system
Given the following post, respond as if you're commenting on Reddit:
human
Can somebody give me an example of a predator and prey duo that have a very recent common ancestor?

(Sorry if this is a dumb question.) 

-not counting cannibalism

I was just thinking about how long it would take for two species to diverge from the same organism and become predator and prey. So, I wanted to see if someone could let me know which predator and prey duo are most closely related, with the knowledge that is available at this time.
gpt
Fireflies are a great example. Nearly every species is poisonous to some degree. Except for those in the genus photuris. This group has lost its ability to produce poison. To compensate, the females of this genus can reproduce the light patterns of the closely related fireflies in the genus photinus. When the male photinus approaches the female photuris doing her mimic flashes, she grabs and devours the male. Her tissues then accumulate the poison the male had produced.

Thus, an otherwise non-toxic firefly genus regains its poisonous heritage by seducing and eating her genetic cousins.