Monarch butterflies have been the subject of grave concern over the last several years due to their radically declining numbers.
But this year, scientists noticed some improvement.
By now, ninety-nine per cent of the monarchs have left Canada on their annual migration south to Mexico, according to Maxim Larivee, Head of Research and Collections at the Montreal Insectarium.
ListenHe spearheaded the Citizen’s Science projects that have helped monitor the Monarch’s populations over the last few seasons, and became a unifying mission for Canada the United States and Mexico.
He says this past summer, “the situation has improved ever-so-slightly”.
“We’re around probably 100,000 million as of last year but we had several signs this summer that this number might increase as we recorded, on average, all across the northeast, three to four times more butterflies than in the average of the last five years, so ever since the crash,” Larivee says.
The scientists have a target of 250,000 million Monarch butterflies that will be more resilient to the many threats they face.
This summer, however, many people may have been confused by the appearance of a huge population of a similar butterfly, known as the Painted Lady.
“The big difference”
Painted Ladies are not Monarch’s but they’re also migratorial.
“The big difference with them is that they basically migrate down south, just like migratorial birds would do, but don’t go back to the exact same place in the high mountains of Mexico like Monarchs do,” Larivee says.
He says they go down to the Sonoran desert where they can survive the winter and breed in southern Texas and Mexico.
Painted Lady butterflies are smaller, with a wing-span of five or six centimetres, whereas monarchs have a span of 8 to 10 centimetres and are completely orange, with black lines.
“An extra generation to reproduce”
“What we’re witnessing currently in all of southern Quebec and now in Ontario and in the northeastern United States is an inordinate amount of individuals of Painted Ladies that was brought upon highly likely by an extremely early migration of a large quantity of Painted Ladies, historically early almost, in mid-April, so it allowed them to have an extra generation to reproduce which basically doubled or more their population this summer.” Larivee says.
This, and the fact that the powerful southern currents coming up from the Caribbean, associated with the hurricanes, kept the Painted Ladies stranded in Canada, where there have been so many sightings at summer’s end.
As for the Monarchs, Larivee says “most experts predict that the colony will have grown this winter in Mexico, but in order to start to feel safe again in terms of the population size and everything, we need, i would say, three, four, five consecutive years like the one we just had, for sure.”
It remains to be seen how many migrating butterflies will make it to Mexico, as many may have been buffeted by the record-setting hurricane winds this season.
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