, 2012, Kovac et al., 2007, Petz et al., 2004 and Stabentheiner et al., 2012. The test chamber dimensions (volume = 18 ml) allowed unhindered movement of the wasps during the experiment. As the wasps stayed in the chamber over long time spans (>6 h, typically overnight) they were also provided with 1.5 M sucrose solution ad libitum as a food source. Experimental temperature was set by an automatically controlled water bath (Julabo F33 HT, Julabo Labortechnik GmbH,

Seelbach, Germany; temperature regulation to 0.1 °C). As the temperature inside the test chamber deviated slightly from that of the water bath we measured the actual experimental temperature (Ta) with a thermocouple inside the chamber, close (<10 mm) to the wasp. Outside air was led through the reference channel of a differential infrared gas analyser (Advance Optima URAS 14, Omipalisib in vitro ABB Analytical, Frankfurt, Germany) sensitized to carbon dioxide, the

measurement chamber and subsequently through the measurement channel. Gas flow was set at 150 ml min−1 by a mass flow controller (Brooks 5850S; 0–1000 ml/min; Brooks Instrument, Hatfield, USA). This flow allowed Dabrafenib datasheet for an accurate temporal resolution as well as for a good CO2 signal in terms of signal to noise peak ratio (Gray and Bradley, 2006 and Stabentheiner et al., 2012). Carbon dioxide production of the tested wasps was recorded at intervals of 1 s. The measurement gas (i.e. Selleck Palbociclib air) was dried via Peltier element equipped cool traps prior to the reference and measurement channel. Relative humidity in the test chamber was regulated by a set of humidifying bottles filled with distilled water, immersed in another Julabo water bath adjusted to the desired dew point temperature to keep the relative humidity in the measurement chamber at the desired level (50% at 45–15 °C, 60% at 12.5 °C, 70% at 10 °C, 80% at 7.5 °C, 90% at 5 °C and 100% at 2.5 °C). Formulas for dew point calculation are given in Stabentheiner et al. (2012). The empty test chamber was recorded for 5 min before

and after each experiment to determine any initial CO2 signal offset from zero as well as a possible signal drift from the start to the end of the experiment. The long duration of each experiment required regular (3 h intervals) automatic zero- and end point calibration of the URAS gas analyser, utilizing internal calibration gas cuvettes containing a defined concentration of carbon dioxide. The tube length between measurement chamber and measurement channel of the DIRGA resulted in a signal delay that was corrected for synchronization of the CO2 trace recordings with infrared video sequences. Data analysis and statistics were conducted using custom made peak and valley finding formulas in Excel (Microsoft Corporation, Redmond, USA), OriginPro 8.5 (OriginLab Corporation, Northampton, USA) and Stathgraphics Centurion XVI (StatPoint Technology Inc., Warrenton, USA).