Thermal Constant (K)
Definition
The total ADD or ADH required to complete a developmental phase from egg to a defined endpoint. Different from the isomegalen approach in that K targets a stage endpoint rather than a continuous body-length value.
- Represents
- Total ADD or ADH for a development phase
- Endpoint
- Egg to a defined developmental stage
- Contrast with isomegalen
- Targets a stage endpoint, not continuous length
- Use
- Species-specific development models
Common questions
Why use a thermal constant instead of a body-length curve?+
K gives a single threshold for reaching a discrete life stage such as pupariation, useful when only the presence or absence of that stage can be observed rather than a continuous larval measurement.
What causes error in K-based PMI estimates?+
Applying a K value derived from a different geographic population or a related species without local validation can introduce substantial error into the resulting PMI estimate.
Related terms
- Isomegalen Diagram
- A contour plot with temperature on the y-axis and age on the x-axis, where each contour line connects all (temperature, age) combinations...
- Isomorphen Diagram
- A contour plot of the same axes where each contour connects all (temperature, age) combinations that produce the same morphological developmental stage...
- Larval Instar
- One of three larval stages (L1, L2, L3) separated by moults. Each instar has distinctive mouth-hook and posterior spiracle morphology that allows...
- Larval Length (Body Length)
- The maximum extended length of a blow fly larva, measured from the anterior tip to the posterior end in freshly killed or...
- Rearing Temperature
- The constant or mean temperature at which a larval cohort was held in the laboratory experiment that generated the developmental dataset. The...