The infectivity and behaviour of exsheathed and ensheathed\ud Heterorhabditis megidis infective juveniles

摘要

The consequencesof sheath loss on infectivityand behaviourof infective juveniles (IJ) were investigatedin Heterorhabditis\udmegidis. Ensheathed IJ were more infective, killing 32% of wax moth larvae, compared to 18% killed by exsheathed IJ. The percentage\udof time engaged in seven behavioural activitieswas recordedfor individuallystored IJ but no differenceswere found between exsheathed\udand ensheathed IJ. Immobility was the most common behavioural category exhibited by both exsheathed and ensheathed IJ, occupying\udone third of the observation time. Storage conditions affected the rate of exsheathment; 40% of IJ stored for 28 days in water in bulk\ud(50 in 8 ml) exsheathed compared to only 23% of those stored individually (1 in 2 ml).