Ever wonder why some places have lots of butterflies and others have few or none at all? Various factors influence whether butterflies are attracted or even welcome in a habitat, so maybe we should focus on what we can do to encourage butterflies and adapt our gardens and landscapes so that they can attract and sustain butterflies.
Why attract butterflies? What’s good for butterflies is good for other pollinators, such as bees, as well as other forms of wildlife. Many pesticides, including natural ones such as Bacillus thuringiensis (or Bt), are toxic not only to butterflies, but to other flower pollinators. The best indicator of a healthy, sustainable garden or landscape is the presence of both plant and wildlife diversity. To have all that, we need to reconsider our need to control nature, and accept its imperfect beauty. Butterflies are both beautiful and entertaining. We may have to get used to the idea of chewed upon leaves, but the rewards of growing our own caterpillars are worth it. Let’s talk about several butterflies that we all remember from our childhood days, and learn more about why they’re not as common as they once were.
Monarch butterflies are admired both for their beauty and their fortitude. They migrate to central Mexico every winter, but the numbers arriving at the World Heritage site butterfly reserve there are declining. The leaves of various species of milkweed (asclepias) provide food for developing caterpillars.
(Photo © Cathy Keifer – Fotolia.com)
Industrial farming techniques rely heavily on herbicides, which prevent milkweed from popping up in between the crop rows, resulting in major losses of feeding areas for Monarchs and other butterflies that prefer milkweed. Many people are planting milkweed to attract Monarchs, but something’s not right, particularly in the southern US. Native species of milkweed in the southeast are asclepias humistrata, a. incarnata, a. perennis, a. syriaca, a. tuberosa, a. variegata, and a. verticillata. In many plant nurseries, the only species of milkweed sold is asclepias curassavica, native to the tropics. This species thrives in areas where warm winter temperatures do not kill the plant, and discourages Monarchs from migrating to Mexico. Scientists believe that a. curassavica, in particular, harbors a protozoan parasite that weakens and debilitates both Monarch and Queen butterflies whose caterpillars consumed parasitic spores on the leaves. The infected Monarch butterflies infect other butterflies, lay infected eggs, and are unlikely to survive the migration to central Mexico, which is considered critical for the survival of the species. Regardless of which type of milkweed is present in our gardens, the recommended practice involves cutting down milkweed plants every few weeks during warm winters and disposing of the cuttings. That way the Monarchs returning in the spring can’t be infected or lay their eggs on infected milkweed plants.
Gulf Fritillary and Variegated Fritillary caterpillars are passionate for passion flower leaves. Unfortunately for us gardeners, the native passion flower species, passiflora incarnata, can be quite invasive. P. incarnata, P. caerulea, and hybrids of the two are the best choices to feed most Fritillary caterpillars. Avoid P. racemosa, which is toxic to caterpillars. Passion flowers (aka Maypops) are also feeder plants for the caterpillars of the Julia and Zebra Longwing butterflies. Loss of habitat and food seem to be the greatest threats, not only to Fritillaries, but to most butterflies and other flower pollinators.
To encourage the Swallowtails – Black, Eastern Tiger, Giant, Pipevine, Spicebush, and Zebra in our area – plant Joe Pye weed and button bush for adult butterflies, and parsley, dill, and fennel for caterpillars. As is the case with
Fritillaries and Monarchs, loss of feeding areas and habitats are significant threats in some areas.
Highly recommended nectar sources for a variety of butterflies include Lonicera sempervirens, Asclepias, Zinnia, Lantana, Echinacea purpurea, Tithonia rotundifolia, Liatris and Phlox.
The internet sources below offer a wealth of information on all the various types of butterflies found in Georgia, and the best nectar producing flowers and caterpillar feeding plants to include in our gardens and landscapes. The National Wildlife Federation (NWF) article on attracting butterflies provides invaluable information on attracting and keeping butterflies, pollinators, and wildlife in our personal habitats. The North American Butterfly Association (NABA) has extensive information on their website, but there is no online garden guide for our Piedmont area. The link provided below for their Tennessee central basin garden guide is still quite helpful.
Sources:
http://www.monarchjointventure.org/get-involved/create-habitat-for-monarchs/
http://news.sciencemag.org/biology/2015/01/plan-save-monarch-butterflies-backfires
http://www.birdsandblooms.com/blog/passionvine-and-its-butterflies/
http://nababutterfly.com/purple-passionflower/
http://nababutterfly.com/wordpress/wp-content/uploads/2014/03/tn_centralbasin.pdf
This webpage provides images of passion flowers and the caterpillars who love them.
http://www2.stetson.edu/~pmay/woodruff/passiflora.htm
These last two webpages provide an extensive collection of Georgia butterfly/caterpillar/cocoon photographs.
http://www.shrike.net/butterflies/
http://www.nelsondobbs.com/Georgia_Butterflies.html
Header Photo:
Monarchs on Eupatorium in Michoacan, Mexico © ALCE – Fotolia.com