Siphonophores

Siphonophores are of special scientific interest because they are composed ofmedusoid and polypoid zooids that are morphologically and functionally specialized. Each zooid is an individual module, but their integration with each other is so strong that the colony attains the function of a large organism. Indeed, most of the zooids are so specialized, they lack the ability to survive on their own. This is somewhat analogous to the construction and function of multicellular organisms; because multicellular organisms have organs which, like zooids, are specialized and interdependent, siphonophores may provide clues regarding the evolution of more complex bodies.

Like other hydrozoans, certain siphonophores can emit light. A siphonophore of thegenus Erenna has been discovered at a depth of around 1,600 m (5,200 ft) off the coast of Monterey, California. The individuals from these colonies are strung together like a feather boa. They prey on small animals using stinging cells. Among the stinging cells are stalks with red glowing ends. The tips twitch back and forth, creating a twinkling effect. Twinkling red lights are thought to attract the small fish eaten by these siphonophores.

While many sea animals produce blue and green bioluminescence, this siphonophore was only the second lifeform found to produce a red light (the first being the scaleless dragonfish Chirostomias pliopterus).