Sequential Feedings by Two Species of Argasid Tick on Laboratory Mice: Effects on Tick Survival, Weight Gain, and Attachment Time

Preliminary observations made during colony maintenance of argasid ticks led us to suspect that the host immune response of laboratory mice being used for tick feeding might be causing increased tick mortality. Sequential feeding trials were conducted on laboratory mice using fast- and slow-feeding Ornithodoros larvae. Acquired host resistance was demonstrated. With the fast-feeding O. turicata (Dugès), the average amount of weight gained during feeding decreased significantly the second and third times larvae were exposed to the same mice. With the slow-feeding O. talaje (Guérin-Méneville), mortality at the second and third exposure significantly increased when compared with that seen upon naive mice. Implications for natural modulation of argasid tick populations resulting from nearly constant host exposure to ticks of this nature are also discussed.