Megan's Nature Nook
Nature Notes, Phenology, Photography, Fun Facts, Trips, Maybe Even a Bad Joke or Two... and More!
Winter and cold temperatures have finally hit us in Minnesota. Many birds (and some insects) migrate to escape the cold, other animals grow thick winter coats and adapt their diets to what is available, while others decide to skip the cold weather and just sleep through it. These tactics are all great ways to survive harsh winters, but did you know that some animals actually survive cold weather by freezing themselves and thawing out in the Spring? Usually freezing is not a good thing for living organisms - think frostbite. When ice forms, cells can be pierced by the growth of sharp ice crystals or the cell can rupture because of the expansion of fluids in the cell resulting in the death of the cell. Luckily some animals have special cryoprotectant (cryo = ice, cold, frost in Greek) substances in their tissue that protects the tissue from freezing and being damaged. Wood Frog Wood frogs (Lithobates sylvaticus) live in wooded areas and when cold weather approaches they bury themselves under leaf litter just under the surface of the soil. They can freeze up to 70% of their body including the brain and lenses of the eyes. Their heart completely stops, their breathing stops, and there is no muscle movement. Then in Spring when their body warms up, water will return to the cells and the frog returns to normal functions. They will repeat this process each year. How can they freeze and essentially cease to live for such a long time? Wood frogs have special nucleating proteins that suck most of the water out of their cells. The liver produces glucose (sugar) to fill the cells and prevents them from freezing solid and rupturing. This natural antifreeze protects their cells in cold weather. Woolly Bear Caterpillar Woolly Bear Caterpillars (Pyrrharctia isabella) are the larval stage of the Isabella Tiger Moth. These fuzzy black and brown caterpillars are usually seen in the fall as they search for their overwintering spots inside cavities, under leaves, rocks, logs, or bark. Their long “fur,” called setae, helps them to freeze more controllably. They produce a natural antifreeze called glycerol which keeps cells from fully freezing and bursting. Woolly Bear Caterpillars will spend winter in this mostly frozen state and will thaw in the Spring and make a cocoon, later emerging as a moth. These small yet mighty insects can survive down to -90°F! Painted Turtle Hatchling
Painted Turtles (Chrysemys picta) lay their eggs in early summer (June) and they hatch in late summer (August). Although many turtle hatchlings will emerge from the nest to start their new lives, some will overwinter as hatchlings underground in the nest. Environmental cues dictate whether the turtles should emerge or stay in the nest for winter. Painted Turtle hatchlings can do something called supercooling. They’re able to lower their body temperature to as low as 10°F without having their body fluids freeze. They’re able to do this because they don’t have Ice Nucleating Agents (INAs) internally. INAs are particles that an ice crystal can form around. So without INAs they can cool below freezing without ice forming and causing damage to the cells. It’s pretty amazing what each of these small creatures can do to survive our harsh winters! Animals have a variety of ways to help them survive winter, but I think freezing themselves and being able to thaw out in the spring is one of the most unique ways! As you bundle up to enjoy the great outdoors this winter, think of all the animal popsicles that may be hiding just out of sight awaiting the warmth of Spring.
