Physiology Of The Herbivore

Host-seeking behavior is restricted to times when the ovipositing or feeding insect is in a suitable physiological state. For example, insects about to molt do not feed and are generally not responsive to host odors; in adult females, a load of eggs ready for laying alters motivation so that searching for a host takes priority over other behaviors. Similarly, an insect that has been deprived of food seeks hosts more readily than one that is replete. In nymphs of the desert locust, for example, positive anemotactic responses to the odor of grass in a wind tunnel were not seen in well-fed individuals but were dramatic in nymphs that had been deprived of food for 4 h.

In the bean aphid, Aphis fabae, winged individuals that fly distances from one host to another are attracted, when they take off, to the short wavelengths of the blue sky. After flying certain distances, they are preferentially attracted to the longer wavelengths of yellow, so that they then tend to land on plants in the vicinity. A number of aphid species bias their landings toward the yellower greens that often are associated with plants in an appropriate physiological state rather than toward plants of a particular species.

See Also the Following Articles

Eyes and Vision • Learning • Migration • Orientation • Phytophagous Insects

Further Reading

Barton Browne, L. (1993). Physiologically induced changes in resource oriented behavior. Annu. Rev. Entomol. 38, 1—25. Bell, W. J. (1991). "Searching Behaviour: The Behavioural Ecology of

Finding Resources." Chapman & Hall, London. Bell, W. J., Kipp, L. R., and Collins, R. D. (1995). The role of chemo-orientation in search behavior. In "Chemical Ecology of Insects" (R. Cardé and W. J. Bell, eds.), Vol. 2, pp. 105-152. Chapman & Hall, New York.

Bernays, E. A., and Chapman, R. F. (1994). "Host-Plant Selection by

Phytophagous Insects." Chapman & Hall, New York. Jones, R. E. (1991). Host location and oviposition on plants. In "Reproductive Behaviour of Insects" (W. J. Bailey and J. Ridsill-Smith, eds), pp. 108-138. Chapman & Hall, London. Morris, W. F., and Kareiva P. M. (1991). How insect herbivores find suitable host plants: The interplay between random and nonrandom movement. In "Insect-Plant Interactions" (E. A. Bernays, ed.), Vol. III, pp. 175-208. CRC Press, Boca Raton, FL. Murlis, J., Elkinton, J. S., and Cardé, R. (1992). Odor plumes and how insects use them. Annu. Rev. Entomol. 37, 505-532. Papaj, D. R., and Prokopy, R. J. (1989). Ecological and evolutionary aspects of learning in phytophagous insects. Annu. Rev. Entomol. 34, 315-350. Prokopy, R. J. (1986). Visual and olfactory stimulus interaction in resource finding by insects. In "Mechanisms in Insect Olfaction" (T. L. Payne, M. C. Birch, and C. E. J. Kennedy, eds.), pp. 81-90. Clarendon Press, Oxford, U.K.

Schoonhoven, L. M., Jermy, T., and van Loon, J. J. A. (1998). "Insect-Plant

Biology: From Physiology to Evolution." Chapman & Hall, London. Visser, J. H. (1988). Host plant finding by insects: Orientation, sensory input and search patterns. J. Insect Physiol. 34, 259-268.

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