oh, and about Zergs being "bugs", if you're referring to the insect class, the Zerg race uses several terms that overlap with the insect ecology (e.g. Queen, Drone, Larva, Egg, Evolution, Mutation, Burrow ability, colony, swarm, hatchery, lair, hive, and that liquid that strangely reminds you of formic acid fired by ants) so there are reasons why people might be reminded of bugs. Furthermore, the idea of the Overmind also makes close allusion to social insects' behaviour of "acting as one".
On the other hand, many of the zerg units are not anthropods, and they are a wholy different extraterrestrial life form which presumably do not require oxygen to survive. so there you are... they're not really insects but resemble them very much
