Umm.....actually the insect thing has a good basis in fact and I have never read it on the internet.
Within the soil that was last placed on Silbury in the Neolithic (Radiocarbon date 2145 ce +- 95 years) insects that only appear at this time of year were found, presumably winged ants.
SOURCE: Dames, M. (1976) The Silbury Treasure, Thames and Hudson, quoted in Castleden, R. (1983) The Wilmington Giant, Turnstone Press.