Monarchs are an iconic species to many Canadians. They are large, bright orange butterflies with heavy black veins and wide black wing borders containing two rows of white spots. The larvae (caterpillars) are striped yellow, black, and white, and are 5 cm long. Its gold-green chrysalis (cocoon) typically hangs from a milkweed leaf or branch.
The Monarch is found throughout Nova Scotia wherever wildflowers flourish, such as open fields, meadows, and along roadsides. Monarchs require milkweed to lay their eggs on its leaves. Caterpillars then feed on the milkweed which makes them toxic to predators. Wildflowers such as goldenrods and asters are important nectar sources for adults. Monarchs are usually seen in July and August and are an indicator that your non-production areas of the farm are healthy.
There are two species of native milkweed used by Monarchs in Nova Scotia. Common Milkweed is often in roadsides and unmanaged open areas and Swamp Milkweed (less weedy) is often found in riparian areas and wetlands.
A warning about milkweed
Common milkweed, with it’s broader leaves and distinctive fat seed pods, can invade fields and pastures. Due to its toxicity it can pose a risk to livestock and is not suitable as forage. Although this toxicity is not good for humans and livestock it it a critical part of the monarch lifecycle and provides important protection from predators. For this reason, it is best leave milkweed alone when it is in ditches away from livestock and to manage it as you see fit in fields and pastures. Swamp milkweed is a great alternative: it won’t invade fields (it only likes wetter areas) and still provides habitat for monarchs. Keep in mind that it is still toxic for livestock and should be kept to uncultivated areas away from animals including pets.
Thousands of individuals roost in the exact same trees every year along migration routes to their overwintering grounds in Mexico. It takes several generations to return north each year. It is a mystery how the Monarchs correctly navigate their way, since no living migrants have made the journey before.
The Viceroy butterfly looks very similar to the Monarch. It mimics the Monarch’s colouration (with has an inner margin of black on the hind wings), but it is slightly smaller and is not poisonous.
How You Can Help:
Allow milkweed, to persist where it doesn’t interact with livestock (ditches, unmanaged open areas, gardens) and encourage areas of wildflowers, flowering shrubs and other native flowering plants as nectar sources for adults (also beneficial for crop pollinating insects).
Minimize use of pesticides and herbicides when possible. Learn to recognize Monarchs and report any sightings to e-butterfly. Butterflies and Monarchs in particular, are some of the most recognizable and beautiful invertebrates. By conserving Monarchs you are also likely contributing to the conservation of other invertebrate species, which provide ecosystem services like pollination and pest control.
Nova Scotia Butterfliesis a great resource to learn more about monarchs and other butterflies in the province.
Monarch Watch has plenty of information on the biology, behaviour and incredible migration made by monarchs each year.
To learn more about the threats faced by monarchs and to report sightings to an international database visit Journey North.
If there is a budding butterfly enthusiast in your family visit www.e-butterfly.org and indulge their hobby by exploring data of sightings from across North America. You can also join the Mersey Tobeatic Research Institute’s ‘Butterfly Club’ here.