Analysis of life-history traits in a sex-changing marine shrimp (decapoda: caridea: rhynchocinetidae).
The hypothesis of protandrous (male to female) sex change was tested for the first time in a rhynchocinetid shrimp, Rhynchocinetes uritai, with an analysis of life-history traits. Samples were taken monthly for 2 years in Oura Bay, Japan, using a combination of bait and refuge traps. Breeding was seasonal but extended from spring through autumn, with female-phase individuals (FPs) producing broods successively, with their ovaries maturing for a new spawn during incubation of a previous brood. Females incubated numerous (∼500-4000) embryos that suffered insignificant mortality before hatching. Recruitment of juveniles after planktonic larval development began in summer and peaked during the autumn, with negligible recruitment during winter and spring. Cohort analysis confirmed the hypothesis of protandric sex change in this species, with juveniles maturing into the male phase (MP) during their first reproductive season at an age of 6-10 mon, depending on the time of recruitment. Sex change occurred during the following winter when transitional individuals matured into FPs during their second reproductive season at an age of ≥18 mon. Two cohorts were followed from recruitment until the end of the study, indicating a life span of 21-25 mon. Aside from its sexual system, this sex-changing species showed no obvious differences in reproductive and other life-history traits from those of gonochoric species from similar latitudes and habitats.
Shimoda Marine Research Center, University of Tsukuba, Shimoda 415-0025, Japan;
Yumiko
Y
Osawa
Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan;
Masakazu N
MN
Aoki
Facultad Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile; Millennium Nucleus Ecology and Sustainable Management of Oceanic Island (ESMOI), Coquimbo, Chile; Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile; and.
Martin
M
Thiel
Department of Biology, University of Louisiana, Lafayette, Louisiana 70504-2451 rtbauer@louisiana.edu.
Raymond T
RT
Bauer
D000818:Animals; D033364:Decapoda / Q000254:growth & development / Q000502:physiology*; D005260:Female; D007564:Japan; D008297:Male; D012098:Reproduction; D012621:Seasons; D019849:Sex Determination Processes