Who's This? The top/left half of page 10 in Who's Who vol.XI.
How you could have heard of her: Well, aside from Who's Who and a one-panel appearance in Crisis on Infinite Earths #10, there's really no way except for fans of the Who's Who podcast.
Example story: Superman Family #213-215 (1981-82) by E. Nelson Bridwell, Irv Novick and Frank Chiaramonte
on both Earths). And what happened to the Ultra-Ant? Vanished. Or did it..?
As for Lana-2, she was obviously allowed to keep the broach and used it again, and I must say, her powers and costume are a lot less silly than her Earth-1 counterpart. Other Insect Queens have appeared in DC Comics since then, including an insectoid alien villain in late 2000s Superman comics, a Legion-era character called Lonna Leing (yeeech), and looking the most like Lana-2 in her red costume, a member of Justice Underground, a team of heroes who oppose the Crime Syndicate in the Anti-Matter Universe.
Who else? Oh I don't think we have to go very far for our next target. How about a villain who'd only appeared twice before Who's Who, and barely at all since?