Butterflies hover differently from other flying organisms, thanks to body pitch / 22% of butterflies in U.S. disappeared in 2 decades, study finds / Commercial catching of butterflies threatens Arctic species -- scientist / How you can help save declining butterflies / Butterflies declined by 22% in just two decades across the US--there are ways you can help save them / Butterflies in U.S. vanishing at alarming rate, study finds / Large-scale analysis reveals 20% of butterflies in the US have disappeared since 2000 / Ecologists find that eastern monarch butterflies are delaying fall migration / Another bad year for butterflies in the Netherlands despite peak in September / Monarch butterflies to be added to threatened species list in the US