Table 5.

Predicted change in the date of field CDL based on CDL values measured under laboratory conditions^*

		Predicted date for 50% diapause in the field†
Field site	CDL	With original CDL	CDL from this study	Difference (days shifted)
LWY	14.71	August 14	August 19	5
LNV	14.16	July 31	August 24	25
PCO	14.48	July 24	August 11	18
ANM	13.96	Univoltine‡	August 14	–
PCO (field)§	14.23	July 26	August 10	15

ANM, Artesia New Mexico; LNV, Lovelock, Nevada; LWY, Lovell, Wyoming; PCO, Pueblo, Colorado.

^*CDL was originally measured at 14.88 h under controlled conditions, while field CDL was measured at 14.65 h based on the average at five field sites (Bean et al. 2007b). Field CDL is calculated by subtracting 0.23 h (14 min) from laboratory-measured CDL.

^†These are predicted dates given the CDL measured in the laboratory for each population. The original CDL predictions had already been made for field sites LWY, LNV, and PCO and agreed closely with actual CDLs measured in the field (Bean et al. 2007a).

^‡Day lengths never reach 14.65 h at the ANM site, so using the original CDL, there would be no reproduction in the first summer generation, making insects at this site univoltine.

^§These data are taken from field measurements carried out in 2003 and again in 2008 and represent actual developmental status in the field. Field measurements closely match laboratory based predictions in 2003 (July 24 versus July 26, Bean et al. 2007a) and again in 2008 (August 10 versus August 11, see Fig. 2).