Journal of Insect Physiology 51 (2005) 1255–1260 Evidence for trichromacy in the green peach aphid, Myzus persicae (Sulz.) (Hemiptera: Aphididae) S.M. Kirchner à , T.F. Do¨ring, H. Saucke Department of Ecological Plant Protection, University of Kassel, Nordbahnhofstr. 1a, 37213 Witzenhausen, Germany Received 5 May 2005; accepted 6 July 2005 Abstract The green peach aphid, Myzus persicae (Hemiptera: Aphididae) is an important phytophagous pest of greenhouse and field crops. In the host finding process visual cues are of paramount importance. In order to contribute to the understanding of the perception of visual stimuli in this species, we measured the electroretinogram of alate female summer migrants of M. persicae. The spectral sensitivity was measured in 10 nm steps under both dark and light adaptation from 320 to 640 nm. The dark adapted spectral sensitivity curve showed one maximum in the green region around 530 nm and a distinct shoulder between 500 and 510 nm. In presence of adapting light, a secondary blue–green peak (490 nm) and a third peak in the near UV (330–340 nm) were observed. From these results we conclude that M. persicae has three spectral types of photoreceptors. r 2005 Elsevier Ltd. All rights reserved. Keywords: Aphids; Electroretinogram; Insect vision; Spectral sensitivity 1. Introduction Myzus persicae is a serious phytophagous pest of greenhouse and field crops (Miles, 1989), acting indirectly as a vector of many virus diseases (Ossian- nilsson, 1966; Sylvester, 1989; Radcliffe and Ragsdale, 2002), as well as directly by feeding on plant assimilates (Hoffmann and Schmutterer, 1999). In the host finding process visual cues are of major importance (Moericke, 1955; Dixon, 1985; Klingauf, 1987; but see Chapman et al., 1981; Powell et al., 1995). There are numerous studies which substantiate the attractiveness of yellow targets to aphids during alight- ing flight (e.g., Moericke, 1951; Kring, 1967; Gonza´ lez and Rawlins, 1968; Do¨ring et al., 2004). The preference of many phytophagous insects species for yellow over green (Bernays and Chapman, 1994) has been inter- preted as a super-normal foliage-type stimulus, where yellow reflects light with a greater intensity in the insect- visible wavelength range than green (Prokopy and Owens, 1983). Also, the repellence of metallised or plastic mulches (Smith et al., 1964; Heathcote, 1968; Loebenstein et al., 1975) has been attributed to their shortwave light-reflecting properties (Kring, 1964; Gib- son and Rice, 1989), although the key wavelengths are still unknown (Do¨ ring et al., 2004). For a more comprehensive understanding of the behavioural reac- tion of animals to colours it is necessary to gain information about the physiological basis of the vision systems involved (Prokopy and Owens, 1983), namely the spectral sensitivity function. While for flower- visiting insects like adult Hymenoptera and Lepidop- tera, the electrophysiological spectral sensitivity func- tions of many species are known, phytophagous life stages of insects are surprisingly underrepresented (Briscoe and Chittka, 2001). Until now, only the cabbage root fly, Delia radicum (L.) (Brown and Anderson, 1996), the western flower thrips, Frankliniella ARTICLE IN PRESS www.elsevier.com/locate/jinsphys 0022-1910/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jinsphys.2005.07.002 à Corresponding author. Tel.: +49 55 42 98 15 69; fax: +49 55 42 98 15 64. E-mail address: skirch@uni-kassel.de (S.M. Kirchner).