Table 2.
Metrics of cardiac function: initial heart rate (fH0), peak heart rate (fHpeak), difference between initial and peak heart rate (∆fHpeak-H0), rate of increase in heart rate with temperature prior to Arrhenius breakpoint temperature (dfH/dT), Arrhenius breakpoint temperature (TAB), temperature where heart rate reaches a maximum (Tpeak), and temperature where arrhythmia first occurs (TArr) at different incubation temperatures for each clutch. P values for pairwise comparisons between incubation temperatures are listed for each cardiac function metric. Bolded P values indicate statistically significant (P < 0.05) differences among clutches and incubation temperature groups.
| Temp (°C) | Clutch 1 | Clutch 2 | Clutch 3 | Clutch 4 | Clutch 5 | Average | |
|---|---|---|---|---|---|---|---|
| f H0 (beats min−1) | 9 | 57.4 ± 0.4 | 58.2 ± 1.3 | 52.9 ± 0.4 | 48.9 ± 0.7 | 55.9 ± 0.6 | 55.5 ± 0.4 |
| 12 | 58.3 ± 0.4 | 61.2 ± 0.6 | 55.9 ± 0.6 | 54.6 ± 1.4 | 52.3 ± 1.0 | 56.9 ± 0.4 | |
| 15 | 60.0 ± 0.7 | 63.1 ± 1.2 | 59.8 ± 0.4 | 52.5 ± 0.6 | 54.2 ± 1.4 | 59.8 ± 0.5 | |
| f Hpeak (beats min−1) | 9 | 102.4 ± 2.0 | 97.0 ± 3.0 | 75.6 ± 1.1 | 68.8 ± 2.3 | 85.6 ± 1.4 | 87.9 ± 1.4 |
| 12 | 115.9 ± 2.1 | 127.1 ± 3.1 | 98.5 ± 3.1 | 96.8 ± 6.0 | 98.4 ± 3.4 | 109.2 ± 1.6 | |
| 15 | 132.5 ± 3.7 | 159.5 ± 6.0 | 138.7 ± 2.5 | 101.7 ± 2.2 | 128.6 ± 11.5 | 140.9 ± 2.5 | |
| ∆fHpeak-H0 (beats min−1) | 9 | 44.9 ± 1.8 | 38.9 ± 2.7 | 22.7 ± 0.8 | 19.2 ± 2.2 | 29.7 ± 1.3 | 32.4 ± 1.1 |
| 12 | 57.6 ± 2.0 | 65.9 ± 2.9 | 42.6 ± 2.8 | 42.3 ± 6.0 | 46.0 ± 3.4 | 52.2 ± 1.5 | |
| 15 | 72.5 ± 4.0 | 96.3 ± 5.3 | 79.1 ± 2.5 | 49.2 ± 2.0 | 74.3 ± 11.5 | 81.1 ± 2.2 | |
| dfH/dT (beats min−1∙°C−1) | 9 | 5.8 ± 0.2 | 6.7 ± 0.5 | 5.4 ± 0.1 | 4.8 ± 0.2 | 6.1 ± 0.2 | 5.9 ± 0.1 |
| 12 | 6.3 ± 0.1 | 6.2 ± 0.1 | 6.3 ± 0.3 | 5.7 ± 0.8 | 5.7 ± 0.4 | 6.0 ± 0.1 | |
| 15 | 5.9 ± 0.3 | 6.8 ± 0.3 | 6.6 ± 0.3 | 6.5 ± 0.1 | 7.3 ± 0.9 | 6.6 ± 0.1 | |
| TAB (°C) | 9 | 16.5 ± 0.3 | 14.7 ± 0.3 | 13.8 ± 0.3 | 14.1 ± 0.9 | 14.2 ± 0.5 | 14.7 ± 0.2 |
| 12 | 17.7 ± 0.4 | 17.9 ± 0.3 | 15.3 ± 0.4 | 16.8 ± 0.6 | 16.9 ± 0.5 | 17.0 ± 0.2 | |
| 15 | 18.8 ± 0.5 | 19.4 ± 0.3 | 17.9 ± 0.5 | 16.5 ± 0.7 | 18.0 ± 0.8 | 18.4 ± 0.2 | |
| Tpeak (°C) | 9 | 18.7 ± 0.3 | 17.6 ± 0.3 | 16.7 ± 0.2 | 16.6 ± 0.7 | 16.7 ± 0.2 | 17.3 ± 0.2 |
| 12 | 19.1 ± 0.4 | 20.4 ± 0.3 | 18.3 ± 0.3 | 18.9 ± 0.5 | 19.9 ± 0.5 | 19.5 ± 0.2 | |
| 15 | 20.3 ± 0.4 | 21.4 ± 0.3 | 20.6 ± 0.3 | 19.4 ± 0.4 | 20.2 ± 0.8 | 20.7 ± 0.2 | |
| TArr (°C) | 9 | 21.0 ± 0.2 | 20.1 ± 0.2 | 19.4 ± 0.2 | 18.6 ± 0.5 | 19.5 ± 0.2 | 19.8 ± 0.1 |
| 12 | 22.1 ± 0.3 | 22.3 ± 0.2 | 20.4 ± 0.2 | 20.8 ± 0.4 | 21.3 ± 0.3 | 21.4 ± 0.1 | |
| 15 | 22.4 ± 0.4 | 23.3 ± 0.2 | 22.9 ± 0.3 | 21.8 ± 0.4 | 22.3 ± 0.5 | 22.8 ± 0.2 |