Infrared spectral sensitivity of Melanophila acuminata

The spectral sensitivity of the pit organ of the beetle Melano hila acumina ta (Coleoptera:Buprestidae) was measured using an ultrafast tunable infrare d laser source and standard electrophysiological techniques. The pit organ may be classified as a broadband detector as the beetles responded to all i nfrared excitation wavelengths from 2 to 6 mum. There was a decrease in res ponse threshold and latency and an increase in the magnitude of the respons e in the region from 2.8 to 3.5 mum, which corresponded to a region of decr eased transmittance (increased absorbance) as measured by Fourier transform infrared spectroscopy. The implications of the correlation between spectra l response and optical properties are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.