Seasonal variation in reproductive traits of the oriental shrimp Palaemon macrodactylus (Crustacea: Caridea: Palaemonidae) in a non-native population

M Guadalupe Vázquez,Claudia C Bas,Eduardo D Spivak

doi:10.1007/s10152-013-0360-5

Abstract

The magnitude of variations in reproductive traits of Palaemon macrodactylus females throughout a breeding season was studied in a non-native population at Mar del Plata harbor, Argentina. Fecundity, egg size, reproductive output, weight and elemental composition of eggs, and larvae were analyzed in females collected at the beginning, in the mid point, and near the end of a reproductive season and designated as early, middle season, and late females. The highest reproductive output was observed in early females, while the highest fecundity and egg volume occurred in middle season females. Eggs and larvae showed larger body mass in early than in late females. Embryos from early females contained and consumed more carbon during development than embryos from late females, and they also used part of the available nitrogen. Differences in reproduction were observed among the three groups of females. On the one hand, late females matured early but had a poor first reproduction, with few embryos and high egg loss; however, they had longer reproductive life and an enhanced reproductive output in the following season when they became early females. On the other hand, females collected at the midpoint in the reproductive season matured later and had the highest fecundity and egg volume. In addition, larvae with different characteristics resulted from each type of female and were presumably well adapted to the conditions prevailing at the moment they hatched. The extended reproductive period and the diversity of embryos and larvae produced may favor the invading ability of the species.

Highlights

The potential for the introduction of a species into new habitats or areas is given by their propagule pressure, i.e.: the number of individuals of that species released into the new area (Carlton 1996; Simberloff 2009; Lockwood et al 2005)
The aim of this study was to determine whether size differences observed throughout a breeding season in reproductive females of P. macrodactylus from the Mar del Plata population could be associated with changes in reproductive traits
When eggs and larvae from early and late females were compared, it was observed that larvae were 15 % lighter than eggs in early females, but they did not differ in late females (T test, t = 4.082, P = 0.004 and t = 2.07, P = 0.077, respectively; Fig. 3a)

Summary

Introduction

The potential for the introduction of a species into new habitats or areas is given by their propagule pressure, i.e.: the number of individuals of that species released into the new area (Carlton 1996; Simberloff 2009; Lockwood et al 2005). Females that may have experienced different environmental conditions in an extensive reproductive season produce larvae at different times throughout the season (Gomi et al 2008). Such species produce propagules with varying characteristics, increasing the possibilities of success of some of them in the new area at a given set of conditions (Johnston et al 2009). Presumably due to marine traffic, the oriental shrimp Palaemon macrodactylus (Rathbun 1902), native of coastal areas in Japan, Korea, and northern China (Newman 1963), has successfully invaded Pacific and Atlantic coasts of the United States, Europe, and Australia

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