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Abstract  

In the photomicrocalorimetric module designed by Johansson and Wadsö for a commercial Thermometric TAM heat conduction batch microcalorimeter, the incident light from an external xenon lamp was divided by a beam splitter and directed to the two vessels of the differential system by light guides ideally to give zero heat flow. In practice this proved difficult and so to improve the balance between the vessels in terms of the incident light heat output as well as potentially to give more versatility regarding the choice of wavelengths, the xenon lamp-based system was replaced in the first stage by a pair of cold white LEDs embedded directly in the test and reference vessels. The LEDs had independent electrical circuits to achieve the balance by manual adjustment. As a second stage, the test vessel was equipped with PTFE tubing for changing the liquid phase in it while it was in the middle thermal equilibrium position. This improved the reproducibility of the results.

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Summary  

Heat and CO2rates are measured on M. domesticapupae as a function of age and temperature. Heats of combustion of flies, pupae, and puparia are also measured. Heat and CO2rates decrease for 3 d post-pupation and increase exponentially over 4 d prior to eclosure. Heat and CO2rates are low and increase slowly from 5 to 23C, then rapidly increase from 23 to 26C, then more slowly up to 38C where pupae are stressed. Respiratory substrate varies with age and temperature, is a mix of lipids and carbohydrates, and has an average carbon oxidation state of -0.3 at room temperature. Humidity, elevated CO2, or reduced O2did not affect pupal metabolism.

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to monitor changes of the rate of metabolically generated heat and to calculate total heat effects in the examined processes. A combination of calorimetric method with respirometric measurements is known as calorespirometry. Redl and

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