Meeting Abstract
Ticks are obligate blood feeding arthropods that spend most (> 95%) of their lives off host in an unfed state where they must contended with extended periods of starvation between blood meals. The success of these arthropods as vectors of disease depends on their ability to survive prolonged off-host periods; however, little is known about the underlying mechanisms associated with tick starvation. In this study, we examined the transcriptomic, bioenergetic, and behavioral changes of American dog ticks, Dermacentor variabilis, as starvation progressed. Ticks utilized glycogen and lipid, and later protein as energy reserves as starvation continued with the mobilization of endogenous nutrients being facilitated by proteolysis and autophagy. Tick metabolic rate was expectedly low, but showed a slight increase as starvation extended beyond 12 weeks, possibly reflecting an increase in energetically costly processes such as host-seeking behaviors. Starved ticks had higher activity levels, increased questing behavior, and augmented expression of genes related to feeding. The shifts in gene expression and associated behavioral and physiological processes are critical to allowing these parasites to exploit their ecological niche as extreme sit-and-wait parasites.
