Survival Strategy To Escape Desiccation in a Freshwater Ostracod

[Torpid, highly desiccated juveniles of the freshwater ostracod Candona patzcuaro Tressler, 1954, were collected from dry playa lake soil (4 to 5% moisture) on the South Plains of Texas, U.S.A. To ascertain their tolerance to drying 7th instar desiccated juveniles were subjected to temperatures of -20° C and +32° C, and several humidities (0, 14, 40% R.H.) for up to 30 months. Torpid juveniles survived for 18 months in high percentages at the various temperatures and humidities, except at 0% R.H. High mortality after 24 months occurred in all torpid juveniles at 20° C, but at -20° C the desiccated juveniles experienced low mortality for up to 30 months. Low temperature also influenced the rate of revival from torpor and the time necessary for the terminal molt to the sexually mature adult. Candona juveniles can survive well over a year in dry pond soil between -20 and 32° C and in dry soil with water moisture values as low as 4 to 5%, and are able to develop from desiccated 7th instar larvae to second generation 7th instars in about four weeks. Ecological implications of such an unusual survival strategy to escape desiccation are discussed., Torpid, highly desiccated juveniles of the freshwater ostracod Candona patzcuaro Tressler, 1954, were collected from dry playa lake soil (4 to 5% moisture) on the South Plains of Texas, U.S.A. To ascertain their tolerance to drying 7th instar desiccated juveniles were subjected to temperatures of -20° C and +32° C, and several humidities (0, 14, 40% R.H.) for up to 30 months. Torpid juveniles survived for 18 months in high percentages at the various temperatures and humidities, except at 0% R.H. High mortality after 24 months occurred in all torpid juveniles at 20° C, but at -20° C the desiccated juveniles experienced low mortality for up to 30 months. Low temperature also influenced the rate of revival from torpor and the time necessary for the terminal molt to the sexually mature adult. Candona juveniles can survive well over a year in dry pond soil between -20 and 32° C and in dry soil with water moisture values as low as 4 to 5%, and are able to develop from desiccated 7th instar larvae to second generation 7th instars in about four weeks. Ecological implications of such an unusual survival strategy to escape desiccation are discussed.]