By Jeremy Hance In 1978, when he moved to his current home on the rural outskirts of Campinas, Brazil, Thomas Lewinsohn, a professor of ecology at Campinas University, routinely encountered a “rewarding assortment of insects” at night, he writes in a new paper in Biology Letters. Today, Campinas, 100 kilometers (60 miles) from São Paulo, is a booming urban and suburban agglomeration of more than 3 million people. Conversely, in the 40-plus years since his arrival, Lewinsohn reports insect populations have “plummeted.” The scientist has failed to see many species, including plume moths and flat…