Megan's Nature Nook
Nature Notes, Phenology, Photography, Fun Facts, Trips, Maybe Even a Bad Joke or Two... and More!
This time of year, we hear about Monarch and Painted Lady butterflies during their great migration of thousands of miles. Well, butterflies aren’t the only insects that migrate! Various species of butterflies, moths, beetles, and dragonflies partake in seasonal migration including the Common Green Darner Dragonfly (Anax junius). The basics are known about their migration, but there is still more to learn. Tracking Dragonfly Migration Dragonflies can be hard to track since they’re fast fliers making them hard to catch, they don’t travel in swarms like some butterflies so they can be hard to spot, and they’re small so putting a radio transmitter or leg band on isn’t easy. Since scientists cannot use these traditional ways to track Green Darners and their migration patterns, they use something else to track and learn more about them – water! This is going to get a little science-y, so bear with me. Water is made of 2 hydrogen and 1 oxygen atoms. Most hydrogen atoms have 1 proton and no neutron. A very small fraction of hydrogen atoms have 1 proton and 1 neutron, this is called deuterium. The amount of deuterium in water varies roughly by latitude in North America. So, the water in Manitoba has a different deuterium-to-hydrogen ratio than water in Mississippi. Dragonflies start their lives in the water as eggs then nymphs (the teenage stage of dragonflies). Since they are growing and developing in the water, the local deuterium ratio is incorporated into their tissue. Scientists can test adult wing samples for three hydrogen isotopes, which each have their own chemical signature. Each isotope varies geographically, so by identifying the isotopes, they are able to narrow down where the dragonfly was born. This is how scientists are able to tell that Green Darners migrate. They were finding adults with isotopes that didn’t match the region that they were found, but instead a region farther away. Think Texas vs. Minnesota, they would have different isotopes found in their wings if they grew up in different areas with different deuterium-to-hydrogen ratios. Green Darner Generations & Migration Green Darners partake in an annual, multi-generational migration with three generations traveling more than 1,500 miles. Although Green Darners migrate, not all of them do. There are two populations, resident and migratory. The resident population doesn’t migrate. They breed in the north in the summer and the nymphs overwinter in ponds or lakes in the north, emerging in the spring and spending summer as adults where the cycle then starts over again. The migrating population is a bit more complex. First Generation In February to March, the first generation emerges from ponds and lakes in the southern United States, Mexico, and Caribbean. In May they will arrive in New England or the upper Midwest, laying eggs and the dying. Second Generation The second generation is split into two group, some will overwinter as nymphs in northern waters, emerging as adults in the spring. Others will transform into adults and fly south July through October. Once in the south, the second generation will lay eggs and die. Third Generation The third generation will live as adults on the coast for the winter, laying eggs in the spring then dying. Then the process will start over again with the first generation of the great migration heading north. This graphic shows how it takes 3 generations to complete the year long migration. The red represents many dragonflies and gray means no dragonflies. Continued Research There is still more to learn about Green Darner migration, but they have found out some information through studies and data collected through citizen science projects. Temperature plays a big role in triggering migration. Scientists have found that they don’t start migrating until 9.5°C or about 49°F. Then they progress northward as the temperatures increase in the spring. Climate change poses a big concern for Green Darners, among other species as it would greatly affect their migration and lifecycle. Dragonflies are a key part of the food web, since they eat many insects, like mosquitoes, and help to keep pests in check. They also are a food source both as nymphs and adults to waterfowl, fish, toads, birds, and more. Losing such a key component in the ecosystems could cause many problems. Although dragonflies may not be the easiest to track and research, scientists are busy at work learning as much as they can about these interesting creatures! If you’re interested in learning more about dragonfly migration or participating in dragonfly citizen science, check out the Migratory Dragonfly Partnership by clicking the button below. Keep your eye on the sky and you may be lucky enough to spot some of these dragonflies on their way south!
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Fall tends to get a bit of a bad wrap since many of the seasonal changes that are happening are things dying or leaving. Pretty fall colors lead to bare trees, forest plants turn brown and die down, and many of our summer birds head south. Even though our cool weather and shorter days means less plants and birds around, do not be dismayed, as fall is a great time to look for fungi! Many species are still fruiting into September, October, and even a few into November. The term “fruiting” may seem odd to use when talking about fungi (the plural of fungus). The fleshy, fruiting body of a fungus is called a mushroom. The mushroom holds spores and is the reproductive part of the fungus, like a seed or nut is the reproductive part of a plant. The mushrooms we see above ground are only a small part of the fungus. A majority of the fungus is not seen as it is underground or in decaying wood. The part we don’t see is the mycelium. The mycelium, and mushrooms, are made up of a network hair-like structures called hyphae. This past week Tony and I explored a new area in northern Wisconsin. On walks through the woods there were tons of different fungi around! I have never seen so many different colors, shapes, and species all at the same time. It seemed like every few feet there were fungi to be found. It was exciting to see what we could find! You might be surprised by some of the shapes and colors we came across, not your typical brown umbrella shaped mushrooms. Here is just a sampling of the fungi we found: Red Waxy Caps - (Hygrocybe spp.) Mushrooms often look different in their various stages of growth, sometimes making identification difficult. Yellow-Orange Waxy Caps - (Hygrocybe spp.) Violet Coral (a Worm Coral) - (Clavaria zollingeri) Coral Fungus There are various types of coral and false coral fungi. I'm not sure of the exact one, but I know it is a coral fungus. Mushrooms can be tricky to identify, so even just narrowing it down to a type can be satisfying. Ochre Jelly Club - (Leotia lubrica) Another name for these little mushrooms is Jelly Babies. Pear-Shaped Puffball - (Apioperdon pyriforme) Puffball mushrooms are well named since they release their spores in a "puff" when tapped. Watch my video below to see this mushroom in action. Mushrooms can be hard to identify, but also a fun challenge! They are interesting to learn about and as an added bonus have some fun and goofy names! Here are two of my favorite field guides for identifying mushrooms and learning more about fungi. Fascinating Fungi of the North Woods 2nd Edition By Cora Mollen and Larry Weber This book has awesome illustrations with useful and fun facts about the different fungi. I really like how this book is organized because it splits up the fungi into different groups based on where they grow and if they have gills or not, making it easy to find your mystery mushroom. It also has a handy chart for each fungus that shows when you'll most likely find it, breaking it down to the months of the year instead of just saying summer or fall. Mushrooms of the Upper Midwest 2nd Edition By Teresa Marrone and Kathy Yerich This guide has great full color pictures of the various fungi making ID easier. It has detailed descriptions and goes more in depth for various types and species of fungi. This one is organized by shape and if it has gills or pores, it also has a section about which fungi are popular edibles and which you should stay away from. Don't let the cooler weather and shorter days keep you from exploring! Head outside with your field guide and see what you can find! And keep checking back, mushrooms can appear and disappear quickly. A favorite trail may produce different fungi each time you're out and about. Joke of the Day Why does the mushroom get invited to all the parties? Because he's a Fungi! (Fun-guy) A few more of our fungi finds: |
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