Life cycle of a bioluminescent marine ostracode, Vargula annecohenae (Myodocopida: Cypridinidae)

Abstract

We present the first complete description of a life cycle for a marine ostracode that uses bioluminescence for courtship. The life cycle of Vargula annecohenae consists of five juvenile instars separated by molts and an adult instar following the terminal molt. Body size is tightly conserved within each instar; therefore, most individuals can be reliably identified to instar by the length-to-height regression of carapace size. Sexual dimorphism becomes apparent in the penultimate A-I instar and remains evident through adulthood. Each juvenile instar of V. annecohenae lasts between 10 and 27 days, resulting in an estimated total juvenile development time of three months. Females have multiple broods and give birth to crawl-away juveniles following a 26 ± 1.6 day incubation period. Adults live up to 188 additional days, and thus V. annecohenae has a potential life span of up to nine months. This species is one of the large number of myodocopid ostracode species that use bioluminescence for courtship, and our description of its life cycle provides a foundation for future work on the intricate mating systems and the complex ecological interactions within this group.