Varroa mites were detected in Arizona in 1993, and in Texas in 1995, and both populations experienced massive mortality in 1996 (~60%), but started to recover the following year Pinto et al. 2004; Loper et al. 1999). By 1998-1999, they recovered to about half their original population size, and remained at that level until at least 2013 (Rangel et al. 2016). Each circle represents an individual worker's genome, split into three color-coded ancestral populations. Mitochondria of African descent are shown as black circles. Lines connect individuals with at least 0.78% of their genomes identical by descent, corresponding to human third cousins (i.e., 8 degrees of relation).