Feeding Behavior Under Natural Conditions

In the field, feeding behavior is determined to a large extent by environmental factors, although relatively few extensive studies have been carried out. Temperature has a major effect on feeding behavior, as it does on other insect activities, with

FIGURE 7 Feeding is limited by temperature. Most caterpillars of G. groenlandica, living within the Arctic Circle, feed during a 2-h window when the sun is at its zenith. For most of the time, the insects bask to raise their body temperatures, enabling them to feed efficiently; during feeding their temperature falls rapidly. [Reproduced, with permission, from Kukal, O., Heinrich, B., and Duman, J. G. (1988). Behavioural thermoregulation in the freeze-tolerant Arctic caterpillar, Gynaephora groenlandica. J. Exp. Biol. 138, 181-193. Copyright Company of Biologists.]

FIGURE 7 Feeding is limited by temperature. Most caterpillars of G. groenlandica, living within the Arctic Circle, feed during a 2-h window when the sun is at its zenith. For most of the time, the insects bask to raise their body temperatures, enabling them to feed efficiently; during feeding their temperature falls rapidly. [Reproduced, with permission, from Kukal, O., Heinrich, B., and Duman, J. G. (1988). Behavioural thermoregulation in the freeze-tolerant Arctic caterpillar, Gynaephora groenlandica. J. Exp. Biol. 138, 181-193. Copyright Company of Biologists.]

little feeding occurring at low or at very high temperatures (Figs. 6A and 6C). The effects of temperature are most obvious in insects living under extreme conditions of low or high temperature. For Gynaephora groenlandica caterpillars living within the Arctic Circle, feeding is possible only when the insect has raised its body temperature by basking. As a result, most feeding occurs in a relatively narrow window of time around noon each day, when the sun is highest in the sky (Fig. 7).

Darkness also tends to reduce feeding. For many visually foraging insects, finding food at night is impossible, although night-flying moths obtain nectar only during darkness and some blood-sucking insects, such as mosquitoes, feed most actively at night or in the crepuscular periods. These insects locate their host primarily by odor, although night-blooming flowers often also present conspicuous targets because of their size and whiteness.

Biotic factors may also have a profound effect. For example, a caterpillar of M. sexta that has defended itself from the attack of a tachinid fly does not feed for some time after it has successfully repelled the attacker.

See Also the Following Articles

Blood Sucking • Mouthparts • Salivary Glands

Further Reading

Bernays, E. A. (1997). Feeding by lepidopteran larvae is dangerous. Physiol.

Entomol. 22, 121-123. Bernays, E. A., and Simpson, S. J. (1995). Control of food intake. Adv.

Insect Physiol. 16, 59-118. Chapman, R. F., and de Boer, G. (eds.) (1995). "Regulatory Mechanisms of

Insect Feeding." Chapman & Hall, New York. Dethier, V. G. (1976). "The Hungry Fly." Harvard University Press, Cambridge, MA.

Simpson, S. J. (1995). Regulation of a meal: Chewing insects. In "Regulatory Mechanisms of Insect Feeding." (R. F. Chapman and G. de Boer, eds.), pp. 137-156. Chapman & Hall, New York. Simpson, S. J., Raubenheimer, D., and Chambers, P. G. (1995). The mechanisms of nutritional homeostasis. In "Regulatory Mechanisms of Insect Feeding" (R. F. Chapman and G. de Boer, eds.), pp. 251-278. Chapman & Hall, New York. Stoffolano, J. G. (1995). Regulation of a carbohydrate meal in the adult Diptera, Lepidoptera, and Hymenoptera. In "Regulatory Mechanisms of Insect Feeding" (R. F. Chapman and G. de Boer, eds.), pp. 210-247. Chapman & Hall, New York.

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