Preliminary Characterisation of the Spectral Sensitivity in the Cabbage Aphid with Electroretinogram Recordings (Hemiptera: Aphididae)
Döring, Thomas F; Kirchner Sascha, M
The methods and apparatus were the same as described in a previous paper [Kirchner et al 2005]. In short, monochromatic light flashes of 0.5 s duration and of different wavelengths and light intensities were produced with a Xenon arc lamp and colour and grey filters and were applied to the compound eye after 30 min dark adaptation. The summed response from light sensitive cells in the compound eye was recorded with a tungsten electrode inserted into the eye with a micromanipulator, while an indifferent electrode rested in the abdomen of the animal. The signal was amplifed and displayed on an oscilloscope. Recordings were done in 10 nm steps from 320 to 610 nm at varied light intensities to elicit a predefined criterion response. Sensitivity was calculated as the reciprocal of the number of photons required to elicit the criterion response, and then normalised to maximal sensitivity. The ERG response to single light flashes was similar to that observed in the green peach aphid, Myzus persicae (Sulzer 1776) [Kirchner et al 2005], with a hyperpolarising response shortly after the onset of the flash and a smaller depolarising off-effect.