Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 22, 2004
Publication Date: August 2, 2004
Citation: Popham, H.J., Shelby, K. 2004. Selenium impacts the infectivity of acmnpv in trichoplusia ni [abstract]. Society for Invertebrate Pathology Annual Meeting p. 51. Technical Abstract: Herbivorous insects encounter a range of dietary nutrients, antioxidants, co-factors and plant secondary metabolites which may modulate their resistance to microbial infections. A colony of the lepidopteran pest insect Trichoplusia ni has been maintained at BCIRL for generations on an artificial diet with no added Se. These depleted or low Se, insects grow and reproduce normally. Supplementation of the diet of these Se-depleted larvae with 10 ppm or less Sodium Selenite resulted in no deleterious effects on larval growth. Larvae were reared on three different regimes of increasing levels of Se: 1) Se throughout their larval development; 2) Se depletion until the onset of the fourth instar then repletion of Se; and 3) Se up to the fourth instar followed by Se depletion. Selenium levels of pupae from Se fed larvae showed increasing levels depending on the amount of Se added to the diet while larvae fed Se until the fourth instar displayed the same amount of Se in all groups tested. Larvae reared on the three regimes were infected per os with increasing doses of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV). LC50s were not significantly different between control larvae and larvae fed 5 and 10 ppm Se, except larvae fed Se until the fourth instar and then moved to control diet. These larvae had a 5 or 10 fold higher LC50 when fed 5 or 10 ppm Se, respectively. This study indicates that dietary selenium levels do impact the infectivity of AcMNPV in Selenium-depleted T. ni.