Fig 1. Units and dates in an apartment complex from which bed bugs were collected from May 2012 to April 2013.

Consecutive sample numbers 11 & 12, 16 & 17, 29 & 30, 39 & 40, and 43 & 44 represent two sites in the same apartment from which bed bugs were collected on the same date. The number of bed bugs in each sample (n) is provided after the sample number. Sample 24 was an internal laboratory colony and is not shown. Samples 31 and 32 were collected at a hotel and homeless shelter, respectively, and were used as outgroups. Because all five floors have the same layout, a common floorplan is provided to help visualize the proximity of units to one another.