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Earlier this summer, Tony came to visit me at the zoo and spotted a caterpillar hanging on the rock wall in a “J” formation. When you see a caterpillar in the “J” it means that it will be transforming into its chrysalis within the next 24 hours. This spiky caterpillar wasn’t one that we were familiar with, so we did some searching and found out that it was a Mourning Cloak caterpillar. As I was researching Mourning Cloaks, I found some interesting information about these butterflies! Mourning Cloak Butterflies (Nymphalis antiopa) can be found throughout the United States and most of Canada down to central Mexico. They’re not a very common species but can be seen throughout the warmer months. Mourning Cloak butterflies have a wingspan of 3-4 inches. Wings are dark, chocolate brown in the middle, with a yellow/cream color on the boarder. The wings are adorned with blue spots just inside the yellow edging of the wings. Both the fore and hind wings have rough edges with protruding parts of the wing. Caterpillars are black with spikes all over the body. They have light speckles throughout the body and rusty red spots along the back. Their lifecycle is similar to other butterflies. Adults mate in the spring and female butterflies lay eggs on host plants which include willow, cottonwood, aspen, birch, elm, hackberry, and other species of trees. They lay multiple eggs at a time, circling twigs of the plant. When the eggs hatch out after a few days to a few weeks, the caterpillars live in a communal web and feed on the plants. After three to four weeks of feeding and growing, it is time for the caterpillars to transform into a chrysalis where their metamorphosis into a butterfly will happen. They usually pupate and transform into butterflies in June or July. Adult butterflies feed on tree sap, fruit (especially rotting), and occasionally flower nectar. They’ll feed briefly after emerging from their chrysalis and then estivate until fall when they reemerge and feed to store energy for their winter hibernation. Estivation is when an animal spends a hot or dry period in extended dormancy. Some adults may migrate south to warmer weather in the fall instead of hibernating.
Mourning Cloak butterflies are a special species because they overwinter as adults. Most insects overwinter as eggs or larvae. Because of this, they’re one of the last butterflies we see in the fall, and one of the first we see in the spring. As temperatures cool in the fall, they find a protected area under bark, in a log, or a crevice of a building where they will spend the winter until temperatures reach about 60 degrees in the spring and they become active again. Then the cycle will start again, egg, caterpillar, butterfly. Mourning Cloak butterflies can live as long as 10 - 11 months, most butterfly species are a few weeks to a few months so they may be the longest-lived butterfly! 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!
Recently on a walk through the prairie I stopped to observe and admire some frothy, foamy bubbles perched on the stem of a plant. I’ve seen these bubbles before and referred to them as something from a Spittlebug. But what exactly are these bubbles? Why did this insect leave them on a plant? What is the purpose? What exactly is a “Spittlebug,” is that the real name? I had all these questions and wanted to learn more. My curiosity prompted me to do a little investigating and close observation to get to the bottom of what exactly a Spittlebug is and what these bubbles are all about. Spittlebugs are in fact insects; they are part of the superfamily Cercopoidea. There are 54 species in Minnesota, with the Meadow Spittlebug (Philaenus spumarius) being the most common. The Spittlebug is the nymph stage, basically like a teenager in the insect world, that will then transform into the adult stage called Froghoppers. The nymph Spittlebugs have soft bodies up to ¼ inch long. They change in color from orange to yellow to green as they grow and have large red eyes located on the side of their head. The nymphs live in frothy, foamy, bubble masses that can be up to ¾ inches in size. The adult stage, often called Froghoppers because of their large hind legs for jumping, are ¼ inch long starting green in color and changing to brown or gray. Adults are not often seen. Spittlebugs get their name from the bubble masses they produce that look like blobs of spit on the stem of plants. These bubble masses are not actually spit but are made from emitting air from the abdomen into their urine along with another fluid that stabilized the bubbles and makes them last longer. So, they aren’t really Spittlebugs, but more like Piddlebugs! (Not my joke, but I wish it was! Philip G. D. Matthews, a researcher in the zoology department at the University of British Columbia came up with this more fitting description). Spittlebugs produce 150 - 280 times their body weight in urine a day, which would be equivalent to a 150-pound human emitting 2,700 gallons of urine in a day! With that much urine, they have a good supply to make as many bubbles as needed! Some species can even produce as many as 80 bubbles a minute!
