Intraspecific variability in life-history traits of a "freshwater shrimp", Palaemonetes argentinus

Ituarte, Romina B.; Spivak, Eduardo D.; Anger, Klaus

doi:10.1051/limn:2007007

Cited by 14 publications

(13 citation statements)

References 31 publications

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“…Ovigerous females, females with fully developed ovaries, and males of Palaemonetes argentinus were collected from Lake Chascomús (35°36' S, 58°W), Province of Buenos Aires, Argentina. The salinity of Lake Chascomús may vary between oligohaline (0.5 to 5 ‰) and hypohaline conditions (< 0.5 ‰), depending on rain, evaporation, and winds (Ituarte et al 2005(Ituarte et al , 2007. During the present study, however, salinity varied only very little around 0.5 ‰ (conductivity ranging between 0.97 and 1.13 mS cm -1 ).…”

Section: Methodsmentioning

confidence: 51%

Activity of Na+,K+-ATPase in a ‘freshwater shrimp’, Palaemonetes argentinus (Caridea, Palaemonidae): ontogenetic and salinity-induced changes

Ituarte¹,

Mañanes²,

Spivak³

et al. 2008

Aquat. Biol.

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Section: Methodsmentioning

confidence: 51%

Activity of Na+,K+-ATPase in a ‘freshwater shrimp’, Palaemonetes argentinus (Caridea, Palaemonidae): ontogenetic and salinity-induced changes

Ituarte¹,

Mañanes²,

Spivak³

et al. 2008

Aquat. Biol.

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“…While the shift to small-bodied zooplankton in spring and summer in Lake Rodó and other warm lakes could potentially be a physiological response to increased temperatures, it also coincides with the time when small omnivorous-planktivorous fish reproduce and shrimps start hatching and reach their highest densities (Iglesias et al, 2007). Both shrimps and the dominant fish species have multiple reproductive events starting in spring and recruit high numbers of potentially zooplanktivorous individuals in spring to early summer (Boschi, 1981;Lorier & Berois, 1995;Garcia et al, 2004;Ituarte et al, 2007). Supporting this view Daphnia dominated in Lake Rivera during all seasons except the summer before the fish kills.…”

Section: Discussionmentioning

confidence: 98%

High predation is of key importance for dominance of small-bodied zooplankton in warm shallow lakes: evidence from lakes, fish exclosures and surface sediments

et al. 2011

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The mean body size of limnetic cladocerans decreases from cold temperate to tropical regions, in both the northern and the southern hemisphere. This size shift has been attributed to both direct (e.g. physiological) or indirect (especially increased predation) impacts. To provide further information on the role of predation, we compiled results from several studies of subtropical Uruguayan lakes using three different approaches: (i) field observations from two lakes with contrasting fish abundance, Lakes Rivera and Rodó, (ii) fish exclusion experiments conducted in in-lake mesocosms in three lakes, and (iii) analyses of the Daphnia egg bank in the surface sediment of eighteen lakes. When fish predation pressure was low due to fish kills in Lake Rivera, large-bodied Daphnia appeared. In contrast, small-sized cladocerans were abundant in Lake Rodó, which exhibited a typical high abundance of fish. Likewise, relatively large cladocerans (e.g. mesocosms after only 2 weeks, most likely hatched from resting egg banks stored in the surface sediment, but their abundance declined again after fish stocking. Moreover, field studies showed that 9 out of 18 Uruguayan shallow lakes had resting eggs of Daphnia in their surface sediment despite that this genus was only recorded in three of the lakes in summer water samples, indicating that Daphnia might be able to build up populations at low risk of predation. Our results show that medium and large-sized zooplankton can occur in subtropical lakes when fish predation is removed. The evidence provided here collectively confirms the hypothesis that predation, rather than high-temperature induced physiological constraints, is the key factor determining the dominance of smallsized zooplankton in warm lakes.

