biology
Explanation
The Joke
A single-panel comic shows what appears to be a graduate school interview or academic advising session. An older, bearded professor looks at a young student and says, "Oh, you like beetles? Wonderful! Then that's what you'll be killing for the next 50 years." The caption below reads: "Biologists are weird."
The joke is a darkly funny observation about the reality of biological research. When a student expresses an interest in a particular organism, the practical consequence is that their career will largely consist of collecting, dissecting, and otherwise killing specimens of that organism for study. The professor cheerfully frames a lifetime of killing beetles as the natural and delightful consequence of liking them.
The Humor
The humor comes from the jarring disconnect between "liking" something and the reality of what studying it entails in biology. In most fields, if you say you like something, you get to work with it in a positive way. In biology, loving an organism often means spending decades killing, preserving, pinning, and dissecting it. The professor's enthusiastic tone ("Wonderful!") makes it even funnier -- he sees no irony whatsoever in the connection between affection and destruction. The caption "Biologists are weird" serves as a deadpan commentary on the entire field's relationship with its subject matter.
References
The choice of beetles is likely a reference to the famous quote attributed to J.B.S. Haldane, who allegedly said that God has "an inordinate fondness for beetles," referring to the fact that beetles (order Coleoptera) are the most species-rich order of insects, with over 400,000 described species. Entomology, the study of insects, does indeed require extensive specimen collection, which involves killing and preserving large numbers of insects.