The American Soybean Association is touting a new study that finds a lack of nectar sources, habitat fragmentation, and changing weather patterns are the primary contributors to a decline in monarch butterfly populations.
The study by Cornell researchers found “problems in the butterflies' migration from the U.S. and southern Canada to Mexico in the fall, rather than with lack of milkweed - the only food source for caterpillars in the summer,” the ASA said. Other theories have blamed the species' decline on the widespread planting of genetically engineered crops and an increase in herbicide use.
To help the monarch survive, he advised ASA members to “be aware of existing milkweed in your non-crop areas,” and cautioned against spraying those areas. “These milkweed are critical for the survival of this species. While this new study suggests monarchs are facing several challenges, we can do our part to ensure a sustainable population.”
Anurag Agrawal, Cornell professor of ecology and evolutionary biology, said “lack of milkweed, the only host plant for monarch butterfly caterpillars, is unlikely to be driving the monarch's population decline, as the problem appears to occur after they take flight in the fall.” Agrawal was the lead author on the paper published this month in Oikos, an online journal.