title: Comparing salinity tolerance in embryonic and larval development of two species of water strider, Aquarius paludum and Gerris latiabdominis (Hemiptera: Gerridae).
abstract: Water strider Aquarius paludum (Fabricius) is a cosmopolitan species colonizes mainly freshwater but occasionally brackish habitats throughout the Palearctic and Oriental regions. Water strider Gerris latiabdominis (Miyamoto) is a common species in Japan lives in temporary habitats as freshwater paddy fields. These two species often occur syntopically. We investigated differences in the developmental response to brackish water during embryonic and larval stages between the two species. Eggs were exposed to 0-1.8% NaCl solutions within 24 h of oviposition. Larvae of G. latiabdominis were exposed to salinities of 0, 0.5%, and 0.9% from the first instar until adult emergence. Limits of NaCl concentration for hatching were 1.3% and 1.0% for A. paludum and G. latiabdominis, respectively. The hatching rate of G. latiabdominis was lower than that of A. paludum at salinities ≥ 0.9%. The period of embryonic development of G. latiabdominis was more prolonged than that of A. paludum at a given salinity. Although the salinity tolerance of G. latiabdominis was lower than that of A. paludum, our results suggest G. latiabdominis has the physiological capacity to expand into brackish waters. High and low salinity tolerances of A. paludum and G. latiabdominis, respectively, reflect the relatively wide range of habitat salinities utilized by A. paludum and the relatively restricted habitats preferred by G. latiabdominis. The high salinity tolerance of A. paludum could be an important factor contributing to their cosmopolitan distribution because high tolerance to salinity means the possibility of them to be dispersed via ocean or sea to other continents and islands.
authors: Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Japan. kishi@hotmail.co.jp
authors: Manabu
authors: M
authors: Kishi
authors: Tetsuo
authors: T
authors: Harada
authors: Kenji
authors: K
authors: Fujisaki
mesh_terms: D000818:Animals; D017753:Ecosystem; D006430:Hemiptera / Q000196:embryology / Q000502:physiology*; D007814:Larva / Q000254:growth & development / Q000502:physiology*; D055049:Salt Tolerance; D012965:Sodium Chloride / Q000378:metabolism
chemical_list: D012965:Sodium Chloride
keywords: embryo; larva; salinity tolerance; water strider