Receivers of acoustic communication signals evaluate signal features to identify conspecifics. Changes in the ambient temperature can alter these features, rendering species recognition a challenge. To maintain effective communication, temperature coupling—changes in receiver signal preferences that parallel temperature-induced changes in signal parameters—occurs among genetically coupled signallers and receivers. Whether eavesdroppers of communication signals exhibit temperature coupling is unknown. Here, we investigate if the parasitoid fly Ormia ochracea , an eavesdropper of cricket calling songs, exhibits song pulse rate preferences that are temperature coupled. We use a high-speed treadmill system to record walking phonotaxis at three ambient temperatures (21, 25, and 30°C) in response to songs that varied in pulse rates (20 to 90 pulses per second). Total walking distance, peak steering velocity, angular heading, and the phonotaxis performance index varied with song pulse rates and ambient temperature. The peak of phonotaxis performance index preference functions became broader and shifted to higher pulse rate values at higher temperatures. Temperature-related changes in cricket songs between 21 and 30°C did not drastically affect the ability of flies to recognize cricket calling songs. These results confirm that temperature coupling can occur in eavesdroppers that are not genetically coupled with signallers.

Receivers of acoustic communication signals evaluate signal features to correctly identify conspecifics. Environmental variation such as changes in the ambient temperature can alter signal features that may render species recognition a challenge. In field crickets, song temporal features evaluated for species recognition vary with temperature, and the intended receivers of these signals exhibit signal preferences that are temperature-coupled to maintain effective communication. Whether eavesdroppers of communication signals exhibit similar temperature-coupled preferences is unknown. Here, we investigate whether the parasitoid flyOrmia ochracea, an eavesdropper of cricket calling songs, exhibit song pulse rate preferences that are temperature-coupled. We use a high-speed treadmill system to record walking phonotaxis at three ambient temperatures (21, 25, and 30 ℃) in response to songs that varied in pulse rates (20 to 90 pulses per second). Total walking distance, peak steering velocity, angular heading, and the phonotaxis performance index varied with song pulse rates and were affected by ambient temperature. The peak of phonotaxis performance index preference functions became broader and exhibited a high-pass shape, shifting to higher pulse rate values at higher temperatures. Temperature related changes in cricket songs between 21-30 ℃ will not drastically affect the ability of flies to recognize cricket calling songs.