Every year thousands of monarch butterflies dancing through the air across North Florida, migrating between their breeding in Mexico and their regular homes along the Atlantic coastline.
Every year there was less and less.
The new Florida University study for 37 years, the longest such kind, has revealed that the number of caterpillars and butterflies in North Florida has been steadily decreasing since 1985.
Since 2005, the number has dropped by 80 percent.
"It's alarming," said associate professor Jaret Daniels, co-author of the study. "Before 2005, there was a greater fluctuation in data, since 2005 the rate of decline was stable."
Scientists involved in the study say the causes of the fall are not entirely clear, but believe there are two major factors at work.
One of them is the development of areas that were planted with native dairy milk, the favorite food of young monarchs. Another widely used herbicide is Glyosphate, often applied to agricultural fields for the weeding of weeds. One of the weeds that kills is the milk tissue.
The research was conducted by an internationally renowned expert of the monarch called Lincoln Brower, who died earlier this year, just before the study was published in the Journal of Natural History. Brower began studying the 1950s rulers and was instrumental in finding a place in Mexico where they spent the winter before going back to Florida.
"Florida is a type of field reclamation for a large part of the east coast," said Daniels. "If these populations are low then the northern population will be at a similar level."
Under Brower's direction, the team of scientists carefully watched how many monarchs appeared each spring in a herbicide-free ranch in Cross Creek, a former homeowner of Marjorie Kinnan Rawlings, Florida.
At 20 miles south of Gainesville, the team gathers each year to inspect pasture landslides for all caterpillars. They also captured adult monarch butterflies to check the growth or decline of the population. The 37 years they spent doing this is roughly equivalent to 140 generations of monarchs.
One Study Findings: Monarchs leave Mexico in the spring to coincide with the optimal growth of dairy fat in Florida and other southern states. While adult monarchs can eat a multitude of plants, a diet of young people does not only consist of milk fat. Plants contain stored toxins to protect predators.
Florida has 21 original types of dairy legumes. There are three types of best for the rulers, Daniels said: swampy wetland swamp, blueberries and, of course, butterfly butterflies.
Contact Craig Pittman at [email protected] Follow @craigtimes.