A 2012 in situ study sought to recreate hypothesized conditions of the initial outbreak of CCD in 2006/2007 by feeding honey bees high fructose corn syrup (HFCS) that the researchers laced with varying sub-lethal amounts of imidacloprid assumed to have been present in HFCS feed at the time. All but one of the colonies exposed to imidacloprid perished between 13 and 23 weeks post imidacloprid dosing, providing evidence that long-term sub-lethal exposure to the neonicotinoid causes honey bees to exhibit symptoms consistent with CCD months after exposure.