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Feeding preference for diseased and wilted sunflower in the grasshopper, melanoplus differentialis
- LEWIS, A.C.
- Entomologia experimentalis et applicata 1979 v.26 no.2 pp. 202-207
- Helianthus annuus, Melanoplus differentialis, Puccinia, chemical defenses, feeding preferences, grasshoppers, leaves, plant biochemistry, plant pathogenic fungi, rust diseases
- Field observations indicate that the polyphagous grasshopper Melanoplus differentialis (Thomas) prefers sunflower (Helianthus annuus L.) leaf tissue that (1) has been damaged by previous feeding of other insects, (2) is infected with rust fungus, Puccinia helianthii, and (3) is wilted, to healthy tissue from the same plant. Laboratory and field tests on M. differentialis preference for diseased and wilted leaves over healthy leaves confirm the field observations. Evidence cited from this and other species suggests that this preference is due to favorable alterations in the nutritional and/or defensive chemistry of the plant. These results partially support theories which link changes in plant chemistry to outbreaks of some insects.