Infrared Transmittance as an Alternative Thermal Strategy in the Desert Beetle <i>Onymacris plana</i>

Abstract

Elevated elytral transmittance to shortwave infrared radiation is used by the black diurnal desert beetle Onymacris plana to increase heat gain at the beginning and end of the day. Near-infrared transmittance increases the percentage of radiation absorptance at times of low sun angle as a result of the relatively greater attenuation of visible to shortwave infrared radiation by longer atmospheric path lengths. Visible and ultraviolet radiation are absorbed by the insulated elytra, facilitating heat loss by convection at times of high sun angle.