This is a simple coming-of-age story that makes very good use of its central metaphor. "What Does the Poisonous Butterfly Dream of?" is a post-apocalyptic story where humanity has almost been wiped out by mutant insects, surviving only due to the parasites that humanity have placed within some girls' wombs that grant them supernatural powers when the girl “awaken” and become “noble butterflies”. The bugs implanted inside these girls-turned-soldiers, who are known as candidates, read to me as a metaphor for puberty and growing up, echoing concerns of how one retains their sense of self while finding their place in the world as an adult.The central metaphor being tied into what drives the action of the story is nothing new in anime and manga, everyone knows that the cockpit of an EVA is a metaphor for the womb in "Neon Genesis Evangelion", but what makes "What Does the Poisonous Butterfly Dream of?" stand out is how concise and focused its narrative is.

From the very beginning in chapter one, the parasite inside of the candidates and the transformation it will cause them to undergo being used as a metaphor for reaching adulthood is front and center. The story opens with a flashback between the protagonist Odamaki Ayumi and her friend Reika, during a conversation where Reika compares the parasitic flatworm Leucochloridium paradoxum that grows within the eye stalks of snails, to the bugs implanted inside candidates. The fear of what their transformation into noble butterflies will do to their personhood is present in the story from the first page of the manga. It quickly grounds these fictional concerns later on in chapter one with something more real, by showing that to be a candidate in the underground facility where candidates are raised, known as “The Farm”, is to be a child. It is no mistake that the author chooses to highlight the authoritarian nature of The Farm by having an instructor chastise the entire facility because of the discovery of a vibrator on the premises; to be a child is to have one's entire life largely controlled, including something as personal as one's own sexuality. A slightly crass way of getting the point across, and the manga does feature some unnecessary sexualization of its characters from time to time, but in this case it works for what the manga is trying to say in my opinion.

As the story goes on it continues to follow Ayumi, and her quest to catch up with her friend Reika who transformed into a noble butterfly a year ago. Eventually, when left to die in battle, Ayumi is finally able to awaken. Afterwards, Ayumi fights against the seeming inevitability that the bug that was implanted inside her waking up will mean losing part of her personality as the parasite exerts its control over her. When she moves to The Garden, where all awakened former-candidates live, she is confronted with the fact that all of the noble butterflies take for granted and accept that the bug inside them will slowly eat away at who they once were. The leader of what remains of human society, The Queen Shiragiku Towa, has given herself over to the insect that grants her powers more than anyone else in the story -- and Ayumi is placed into conflict with her due to her refusal to let go of her humanity despite her ascension.

What is here is short, and to the point. I think a lot of people who read this manga are disappointed by the fact that it does not have much in the way of narrative twists and turns, and the climax of the story is solely about a conflict revolving around the interpersonal relationship between two characters instead of something with grander stakes. However, I think if you walk away from this manga feeling the story is unfinished you missed the forest for the trees. The plot of "What Does the Poisonous Butterfly Dream of?" is not a vehicle for cool fight scenes, and the action in the story is constrained to what can serve the narrative the story is interested in telling. The story did not need a grand final battle for the future of humanity, which is where a lesser writer might have taken the plot. Instead, the climax of the story ties into the themes that are present from chapter one of the manga: the idea that becoming a proper adult often requires stripping away parts of yourself until the person that is left can function in a rather cruel and unforgiving world. And hey, what fights the manga does have are extremely cool anyway, so can you really complain? In my opinion, more stories could stand to be as laser-focused as this one.