[The effect of immersion in distilled water on the engorged larvae and nymphs of Amblyomma cajennense (Fabricius,1787)(Acari: Ixodidae)]. / Efeito da imersão de larvas e ninfas ingurgitadas de Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) em água destilada.

To evaluate the effect of the immersion of engorged larvae and nymphs of Amblyomma cajennense, these stages were immersed by 24, 48, 72 and 96 hours in test tubes containing distilled water. The period of premolt of the nymphs increased proportionally to the time of immersion (p<0.05). The ecdisis period, the longevity and the mortality (days) were similar in all of treatments (p>0.05). The percentage of ecdisis in nymphs was reduced after 72 hours of immersion of the larvae (p<0.05). None of the engorged nymphs survived 96 hours of immersion. The period of the adult premolt increased after 48 hours of immersion (p<0.05). The ecdisis period was similar in the treatments of 24 and 48 hours of immersion (p>0.05). The percentage of ecdisis decreased starting from 24 hours of immersion (p<0.05). There was not statistical difference (p<0.05) between the control group and the 24 hours group of immersion for the parameters longevity and mortality. These findings suggest that the engorged nymphs were more sensitive to the immersion that the engorged larvae.