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

Kevin Farnier,Adrian G Dyer,Martin J Steinbauer

doi:10.3389/fevo.2014.00067

Abstract

Most innate responses to color stimuli lead herbivorous insects to orient to “green” and “yellow” surfaces. Early research showed that aphid orientation to plants is influenced by foliar pigments and leads them to alight on leaves of a specific physiological state regardless of whether or not it is their actual host. In this study, we quantified the color preferences of four psyllids specialized on young to recently expanded leaves of different Eucalyptus hosts presenting distinct between (inter-specific) and within canopy (ontogenic) optical characteristics. Color preferences of Ctenarytaina eucalypti and C. bipartita were similar to those observed in aphids with more frequent selection of yellow and green stimuli, consistent with the coloration of their host leaves. However, attraction of Anoeconeossa bundoorensis and Glycaspis brimblecombei to a red stimulus contrasts strongly with the literature for hemipteran and herbivorous insects generally for which attraction to red is peculiar. Interestingly, both red-attracted species occur on the same host eucalypt, which expresses anthocyanic (red) young leaves. Our experiments demonstrate that these two species are sensitive to long wavelength radiation. Behavioral work and modeling of putative “aphid-like” photoreceptors were conducted to investigate whether achromatic vision mediates perception of “red”. Our results do not provide strong evidence for an intensity-dependant type of attraction. Nevertheless, the current knowledge of photoreceptors in Hemiptera identifies the achromatic as the most likely mechanism for detecting long wavelengths. Thus, our findings highlight the need for physiological work with Psylloidea to dissect the mechanisms responsible for such atypical responses. We discuss the ecological implications of our work in relation to red foliar pigments in expanding leaves of perennial plants which differs greatly from the thoroughly studied aphid-autumnal leaves system involving senescing foliage.

Highlights

Hemiptera is an ancient insect order (Permian) widely represented with nearly 100,000 species described in 145 families (Grimaldi, 2005; Gullan and Cranston, 2009)
PSYLLIDS Psyllids were field collected within the State of Victoria (Australia) and colonies of each species maintained in a climate-controlled glasshouse on potted hosts of Eucalyptus globulus (C. eucalypti), E. kitsoniana (C. bipartita), and E. camaldulensis (A. bundoorensis and G. brimblecombei)
Glycaspis brimblecombei responded in a similar manner as A. bundoorensis (Figure 4D)

Summary

Introduction

Hemiptera is an ancient insect order (Permian) widely represented with nearly 100,000 species described in 145 families (Grimaldi, 2005; Gullan and Cranston, 2009). With the exception of a few predators and scavengers, Hemiptera are dominantly phytophagous (≈90% of species) and feed on a wide array of angiosperms and a few gymnosperms. They possess characteristic sucking mouthparts that they use to pierce plant tissues to access their feeding site (i.e., phloem, xylem or parenchyma) and a filtering chamber allowing them to extract liquid content (Carver et al, 1991). The superfamily Psylloidea, which is more abundant and diverse in Australasia than in the northern hemisphere, is largely composed of acacia and eucalypt-feeding species, with the latter arguably having the closest associations with their host plants (Carver et al, 1991; Hollis, 2004; Hodkinson, 2009). The mechanisms psyllids employ to locate their host in complex mixed-vegetation habitats remain poorly understood

Methods

Results

Conclusion