Table 1. Definition of geographic and weather traits.

Trait Name	Trait Codea	Number of Strainsb	Description
Latitude	latitude	149	Latitude coordinate where the nematode strain was collected (°)
Absolute value of latitude	abslat	149	Absolute value of the latitude coordinate where the nematode strain was collected (°)
Longitude	longitude	149	Longitude coordinate where the nematode strain was collected (degrees)
Absolute value of longitude	abslong	149	Absolute value of the longitude coordinate where the nematode strain was collected (°)
Elevation	elevation	149	Calculated elevation based on latitude/longitude coordinates using “geosphere” package (m)
Temperature	temp	145	Average dailyc temperature of the air (°)
Relative humidity	rh	129	Amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature (%)
Wind direction	wd	134	Angle, measured in a clockwise direction, between true north and the direction from which the wind is blowing (°)
Wind speed	ws	136	Rate of horizontal travel of air past a fixed point (m/sec)
Cloud heightd	ceil_hgt	122	Height above the ground level of the lowest cloud or obscuring phenomena layer with 5/8 or more summation total sky cover, which may be predominantly opaque, or the vertical visibility into a surface-based obstruction (m)
Dew point	dew_point	129	Temperature to which a given parcel of air must be cooled at constant pressure and water vapor content in order for saturation to occur (°)

Definitions for traits obtained from the Federal Climate Complex Data Documentation for Integrated Surface Data http://www1.ncdc.noaa.gov/pub/data/ish/ish-format-document.pdf (August 20, 2015).

^aAbbreviation for weather traits obtained from the raw data file format.

^bNumber of wild isolates with data for each geographic and weather trait. Number of strains for the weather traits was obtained from the 3-month mapping dataset.

^cAll weather traits were defined by averaging the average daily values (see Materials and Methods).

^dCloud height data were only sufficient to analyze for the three-year dataset.