Monarchs: Inside or Out?
By: Stacey Wildberger
In these times of mass extinction and climate change we sometimes feel helpless and ineffectual in our actions but we can make a difference one backyard at a time. Doug Tallamy writes in his book “Bringing Nature Home” the idea that our own small pieces on earth –our backyards- can be the difference in restoring ecosystems. What better way to do this than by planting native plants that support pollinators and food webs. Providing the host plants needed for our butterflies to lay their eggs because caterpillars can usually eat only one type of plant. There are many relationships between insects and plants but the most widely recognized is the link between Monarch Butterflies and Milkweed. Monarchs must have milkweed to lay their eggs. When the egg hatches the caterpillar grows through various instar phases until he is ready to form his chrysalis where he will emerge as the iconic Monarch Butterfly. Beyond milkweed though these Monarchs need nectar to support their long migration in the fall.
Many people have started collecting the eggs they see on their milkweed, along with the milkweed plants, to raise them indoors. There are of course two viewpoints if this is the best way to help Monarchs. Advocates for raising Monarchs indoors claim they are increasing their chances of survival by keeping them away from predators. What they are ignoring is the caterpillars place in the food web; 97% of terrestrial birds are reared on caterpillars and other insects. It takes 7000-9000 caterpillars to raise a clutch of chickadees. Without the caterpillars for the birds to feed their young many will perish.
Beyond the fact that you are removing an important food source from the food web there are many other reasons to leave the Monarchs in the garden and let nature take its course. Raising Monarchs indoors can have many negative effects on the butterflies themselves. They are often smaller than wild raised ones-just a millimeter difference in wings size can have deadly results on their migration to Mexico. They often do not develop the correct physiology to migrate, have under-developed reproductive organs and, instead of having the instinct to breed, they are cued up just to fuel up on nectar. Being exposed to an indoor environment with artificial light, constant temperature and top choice of milkweed provided by their captors they do not develop the environmental cues needed for pre-migratory behaviors. There is also a higher chance of developing OE (Ophryocystis elektroscirrha), a harmful protozoan that can be blamed on the overcrowded and unhygienic conditions of indoor living. The butterfly may seem healthy but can spread this deformity causing disease to other butterflies. Even worse when these infected Monarchs are released they spread it to the wild population, thereby causing more harm than the good that was intended (i.e., helping boost populations).
Of course it is exciting and an educational experience for child to see the full life cycle of these beautiful butterflies so I am not saying not to raise a few in the classroom or living room for the wonderment and discovery of youth but the widespread collection of eggs and even ordering them online (!) can and will cause more devastation than the problems of loss of habitat, disease, weather issues and predation.
Instead of collecting eggs and raising them indoors, what can we do to help? Provide milkweed. Lots of milkweed for them to lay their eggs. Make sure the milkweed you are planting is native to your area. In Maryland we have Whorled milkweed (Asclepias verticillata), Swamp milkweed (Asclepias incarnate), Butterfly weed (Asclepias tuberosa) and Common milkweed (Asclepias syriaca) to choose from. Choose the one or ones that are right for your conditions. While swamp prefers a little moisture the others thrive in just about the worst conditions you can throw at them. In addition to providing their host plant, milkweed, they require plants they can nectar on in during the fall migration. There are many beautiful fall blooming nectar plants you can provide for them.
- Goldenrod (Solidago sp.)
- Asters sp. New England Aster (Symphyotrichum novae-angliae), Aromatic Aster (Symphyotrichum oblongifolium), White Wood Aster (Eurybia divaricate)
- Conoclinium coelestinum Blue Mistflower (Conoclinium coelestinum)
- Joe_Pye Weed (Eutrochiumsp.)
- Boneset (Eupatorium sp.)
- Woodland Sunflower (Helianthus divaricatus)
- Tall coreopsis (Coreopsis tripteris)
As always is my advice (I probably sound like a broken record) the best you can do is plant native plants, natives that are hosts to our native fauna, native plants that provide nectar and pollen to our native pollinators and native plants that provide nesting and resting places as well. When in doubt, choose native plants over the ornamentals. Whenever possible choose the straight species over a cultivar that has had its bloom shape, color and height changed to fit our idea of pretty the last thing I implore you to do is not to plant Butterfly bush (Buddleja davidii). While the name may imply you are doing right by the butterflies you are in fact providing the equivalent of a sugary soda or candy and not much else in the way of national value. Not only that, but they do not host any butterfly larvae and they are highly invasive. Their seed is spread into our natural areas thanks to the birds and outcompetes native plants. If you have them in your yard and absolutely won’t remove it at least be vigilant about removing the dead seed heads to keep it from spreading. There are some lovely alternatives to butterfly bush if you wish to replace it with a native:
- Southern arrowwood (Viburum dentatum)
- Sweet pepperbush(Clethra alnifolia)
- Buttonbush (Cephalanthus occidentalis)
- New Jersey tea(Ceanothus americanus)
- Blazing star (Liatris spicata)
- Asters sp. New England Aster, Aromatic Aster
- Purple Coneflower(Echinacea purpurea)