Phylogeographic dynamics of the arthropod vector, the blacklegged tick (Ixodes scapularis)

The emergence of vector-borne pathogens in novel geographic areas is regulated by the migration of their arthropod vectors. Blacklegged ticks (Ixodes scapularis) and the pathogens they vector, including the causative agents of Lyme disease, babesiosis, and anaplasmosis, continue to grow in their population sizes and to expand in geographical range. Migration of this vector over the previous decades has been implicated as the cause of the re-emergence of the most-prevalent infectious diseases in North America. We systematically collected ticks from across New York from 2004 to 2017 as part of routine tick-borne pathogen surveillance in New York. This time frame corresponds with an increase in range and incidence of tick-borne diseases within New York. We randomly sampled ticks from this collection to explore the evolutionary history and population dynamics of I. scapularis. We sequenced the mitochondrial genomes of each tick to characterize their current and historical spatial genetic structure and population growth using phylogeographic methods.