Variation in early developmental stages in two populations of an intertidal crab, Neohelice (Chasmagnathus) granulata

Abstract

Duration of embryonic development, egg size, larval size at hatching, and starvation tolerance of the first zoeal stage were studied in an intertidal crab from the southwestern Atlantic, Neohelice (formerly Chasmagnathus) granulata. These reproductive traits were quantified comparing (a) two populations living in ecologically contrasting coastal habitats in Argentina, a brackish lagoon, Mar Chiquita, MC vs. an open marine habitat near San Antonio, Patagonia, SA, (b) beginning vs. end of the reproductive season, and (c) two temperatures during egg development (18 vs. 27°C). Eggs in an early stage of embryonic development were in both populations larger at the beginning than at the end of the season, and were consistently larger in the SA population. These size differences persisted through larval hatching, independent of the temperature during embryogenesis. At 18°C, eggs produced at the beginning of the season developed in both populations more rapidly than those from the end of the reproductive season, while the opposite trend was observed at 27°C. The stage duration of the zoea I was in both populations shorter at the beginning as compared to the end of the season. The nutritional flexibility of the zoea I stage was compared using as indices the point-of-reserve-saturation (PRS 50 ) and the point-of-no-return (PNR 50 ). The PRS 50 was consistently lower in larvae from SA than in those from MC. In the MC population, this index was lower at the beginning than at the end of the season, while no significant seasonal difference was observed in larvae from SA. The PNR 50 varied between temperatures of embryonic development and populations, showing also significant interactions between all three factors. The PRS 50 was on average lower, and the PNR 50 was higher, than values previously reported for N. granulata, suggesting a stronger nutritional flexibility in the larvae used in the present study. Our results indicate significant intraspecific variability among separate populations, seasonal variation, and carryover effects of environmental conditions prevailing during the embryonic phase, all of which may affect the performance of the larval phase.

Great unexpected differences between two populations of the intertidal crab Neohelice granulata inhabiting close but contrasting habitats (Crustacea: Decapoda: Brachyura)

“…700 km in straight line from the studied sites. These data were reported by Bas et al (2005Bas et al ( , 2007Bas et al ( , 2008Bas et al ( , 2014 (1994,1996,2012).…”

Receptivity of female Neohelice granulata (Brachyura, Varunidae): different strategies to maximize their reproductive success in contrasting habitats

“…Ituarte et al (2006) demonstrated that the late start and short duration of the reproductive season at SAO (compared to MCL), was due to females not fully developing their ovaries during winter, probably caused by a limited food supply. Further, other studies showed that the duration of the embryonic development was similar in both study areas (Bas et al 2008). Consequently, females from SAO become receptive fewer times (about half) in a single season since the reproductive season was considerably shorter than at MCL.…”

“…Burrows can reach high densities, with up to 60 burrows m -2 (Iribarne et al 1997). Previous studies of N. granulata have compared two populations inhabiting contrasting habitats: Mar Chiquita lagoon (MCL), an oligo-polyhaline estuary located in Buenos Aires Province, Argentina (37°45 0 S; 57°19 0 W), and San Antonio Oeste (SAO) bay, an eu-hyperhaline habitat located in Río Negro Province, Argentina (40°46 0 S; 64°50 0 W), where differences related to the population structure (Bas et al 2005), reproductive biology (Ituarte et al 2006), number, size and composition of eggs and embryonic development (Bas et al 2007(Bas et al , 2008 were found to be linked to the type of habitat and the environmental conditions. Those studies demonstrated that the reproductive season is longer in MCL than in SAO, extending from September to February and from November to January, respectively, although the differences in the reproductive traits were not associated with a latitudinal temperature gradient; instead, the quality and quantity of benthic food resources and productivity may be responsible for the observed reproductive differences (Ituarte et al 2006;Bas et al 2007).…”

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

“…The production of eggs with different characteristics along the reproductive cycle has been documented in other crustacean species (see Díaz 1980;O'Leary Amsler and George 1984;Paschke et al 2004;Bas et al 2007Bas et al , 2008Urzúa et al 2012;Bell and Fish 1996), but factors responsible for such developmental plasticity are, in most cases, matter of speculation. Differences observed in P. macrodactylus females might be simply the result of varied resource investment performed by individuals of different age or size.…”