Assessment of the physiological performance of the invasive oriental shrimp Palaemon macrodactylus from an atypical marine population.

Since 2000, a well-established population of the invasive oriental shrimp Palaemon macrodactylus has been present in fully marine conditions in the southwestern Atlantic Ocean (~38° S). To assess the physiological performance of this atypical population restricted to fully marine conditions, we conducted a laboratory experiment in which individuals were transferred from 35 ‰S (local seawater) to 2 ‰S; 5 ‰S; 10 ‰S; 20 ‰S; 50 ‰S and 60‰ for short (6 h), medium (48 h), and long (>504 h) acclimation periods. We measured the time course response of relevant parameters in the shrimp's hemolymph; activity of Na, K-ATPase (NKA), and V-H-ATPase (VHA); and muscle water content.

Decapod egg membranes: powerful barriers or regulatory structures?

Osmoregulatory abilities and mechanisms of adults and larvae of decapod crustaceans have been extensively investigated. However, how embryos carried by their mothers can deal with changing or extreme salinities is less understood. The egg membranes are believed to isolate embryos from a challenging environment, although osmoregulatory ability has been demonstrated in early developing embryos (naupliar stage) of two crabs.

Chemically induced plasticity in early life history of : are chemical alarm cues conserved within palaemonid shrimps?

Most aquatic animals use infochemicals from both conspecifics and heterospecifics to assess local predation risks and enhance predator detection. Released substances from injured conspecifics and other species (chemical alarm cues) are reliable cues to indicate an imminent danger in a specific habitat and often mediate the development of inducible defenses. Amphibian and fish embryos have been shown to acquire this information while at the embryonic stage of development, in relation to the developing nervous system and sensory development.

Immunolocalization and expression of Na(+)/K(+) -ATPase in embryos, early larval stages and adults of the freshwater shrimp Palaemonetes argentinus (Decapoda, Caridea, Palaemonidae).

The euryhaline shrimp Palaemonetes argentinus exemplifies an evolutionary transition from brackish to freshwater habitats that requires adequate osmoregulatory capacities. Hyperosmoregulation is functional at hatching and it likely begins during the embryonic phase allowing this species to develop entirely in fresh water. Here, we investigated the Na(+)/K(+)-ATPase α-subunit gene (nka-α) expression using quantitative real-time PCR and localized Na(+)/K(+)-ATPase (NKA) in ion-transporting epithelia through immunofluorescence microscopy.

Carryover effects of predation risk on postembryonic life-history stages in a freshwater shrimp.

For organisms with complex life histories it is well known that risk experienced early in life, as embryos or larvae, may have effects throughout the life cycle. Although carryover effects have been well documented in invertebrates with different levels of parental care, there are few examples of predator-induced responses in externally brooded embryos. Here, we studied the effects of nonlethal predation risk throughout the embryonic development of newly spawned eggs carried by female shrimp on the timing of egg hatching, hatchling morphology, larval development and juvenile morphology.