Desiccation tolerance of Muellerius capillaris first-stage larvae from Israeli arid and French temperate habitats and their compatibility to the landsnail Theba pisana

The survival capacities of Muellerius capillaris (Nematoda: Protostrongylid ae) free-living larval stages (L1) of an Israeli desert isolate (Nubian iso late) (92 mm rain per annum) and a French isolate from a temperate habitat (650 mm rain per annum) were compared under humid and extreme dry condition s. Under the dry conditions (7% relative humidity [r.h.] and 33% r.h. at 23 degrees C), both isolates exhibited the same remarkable survival capacity for periods of 17 and 28 days, respectively (>92%, survival, P > 0.1). Howe ver, during and after recovery from the anhydrobiotic slate, different beha viour patterns of L1 were observed in each isolate. Under humid conditions (97%, r.h.) for 10 days, both isolates exhibited similarly low survival per centages (13.4 +/- 4.6%, S.E., survival for the Nubian isolate, 3 +/- 3 0,6 for the French isolate, P > 0.05). In water, the French isolate was less a ctive, survived better (52 +/- 8.4%, vs 28.7 +/- 3.7, by day 28, P < 0.05) and retained a better morphological appearance (shrunk less) than the Nubia n isolate. Larval development of the French isolate in the land snail Theba pisana was significantly faster than that of the Nubian isolate, reaching a higher proportion of infective stages (L3) on day 36 post-infection (78.6 % vs 56% P > 0.05). However, similar infection intensities were recovered i n snails infected with either of the isolates (59.8 +/- 10.3, S.E., n = 14, for the French isolate, 53 +/- 6, n = 13, for the Nubian isolate, P < 0.05 ).