Monarch butterfly: is the glass half empty or half full?

Monarch butterfly at Butterflies Go Free event
Credit: Espace pour la vie (André Sarrazin)
Danaus plexippus
  • Danaus plexippus
  • Graphic - monarch populations between 1993 and 2014
Monarch butterfly: is the glass half empty or half full?

The eagerly awaited figures came out last week. The monarch population in eastern North America went up by 69 percent compared to last year. There are 1.13 hectares of Mexican forest covered by monarchs, compared to 0.67 hectare the year before. Wonderful news, which reflects the ability of this surprising lepidopteron to bounce back thanks to its great reproductive capacity.

Can we celebrate?

Despite the increase, this is still the second smallest population ever recorded. The size of the population is a long way from the average of the last 22 years (6.1 hectares), and much farther from the record of 18.2 hectares documented in 1996-1997. Are the good periods gone forever? Let’s hope not…


Important measures will have to be put in place if we want to turn the trend around. The primary cause of the decline in the monarch population is the loss of breeding habitat in favor of the cultivation of genetically modified corn and soya resistant to herbicides. The agricultural environment, once so welcoming to monarchs, has become a desert where these butterflies starve to death. The females that fly over them during their migration look in vain for milkweed, the only food accepted by their caterpillars. Of course, milkweed grows elsewhere as well, but it’s becoming increasingly rare wherever it’s found. Major climatic changes and illegal deforestation on the Mexican wintering grounds are other great challenges that this little insect has to meet.

Rescuing the butterfly

At an official meeting in 2014, the heads of state of Canada, the United States and Mexico decided to cooperate to ensure the survival of the monarch, a symbol of their association. At the same time, in Canada and the U.S., government agencies are assessing the possibility of increasing the fragility index of the population of eastern North America, which would enable us to add to the resources devoted to its conservation.

Probably the most studied butterfly of all time, the monarch benefits from the sympathy of the human population, who recognize it, take to it right away and concern themselves with its well-being. Citizens also get involved by creating gardens for monarchs around houses, schools, businesses and parks that offer nectar-producing flowers to feed the adults, and milkweed for the offspring.

Meeting the challenge

In March, the monarchs will leave their wintering grounds to make the trip back north. Imagine: the equivalent of seven football fields will have to repopulate about 20 million square kilometers in North America… Long odds that the monarchs will endeavor to overcome once again, this summer. And for a long time to come, let’s hope!

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1 Comment(s)
Dominique lalonde's picture
Dominique lalonde

J'espère que beaucoup de gens participeront en grand nombre en créant des jardins pour aider les monarques. J'adore les monarques et j'essaie de sensibiliser les gens avec mon blog et ma chaîne web TV. Dominique lalonde, photographe et cinéaste naturaliste

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