Over the years, although there were many observations of butterfly routes, without "direct evidence" from the recapture of marked butterflies, the controversy was not resolved.
多年來雖然有不少蝶道觀察的「間接證據」，由於缺乏同一隻蝶經標記後再捕獲的「直接證據」，爭議也就懸宕未解。