Critical thermal endpoints and CO2 output
| . | . | Temperature (°C) . | . | |
|---|---|---|---|---|
| Thermal endpoints . | TKD line . | Lower mode . | Upper mode . | |
| TKD | HN | 37.1±0.2 | 41.0±0.1 | |
| CN | 35.2±0.1 | 38.6±0.3 | ||
| LN | 34.7±0.1 | 38.1±0.2 | ||
| CTmax | ||||
| Spiracular control | HN | 41.0±0.3 | ||
| CN | 41.0±0.1 | |||
| LN | 40.9±0.1 | |||
| Locomotor function | HN | 40.8±0.3 | ||
| CN | 40.8±0.2 | |||
| LN | 40.7±0.1 | |||
| TMetMax | HN | 38.4±0.3 | ||
| CN | 38.3±0.3 | |||
| LN | 38.2±0.2 | |||
| V̇CO2 parameters | TKD line | V̇CO2 (μl h–1 mg–1) | ||
| At CTmax | ||||
| Spiracular control | HN | 10.8±0.7 | ||
| CN | 10.4±0.8 | |||
| LN | 11.3±0.5 | |||
| Locomotor function | HN | 10.8±0.6 | ||
| CN | 10.7±0.6 | |||
| LN | 11.3±0.7 | |||
| At TMetMax | HN | 13.9±0.8 | ||
| CN | 13.3±0.8 | |||
| LN | 14.1±0.7 | |||
| . | . | Temperature (°C) . | . | |
|---|---|---|---|---|
| Thermal endpoints . | TKD line . | Lower mode . | Upper mode . | |
| TKD | HN | 37.1±0.2 | 41.0±0.1 | |
| CN | 35.2±0.1 | 38.6±0.3 | ||
| LN | 34.7±0.1 | 38.1±0.2 | ||
| CTmax | ||||
| Spiracular control | HN | 41.0±0.3 | ||
| CN | 41.0±0.1 | |||
| LN | 40.9±0.1 | |||
| Locomotor function | HN | 40.8±0.3 | ||
| CN | 40.8±0.2 | |||
| LN | 40.7±0.1 | |||
| TMetMax | HN | 38.4±0.3 | ||
| CN | 38.3±0.3 | |||
| LN | 38.2±0.2 | |||
| V̇CO2 parameters | TKD line | V̇CO2 (μl h–1 mg–1) | ||
| At CTmax | ||||
| Spiracular control | HN | 10.8±0.7 | ||
| CN | 10.4±0.8 | |||
| LN | 11.3±0.5 | |||
| Locomotor function | HN | 10.8±0.6 | ||
| CN | 10.7±0.6 | |||
| LN | 11.3±0.7 | |||
| At TMetMax | HN | 13.9±0.8 | ||
| CN | 13.3±0.8 | |||
| LN | 14.1±0.7 | |||
Critical thermal endpoints for knockdown (TKD),spiracular control, locomotor function and TMetMax, which is the temperature at which maximum CO2 output occurred. V̇CO2 is listed at all critical temperatures, except TKD. Values are means± s.e.m.
TKD values are maximum likelihood estimates for the upper and lower mode of a bimodal distribution for TKD,measured in ∼4000 flies per selection group(Folk et al., 2006). Nearly all HN females (98%) and HN males (93%) are within the upper mode of the TKD distribution, whereas 66% of LN females and 90% of LN males are in the lower mode
Mean CTmax and V̇CO2 parameters were estimated from thermolimit respirometry analysis of four individuals from each of the four replicate populations within the HN, LN or CN groups(N=16 per group). While the populations show significant divergence in TKD, no significant differences were found among the groups for all other parameters. (See Results for test statistics)