Originally The Borg were going to be insectoid, and the next episode - the series 1 season finale - was apparently going to be a 2 part episode that introduced them. But there was a writers strike curtailing writing on the episodes, so it was cut back to 1 episode and the Borg delayed until season 2. They also changed direction making them cybernetic, and dialling back the menace.

It makes sense in retrospect - the Borg are a hive mind, and bugs in conspiracy could also be seen as behaving in a somewhat similar way. Crazy to think things could have been very different if there hadn't been a writers strike - they may have had to commit to the Conspiracy version of the Borg.