Four years ago, the cedar trees near the river in my backyard were the way station for swarms of Monarch butterflies. The little creatures were resting from the long day’s migration flight. Small groups of them stopped for nectar at my flower bed. I tried guesstimating how many of the orange and black insects were in the yard. I supposed there were several thousand of them.
There was pretty much a pattern. Each late summer, I’d see hundreds or thousands of Monarchs visit my home. Some years, there were perhaps only a couple of hundred. A few remarkable years, they numbered in the thousands. Last year, I think maybe only two individuals caught my attention. This year, I have yet to see even one Monarch butterfly. The milkweed plants have been untouched by insects. I wondered if they just decided to spend the spring and summer in Mexico.
Monarch butterflies have amazed entomologists and butterfly lovers for decades. Aside from being a very attractive bug, they travel a 3,000 mile migration route. Monarchs fly their amazing journey out of a remote forest reserve in central Mexico into the United States and parts of Canada. There have been estimates of 25,000,000 Monarchs per acre at the times they find rest, flowering plants and crops on their way. After a few generations of breeding, the younger Monarchs begin their instinctual migration to or from central Mexico.
I decided to look into the lack of Monarch butterflies in my part of Nebraska. Apparently there are a couple of major reasons for the decline in Monarch populations.
Chip Taylor of the University of Kansas has reported there is illegal logging activity at the Mexican forest reserve. The Monarch Biosphere Reserve is a 217 square mile nature reservation in a remote section of the central Mexican forestland. According to the locals, the poachers are armed and have often threatened area residents. The loggers have been known to clear out 3 hectares of trees at a time and carry the logs out with sometimes 100 trucks.
Entomologists report a sharp decrease in the Monarch populations at the Biosphere during the past dozen years. The researchers believe the butterflies are dying off due to winter exposure caused by deforestation. This past season has seen the lowest population levels in 20 years.
The surviving Monarchs then must encounter another problem as they fly northward. In the U.S., they pass through modern agricultural land. The radical destruction of natural habitat due to biofuel usage, massive herbicide application, and genetically modified crops have impacted the Monarch’s flyways. The most worrisome effect is the stark reduction of milkweed plants in the Great Plains.
Milkweed is vitally important to Monarchs, because it is the only plant that the Monarch caterpillars have evolved to eat. Adult, female Monarch butterflies lay their eggs on milkweed. Upon hatching, the young caterpillars munch on the milkweed leaves, then go into their pupal stage. After the new butterflies pump up their wings, they eat the nectar from milkweed flowers and eventually move on to other plants like field clover, alfalfa, and goldenrod.
It is during the time that butterflies eat nectar, that they are an important part of crop pollination. Just as honeybees and bumblebees are necessary for plant pollination, so are Monarch and other varieties of butterflies important to certain crops. Monarchs are crucial because of their large population numbers and their flying abilities.
The crucial drop in milkweeds has happened because of the application of glyphosate herbicides. Corn and soybean fields have been planted with over 120,000,000 acres of genetically modified crops that resist glyphosates. That allows the herbicide to kill milkweed and other weeds and not kill the crops. So, when the milkweed is absent, so are the Monarchs.
The GMO type of crops and growing techniques have largely supplanted conventional hybrid corn and soybeans in the Great Plains including Iowa, the Dakotas, and Nebraska.
Because there is a downward spiral in Monarch population, the rest of the ecology is affected. Smaller butterfly and bee populations mean less food for birds. Fewer birds means less food for larger animals that eat birds. Fewer Monarchs and fewer bees also mean less pollination of cropland. This leads to crop failures and higher prices for our food at the supermarket.
The combination of logging in Mexico, GMO crops in the United States, and the severe drought dries up crops, milkweed and flower nectars. These present serious problems for the pollinator insects, including Monarch butterflies.
The best solutions are obvious. A crackdown on illegal tree harvesting in Mexico is a good start. A return to more traditional forms of agriculture and crops in the U.S. and Canada will be crucial to the survival of Monarch butterflies, bees, and us.
The Blue Jay of Happiness notes that this “Butterfly Effect” is different from the one that is usually cited in that this one involves the survival of actual butterflies.