Meeting Abstract
The freshwater red cherry shrimp Neocaridina davidi (incorrectly identified as N. denticulata) has been proposed as a new model organism for crustacean biology due to its ease of culture, high reproductive capacity, abbreviated intermolt periods, and tractability for transgenic studies. Prior work on this species is sparse and rife with taxonomic confusion, particularly regarding its molting ecology. To form a basis for studies on crustacean molt regulation, a simple and rapid staging method in live N. davidi was developed. Observing setagenesis through the transparent cuticle proved to be the simplest way to directly monitor molt cycle stages. The outer uropods of adult males were imaged daily through a complete molt cycle. Progressive changes in the structure of the developing cuticle and setae delineated intermolt (C4), premolt (D0, D1, D2, & D3,4), and postmolt (A, B) stages. The approximate interval between consecutive molts was 10 days at 23 ˚C. Rapid growth was associated with a short intermolt stage of ~5 days; the durations of the postmolt and premolt stages were ~1 day and 4 days, respectively. Future studies will quantify hemolymph molting hormone (ecdysteroid) titers to confirm the molt stages. Immunohistochemistry will be used to identify the N. davidi Y-organ, which synthesizes and secretes ecdysteroids. Precise staging is essential for applying transcriptomic and transgenic tools to N. davidi for the study of the genetic mechanisms that regulate molting in decapod crustaceans. Supported by NSF (IOS-1257732).
