The monarch butterfly’s orange and black wing markings and polka-dotted abdomens contribute to a seemingly dainty persona as they flit about on the late summer breeze. But these fluttering insects boast a tenacity far greater than their diminutive appearance suggests.
The monarchs we spot in the gardens and fields around New Hampshire now are preparing to travel thousands of miles to their winter abode in the Transvolcanic Mountains of central Mexico. And a cadre of citizen scientists across the United States and in Mexico is helping track the monarchs’ travels and the health of this butterfly population.
“I’d love to see an uptick in participation in citizen science in the Northeast,” said New Hampshire Fish & Game Wildlife Diversity Biologist Heidi Holman, who will help lead a monarch monitoring and milkweed demonstration program next weekend. “Over 20 percent of scientific literature comes from citizen science data.”
The program, a collaboration between New Hampshire Fish & Game and UNH Cooperative Extension, is slated for Saturday, Sept. 14, in Stratham. Participants will learn how to prepare seeds to grow milkweed, which is essential to the monarchs’ lifecycle, as well as how to tag the butterflies as they migrate south and how to record data that will help scientists track monarchs.
Tagging — placing a tiny, numbered sticker onto the hind wing of a butterfly — helps scientists determine where the butterflies that end up in Mexico have come from, when their migration began and how long it took, mortality during migration, and shifts in geographic distribution.
The workshop corresponds with peak monarch migration, which is Sept. 13 in New Hampshire.
Some of the challenges facing monarchs in recent decades include loss of breeding habitat, disease, and changes in climate patterns that affect their ability to find nectar on their southward migration.
Holman said monarch populations had dropped significantly by 2014, but that numbers seem to be climbing the last two years.
The butterflies now feeding in gardens and fields around New Hampshire are filling up on nectar to prepare for the flight south to Mexico. Once there, they’ll join millions of other monarchs and spend months hanging in clusters from oyamel fir trees — at just the right elevation and latitude — before once again venturing north in the spring.
It takes four generations of monarchs to complete a round-trip from more northern realms, like New Hampshire, to Mexico.
The butterflies that make the southward journey and overwinter successfully will head turn north again come March. They’ll stop in Texas or Oklahoma or elsewhere in the southern U.S. to lay eggs on milkweed plants. A few days later, those eggs will hatch into caterpillars that will grow through five instars — over about two weeks — shedding their skin after each.
The glycosides in milkweed leaves, which is the sole food source for monarch caterpillars, make both the caterpillars and the butterflies toxic to predators. A fully-grown caterpillar will seek a sheltered spot near the milkweed plant to suspend its chrysalis. Nine to 14 days later, an adult butterfly will emerge.
Those second-generation butterflies will head north again. Some will land in New Hampshire and repeat the cycle. The third-generation monarch — those we see in early or midsummer — will stay close to where they began and produce the fourth generation, which will fill up on the nectar of late summer flowers before heading south.
While spring and summer monarch butterflies live for up to five weeks, this migrating generation lives from six to nine months, going into reproductive dormancy to make the long journey to Mexico and spend the winter in a quiet state of torpor.
During the monarch monitoring and milkweed demonstration, participants will be able to observe each step of the monarch’s lifecycle, will help tag migrating butterflies, and will learn how to participate in citizen scientist programs like the Monarch Joint Venture.