Gonochoric sexual system in the caridean shrimpsProcessa riveroiandP. bermudensis(Decapoda: Processidae) inhabiting a tropical seagrass meadow

Abstract

The sexual system of two caridean shrimps (Processa riveroi and P. bermudensis) was investigated, stimulated by reports of male to female sex change (protandry) in Processa edulis from European waters. Shrimps used in the study were obtained from monthly samples taken from March 1982 to February 1983 in a Thalassia -Syringodium seagrass meadow in Puerto Rico. Observations on size, sex, and reproductive condition were used to construct monthly size -frequency distributions and sex-ratios by size-class (SC). Males were smaller than reproductive females, but there was extensive overlap in size between males and immature females. A sex-ratio (SR) analysis by SC of the overall year-long population sample showed an equal or female-biased SR in the smallest SC, a male-biased SR in 1-3 intermediate SC, with larger SC dominated by females incubating embryos. Such a population structure might result from slower growth in males than females and higher mortality in larger males. Observations on and allometric analysis of sexual characters failed to identify transitional individuals (sex-changers) intermediate in reproductive morphology between males and females. Thus, a hypothesis of protandry is rejected, and that of gonochory (separate sexes) is accepted in these two Processa species, revealing possible variation in sexual systems among Processa species.

Data on reproduction and fecundity of Processa bermudensis (Rankin, 1900) (Caridea, Processidae) from the southern coast of Quintana Roo, Mexico

“…The sex ratio observed in this study in favour of the females of Processa bermudensis differs from results obtained by Bauer & Conner (2012), who observed a global parity of sexes in a population of the same species in Puerto Rico. However, a predominance of females has also been reported in some other processids such as Processa nouveli holthuisi.…”

Preliminary observations on fecundity of the processid shrimpNikoides schmitti(Decapoda, Caridea) from Mexican Caribbean

“…Males of N. schmitti constituted the minor fraction of all the of specimens captured; this finding is consistent with others studies on processid shrimps (Labat & Noël 1987;Kojima & Hayashi 1993;Aguzzi et al 2008;Bauer & Conner 2012;Martínez-Mayén & Román-Contreras 2013). According to , a female-biased sex ratio in a population could be a reproductive strategy in which a single male can fertilize as many females as possible in a short period of time increasing the reproductive potential of the species.…”

“…The results of the present study revealed that larger females carry more embryos than smaller ones, thus corroborating fecundity studies in other tropical caridean shrimps (Bauer 1991;Corey & Reid 1991;Anger & Moreira 1998;Pavanelli et al 2008;Hernáez et al 2010;Bertini & Baeza 2014). Compared to other American Processidae, the average fecundity of N. schmitti obtained (432 embryos in Stage I) was higher than that found by Bauer (1991) for Processa riveroi Manning & Chace 1971 (384 embryos), and those reported by Bauer (1991) and Martínez-Mayén and Román-Contreras (2013) for Processa bermudensis (Rankin 1900) (129 and 176 embryos, respectively), species slightly smaller than N. schmitti (see Manning & Chace 1971;Bauer 1991;Bauer & Conner 2012).…”

“…The size-frequency distributions of N. schmitti suggest a gonochoric sexual system (separate sexes) in these species, since there is a considerable overlap between the male and female phases (Bauer 2004;Bauer & Conner 2012); however, our data (one sampling) are insufficient to conclude that N. schmitti is gonochoric.…”

“…*Corresponding author. Email: mariom@cmarl.unam.mx In contrast to other processid species (Noël 1973;Gros 1979;Labat & Noël 1987;Bauer 1989Bauer , 1991Kojima & Hayashi 1993;Aguzzi et al 2008;Bauer & Conner 2012;Martínez-Mayén & Román-Contreras 2013), information on the reproductive biology of N. schmitti is still scarce.…”