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“…In addition to the analysis of sampled and fixed materials (Table 1), 76 ovigerous females with eggs in a late developmental stage (III) were collected from the pond culture, and individually transferred to aquaria with freshwater (2L volume; aeration; ca 30°C; natural light conditions). Larvae hatching within five days were counted under a stereo microscope in order to detect possible differences between the initial egg number ("realised fecundity") and the number of larvae that eventually were released by females with a given body size; differences were considered as an indication of egg losses occurring during the time of embryogenesis (Anger & Moreira 1998, Briggs et al 2002, Ituarte et al 2007. Fecundity, in terms of either egg or larval numbers per female, could be described as a linear function of female FW, Fec=a+b•FW, or as a power function of size dimensions (x=CL or TL), Fec=a+x b .…”

Section: Sampling Sites Collection Of Shrimpsmentioning

confidence: 99%

Reproductive and morphometric traits of <i>Macrobrachium amazonicum</i> (Decapoda: Palaemonidae) from the Pantanal, Brazil, suggests initial speciation

Hayd

Anger

2013

RBT

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The palaemonid shrimp Macrobrachium amazonicum shows an unusually large geographic range (ca. 4 000km across) living in coastal, estuarine, and limnic inland habitats of the upper Amazon, Orinoco, and La Plata basins. This raises doubts whether allopatric, ecologically diverse populations belong to the same species. While shrimps from estuarine and Amazonian habitats have been studied in great detail, very little is known about hololimnetic inland populations. In the present study, biological traits related to growth (maximum body size, fresh weight, morphometric relationships) and reproduction (sex ratio; occurrence of male morphotypes; minimum sexable size; minimum size of ovigerous females; fecundity; egg size), were studied in M. amazonicum collected from a pond culture and two natural freshwater habitats (Rio Miranda; Lagoa Baiazinha) in the Pantanal of Mato Grosso do Sul, Brazil. In total, 2 270 shrimps were examined (603 males; 1 667 females, 157 of these ovigerous). Sex ratio (males:females) was at all sampling sites strongly female-biased, ranging from 0.2-0.6. Maximum body size was larger in natural habitats compared to the pond culture, suggesting reduced growth or a shorter life span under artificial mass rearing conditions. Maximum fecundity observed in our material was 676 eggs, reached by the largest female (TL=65mm; Lagoa Baiazinha). A significant difference between slope parameters of linear regressions describing fecundity, either in terms of numbers of eggs laid or of larvae released, in relation to female fresh weight, indicates egg losses. This may be due in part to a 2.4-fold increase in egg volume occurring during the course of embryonic development, while the available space under the abdomen remains limited. Size-weight relationships differed significantly between males and females, indicating sexspecific morphometric differences. Males appear to have a more slender body shape than females, reaching thus lower weight at equal TL. When reproductive and morphometric traits are compared with literature data from estuarine and inland populations living in the Amazon and Orinoco plains, shrimps from the Pantanal show conspicuous peculiarities differing from other populations: (1) maximum body size is far smaller, suggesting shorter longevity; (2) females are consistently larger than males; (3) different male morphotypes are absent; (4) minimum sexable size and (5) minimum size of ovigerous females are smaller. These traits suggest a heterochronic shift (predisplacement) of sexual maturation and r-selection. In summary, our data show biologically relevant differences in life-history traits of shrimps from the Pantanal compared to M. amazonicum populations in other regions. All these differences persist also in long-term cultures maintained under constant conditions. Altogether, our data support the hypothesis that M. amazonicum in the Paraná-Paraguay drainage basin has phylogenetically diverged from allopatric populations that are hydrologically separated by continental watersheds, implying an ...

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Intraspecific variability in life-history traits of a "freshwater shrimp", Palaemonetes argentinus

Cited by 14 publications

References 31 publications

Activity of Na+,K+-ATPase in a ‘freshwater shrimp’, Palaemonetes argentinus (Caridea, Palaemonidae): ontogenetic and salinity-induced changes

Activity of Na+,K+-ATPase in a ‘freshwater shrimp’, Palaemonetes argentinus (Caridea, Palaemonidae): ontogenetic and salinity-induced changes

High predation is of key importance for dominance of small-bodied zooplankton in warm shallow lakes: evidence from lakes, fish exclosures and surface sediments

Reproductive and morphometric traits of <i>Macrobrachium amazonicum</i> (Decapoda: Palaemonidae) from the Pantanal, Brazil, suggests initial speciation

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