By Staff
For you "wish-I-were-a-biologist" readers I occasionally throw out meaningful scientific projects that enlist the aid of amateurs. I have had great fun and met some very interesting folks while participating in such projects. One coming up now for people of all ages is Project Monarch Watch. Based at the University of Kansas, it was formed in 1992 as an educational outreach program and has since evolved into a leading monarch butterfly conservation and research program. Most of the field work is done by volunteers like you and I.
The orange and black striped monarch is one of our showiest butterflies and most of us are in awe at their monumental migration every fall to the mountains of central Mexico. Some individual monarchs fly up to three thousand miles to reach this wintering ground. No other butterfly even comes remotely close to such a feat. Precisely how they do it, the perils they encounter and how they know where to go are just a few of the things Project Monarch Watch is trying to figure out.
It was long known that monarchs west of the Rocky Mountains migrate to coastal California where they over winter as adults. This is quite unusual as most butterflies in cooler climes endure the colder months as eggs or chrysalis (cocoons). It wasn't until 1975 that scientists discovered monarchs from east of the Rockies spent their winters in a small, mountainous area of central Mexico. There they roost by the millions in oyamel fir trees, only leaving the roost on exceptionally warm days to go for water.
The only plants monarch larvae eat are various species of milkweed. In the second week of March, as the milkweed begins to grow in the southern U.S., the monarchs mate and start wandering north. This over wintering generation repopulates the southern states and then die. The newly emerged generation of monarchs continues the journey north, following sprouting milkweed all the way to their parent's homeland. Throughout the summer two or three more generations of monarchs come and go, each one living only three to five weeks. Then in August a generation emerges that is uniquely different. Their abdomens are smaller, trimming weight for the upcoming flight. They do not mate and lay eggs.
Starting in late August the most northerly monarchs congregate and aim their gossamer wings south. As they progress, more monarchs join in and the mass grows. They nectar heavily along the way, actually gaining weight. Different groups travel different routes but it's unknown if they follow distinct paths. Most converge in Texas, some even crossing the Gulf of Mexico to get there. Eventually they all end up vying for a spot on the stand of oyamel firs in Mexico. Many find the exact same tree their great, great grandparents occupied last winter. By the time they return to the southern U.S. they will have lived eight or nine months, an astronomical age for a butterfly.
Now monarchs are in trouble. According to Monarch Watch, a large percentage of the milkweed, and therefore monarchs, occur in agricultural areas. That is disappearing at the rate of 3,000 acres a day and the rate is increasing each year. In the last five years eighty million acres of farmland, roughly the size of the state of Maryland, fell to development. Even more imminent and alarming, the growing use of crops genetically modified to withstand herbicide is finding more and more farmers controlling weeds with herbicide rather than tilling. Milkweed and vital nectar flowers can withstand tilling but have no chance against herbicide.
Program Monarch Watch is calling for volunteers all across the country to catch monarchs and place a tiny, coded tag on their hind wing. As tagged monarchs are recaptured by other researchers the code will be recorded to note the travel of that butterfly. How's that for a cool scout or church group project? If that's a bit much for you, Monarch Watch also gleans valuable information from volunteers simply documenting their observations of monarch behavior. All the details on ways to participate as well as other monarch conservation projects such as creating way stations can be found on their website, www.monarchwatch.org. Carpe diem.