- Author: Susan P Croissant
Recently, I blogged on the influx of Oleander aphid (Aphis neril) on Milkweed (Asclepias syriaca), which serves as host to the Monarch butterfly (Danaus plexippus) and its larvae.
MONARCH-WATCH ALERT......The week of September 17 begins the annual southern migration of Canada and U.S. monarchs to Mexico. Keep your eyes open for these black-and-orange beauties flitting over gardens.
The late October and early November arrival of monarchs in Mexico coincides with that country's holiday "Dia de los Muertos" (Day of the Dead). Many locals believe the butterflies represent the souls of their departed loved ones, returning to gather in trees and stretch out in shimmering carpet on the forest floor. They roost in Oyamel Fir forests (Abies religiosa), nearly 2 miles above sea level in a unique mountain habitat.
Over the past 20 years, monarchs' numbers have declined by 80 percent. Habitat loss is driven by pesticide use, development and climate change. The Midwestern Corn Belt is the "core" of the monarch's migration range, where most are born on Milkweed plants growing in agricultural fields. This plant is disappearing and the use of Roundup on genetically modified corn and soy crops is s key factor in driving its loss.
In August 2014 the Center for Biological Diversity and partners petitioned to protect the monarch under the Endangered Species Act. Read about the Center's work at:
http://www.biologicaldiversity.org/species/invertebrates/monarch_butterfly/index.html
Check out maps of this year's southward migration and read more at: https://www.learner.org/jnorth/maps/monarch_all_fall2015.html
Other migration sites:
http://www.monarch-butterfly.com/monarch-migration.html
http://monarchlab.org/biology-and-research/biology-and-natural-history/migration