Spittlebugs don’t produce bubble masses just because they produce a good supply of urine. They create these bubble masses during their nymph stage to protect themselves. As nymphs, their bodies are soft, so the bubble mass creates an environment that stays humid enough to prevent them from drying out. It also protects them from temperature extremes. Lastly, the bubble mass helps to protect them from predators, not only keeping them hidden from potential predators such as other insects or birds, but the bubbles have a bitter taste deterring potential predators from eating them. Spittlebug bubble masses can be seen in spring and early summer as the nymphs are growing. Eventually they will encase themselves in one large bubble where they will transform into an adult. The adults will spread out hopping from plant to plant and looking for available food sources as some plants dry out. In September to October females will head back to where the nymphs were and will lay clusters of eggs in plant debris like leaves and stems. The eggs overwinter in the leaflitter and will hatch in late April to early May. The newly hatched nymphs feed at the base of plants, moving up as the plant matures. They will spend about a month or two in their bubble masses before transforming into adults. The adults will continue to feed the rest of the summer. There is only one generation of Spittlebugs a year. Both the nymphs and adults feed on plant sap. They feed on a variety of plants including grasses, weeds, and herbaceous plants, especially goldenrod. You can often find them in gardens feeding on roses, chrysanthemums, and Shasta daisies. They also like alfalfa, clover, and strawberries to name a few. Spittlebugs are generally not damaging to plants unless there are large populations in a small area. At times they can cause leaves to lose their shape but often are not a problem. If there are large populations you can spray the bubble mass with a steady stream of water, but it will only be a temporary fix as they will just produce more bubbles soon after. Who knew those little frothy, foamy, bubbles held so much information! Take a walk through you garden, local park, or a prairie in spring to early summer and see if you can spot any of these bubble masses! Take a close look, can you spot any nymphs inside?! I’m going to cut to the chase and just say, this book is amazing! Whether you’re an admirer of insects or categorize them as “creepy crawly,” this book is a must read! It will teach you more about insects and their many unique characteristics. It also explains all the different things insects do in our world, why we need them, and how to help them. You will gain a new appreciation for insects and all they do after reading this book. Anne Sverdrup-Thygeson the author of Buzz, Sting, Bite: Why We Need Insects is a professor at the Norwegian University of Life Sciences and knows her stuff. She does a great job of explaining insects and what they do in a way that is easy to understand. She covers many topics throughout the book, giving you a taste of the importance of insects without dwelling on a single topic. She also adds in humor and fun references along the way to keep you on your toes. For me this wasn’t a book where you sit down and read cover to cover in a short amount of time. Sverdrup-Thygeson covers a lot in this book so for me it was one of those books where you read a small section then have to digest what was all said before moving onto the next section. As I was reading, I had to keep stopping to tell whoever was around me what cool thing I had just read, so that may be why it took me longer to read, too! Not sure if this book is for you? (Trust me, it is). Do you like chocolate? Insects help pollinate the plant to make chocolate possible. Did you know you can remotely control a cockroach? They have been used to locate and rescue people in building collapses. Did you know some insects can eat plastic? This could help solve some of our plastic pollution problems. These topics are just a handful of the many interesting things Sverdrup-Thygeson covers in Buzz, Sting, Bite! Insects are small but mighty creatures that do some amazing things for us! Without insects our world truly would not be able to function. Insects do many things for us that often get overlooked. Not just out in the wilds of nature, but they are important in the medical world and are needed in order for us to have food. Insects are important in many ways and understanding them better will help you to foster an appreciation for all they do for us. Without them, we would not be able to continue living the way we do. I gave Buzz, Sting, Bite: Why We Need Insects 5 out of 5 stars on GoodReads rating it as “it was amazing.” I’m already wanting to reread it and will need to add it to my personal bookshelf! To learn more about the book, visit GoodReads by clicking the button below. This book was recently republished with the new title of Extraordinary Insects, but has the same great content! Whether you’re an insect lover or not, grab a copy and educate yourself on the importance of insects. You’ll be surprised at what you learn along the way and won’t look at insects the same way!
