2.1: A phylogeographic perspective on invasive species
A useful application of population genetics is to quantify patterns of
isolation-by-distance to identify genetically distinct management units,
infer the source population(s) of invasive species, and estimate the
timing of introduction(s) (Cristescu, 2015). Both phylogenetic and
assignment-based population genetic methods, typically using
mitochondrial DNA or microsatellite samples from native and invasive
populations, have been applied to hundreds of invasive species over
several decades (reviewed by Estoup & Guillemaud, 2010). The same
methods can be used with WGR data, which can add resolution especially
in systems with little population structure (e.g. , recent
introductions or high inter-population connectivity). For example, WGR
data were used to trace incursions of Spodoptera frugiperda (fall
armyworm) into Africa and the Asia-Pacific region with unprecedented
resolution (Tay et al., 2020); to show that the cosmopolitan crop pestPlutella xylostella (diamondback moth) most likely originated in
South America (You et al., 2020); and to infer multiple independent
introductions of Aedes aegypti into California (Lee et al.,
2019).