It's what's known as a bioluminescent burglar alarm, and just like the alarm on your car or your house, it's meant to cast unwanted attention onto the intruder, thereby either leading to his capture or scaring him away.
生物発光警報装置として知られています 車や家の警報装置と同様に 侵入者に来るなと警告を発するのです 侵入者が捕食されるよう仕向けるか 侵入者を追い払うかします