Table 3.
Analysis of survival upon cold shock.
| Sex | Temperature | Direction | χ2 | P | n |
|---|---|---|---|---|---|
| Female | 18°C | FI = FS | 0.64 | 0.43 | 197 (887) |
| FI = MS | 0.88 | 0.35 | 199 (888) | ||
| FS = MS | 0.02 | 0.89 | 210 (893) | ||
|
| |||||
| 25°C | FI < FS | 47.39 | <0.0001† | 694 (897) | |
| FI < MS | 77.48 | <0.0001† | 664 (896) | ||
| FS < MS | 4.18 | 0.04 | 580 (899) | ||
|
| |||||
| Male | 18°C | - | - | - | 0 (896) |
| - | - | - | 0 (897) | ||
| - | - | - | 0 (895) | ||
|
| |||||
| 25°C | FI = FS | 2.01 | 0.16 | 737 (887) | |
| FI = MS | 2.35 | 0.14 | 734 (885) | ||
| FS = MS | 0.01 | 0.90 | 719 (886) | ||
The columns show the directionality of survival upon cold shock for each pairwise comparison between the three karyotypes (FI = Florida inverted, FS = Florida standard, MS = Maine standard), grouped by sex and temperature. χ2 test statistics and P-values are from generalized Wilcoxon tests. Significant effects are in bold; significance after Bonferroni correction is indicated by † (α′ = 0.05/3 = 0.016). n represents the number of dead individuals; the total cohort size is shown in parenthesis. Note that at 18°C all males survived 24 hours of cold shock and were thus all censored. See Results and Fig. 3 for further details.