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|Title:||Chemical Ecology of Defense Compounds in Anasa Species (Heteroptera: Coreidae) and Volatile Attractants for Diabrotica Species (Coleoptera: Chrysomelidae) (Attractants, Glands, Corn Rootworms, Electron Microscopy, Squash Bug)|
|Author(s):||Lampman, Richard Lee|
|Department / Program:||Entomology|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Two separate investigations of insect chemical ecology were conducted. The first study elucidated the ultrastructure of the metathoracic scent glands of Anasa tristis and the chemical composition of secretions from the metathoracic glands of A. tristis and A. armigera and the abdominal glands of A. tristis. Lateral glands from A. tristis consist of secretory cells and duct cells, surrounding the central lumen of a gland tubule. The secretory cell possesses an electron dense collecting area and a microvillar network that projects into the cytoplasm. The secretory cell has numerous mitochondria, grouped glycogen deposits, free ribosomes, and tracheoles, suggesting a high metabolic activity. Multivesicular bodies (MVB) were frequently found adjacent to the end-apparatus (microvilli and collecting area) and may function in secretory or autolytic activities. The duct cells surround cuticular-lined ductules and the lumen of the gland tubule. Septate desomosomes and membranous folds are evident at the junctions of duct cells and secretory cells and between duct cells and the lumen of the gland tubule.
The chemical composition of reservoir contents from adult A. tristis and A. armigera include acetic acid, hexanal, hexanol, hexyl acetate, and several minor components, some of which have been tentatively identified as hexyl butanoate, octyl or decyl acetate, and a hexanal trimer. Occasionally, some secretions contained only acetic acid or hexanal. Topical application of hexyl acetate to houseflies, Musca domestica, resulted in a prolonged knockdown (greater than twenty minutes). The secretions from the abdominal glands of A. tristis are biphasic; the clear phase is primarily 4-oxo-trans-2-hexenal and the yellow phase, trans-2-hexenal.
In the second part of this thesis, field tests showed that Diabrotica undecimpunctata howardi, D. virgifera virgifera, and D. barberi are attracted, in a species-specific manner, to structurally related phenyl-compounds. The most effective attractants for D. u. howardi were veratrole and phenylacetaldehyde; for D. v. virgifera, estragole, trans-anethole, and indole; and for D. barberi, eugenol and isoeugenol. To varying degrees, Diabrotica adults exhibit seasonal and sexual variations in their response to these semiochemicals. The attractivity of these compounds may be related to pollen-finding by adult beetles.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
|Date Available in IDEALS:||2014-12-16|