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United States Department of Agriculture

Agricultural Research Service

Title: Surface Lipids of Whitefly Parasitoids

Author
item Nelson, Dennis

Submitted to: Journal of Insect Science
Publication Type: Proceedings
Publication Acceptance Date: April 25, 2003
Publication Date: May 20, 2003
Citation: Nelson, D.R. 2003. Surface lipids of whitefly parasitoids. Journal of Insect Science. 3:33 p. 16-17. Available online: insectscience.org/3.33.

Technical Abstract: Surface lipids from 3 collections of Encarsia formosa and Eretmocerus emeratus, E. hayati and E. mundus were characterized by gas chromatography-mass spectrometry. The surface lipids were largely hydrocarbons, mainly methyl-branched alkanes, ranging in size from about C23 (tricosane) to C49 (dimethylheptatetracontane). Encarsia hydrocarbons were 15-23% n-alkanes but Eretmocerus species had 2% or less n-alkanes. Trace amounts (<1%) were detected only in the surface lipids of E. formosa. All Eretmocerus species had similar GC-MS profiles and the major peaks ranged from C31 (2-methyltriacontane) to C37 (dimethylpentatriacontane). The average composition of Eretmocerus hydrocarbons was: n-alkanes (2%), 2-methylalkanes (19%), 3-methylalkanes (4%), internally branched monomethylalkanes (14%), 5,X- and internally branched dimethylalkanes (58%), and trimethylalkanes (3%). Major peaks were 2-methyltriacontane (14%), 15-, 13- & 11-methylhentriacontanes (6%), 11,15- & 13,17-dimethylhentriacontanes (18%), 11,15- & 13,17-dimethyltritriacontanes (22%), and 11,15- & 13,17-dimethylpentatriacontanes (10%). Encarsia had more components than Eretmocerus: major components ranged from C27 (heptacosane) to C33 (dimethylhentriacontane). Average composition of Encarsia hydrocarbons was: n-alkanes (17%), 4-methyalkanes (1%), 2-methylalkanes (<1%), 3-methylalkanes (25%), internally branched monomethylalkanes (29%), 5,X- and internally branched dimethylalkanes (21%), 3,X-dimethylalkanes (4%), and trimethylalkanes (1%). Major individual peaks were C27 (5%) and C29 (8%), 3-methylheptacosane (13%) and 3-methylnonacosane (10%), 15-, 13-, 11-, 9- & 7-methylnonacosanes (15%), and 9,13- & 13,17-dimethylnonacosanes (10%). Notable differences in the relative amounts of hydrocarbon classes between [Encarsia]-(Eretmocerus) were: n-alkanes [high]-(low), 2-methylalkanes [low]-(high), 3-methylalkanes [high]-(low), 4-methylalkanes [low]-(none), internally branched monomethylalkanes [high]-(low), internally branched dimethylalkanes [low]-(high), 3,X-dimethylalkanes [high]-(low), and internally branched trimethylalkanes [low]-(high).

Last Modified: 7/22/2014
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