While out on a morning walk this little, or should I say big, guy almost got stepped on! This Giant Water Bug (Lethocerus americanus) was in the middle of the walking path near the parking lot of a department store. Why would a water bug be on a paved walking path far from any water sources? Giant Water Bugs also known as “toe-biters” or Electric Light Bugs are about 2 inches long and an inch wide with a four-inch wingspan. They’re easily identified by their large size, a giant pair of pinchers, and a characteristic large mouthpart called a proboscis that is used for piercing and sucking. They are in the insect order Hemiptera – the “true” bugs. Giant Water Bugs are usually found in slow moving water like ponds, lakes, or sloughs where they hunt for food and lay their eggs. They eat other aquatic insects, tadpoles, small fish, crustaceans, and even frogs, baby turtles, and small snakes! They are known as “ambush predators” who wait for their prey to cross their path, then grab it with their large pinchers bringing it to their sharp, piercing mouthpart. They will then pierce their prey and inject toxic digestive juices that immobilize the prey and liquifies their internal parts. After a few minutes the Giant Water Bug will then suck up the slurry for their meal. Some Giant Water Bug species will lay their eggs on the male’s back where he incubates and protects them. Other species will lay the eggs on vegetation in the water or near the water’s edge with the male nearby to protect and care for the eggs. Once the eggs hatch the nymphs look like small versions of the adults and will shed their skin multiple times as they grow and go through 5 different developmental stages eventually becoming an adult. As young, Giant Water Bugs breath oxygen through their skin, but as adults they have to breath air directly. In order to stay under water yet be able to breath, they have an appendage at the base of the abdomen (near the rear end) that acts like a snorkel. They can get air from above the surface of the water and store it as a bubble under their wings somewhat like a scuba tank. Insects don’t have lungs like mammals, but instead breath through a network of tiny tubes throughout their bodies called tracheae. The Giant Water Bug takes in air from under its wings through holes in the abdomen called spiracles and then it is distributed throughout the body through the tracheae. Since Giant Water Bugs breath air, they can easily leave the water and are often found flying around at night looking for new bodies of water or a mate. Unfortunately, artificial light sources like streetlights can easily disorient the insects and cause them to become stranded in unfavorable places like parking lots or streets because they get exhausted from flying around the light source. This is most likely what happened to the Giant Water Bug I found on the paved walking path. If you do happen to find a stranded Giant Water Bug, you can carefully pick it up and return it to a natural water source. Watch your fingers! Their bite can be excruciatingly painful. Giant Water Bugs aren’t the only wildlife affected by artificial lighting. Read my blog post “Lights Out for Wildlife - Save the Birds (And Fireflies)!” by clicking the button below. Even if you’re not a bug person, Giant Water Bugs are quite interesting! Not only are they interesting, but they’re important in the ecosystem. Giant Water Bugs are at the top of their food chain and help to keep other invertebrate populations in check. You can think of them as the wolves and cougars of the insect world. Not a fan of mosquitoes? Thank the Giant Water Bugs for helping to keep the mosquito population down (even if it still seems like there are too many of them)! Fun Fact: When frightened by large predators, like humans, the Giant Water Bug will play dead and may even ooze fluid from their back side to add to the drama. But beware, they may suddenly come to life and pierce the predator with their sharp proboscis! Here's a quick video of meal time for a Giant Water Bug! Thank you Tony Long for the pictures and videos used in this blog post! Each Spring and Fall millions of birds embark on the treacherous journey of migration. Over 250 songbird species migrate at night in an effort to make their journey a little easier. Traveling at night has some advantages such as calmer skies from less weather events at night, cooler temperatures, and the less likely chance of encountering raptors, like hawks and falcons, who migrate and hunt during the day. Although there are these advantages to night travel, it also comes with the dangers of light pollution that can cause disorientation, collisions, and undue exhaustion for the birds. Many birds use stars in the night sky to help them navigate their way. Tall lighted buildings can easily draw them off course and disorient the birds. Birds can end up colliding with buildings and windows causing injuries or death or circle the building reluctant to fly from the light resulting in exhaustion and even death. Cities