The effect of eyestalk ablation on haemolymph osmotic and ionic concentrations during acute salinity exposure in the freshwater shrimp Macrobrachium olfersii (Wiegmann) (Crustacea, Decapoda)

Abstract

The effect of bilateral eyestalk ablation on haemolymph osmotic and Na + , Cl-, K , Mg 2 + and Ca 2 + concentrations was investigated in the freshwater shrimp Macrobrachium olfersii during acute exposure (1, 3, 6, 12 and 24 h) to sea-water of 21%o S. Analysis of variance treatment indicated that haemolymph osmotic and Na', Cl-, K , Mg 2 + and Ca 2 + concentrations were affected by exposure time (p < 0.01). However, only [Na + ] was affected by eyestalk ablation (p < 0.01), destalked shrimps exhibiting haemolymph Na+ concentrations approximately 15 to 30% lower than control shrimps. These results are interpreted to indicate that less Na+ enters the haemolymph of eyestalkless shrimps on exposure to seawater of 21%o S, presumably resulting from the absence of an eyestalk-located neurofactor. A factor causing the influx of Na + into the haemolymph is thus proposed to be present in the eyestalk ganglionic system of intact Macrobrachium olfersii in freshwater. Reduction in secretion of the factor may act to reduce Na+ entry in high salt environments.

Morphometric and Reproductive Traits of Tropical Caridean Shrimps

“…In fact, they are smaller than in the limnic congener P. pandaliformis. However, they are larger than in M, oversii, which is frequently encountered several kilometers upstream in rivers and mountain streams (McNamara and Moreira, 1987;L6pez and Pereira, 1994). The difference in egg size between the two species of Macrobrachium is difficult to explain in this context, since these shrimps have a similar ecology.…”

“…In contrast, all fresh-water palaemonids investigated here are known to develop through the first larval stage in the absence of food: Z? pandaliformis (see Bakker, 1989), M. oversii (see Moreira et al, 1979;McNamara et al, 1980), M. carcinus (see Choudhury,197 la), M. acanthurus (see Choudhury,197 1 b). This gives the larvae sufficient time to leave freshwater streams or rivers, where strong water currents may prevail and plankton production is low.…”

“…As a consequence of their limited adaptation to the limnic parental environment, the larvae can survive in fresh water for a maximum of about one week, but they are not able to develop there beyond the first zoeal stage. Brackish and sea-water conditions, in contrast, allow for successful development from hatching to metamorphosis (Choudhury, 197 1 a, b;Dobkin, 197 1;Dugger and Dobkin, 1975;Moreira et al, 1979;McNamara et al, 1980;Moreira and McNamara, 1984;Bakker, 1989). The larvae of the fully marine species P. northropi, in contrast, are stenohaline, surviving for only a few hours in fresh water (Moreira et al, 1982;Moreira and McNamara, 1984).…”

Putative involvement of crustacean hyperglycemic hormone isoforms in the neuroendocrine mediation of osmoregulation in the crayfishAstacus leptodactylus

“…Moreover, in vivo experiments conducted on different species of shrimps (Nagabhushanam and Jyoti, 1977;McNamara et al, 1990), crayfishes (Kamemoto et al, 1966;Kamemoto and Ono, 1969;Kamemoto and Tullis, 1972) and crabs (Kamemoto et al, 1966;Kamemoto and Ono, 1969;Kato and Kamemoto, 1969;Kamemoto and Tullis, 1972;Heit and Fingerman, 1975;Davis and Hagadorn, 1982) have shown that eyestalk ligation or ablation increased water influx and decreased hemolymph osmolality and/or ions (Na + , Cl -) concentration in animals acclimated to low salinities. In eyestalkless crustaceans, the decrease in osmolality and hemolymph ion concentrations could be due to: (1) a higher influx of water resulting from an alteration in the permeability of the teguments, (2) a greater loss of ions by an increase of permeability and/or a modification of the active ion uptake mechanisms and/or an increase in urine production, (3) a modification of the drinking rate and/or (4) a modification of the function of aquaporins (if they exist in crustaceans) caused by the absence of an eyestalk factor.…”

Revisão das espécies de Macrobrachium, Bate, 1868, pertencentes ao complexo M. olfersii (Crustacea, Palaemonidae): análises morfológicas e moleculares

“…Devido à sua relativa abundância e grande importância econômica, pelo alto potencial na aquicultura e utilização na pesca artesanal e comercial (Sawaya, 1946;Bowles et al, 2000;Murphy & Austin, 2005;Valenti & Tidwell, 2006;Valencia & Campos, 2007), algumas espécies do gênero têm sido objeto de pesquisas que abrangem estudos sobre fisiologia e biologia (McNamara et al, 1985;McNamara et al, 1990;Müller & Prazeres, 1992;Lima et al, 1997;Müller et al 1999), reprodução (Ammar et al, 2001;Mossolin & Bueno, 2002), desenvolvimento morfológico e larval (Dugger & Dobkin, 1975;Lima et al, 1997;Gamba, 1982;Pereira & Garcia, 2002;Mossolin & Bueno, 2003;Müller et al, 2003;Anger & Hayd, 2009;Pantaleão et al, 2011), comportamento, biologia de populações e ecologia (Barki et al, 1991;Jalihall et al, 1993;Ammar et al, 2001;Bauer & Delahoussaye, 2008;Chen et al, 2009).…”