By Chandra L. Mattingly
Staff Reporter
If the monarch caterpillars in our living room are any indication, monarch butterflies' wintering population should be up this year.
Those who love the tropical insects' orange and black stained glass appearance hope so. In a life cycle that stretches from Mexico to Canada, these delicate creatures are dependent on just a few species of plants. Unfortunately, large-scale farming, pesticide use and human development have wiped out many stands of milkweed upon which monarchs' caterpillars feed.
Last winter (2013-2014) the wintering monarch population was the smallest it's ever been since monitoring began, according to Monarch Watch. Efforts even have begun to classify the species as endangered. In our screened butterfly cage, only three monarchs hatched to be released. This year we've already released over a dozen, mostly females.
Milkweeds used to be present along the fence rows and other waste areas dividing and bordering farmers' fields. Some even grew among the crops, as milkweeds are resistant to some pesticides. But stronger pesticides can be used with genetically modified corn and soybeans, and the milkweed occurrence has dropped as a result.
Drought in Texas and other areas hasn't helped, limiting availability of food for caterpillars and adults. Each spring, the butterflies which survive the winter begin to migrate north. As adults lay their eggs, the resulting monarchs fly farther north, and produce another generation which flies even farther. Eventually, as the days grow shorter and fall approaches, instinct kicks in and the last generation flies south to winter near Angangueo, Mexico.
But the initial butterflies heading north must have milkweeds or honeyvine (Ameplamus albidus) plants upon which to lay their eggs, and nectar-producing plants upon which to feed. The milky sap of milkweeds makes monarchs resistant to predators, for it makes them poisonous to most vertebrates, including birds.
Milkweeds (various asclepius species) are easy to identify, with their upright growth habit, milky sap and hourglass-shaped flowers. Honeyvine is more likely to be confused with other vines, yet in our experience receives far more monarch eggs than ascepius species in our area.
At this time of year, mature honeyvine can be identified by the pods hanging from the vines. The flowers occur in round white clusters, have a strong sweet scent and could be called half-hourglasses in shape. Young vines tend to be upright until they reach 6 inches or so, and are stiffer than other vine species.
When weeding, PLEASE don't pull up any honeyvines without checking for the white dots which are monarch eggs (smaller than the tip of a pencil) or the striped monarch caterpillars. The monarch population needs whatever help we can provide right now.
Monarch Watch sells milkweed plants as plugs, and provides free milkweed plants to schools and non-profits - with plants available now for fall planting. Some states have begun planting highway corridors with milkweeds and other plants attractive to pollinators. (Perhaps we could all suggest this to our state legislators!)
Meanwhile, the Dearborn County Soil and Water Conservation District's Backyard Conservation Program offers butterfly weed, an orange-flowered asclepius, and a few other native plants each spring. The district may begin a pollinator-seed program next spring; many of the same plants feed honeybees as well as native pollinators and butterflies.
Folks (and teachers) who would like to raise monarchs can find instructions for doing so on the Monarch Watch site: monarchwatch.org. It takes about a month for an egg to result in a butterfly, and those eggs laid now will become the butterflies that migrate south. Monarch Watch also sells tags so you can tag your adult butterflies in hopes they will be spotted in Mexico and you'll learn if they made the trip successfully. Folks who would like honeyvine seeds may email me at [email protected] with email addresses and/or phone numbers (or call me at 812-438-2011 if you don't have email) and I will contact them when the seeds ripen in a few weeks.
Meanwhile, enjoy the monarchs you see fluttering past; last year the sight here was extremely rare. Let's hope it never becomes nonexistent.
