Abstract
We explore how the thermal sensitivity of organismic performance emerges from the thermal sensitivity of the underlying component processes involved, using growth and feeding of Manduca sexta caterpillars as a model system. We measured thermal performance curves for short-term rates of growth, consumption, protein (casein) digestion, amino acid (methionine) uptake, and respiration in fifth-instar caterpillars over a biologically realistic temperature range from 14°to 42°C. Growth and consumption rates increased between 14°C and 26°C, reached a maximum value near 34°C, and declined rapidly above 38°C. In contrast, protein digestion rate and respiration rate increased monotonically over the entire temperature range, and amino acid uptake rate increased with temperatures up to 38°C and then leveled off between 38°and 42°C. These results suggest that the shape and position of the thermal performance curve for growth rate-in particular the maximum at 34°C and rapid decline above 38°C-was most closely correlated with the thermal sensitivity of consumption rate; the declining growth performance above 38°C was not associated with declines in digestion or uptake rates or with accelerated respiration rates at these temperatures.
Original language | English |
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Pages (from-to) | 631-638 |
Number of pages | 8 |
Journal | Physiological Zoology |
Volume | 70 |
Issue number | 6 |
DOIs | |
State | Published - 1997 |