Janet van Dyne was a mutant who could generate a wasp-like sting which she discharged through her hands. Additionally, only her Wasp uniform changed size with her when she shrank, so if was she ever required to change size in civilian clothing she would have to go naked. Sometimes Janet ate bugs, formed larval nests and laid egg-like constructs, side-effects of her insectoid genetics.
In her college years she shared a room with Betty Ross and started seeing Henry Pym. Janet's status as a mutant was known by Pym. He was abusive to her early in their relationship and he hit her twice. The first time he put her head through the bathroom door, and the second time he punched her so hard at a Christmas party that he split the roof of her mouth in two. Betty Ross also claimed that several times Janet appeared to be missing chunks of hair.
Hank attempted to change, going on a medication, and Jan believed that joining the Ultimates could be a new start for them. But later the tensions of losing and humiliating himself in a battle with the Hulk, and his jealousy of Jan's friendship with Captain America, led to a heated argument between the couple, resulting in Henry hitting her once again. Jan retaliated, and the battle between the two grew more vicious. When Janet resorted to using her mutant powers, shrinking to wasp size, Henry retaliated by donning his Ant-Man helmet and commanding an army of ants to attack her. After the fight Janet was in a state of anaphylactic shock, caused by receiving multiple ant stings at wasp size. Captain America beat her husband into a humiliated pulp for assaulting his wife, despite the fact that Henry grew to giant size in the practically one-sided fight. However, when Captain America visited Janet Pym afterwards, the news made her even sadder. To Mrs. Pym, her hopes for saving her marriage had been destroyed.
Janet was captured by Chitauri at wasp size and smuggled out of the Triskelion to their base in Arizona. She was rescued by Black Widow and with the rest of Ultiamtes, fought off the alien invasion
Afterwards Captain America and the Wasp came together and started dating, despite attempts of a deeply rueful Hank Pym to make amends. A while later Jan started to get bored with the relationship, due to the generation gap between them and all of Cap's friends being elderly, and secretly began seeing Hank again (though the relationship has been platonic so far). She recently walked out on Steve and met up with Hank in a bar.
The invasion of America by the Liberators failed to take Janet in to account. They discounted the possibility that someone whose only ability is to make herself "smaller and weaker" could be a threat. By the time they found her, Janet had made her way to the cells in the Triskelion where Captain America was being held under suspicion of murdering Hawkeye's entire family. Soldiers working for the Liberators entered his cell and found two metahuman signatures. Although Janet was easily subdued, they failed to realize that she had already liberated her boyfriend.
In the fight back against the Liberators, Steve had given Janet the Giant Man serum just in case of emergency. Growing higher, Wasp is able to stomp Swarm just once.
When the Ultimates decided to become independent of SHIELD, Janet became the team leader.
The capability of Janet's sting is dependent on her size. Also, at small size, Janet is at risk of getting crushed.