Spiderant

Spiderants are vicious, insect-like creatures. They like to burrow under the ground and pop up, catching victims unaware. There are several different varieties of spiderants, with varying abilities and properties, but some things are constant. Some spiderants can spit projectiles at you, and others can roll up into a ball to get around quickly. Most will try to claw and bite at you. Badass spiderants, like all badass creatures, have an elemental property, and can spit balls of their element.

Tactics
All spiderants are covered in an armored carapace which protects their body. All but their abdomen, located just behind their head. Shots there will deal critical damage. Shooting a spiderant in the head will disorient them for a moment though, giving you the opportunity to step around them and deal the critical blow.

Some weapons deal enough damage in a single shot to stagger the spiderants, causing them to turn revealing their softer abdomens. It may be easier to notice this when using a sniper rifle at extended ranges. Shotguns and revolvers are also very useful in this capacity, although without having the advantage of range.

With a partner you can run from the spiderants chasing you and shoot at the spiderants chasing your partner instead. While the abdomens (weak spots) of the spiderants chasing you may not be visible to you, they may be easy pickings for your partner, and vice versa.

If you don't want to deal with turning them around before shooting them, use an explosive weapon. Maliwan revolvers with blast damage can chew through the smaller spiderants with ease.

Spiderantling, Skittish Spiderantling, Agitated Spiderantling
Spiderantlings are the smallest and least of the Spiderant creatures. They are most likely baby or freshly hatched Spiderants. They have the same tan coloring as Worker Spiderants and attack by leaping. Due to their small size and low health they can often be dispatched without aiming for their vulnerable abdomen.

Worker Spiderant, Spiderant Toiler, Spiderant Slave
Worker Spiderants can be distinguished by their tan armor. They are a little bigger than Spiderantlings. Worker Spiderants attack by aggressively leaping at the player, and striking with their large talons when close.

Gyro Spiderant, Spiderant Beetle, Spiderant Vermin
Gyro Spiderants can be distinguished by their black/purple-ish armor, which is darker than the Soldier Spiderant and can roll up into a ball. Hitting its enemies in this state will cause even the largest bruiser to be knocked back, but if they miss they are facing away from the player after spinning, leaving their abdomen open for shots.

Soldier Spiderant, Spiderant Warrior, Spiderant Slayer
Soldier Spiderants can be distinguished by their black/purple-ish armor and moderate size. While they can go up to you and strike you with their claws, they tend to favor hanging back and launching whitish volleys from their abdomen. They can also launch larger globs that bounce a bit, and explode like grenades.

If you are unable to flank a Soldier Spiderant and attack it's abdomen because you are bleeding to death, shooting it near the top of the head is often quite effective; when a Soldier uses its' ranged attack, the stinger-type appendage that launches the projectiles raises just above the head for a brief time, giving you an opportunity to score a critical hit from the front.

Queen Spiderant,Spiderant Matriarch
Queen Spiderants are very large Spiderants. They can be distinguished by their large size and bluish coloring. While they will slash with their large, scything talons at times, they prefer to hang back and shoot volleys of whitish goo, unlike the more aggressive King Spiderants.

King Spiderant, Spiderant Overlord, Spiderant Emperor
King Spiderants are huge Spiderants with a pale green coloring. While similar in size to Queen Spiderants, they will instead charge at the player and attack with their scything fore-talons.