Helping the Hine's Emerald Dragonfly

A Blog Story About Nature in Our DuPage Forest Preserves

Helping the Hine's Emerald Dragonfly

Posted by Andres Ortega | 7/3/18 9:07 AM

Being a parent is one of the most difficult — but most rewarding — jobs I have ever had. 

You watch your children grow from someone in need of constant attention and care until, all too sudden, they become independent, self-sufficient young adults. While neither of my children have reached that final stage where they “fly the coop,” I can sense it in the not too distant future. For me, raising the federally endangered Hine’s emerald dragonfly at the District’s Urban Stream Research Center — while obviously different — also has many parallels to parenthood.

We started captive rearing Hine’s larvae in 2016 because the species was in decline, especially in Illinois. The Hine’s population is estimated at only 200 adults, which is incredibly low for an insect. So the need is great to boost their population over normal reproduction rates, and that’s where we step in as foster parents of sorts.

First, before we can raise the dragonflies, we have to go out and collect eggs from them, which is no small feat. We capture females while they’re in flight and “trick” them into laying their eggs in a container with water. We accomplish this by dipping the tip of their abdomen (the part that looks like a tail) into the water, which makes them think it’s time to lay eggs. Collecting eggs in this way does not hurt the female, nor does it hurt the Hine’s population, since usually only one egg out of 100 makes it to adulthood.

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Hine's emerald dragonfly larva 


Once we have the eggs and they hatch into aquatic larvae, we assume the role of parent as we care for these “babies.” The larvae need to be constantly fed the right amount and right size of food as they grow. The water they grow in needs to be monitored to make sure they’re growing in a clean, healthy, regulated environment and to make sure no “bad guys” in the form of other predatory insects have gotten into the aquarium. This period is marked by trials and tribulations, and constant questioning about whether you’re doing the “right” thing. Am I feeding them enough? Should I be doing something differently? Just like parenting a child, often there is no clear-cut answer and you just do the best you can with the best knowledge you have.

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In June 2018 the District released its first captive-bred Hine's emerald dragonflies into the Des Plaines River Valley, which is their primary habitat in Illinois.


In stark contrast to most other insects, raising the larvae can be a pretty lengthy period of time. Many insects develop from egg to adult within a year, but Hine’s larvae take 4 – 5 years to complete their larval development before emerging as flying adults in their natural habitat. Thankfully, in a controlled environment we can reduced this to about 2 years by providing optimal conditions and food. In the blink of an eye, they reach their final stage of development and are ready to “fly the coop.” At this point we transport them to their release site where they morph into flying adults in a small mesh container. This allows them to harden their bodies and wings before we fully release them in an effort to help them better avoid predators. Then, just like that, they’re off on their own as fully independent adults, and we’ve helped in our small way to boost the Illinois population.

So far we’ve helped raise 41 Hine’s larvae since 2016 and more are on the way every day. In June 2018 we were able to release the first 11 that successfully emerging as adults into the Des Plaines River Valley. As more larvae develop into adults, they too will be released into the Des Plaines River Valley, which is their primary habitat in Illinois.

Raising Hine’s emerald dragonflies continues to be an enriching, rewarding experience, and, much like parenthood, is something I look forward to every day. 

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 HED-net-Pitcher3 

 

Topics: Nature, Insider, Wildlife, Conservation, Natural resources

Written by Andres Ortega

Andres Ortega is an ecologist in the Natural Resources department at the District. He has a B.S. and M.S. in biology, both from Northern Illinois University. As the District's invertebrate ecologist, he works to protect and restore beneficial insect populations in DuPage County, and control those that are threats to human or environmental health. At home he likes to share his love of insects with his two sons by searching for butterflies and dragonflies on hikes in the local nature preserves.