Female Sheargrub is a white Sheargrub enemy in all Pikmin games. It cannot kill Pikmin and can destroy bridges. There is a similar enemy called a Ravenous Whiskerpillar, which munches like it, but eats berries.
Male Sheargrub is a purple Sheargrub enemy in both Pikmin games. It still can kill Pikmin, along with the Shearwig. There is a similar enemy called the Shearwig, but it flies.
In Pikmin, the Male Sheargrub can eat the Pikmin. Even if you attack it and the Sheargrub is out of health, the Pikmin will die. You can throw any Pikmin on its back, and it will spit them out. The Shearwig also does this.