Data from: Plasticity through canalization: the contrasting effect of temperature on trait size and growth in Drosophila

In most ectotherms, a reduction in developmental temperature leads to an
increase in body size, a phenomenon known as the temperature size rule
(TSR). In Drosophila melanogaster, temperature affects body size primarily
by affecting critical size, the point in development when larvae initiate
the hormonal cascade that stops growth and starts metamorphosis. However,
while the thermal plasticity of critical size can explain the effect of
temperature on overall body size, it cannot entirely account for the
effect of temperature on the size of individual traits, which vary in
their thermal sensitivity. Specifically, the legs and male genitalia show
reduced thermal plasticity for size, while the wings show elevated thermal
plasticity, relative to overall body size. Here, we show that these
differences in thermal plasticity among traits reflect, in part,
differences in the effect of temperature on the rates of cell
proliferation during trait growth. Counterintuitively, the elevated
thermal plasticity of the wings is due to canalization in the rate of cell
proliferation across temperatures. The opposite is true for the legs.
These data reveal that environmental canalization at one level of
organization may explain plasticity at another, and vice versa.