The Monarch Butterfly also known as the Danaus plexippus, is one of the most well know and recognized butterflies. The World Wildlife Federation currently lists the Monarch’s status as endangered (2019). Herein we will review the monarch’s physical characteristics and outline it’s life history and feeding ecology/preferred foods.
Most easily distinguished by its wing colours of orange, black, and white markings.
The “two pairs of brilliant orange-red wings, featuring black veins and white spots along the edges” (WWF, 2019) give them a stained-glass window effect. As would be expected of a butterfly they barely tip the scale at less than half a gram in weight with their wingspan coming in between 7 and 10 cm.
Alternatively, the caterpillars have yellow, black and white stripes. They grow up to 5 cm. When they metamorphize their chrysalis is “seafoam green with tiny yellow spots along its edge” (NWF, 2019).
The NWF (National Wildlife Federation) explains that monarchs exclusively lay their eggs on milkweed which then take 3-5 days to hatch. They then eat the leaves of the milkweed and then about 2 weeks later, form a chrysalis. The monarch butterfly emerges 2 weeks later. Typically, they only live for a “few weeks” but the last ones to hatch in summer “can live upward of eight months” (NWF, 2019). Its this 4th and last batch of monarchs that migrates south to Mexico or California for those living west of the Rocky Mountains according to Stafford Mader, L, (2014). They leave those wintering grounds in the spring and migrate back to Canada in the summer (WWF, 2019).
Although the Monarch butterfly can feed on the nectar of many flowers like “echinacea, black-eyed susan, sage, goldenrod, zinnias and dahlias” (WWF, 2019, para. 7), the most important food source for the species is still the milkweed plants that their larvae/caterpillars exclusively eat. In Milkweed: Medicine of Monarchs and Humans, Lindsay Stafford Mader explains the connection between the steroid compound called cardenoloid, in milkweed and the decreased risk of infection in the larvae and later the natural toxicity of the butterfly that acts as a defense against predators.
The higher the cardenoloid levels in the milkweed the larvae eats, the higher the caterpillar’s chance of survival and later, not just the individual butterfly’s survival, but the species itself. This would be from the common association response poisonous prey induce in their would-be predators.
NAF. (2019). Monarch Butterfly. Retrieved October 31,
Stafford Mader, L. (2014). MILKWEED: Medicine of Monarchs and
Humans. HerbalGram, (101), 38–47. Retrieved from http://search.ebscohost.com/login.aspx?direct=true&db=awh&AN=94874416&site=eds-live&scope=site
WWF. (2019). Monarch Butterfly. Retrieved October
06, 2019, from http://www.wwf.ca/conservation/species/monarch_butterfly/