Quantifying ecological niche requirements for Amblyomma maculatum morphotypes

Ticks are one of the leading vectors of pathogens worldwide and pose an increasing threat to human and animal health. In North America, Amblyomma maculatum s.l. transmit Rickettsia parkeri, a causal agent of spotted fever group rickettsioses in humans, and other pathogens of veterinary importance. Amblyomma maculatum s.l. (Morphotypes I-IV) are native to the western hemisphere; two morphotypes are found in North America. The Gulf Coast tick (A. maculatum s.s.; Morphotype II) has a broad distribution extending from the Gulf Coast across much of the south and central US and expanding north to Delaware, while Morphotype III was recently identified to occupy the arid/semi-arid southwestern US. Previous studies have modeled the distribution of both morphotypes as a single species. However, given that these morphotypes occupy very different ecological regions in the USA, separate models may provide better insight into the ecological requirements of each morphotype. The objective of this study is to develop species distribution models for each morphotype to independently quantify their ecological niche requirements and predict potential suitable habitats for each morphotype. We used Maxent presence-only modeling to identify climate and landscape variables of importance to the distribution of each morphotype. We identify and present distinct ecological requirements for each morphotype. Although there is a commonality of some variables among the morphotypes, each morphotype showed unique suitability ranges for each variable and land cover type.