title: Internal lipids of sugarbeet root maggot (Tetanops myopaeformis) larvae: effects of multi-year cold storage.
abstract: Sugarbeet root maggots, Tetanops myopaeformis (Diptera, Ulidiidae), survive more than five years of laboratory cold (6 degrees C) storage as mature third-instar larvae. To quantify energy costs associated with prolonged storage, internal lipids of larvae stored for 1, 2, 3, and 5 years were compared and characterized with those of field-collected diapausing larvae. Internal lipid concentration was highest (21.8% wet wt. and 29.8% dry wt.) in diapausing larvae. Lipids decreased progressively over storage time with greater than 70% reductions for 5-year stored larvae. Thin-layer chromatographic analysis revealed that triacylglycerols (TAGs) were the most predominant class of internal lipids, with trace amounts of diacylglycerols and hydrocarbons also being present. Gas chromatography-mass spectrometry (GC-MS) analyses of TAG fractions identified ten major fatty acids (FAs). The proportion of unsaturated FAs was higher (73 to 78%) than saturated FAs in diapausing and stored larval groups. Palmitoleic acid (16:1) was the predominant FA, constituting 40-50% of total unsaturated FAs with lesser amounts of myristoleic (14:1), oleic (18:1), lauroleic (12:1), gadoleic (20:1), and the saturated FAs, palmitic (16:0), myristic (14:0), lauric (12:0), stearic (18:0), and arachidic (20:0) being detected at much lower concentrations. Characterization of intact TAGs by high performance liquid chromatography and GC-MS revealed the presence of more than 40 TAG constituents. In conclusion, TAGs are utilized as an important energy source for T. myopaeformis larvae during diapause and long-term cold storage with no observed impact of multi-year storage on the TAG composition and distribution of their fatty acids.
authors.affiliation: Department of Entomology, North Dakota State University, Fargo, ND 58108, USA.
authors.forename: Anitha
authors.initials: A
authors.lastname: Chirumamilla
authors.forename: James S
authors.initials: JS
authors.lastname: Buckner
authors.forename: George D
authors.initials: GD
authors.lastname: Yocum
authors.forename: Charlotte L
authors.initials: CL
authors.lastname: Fatland
authors.forename: Mark A
authors.initials: MA
authors.lastname: Boetel
mesh_terms: D000818:Animals; D001835:Body Weight; D002851:Chromatography, High Pressure Liquid; D003080:Cold Temperature; D004175:Diptera / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D004734:Energy Metabolism; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D007814:Larva / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D008055:Lipids / Q000737:chemistry*; D013997:Time Factors; D014280:Triglycerides / Q000032:analysis / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D008055:Lipids; D014280:Triglycerides