In order to characterize the spectral sensitivity in adult Colorado potato beetles (CPB, Leptlinotarsa decemlineata Say 1824) responses of photoreceptors to light flashes from 300 to 650 nm were recorded in 10 nm steps. Sensitivity peaks were observed at 530 nm (green), 450 nm (blue) and 370 nm (UV). Additional extracellular recordings produced a sensitivity function with a peak at 500 nm. It was then tested whether the CPB is able to recognize its host plant species by colour by plotting leaf spectra from hosts (Solanum tuberosum Linnaeus 1753, Lycopersicum esculentum Miller 1768 and Solanum ochranthum Humboldt & Bonpland ex Dunal 1816) and from 35 non-host species in the colour space obtained from the photoreceptor sensitivity functions.
The colour ranges of host and non-host leaves overlapped to a large extent, i. e more than the half of the host plant colour points plotted in the colour space came to lie within the colour area demarcated by the non-hosts. Therefore it is concluded that the CPB’s set of photoreceptors is not pre-adapted to allow discrimination between hosts and non-hosts by colour, although leaf coloration may still be used by the CPB in the process of host finding to facilitate the location of appropriate host plants.
Doring, T.F. and Skorupski, P., 2007. Host and non-host leaves in the colour space of the Colorado potato beetle (Coleoptera: Chrysomelidae). Entomologia Generalis, 29(2/4), p.81.
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