Visual ecology of aphids—a critical review on the role of colours in host finding

Abstract

We review the rich literature on behavioural responses of aphids (Hemiptera: Aphididae) to stimuli of different colours. Only in one species there are adequate physiological data on spectral sensitivity to explain behaviour crisply in mechanistic terms. Because of the great interest in aphid responses to coloured targets from an evolutionary, ecological and applied perspective, there is a substantial need to expand these studies to more species of aphids, and to quantify spectral properties of stimuli rigorously. We show that aphid responses to colours, at least for some species, are likely based on a specific colour opponency mechanism, with positive input from the green domain of the spectrum and negative input from the blue and/ or UV region. We further demonstrate that the usual yellow preference of aphids encountered in field experiments is not a true colour preference but involves additional brightness effects. We discuss the implications for agriculture and sensory ecology, with special respect to the recent debate on autumn leaf colouration. We illustrate that recent evolutionary theories concerning aphid-tree interactions imply far-reaching assumptions on aphid responses to colours that are not likely to hold. Finally we also discuss the implications for developing and optimising strategies of aphid control and monitoring.

Outcomes of co-infection by two potyviruses: implications for the evolution of manipulative strategies

“…These aphid preferences were likely mediated by plant-derived olfactory and visual cues, as aphids are known to use both to locate host plants while walking [43][44][45]. Both plant volatile emissions and leaf-colour profiles were also altered to a much greater extent by ZYMV than by WMV, whereas mixed infections elicited a phenotype similar to that exhibited by plants with single ZYMV infections (see figure 2a and electronic supplementary material, S1 and S2).…”

“…more intense yellow coloration) and reduction of the blue component (which was also observed for single WMV infections; electronic supplementary material, figure S1). Aphids typically exhibit a preference for yellow and an aversion to blue to ultraviolet coloration (reviewed in Doering & Chittka [43]). …”

Visual Cues and Host-Plant Preference of the Bird Cherry-Oat Aphid,Rhopalosiphum padi(Hemiptera: Aphididae)

“…Subsequently, it has been suggested that aphids use the ratio between long and short wavelength light to navigate between plants rather than responding to only the one or the other (Kennedy et al 1961;Kennedy & Booth 1963). Döring & Chittka (2007) also argued that the yellow preference shown by aphids should not be viewed as a true colour preference but rather a response that is dependent on the actual light intensity. The yellow preference observed for some aphid species, including summer morphs of R. padi, may be due to yellow representing a superfoliage stimulus to herbivorous insects rather than it being an ecological adaptation (Prokopy & Owens 1983).…”

“…A better understanding of the role of visual stimuli in aphid host plant selection behaviour could lead to improved aphid management, e.g. choice of trap colour and colour intensities for aphid monitoring and use of light reflectance to manage aphid-transmitted plant viruses (Döring & Chittka 2007). Many aphid species preferentially respond to yellow targets, and yellow traps are frequently used for aphid monitoring (Broadbent 1948;Heathcote 1957).…”

“…Whereas aphid composition and abundance in lime-green tile traps in soybean (Glycine max L., Fabaceae), resembling the reflectance spectra of the soybean canopy, correctly estimated aphid landing patterns compared to direct plant counts (Irwin 1980), the green tile trap overestimated aphid species colonizing pepper (Capsicum annuum, L. Solanaceae) (Raccah et al 1985). Reflective mulches are another aphid management tool that rely on aphid vision (Döring & Chittka 2007). Silver reflective mulches have been found to delay the onset of cucumber mosaic cucumuvirus, watermelon mosaic I and II, zucchini yellows mosaic and squash mosaic in summer squash (Cucurbito pepo L., Cucurbitaceae) and cantaloupe (Cucumis melo L., Cucurbitaceae) (Brown et al 1993;Stapleton & Summers 2002).…”