with tall buildings are one of the main obstacles for birds, but even outdoor lighting from homes contributes to light pollution and can cause harm. This is where you can help! Something as easy as turning off the lights can make night migration safer for the birds. During peak migration from March 15 – May 31 and August 15 – October 31 turn off the lights from 11:00 p.m. – 6:00 a.m. Porch lights, outbuilding lighting along with lighted paths and decorative lighting should be turned off. If you are inside with the lights on, close the shades to prevent inside light from flooding outside. If you are unable to turn off all outdoor lighting, consider installing motion sensors or warm lighting and installing light shields so the light is only cast down, instead of all around which affects the birds more. Outdoor lighting is not only affecting migrating birds, but an array of other night dwelling animals. Firefly populations have been dwindling and a major cause is light pollution. Fireflies rely on finding their mates through seeing each other’s lighted blinking patterns. If an area is too bright from outdoor lighting or even indoor light coming through windows, they aren’t able to find their mates. They have a short window of time as adults so every dark minute counts. Consider extending your “Lights Out” time to the beginning of July to help the fireflies! Read more about fireflies from one of my previous blog posts by clicking the button below. There are a variety of “Lights Out” programs across the country through the Audubon Society and local nature centers in conjunction with government agencies. See if you can find one close to your home and pledge to turn the lights out. To learn more about the Audubon Society’s Lights Out program and to see a list of participating cities, visit their website by clicking the button below. For those of you in Minnesota interested in Lights Out Twin Cities (and Rochester) you can visit the Department of Natural Resources Nongame Wildlife Program Page to see a list of participating businesses, by clicking the button below. Turn off your lights and
Save Birds (And Fireflies). Save Energy. Save Money. It’s that easy and a win-win-win for everyone! Woolly Bear Caterpillars are known for being able to forecast what winter has in store. Will it be mild with little snow or frigid temps with plenty of snow to go around? You’re supposed to be able to predict winter by measuring the amount of brown and black on the caterpillar. Is this winter weather forecasting fact or folklore? Read on to learn more about these woolly little meteorologists! Woolly Bear Caterpillars are the larval stage of Tiger Moths. Most often we see the caterpillars of Isabella Tiger Moths (Pyrrharctia isabella). There are eight or more species of caterpillars in the United States that we could consider “Woolly Bears” because of their bristly, dense hair that covers their bodies. Most often we see the caterpillar species with both brown and black hair. You may see an all white or all black caterpillar – don’t worry those don’t mean winter is going to be crazy, they’re just a different species than our weather forecaster caterpillars. In the fall we tend to see Woolly Bear caterpillars more often. They are preparing for winter and are looking for an overwintering site inside cavities, under leaves, rocks, logs, or bark. There they will spend the winter in a caterpillar state whereas most caterpillars will overwinter in cocoons. The Woolly Bear is able to survive in the caterpillar stage because of its fur called setae. The fur helps them to freeze more controllably. They have a natural antifreeze called glycerol which keeps the cells from fully freezing and bursting. The caterpillar will spend its winter curled up and mostly frozen. In the spring it will thaw out and the Woolly Bear will spin a cocoon and later emerge as a moth. The Woolly Bears goes through two generations each year. The second generation in its caterpillar form are the ones we tend to notice as they travel to their wintering spots. Woolly Bear caterpillars have 13 body segments, or bands. It is said that by counting the amount of brown and black bands you can predict what the upcoming winter will be like. Wide brown section = mild winter More black there is = the more severe the winter – longer, colder, snowier The position of the largest black section is supposed to predict which part of winter will be the worst. Head = Beginning will be severe Tail = End of winter will be cold The 13 segments are supposed to correspond with the 13 weeks of winter. Dr. Charles Howard Curran, insect curator at the American Museum of Natural History in New York City, tested this theory from 1948 – 1956. Each fall he and his wife along with some colleagues and friends would go to Bear Mountain State Park to collect caterpillars, count bands, and determine the average number of brown bands. They called themselves The Original Society of the Friends of the Woolly Bear. After their trip, Dr. Curran would forecast