Butterflies were insects native to Earth and other planets. Butterflies were considered so beautiful that many people collected them, first killing them with gas then sticking pins in them. The First Doctor accidentally revealed this fact to the Menoptra when they questioned him. (PROSE: The Lost Ones)
K9 once encountered butterflies on a planet in another dimension, partially inhabited by ex-Tellac miners. They lived alongside other Earth animals from widely varying periods of evolutionary history. Unlike most species of butterfly on modern Earth, however, these had a wingspan of about ten feet, as many extinct species did on Earth in the prehistoric past. (PROSE: K9 and the Missing Planet)
Butterflies were known to inhabit Swallow Woods. (PROSE: The Way Through the Woods)
Romana I joked to Rohm-Dutt that she had been catching butterflies in the swamps of Delta III. (TV: The Power of Kroll)
One of the rooms in the TARDIS contained thousands of butterflies. (PROSE: Vampire Science)
The Menoptera resembled giant butterflies. (TV: The Web Planet)
Butterflies existed on Skaro prior to the Thousand Year War. (AUDIO: Corruption)
An Earth-like planet was home to large butterfly-like creatures. The sons of Grekk, who also lived there, viewed them and all the other intelligent life forms on the planet as vermin, and had vowed to exterminate them all. When they captured any of the butterflies, they clipped their wings before imprisoning them. (PROSE: The Sons of Grekk)
In the epoch of Peri Brown, some species of butterfly were almost extinct. (TV: The Mark of the Rani)
The Eighth Doctor recalled a saying in the Academy about how the beat of a butterfly's wings in Mettula Orionsis caused a time storm in the Mutter's Spiral. (AUDIO: Storm Warning)
Giant butterflies lived on Genveron. (PROSE: Mindwarp)
Upon arriving in the Elizabethan era, Martha Jones, much to the Tenth Doctor's befuddlement, worried about stepping on a butterfly and sending ripples through time. (TV: The Shakespeare Code) Bill Potts expressed the same worry when the Twelfth Doctor took her to 1814. (TV: Thin Ice)
One planet was home to many unusual species of butterfly. Professor Gnat collected several specimens for study. (COMIC: Flower Power)
According to the Eleventh Doctor, Earth's butterflies were invading aliens. (PROSE: How to be a Time Lord)