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Cohen, Randy Wade 2014-12-16T05:57:06Z 2014-12-16T05:57:06Z 10000-01-01 1987 1987 Larvae of the corn earworm, Heliothis zea (Boddie) (Lepidoptera: Noctuidae), prefer to feed on corn silks as early instars but change their feeding preference to corn kernels as they mature. Within the corn kernel, final instar larvae prefer to feed on germ but will always eat some of the endosperm. In the laboratory, germ-fed larvae grow more efficiently than endosperm-feeders, eating less food and completing the final stadium somewhat sooner. However, larvae that feed on endosperm live much longer as adults and produce more eggs in their lifetime than do adults from germ-fed larvae. Thus, in nature, corn earworm larvae strike a balance between larval and adult needs by ingesting entire kernels. Final instar Heliothis zea larvae self-select a complete and balanced diet from two nutritionally incomplete diets, one lacking only casein and the other lacking only sucrose. The physiological processes regulating nutrient self-selection in animals have not been fully elucidated, but recent evidence in mammals links the production of the neurotransmitter serotonin (5-hydroxytryptamine) with carbohydrate feeding. It is well-known that serotonin is present in insect nervous systems. High performance liquid chromatography analysis reveals that H. zea fed on sucrose or starved have increased brain serotonin levels. Larvae feeding on a diet with casein but lacking sucrose or on a nutritionally complete 80:20 (casein:sucrose) diet contain much lower levels of brain serotonin. Incorporation of a serotonin antagonist (p-chlorophenylalanine) in the diet of self-selecting H. zea larvae reduces brain serotonin levels and produces an 85% increase in sucrose consumption, whereas addition of an agonist (tryptophan) results in a 10% decrease in sucrose consumption accompanied by a relatively large but not statistically significant increase in brain serotonin. The data suggest that serotonin may be involved in a physiological feedback loop monitoring nutrient need. Made available in DSpace on 2014-12-16T05:57:06Z (GMT). No. of bitstreams: 1 8721613.pdf: 1972931 bytes, checksum: e83ad5b71313fc120047cde466719f31 (MD5) Previous issue date: 1987 Embargo set by: Seth Robbins for item 71269 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 56 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987. http://hdl.handle.net/2142/71103 (UMI)AAI8721613 Biology, Entomology Behavioral and Physiological Aspects of Self-Selection by the Corn Earworm, Heliothis Zea text Entomology Entomology University of Illinois at Urbana-Champaign Dissertation Ph.D.