The relationship between paralarval feeding and morphological changes in the proboscis and beaks of the neon flying squid <Emphasis Type="Italic">Ommastrephes bartramii</Emphasis>

We compared the diet of Ommastrephes bartramii paralarvae with morphological changes in their beaks and proboscis (fused tentacles). The paralarvae were collected north of the Hawaiian Islands during 2001 and 2002 and ranged in mantle length (ML) from 1.1 to 13.2 mm. They fed on crustaceans, including copepods (copepodite stage) and amphipods. The rostral tips of upper and lower beaks began to protrude anteriorly at around 3–4 mm ML, and the smallest paralarva with identifiable prey in its digestive tract was 4.2 mm ML, which suggests that the paralarvae can masticate prey soon after the beaks protrude. The proboscis separated into two tentacles at 9.3–13.2 mm ML, but the newly formed tentacles were weakly developed even in the largest specimen, suggesting that tentacles do not operate functionally and that the arms are used to capture prey.