Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/25/2006
Publication Date: 3/26/2006
Citation: Chirumamilla, A., Boetel, M.A., Yocum, G.D., Dregseth, R.J. 2006. A remarkable case of longevity in sugarbeet root maggot larvae: Is diapause the key?. [abstract]. Entomological Society of America, North Central Branch Meeting. p. 25.
Technical Abstract: The sugarbeet root maggot (SBRM), Tetanops myopaeformis (Röder), is the most serious economic insect pest of sugarbeet in the Red River Valley of North Dakota and Minnesota. Remarkably, third-instar larvae of this typically univoltine insect have survived more than five years of laboratory storage at 5-7°C. This led to our comparing the physiological status of long-term stored larvae with that of field-collected diapausing larvae to determine if long-term survival was facilitated by larvae maintaining a state of diapause. Respirometry, lipid analyses, and assessments of differential gene expression, as well as survival and emergence studies, were conducted on field-collected diapausing larvae and laboratory stored larvae that had been maintained in cold storage for 1, 2, 3, 4, and 5 years. Respirometry data at both 5 and 20°C indicated that metabolic rates of larvae stored for 1, 2, and 5 years were similar to field-collected diapausing larvae. Survival and emergence studies of larvae stored for 1, 2, 3, and 4 years revealed mixed populations of diapausing and post-diapausal insects, with a high (63%) rate of pupation and emergence (54%), even after four years in cold storage. A major energy source for stored larvae was lipids, which were significantly depleted over a period of five years. Differential gene expression studies revealed that the gene for enzyme alcohol dehydrogenase was up-regulated in diapausing larvae and down-regulated in 1-, 2-, and 5-year laboratory stored larvae. As an extension to this research, future studies will be directed at investigating the symptomology of aging in long-term stored larvae and its relationship with diapause.