The Free Press, Mankato, MN

July 28, 2013

Fewer monarch, caterpillar sightings this summer

Drought, pesticides, loss of habitat affected migrating butterflies

By Edie Schmierbach
eschmierbach@mankatofreepress.com

---- — MANKATO — A couple of monarchs were spotted flitting around Benson Park in North Mankato. One showed up near an Arlington business, reported a worker who was on break when he saw the orange-and-black winged beauty. A Facebook posting from a Mankato man said he found a dead butterfly on his semi's grill.

Traffic is just one of many challenges monarchs face while they follow their migratory routes between Mexico and Canada.

Drought and excessive heat last summer and May's unusually cold temperatures caused back-to-back damage to monarch populations. Low numbers were reported across the insects' breeding range, according to Journey North News, a website favorite for those who track the little travelers.

Minnesotans who enjoy watching butterflies have noticed a definite decline in monarch numbers this year.

Harriet Plotz of North Mankato, president of the Twilight Garden Club, said members who tend the flower beds at Hubbard House have not seen many butterflies visiting the blooms.

"There's been lots of mosquitoes," Plotz said.

"Monarchs are one of the most amazing animals on the planet. I've seen exactly two this summer," said Scott Moeller, director and naturalist for Linneaus Arboretum, where he keeps an eye out for winged visitors to the coneflower prairie at Gustavus Adolphus College.

No monarchs showed up during a two-hour public tour of the prairie last week. The number of butterfly sightings in general are down this year at the arboretum, which offers ideal summer habitat for painted ladies, red admirals, mourning cloaks and their caterpillars.

Butterflies that migrate encounter another set of problems when they are in Mexico. Loss of habitat has been a key factor in the decline of monarchs, which need the pine-oak forests of Mexico for continuation of the species.

"Deforestation is the most likely culprit," Moeller said.

During breeding season, monarchs produce a new generation in about 30 days. The generation that will leave North America this fall for Mexico are the great-great-grandchildren of those who left there last spring.

Monarchs flitting across the state this summer are looking for swamp milkweed to use as worm nurseries. The butterfly will only deposit its eggs on milkweed leaves.

Many gardeners and farmers destroy the butterfly's host plant, which is considered a noxious weed in some states.

"The milkweed that used to be in the fields is gone," said Karen Oberhauser, an entomologist with the University of Minnesota Extension Service.

Some area butterfly lovers are attempting to bring the number of monarchs back up by providing a milkweed oasis in their backyards. Jo Amiot of Mankato, who carefully controls a little patch in her Mankato backyard, noted a small increase in butterfly numbers this summer.

"Last year, there were seven, and so far this year, 15," she said.

Author of "The Mystery of Monarch Metamorphosis," Amiot photographed the butterfly in all stages of its life cycle as her subject for the Minnesota Heritage Publishing book. In summers past, she's snapped pictures of up to 25 chrysalis from her backyard. In the summer of 2012, she found only two.

A productive breeding season this summer is essential for the population to recover. Monarchs breed across a large region, which could add to its comeback potential, according to Journey North News.

Moeller suggestions for helping monarchs include not using pesticides. Butterfly populations often take a direct hit from the poisons intended to kill destructive bugs.

"We need to provide monarchs with more habitat," Moeller said.

A little garden space with milkweed and nectar-producing flowers will help plant pollinators as well as butterflies. Monarch will find milkweed blossoms, even when they are growing in little gardens in the middle of big cities, he said.

"There's really good evidence that vegetables do better when they are planted near wildflowers," Moeller said. "So, help a monarch and you will help a tomato."