There are obviously too few isolates here to definitely define new temperature-fitness rules within this species, but these data strongly suggest that preference-fitness relationships are more complicated than predicted by the classical coadaptation hypothesis.
To date, too few isolates of C. elegans and of C. briggsae from geographically diverse, well-characterized collections (i.e. known microclimate and elevation) have been characterized for both thermal preference and temperature dependent fitness to define relationships among thermal preference, fitness, and latitude, or other ecologically relevant clines.
Hence, lethal temperatures could effectively be replaced by other temperature dependent fitness contours that are measured using standard methods [49].
This corresponds to a situation where an environmental variable, for example, temperature, affects fitness in a straightforward way.
By encompassing this life-history consideration, the optimal temperature for fitness for NEA-cod is 10°C (figure 1 c).
The isolate-specific effects of temperature on fitness were analyzed using ANOVA with isolate as the main effect at each temperature.
In this paper, we run simulations over a wide range of temperatures (2 20°C) to assess the broad-scale relationship between temperature and fitness.
Beyond the optimal temperature for fitness, increased metabolic requirements intensify foraging and reduce survival; oxygen budgeting conflicts thus constrain successful completion of the life cycle.
Although the effects of temperature on fitness vary among isolates of C. elegans (see also [ 44, 67]), this species can generally be described as a " Jack of all temperatures" [ 68] in terms of LRS.
We show that the optimal temperature for fitness is lower than that of aerobic scope, and emphasize how limited oxygen budgets cause trade-offs and act as both constraint and driver of change.
Despite the increased amount of aerobic scope available (figure 2 e), the optimal temperature for fitness remained at 10°C (figure 2 h), much driven by natural mortality responding similarly as in the model runs, with a peaking aerobic scope curve.
