How aphids find their host plants, and how they don't

Abstract

There is a considerable interest in trying to understand how aphids find their host plants because they are a major cause of economic losses in agricultural and horticultural production systems. Indeed, the specific behavioural sequences during host finding by aphids are one of the main reasons for their prominent role as vectors of plant pathogenic viruses. This paper reviews the visual and olfactory stimuli involved in host‐finding behaviour of aphids, both basic and applied aspects are covered. Although controlling aphids by manipulation of visual and olfactory stimuli involved in host finding and host selection can be highly successful, as shown by research, most of these measures can still be further optimised and adoption in practice is currently limited. Research therefore needs to address some critical open questions, including (a) the effects of visual contrasts on aphid behaviour; (b) the specific responses of aphids to ultraviolet (UV) light during different stages in host finding; (c) the quantification of behavioural sequences in the field and (d) the response of aphid behaviour to plant diversity at varying spatial scales; further, (e) a much more comprehensive coverage of aphid taxa and aphid ecological groups is needed in host‐finding related research to uncover ecological principles underlying this critical behaviour.

Pest regulation and support of natural enemies in agriculture: Experimental evidence of within field wildflower strips

“…WFS may have masked wheat plants, while also creating a physical barrier of non-host plants. Moreover, aphids use olfactory cues (i.e., plant volatiles, other aphid pheromones) to find their host plants (Döring, 2014). WFS may have released volatiles that acted as odourmasking substances confusing aphids in their host plant search.…”

Do flower mixtures with high functional diversity enhance aphid predators in wildflower strips?

“…Moreover, it is worth establishing the threshold at which increasing the mixture of FD also improves its attraction for predators and shelters pests. For instance, aphids use visual and olfactory cues to locate host plants (Döring, 2014). Thus, increasing plant functional diversity might increase the chance of including more colours, UV patterns and odours that are attractive to aphids.…”

Related but not alike: not all Hemiptera are attracted to yellow

“…However, whether "red" host leaves elicit similarly strong attraction in natural conditions as artificial "red" color in our bioassay remains to be tested. Visual contrast dictated by color stimuli and the background upon which those are applied has been shown to influence aphid' attraction to "green" stimuli (Döring et al, 2004;Döring, 2014). Future studies should attempt to measure psyllid responses to more realistic stimuli under natural background conditions.…”

“…In contrast, the diversity of visual cues reflected by plants is limited by the narrower variety of foliar pigments, which cause them to vary essentially in the "green-yellow-orange" part of the light spectrum visible to insects. As a result, olfaction is considered to provide more characteristic and reliable cues to insects in search of a specific host (Prokopy and Owens, 1983;Döring, 2014).…”

“…Most studies have shown that aphids (Kennedy et al, 1961;Moericke, 1969;Prokopy and Owens, 1983;Hardie, 1989;Döring, 2014) and whiteflies (Vaishampayan et al, 1975a,b;Coombe, 1982;Isaacs et al, 1999) orient preferentially toward green and yellow surfaces. Insect color perception is dependent upon the sensitivity of their photoreceptors.…”