the coming winter weather, as predicted by the Woolly Bears, to The New York Herald Tribune. This publicity made the Woolly Bear one of the most recognizable caterpillars. Dr. Curran’s eight years of sampling was a small data set and not enough to scientifically prove that Woolly Bears could predict the upcoming winter. Although he couldn’t scientifically prove it, Dr. Curran thought the folklore had some merit and might be true. Woolly Bears may not be able to predict the upcoming winter, but their bands do tell somethings. Instead of predicting the upcoming winter, their bands tell you about the previous year. The amount of brown and black coincide with the age of the caterpillar (how long the growing season was) and moisture levels where the Woolly Bear was growing. Because of this, the Woolly Bears will look different from year to year but they’re telling you about the weather that has already happened, not predicting the upcoming winter. Even though they can’t tell us what the upcoming winter has in store, we can still look forward to seeing them in the fall as they cross our paths on the way to their winter homes. These little caterpillars have quite the story behind them! Since the caterpillars couldn’t tell us what is predicted for winter, here is what The Old Farmer’s Almanac is predicting for winter 2019-2020. Fun Fact:
Woolly Bear caterpillars can survive a temperature as low as -90°F Other names: Woolly Worm, Fuzzy Worm, Fuzzy Bear, Woolly Bear, Hedgehog Caterpillar – because it curls up into a ball when picked up. Festivals: There are many festivals to celebrate the Woolly Bear Caterpillar, some have been going on for many years while others are newer. Many of these festivals include parades, Woolly Bear races, and “official” winter weather predictions. Woollybear Festival in Vermilion, Ohio (1973) Beattyville, Kentucky (1987) Lewisburg, Pennsylvania (1997) Woolly Worm Festival held in Banner Elk, North Carolina (2009) Oil City, Pennsylvania (2008) Lion’s Head, Ontario (2011) The Nature Museum at Bear Mountain State Park started the annual Woolly Bear count 30 years after Curran’s counts ended and continues on today. These little creatures have made quite the impact! As a student in college and an intern at a Wildlife Refuge I have had the opportunity to help with tagging Monarch butterflies (Danaus plexippus). Before participating in tagging I didn’t know much about what it was or what it entailed. Through those experience I was able to learn more about the importance of Monarchs, their population decline, and how tagging can help us learn more about them. This summer I have been helping to tag Monarchs at Oxbow Park & Zollman Zoo where I work seasonally as a Naturalist. It is the first year we have done it and are excited to see how many of our tagged Monarchs make it to Mexico! Migration Did you know that Monarch Butterflies are Minnesota’s state insect? One of the reasons they earned this title is because of their great migration! Each year in the fall, signaled by photoperiod (shortening of daylength), Monarchs make the 2,500 mile journey south to Mexico where they overwinter. It can take up to two months to complete this journey! Population Monarch populations have been on the decline for a number of reasons. Habitat destruction, increased use of herbicides and pesticides, removal of milkweed, and vehicle collisions have contributed to the decline in summer breeding areas and during migration. Monarch tagging helps to monitor the population numbers and to measure the success of conservation efforts using data collected by citizens in a number of locations across North America. Monarch Tagging What is Monarch tagging? Monarch tagging is a non-invasive way of marking Monarchs to tell them apart. The tags are very small stickers that have a unique letter and number combination. The stickers are placed on the discal cell (which looks like a mitten) of the Monarch’s lower wing and do not affect their flight. The process of tagging Monarchs is very easy, sometimes the hardest part is catching the butterflies! Wandering through the prairie or near a flower garden with an insect net is the best way to find and catch Monarchs. Once they are netted you can safely hold them by holding near the body with your thumb and pointer finger to hold all wings together. This keeps them from flying off or injuring a wing. Before we put the tag on, we collect and record data: the tag code, date, sex, if it is wild or reared, and tagging location. This data is then submitted to an online database. Once the tag is firmly placed, the Monarch can be released and sent on their way with warm wishes of safe travels. Migration Each summer there are usually three to four generations of Monarchs and we want to tag the last generation, the ones heading to Mexico to overwinter. It is usually the fourth generation that we tag but could be the third or fifth. Weather and latitude can affect how many generations there are in a summer. The “last generation” doesn’t matter