Monarch butterflies have returned to Minnesota. Keith Anderson hasn’t seen many around his garden, but he knows they’ve been there — he’s been finding their eggs on his milkweed plants.
Anderson found the first eggs of the season May 29.
Most of the dozens he has found are on the underside of leaves of milkweed plants he has in multiple gardens at his home.
Anderson and his wife collect those eggs and help raise the caterpillars to butterflies.
In the wild, monarchs have about a 2 percent chance to survive from egg to butterfly. The past couple years, 78 percent of the eggs Anderson has retrieved from his garden are released as butterflies.
Anyone who has milkweed (or knows where some is) can help some eggs beat those 2 percent odds. Monarch eggs stand out as pale green dots. They’re usually laid on the underside of milkweed leaves.
“In nature, that protects them from rain,” Anderson said.
Anderson usually removes the entire leaf that has an egg. He then cuts the section down to about a half-inch and places the eggs, still attached to their leaf sections, on a damp paper towel in a plastic container with holes in the lid. The damp towel keeps the leaves relatively fresh — they’re an important source of food for the hatchling caterpillar.
Anderson saves the rest of the trimmed portion of the leaves to feed his other hatched caterpillars.
The eggs will hatch four days after being laid. Other steps in the process might vary in the time they take, but Anderson said he has yet to find a viable egg that took more than four days to hatch.
A small black dot appears on the egg when the caterpillar is ready to emerge, Anderson said.
“That’s its head,” he said.
After that, he transfers the newly hatched caterpillars into another box with separated compartments. He covers the box with nylons or a cotton T-shirt to give the caterpillars air. He found out the hard way a window screen allows the small hatchlings to wander off.
They’ll take a walk if they have the opportunity. The compartments help him keep track of the tiny caterpillars and also prevent them from snacking on a neighbor.
Like the hatching box, he places the caterpillars, each with its leaf, on a most paper towel and adds some more milkweed leaf.
Once the caterpillars are big enough they can’t crawl through a fine mesh, he transfers them to their final stop before they go into chrysalis — a simple laundry hamper.
It’s in there the caterpillars go into their most aggressive growth phase.
Next week: Anderson shares how he raises the caterpillars until they’re ready to go into chrysalis.