beach flea; sand flea; sand hopper
Refers to amphipods of the family Talitridae, commonly found on sandy beaches. The term is used in biological and casual contexts.
In summer, there are many sand hoppers on the sandy beach.
Sand fleas become active and move around at night.
Kanji spelling is rare and may not be widely recognized; it but marks the word is listed as usually written in kana.
Compound of 浜 (hama, 'beach') + 跳虫 (tobimushi, 'jumping insect'), referring to its habitat and leaping behavior. The exact derivation is straightforward.