what number generation it is, but rather the time of year it is. The last generation will migrate down to Mexico and roost in the oyamel fir trees for many months. In the spring the Monarchs will leave Mexico to the southern parts of the United States where they will mate, lay eggs, hatch into caterpillars, then metamorphosize into butterflies. Those adults will then move northward as Milkweed begins to bloom and continue the lifecycle process. Here in Minnesota we usually see the third and fourth generations. Some butterflies may even travel farther north into Canada. Since we are only wanting to tag the last generation, it is important to know when the peak migration time is in your area, so you know when to begin tagging. *When talking about migration I am referring to the Monarch populations East of the Rocky Mountains. Populations West of the Rocky Mountains may either overwinter in California or Mexico. Tag Recovery Tagged Monarchs can be reported by anyone who sees them, whether they are alive or dead. Each tag has the website where to report sightings to. Our hopes are that the Monarchs make it all the way to Mexico! Monarch Watch, the organization where we ordered our tags from, hires locales to recover tags from the wintering grounds in Mexico. Any that are found are reported to an online database. In the winter you can check the tag codes of the Monarchs you tagged and see if they were recovered. How You Can Help Monarchs If you are interested in helping with Monarch research, you can become a Monarch tagger! You do not have to be part of a Zoo, Nature Center, or State Park to tag Monarchs, but can do it on your own as a Citizen Scientist. All you have to do is order your tagging kit in the spring or early summer so there is time for it to be shipped before tagging begins. We went through Monarch Watch but there are other organizations that participate in tagging. A kit with 25 tags cost $15.00, the money going towards tag recovery efforts. Other ways to help Monarchs include creating Monarch (and other butterfly) friendly habitat. Plant milkweed for caterpillars and other flowers for nectar, especially native plants and ones that bloom into late summer/fall. Offer an area for “puddling” where butterflies can get minerals and other nutrients from sand and mud. An easy way to do this is fill a shallow dish with sand and keep it moist so they can easily puddle there. Providing large rocks where butterflies can sun bathe and warm themselves is another easy way to attract butterflies to your garden. The migration journey is a pretty amazing feat for such a small and light creature. It is amazing to think that what they do is just a force of nature. Unlike other animals like birds that have others to show them the way, the Monarchs just know what to do. The migrating ones are the great-grandchildren of the original Mexico migrators who made the journey the year before. Nature never ceases to amaze me! Monarch Facts:
If you’ve been outside the past few weeks you’ve probably noticed a buzzing sound coming from the trees that sounds like a high-pitched, far off chainsaw. No, it’s not your neighbors down the road doing some yard maintenance, but instead, cicadas singing away! Cicadas are insects ¾ - 2 ¼ inches long varying in color from black, brown, or green with red, white, or blue eyes. Cicadas are only found in the eastern half of the United States and make their appearance late June through August. They’re known for the loud noise they make, which is mostly males singing to attract females. Each species has their own unique song. To make their unique buzzing sound, cicadas vibrate the tymbals, which are drum-like organs in their abdomen, and the sound resonates in their mostly hollow abdomen. Some cicadas can be heard up to a mile away! The loudest cicada in North America is the Megatibicen pronotalis walker whose song can reach 105.9 decibels. For comparison, a snowmobile or motorcycle are measured at 100 decibels. Cicadas have a very interesting life cycle. After mating, females will lay around 20 rice-shaped eggs in a groove that she made in a tree limb. The eggs will hatch in 6-10 weeks and the young, or nymphs, will crawl from the groove and fall to the ground. They will then dig into the ground to find roots and feed on tree fluids in the roots. The nymphs spend 2-17 years underground, depending on their species. They will go through five growth cycles; each stage called an instar. After 2-17 years the nymphs will emerge from the ground and climb to the nearest tree. There it will shed its exoskeleton, its wings will inflate, and the adult skin will harden. Adults live for 2-6 weeks and spend their time in trees looking for mates. There are three different life cycle types for cicadas:
Annual – emerge every year Periodical – all emerge together after long periods of time, some up to 17 years! Proto-periodical – may emerge every year, every few years emerge in large numbers Cicada Fun Facts:
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