A high gene flow in populations of Amblyomma ovale ticks found in distinct fragments of Brazilian Atlantic rainforest

The genetic structureof populations of the tick Amblyomma ovalefrom five distinct areas of the Brazilian Atlantic rainforestwas evaluated via DNA sequencing and associated with the presence of domestic dogs acting as hosts at the edge of forest fragments. Tickswere collected from domestic dogs and from the environment between 2015 and 2017. Four collection areas were located in the surroundings and within the Serra do Mar State Park, Sao Paulo State (23°37′21"S, 45°24′43"W), where dogs were bimonthly monitored along 2 years using camera trapsand GSM trackers. To determine the spatial limits of genetic structure, tickscollected upon dogs living near the Serra do Baturie, Ceara State (4°15′40"S, 38°55′54"W) were included as well. A total of 39 haplotypes of 16S rRNA and Cox 1 mitochondrial genes sequences were observed, with 27 of them coming from areas within the Serra do Mar State Park. No haplotype was shared between the Serra do Mar and the Serra do Baturie indicating isolation of tickpopulations at the scale of 2000 km. Although three different haplotype lineages of A. ovaleoccurred within the Serra do Mar State Park, no genetic structurewas found across the study sites within this park, suggesting high tickgene flow across a range of 45 km. Monitoring data from domestic dogs and wild carnivores showed that these species share the same habitats at the forest edge, with dogs playing a likely limited role in tickdispersal. Our findings have important implications for understanding the genetic structureof wide spread A. ovalealong Brazilian rainforestremnants, which can further be associated to tick-borne infectious agents, such as Rickettsia parkeri, and used for predicting future patterns of tickdiversity in the Brazilian Atlantic rainforest.