INTRODUCTIONThere are hundreds of thousands of insect species for which plants provide a variety of resources such as adult food, mating encounter sites, oviposi tional sites, food for immatures, shelter from harmful biotic or abiotic agents, or transport (90,149,181). Yet our understanding of the process by which an insect detects a resource-furnishing plant is not well developed. This is particularly true for the visual aspects of plant detection by insects.To date, studies of this aspect have focused on the visual location of fl owers by pollinators (80). Visual location of plants by herbivores, parasitoids, or predators has received no more than marginal or scattered attention (6,64,79,82,88,98,100,104,151,152,156,162,169).Before focusing attention exclusively on insect vision, it is useful to briefl y review some general aspects of animal vision. Here, vision is defi ned as the ability to perceive spatial patterns. The physical stimulus that defines a pattern can be regarded as a spatiotemporal distribution of photo fl ux that differs in total energy and frequency composition, and thus provides the visual color cues of brightness (intensity of perceived reflected light), hue (dominant wavelength of reflected light), and saturation (spectral purity of reflected light). The spatial distribution of photon flux provides information on shape, size, distance, and motion. Visual patterns depend upon the nature of the viewed surface, the optical background, the illuminant, and 337 0066-4170/83/0101·0337$02.00 Annu. Rev. Entomol. 1983.28:337-364. Downloaded from www.annualreviews.org by Stanford University -Main Campus -Lane Medical Library on 09/28/12. For personal use only. Quick links to online content Further ANNUAL REVIEWS 338 PROKOPY & OWENSthe viewer's angle and sensitivity. As an active, complex process, vision depends not only upon events in the entire visual fi eld but also upon patterns of expectation in the visual processing system itself, some of which are established through prior visual experience.Description and analysis of the natural optical environment in terms of the visual system of an animal is known as visual ecology, which presumes that specialized visual systems are of adaptive advantage to the animal possessing them. Visual ecologists quantify physical attributes of optical patterns in the environment, particularly those of resource items. How animals solve common visual problems is best understood when data on the physical environment is combined with data on animal behavior and on the morphology and physiology of visual systems.The visual ecology approach was formulated during studies of sea fishes (94,96,113) and has subsequently been adapted to studies of land-dwelling animals (56,96,147), including insects (80).Our review is concerned primarily with the visual ecology of herbivorous insects. Accordingly, we deal with the following elements that, in combina tion, comprise a visual ecology approach: the evolutionary history of plants and insects; the visual properties of natural illuminan...

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Our findings suggest that Hoplocampa testudinea adults (apparently monophagous) and Rhagoletis pomonella flies (oligophagous) are more specific in orientation to hue and/or form of feeding, mating, or oviposition sites on a common host (apple) than are Lygus lineolaris adults (polyphagous) on apple. We speculate that subject to varying influence by host plant chemical stimuli, many monophagous --oligophagous insects may tend to be visual specialists in comparison with polyphagous insects, especially those polyphagous species whose preferred feeding, mating, or oviposition sites within an individual plant are of diverse physical characteristics. They may tend more toward being visual generalists. Visual traps incorporating the synthetic equivalents of comparatively specific host plant visual stimuli should prove useful in monitoring and possibly even directly controlling a number of monophagous-oligophagous insects on crops.Aspects of the process by which insects select plants as feeding, mating, or oviposition sites have been recently and excellently reviewed by Dethier (1973), Beck (1974), Chapman (1974), Markl (1974), Hedin et al. (1977, Kogan (1977), Schoonhoven (1977), and St/idler (1977).One general conclusion is that the process usually involves a constellation of interacting stimuli, often including olfactory and visual stimuli.Considerably more research attention is presently being given to the olfactory basis of whole plant or plant part selection than to the visual basis. The reasons are several, one being the stimulating effect of the appreciable literature (summarized by Hedin et al., 1977;Kogan, 1977; St/idler, 1977) indicating that a variety of phytophagous insects are attracted to specific sorts of volatile chemicals, usually in appropriate blend, emanating from their respective hosts. In contrast, the literature (reviewed by Markl, 1974; St/idler, 1977) provides fewer examples of phytophagous insects attracted to plants or plant parts on the basis of comparatively specific sorts of visual characters.Here, we focus on aspects of host selection by: tarnished plant bug adults, Lygus lineolaris (P. de B.); European apple sawfly adults, Hoplocampa testudinea Klug.;

Genetically modified potato plants that are resistant to the Colorado potato beetle, plus either the potato leaf roll virus or potato virus Y, have recently been commercialized. As part of the safety assessment for plants produced by modern biotechnology, the composition of the food/feed must be compared to that of the food/feed produced by an equivalent plant variety from a conventional source. The composition of important nutritional and antinutritional factors in tubers produced by virus- and insect-resistant potato plants were compared to tubers produced by conventional potato plants. Key nutritional, quality, and antinutritional components measured were total solids, vitamin C, dextrose, sucrose, soluble protein, and glycoalkaloids. Proximate analyses included fat, ash, calories, total protein, and crude fiber. Minor nutrients measured were vitamin B6, niacin, copper, magnesium, potassium, and amino acids. The results from these analyses confirm that tubers produced by insect- and virus-protected varieties are substantially equivalent to tubers produced by conventional potato varieties.