title: Chronic exposure to soil salinity in terrestrial species: Does plasticity and underlying physiology differ among specialized ground-dwelling spiders?
abstract: In salt marshes, the alternation of low and high tides entails rapid shifts of submersion and aerial exposure for terrestrial communities. In these intertidal environments, terrestrial species have to deal with an osmotic loss in body water content and an increase in sodium chloride concentration when salt load increases. In salt marshes, spiders represent an abundant arthropod group, whose physiological ecology in response to variations of soil salinity must be further investigated. In this study, we compared the effect of salinity on the survival and physiology of three species of Lycosidae; two salt marsh species (Arctosa fulvolineata and Pardosa purbeckensis) and one forest species (P. saltans). Spiders were individually exposed at three salinity conditions (0‰, 35‰ and 70‰) and survival, changes in body water content, hemolymph ions (Na(+), Ca(2+), Mg(2+), K(+); ICP-MS technique) and metabolites (mainly amino acids, polyols, sugars; LC and GC techniques) were assessed. The survival of the forest species P. saltans was very quickly hampered at moderate and high salinities. In this spider, variations of hemolymph ions and metabolites revealed a quick loss of physiological homeostasis and a rapid salt-induced dehydration of the specimens. Conversely, high survival durations were measured in the two salt-marsh spiders, and more particularly in A. fulvolineata. In both P. purbeckensis and A. fulvolineata, the proportion of Na(+), Ca(2+), Mg(2+), K(+) remained constant at the three experimental conditions. Accumulation of hemolymph Na(+) and amino acids (mainly glutamine and proline) demonstrated stronger osmoregulatory capacities in these salt-marsh resident spiders. To conclude, even if phylogenetically close (belonging to the same, monophyletic, family), we found different physiological capacities to cope with salt load among the three tested spider species. Nevertheless, physiological responses to salinity were highly consistent with the realized ecological niches of the spiders.
authors.affiliation: Université de Rennes 1, UMR CNRS 6553, 263 Avenue du Gal Leclerc, CS 74205, 35042 Rennes Cedex, France. Electronic address: david.renault@univ-rennes1.fr.
authors.forename: D
authors.initials: D
authors.lastname: Renault
authors.affiliation: Université de Rennes 1, EA 7316, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France; Terrestrial Ecology Unit, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Puzin
authors.affiliation: Université de Lyon, UMR CNRS 5023 LEHNA, 6 rue Raphaël Dubois, 69622 Villeurbanne Cedex, France.
authors.forename: N
authors.initials: N
authors.lastname: Foucreau
authors.affiliation: Université de Rennes 1, UMR INRA IGEPP, Campus de Beaulieu, 263 Avenue du Gal Leclerc, CS 74205, 25042 Rennes Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Bouchereau
authors.affiliation: Université de Rennes 1, EA 7316, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France.
authors.forename: J
authors.initials: J
authors.lastname: Pétillon
mesh_terms: D000818:Animals; D017753:Ecosystem; D005602:France; D008136:Longevity; D054712:Salinity; D012965:Sodium Chloride / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D013045:Species Specificity; D013112:Spiders / Q000502:physiology*
chemical_list: D012987:Soil; D012965:Sodium Chloride
keywords: Amino-acids; Araneae; GC-FID; ICP-MS; Ions; Polyols; Sugars; UPLC