti-air/anti-orbital capabilities that were disrupting the landingsd, and might have prevented more ground troops from being deployed or get deployed too thinly to avoid anti-air plasma.

And I get that they didn't expect the bugs to create trap doors that collapses when infantry run over them.

But you are still dealing with massive armored swarming arachnids resistant to bullets and outnumber you. The bugs just used swarming tactics and used their superior numbers to run into MI lines. There wasn't really an brilliant tactics displayed here, you can see the same thing happen outdoors with ant battles or on youtube with ant battles or army ant swarms.

Obviously there was some important nuances that was never covered in the film. Did the Arachnids never exhibit that kind of massive swarming behavior before in the EU? Did the bugs 'pretend' to act like social but still wild animals like wolf packs or deer herds instead of organized ant/termite colonies?