Hine’s emerald dragonflies are only found in Illinois, Michigan, Missouri and Wisconsin. And in Illinois, other than Will County, they are only found in Cook, DuPage and possibly Lake and Winnebago.
Although the Hine’s emerald dragonflies released Monday mature to final larval stage in around three years, those in the wild take longer.
“In a natural setting, between egg and adulthood is between four and five years,” Ortega said. “They’re a very long-lived, very slow-growing dragonfly.”
Some of the more common dragonfly species can make it to adulthood in three to nine months. The slow maturation process for the Hine’s emerald dragonfly is one of the reasons the species is endangered.
“When you are stuck in very small habitat for so long, any change … in those five years and you are totally at risk,” Ortega said.
That is why in the wild, very few Hine’s emerald dragonfly eggs make it to adulthood, according to research at the University of South Dakota.
“In general, for every 100 eggs you might get one adult out of them if they’re left to their own devices in nature,” Ortega said.
Giving the insects a three-year head start should help around 50 percent of the larvae survive to adulthood at Lockport Prairie, he estimated.
But they still will have hurdles to overcome, said the University of South Dakota’s Soluk.
“The emergence process is a dangerous time for dragonflies, since larvae have to crawl up the stems of cattails or other emergent plants and then molt into the adult,” he explained. “The process typically takes under an hour, but the freshly emerged adult is very vulnerable to ground predators.”
The first flight also can be fraught with peril because the dragonfly’s wings are weak and it can be attacked by birds.
According to the U.S. Fish and Wildlife Service’s (USFWS), Hine’s Emerald dragonflies also are suffering from pesticides and pollutants in the environment, changes in the flow of groundwater and the loss of wetlands to make way for development.
Stepping in to help