Plummeting number of monarch butterflies in Texas need your help. Here’s how.
By Dalia Faheid
July 27, 2022
July 27, 2022
The monarch butterfly, state insect of Texas, has been rapidly declining in number over the last 20 years, going down by 95% according to some estimates.
Every spring and fall, millions of monarch butterflies come to Texas on their way to and from Mexico. Monarchs pass through Texas each fall on their way from Canada to Mexico, where they spend the winter. Texans start seeing monarchs in August, then peak migration happens in early October. They get to Mexico in early November, before heading north and returning to Texas in March to look for milkweeds and lay eggs. “Overall numbers of monarch butterflies in Mexico are declining,” said Carol Clark, Monarch Watch conservation specialist for North Texas. “What happens to monarchs in Texas affects that overall population number.” On July 21, the International Union for the Conservation of Nature put the migratory monarch butterfly on the endangered species list, saying the population has shrunk by between 22% and 72% over the past decade. The western population is at greatest risk of extinction, IUCN said, having declined from as many as 10 million to 1,914 butterflies between the 1980s and 2021. The larger eastern population also shrunk by 84% from 1996 to 2014. In 2020, Texas A&M noted that migration numbers were down to about 141.5 million, compared to 300 million in 2019. And in 2021, they dwindled down to an estimated 105 million. This year, it’s possible that we’ll see even smaller numbers of monarch butterflies fly through the state. That’s because they’re threatened by habitat loss, pesticide use, increase in disease and loss of milkweeds and nectar plants in landscapes where they used to grow. “There is some information coming from the North that people are seeing monarchs later and in fewer numbers, but lots of factors play into those final migratory numbers and there’s still time for monarchs to do well,” Clark said. “A lot of it will depend on weather in many different parts of the country, and so that is a little bit hard to predict at this point.” Once they pass through Texas this fall, the drought could make conditions worse for the insects. “When it stays dry for the fall migration, then monarchs cannot fatten up as they pass through Texas, which they need to do, they won’t have enough fat stores to get through the winter in Mexico,” Clark said. “So if the drought persists into fall, we won’t have the wildflowers that they need to fatten up on the way to Mexico.” How to help monarch butterfliesThere are a few simple ways you can make an immediate difference for the monarchs, including reducing pesticide use and increasing habitats. The best part — you’ll have your own butterfly garden to marvel at the brightly colored insects. “You can’t wait for the government to do something, it will be too late,” Clark said. “If we manage to save the monarch migration, it’s going to be through individual action, people acting on any size piece of land they have influence over and simply planting wildflowers for nectar and native milkweeds.” In the spring, monarchs need milkweeds to lay their eggs on and nectar plants for energy. If they don’t have that, the monarchs can’t breed and fly north, Clark said. In the fall, they need nectar plants for their journey to Mexico. You don’t have to be a master gardener to help save the iconic butterflies. Putting out a pot on your balcony or yard with a milkweed and a nectar plant should do the trick, Clark says. To step it up a notch if you have more outdoor space for gardening, you can plant several types of nectar plants along with native milkweeds. Texas Parks and Wildlife suggests the following nectar plants for a butterfly garden:
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“If Texas doesn’t do its part, then the cycle is broken, and the monarchs really have trouble continuing,” Clark said. “Just watering a little home patch of flowers turns out to be really important in a dry fall, where there may not be so many flowers in the landscape.”
Where to see monarch butterflies in TexasCelebrate the arrival of the rare monarch butterflies to Texas with butterfly gardens, butterfly releases, festivals and educational programming. “The monarch butterfly is as beautiful and memorable as a Texas sunset, soaring above all other insects in its nobility and determination, and its unique relationship with Texas makes it a truly appropriate symbol of the majestic spirit of the Lone Star State,” the state legislature wrote when it designated the monarch the state insect on June 16, 1995. Native Texas Butterfly House & Garden WHERE: Heard Natural Science Museum & Wildlife Sanctuary — 1 Nature Place, McKinney WHEN: Saturday, June 4 - Sunday, Oct. 2 PRICE: Included in general admission, free for Heard Museum members, buy at heardmuseum.org/tickets/ From June to October, Native Texas Butterfly House and Garden visitors can walk among native butterflies and other pollinators. You’ll be able to get a closeup look at them while learning about their life stages and other fun facts, and you may even witness a butterfly emerge from its chrysalis. Visitors are also able to feed nectar plants to the butterflies and host plants to the caterpillars. Monarch Celebration WHERE: Wildseed Farms — 100 Legacy Dr, Fredericksburg WHEN: Oct. 8 from 9:30 a.m. to 2:30 p.m. PRICE: Free Wildseed Farms is a wildflower farm that has been growing fields of wildflowers for over 35 years. It’s the nation’s largest working wildflower farm, with over 200 acres in Fredericksburg alone. In October, the farm will be celebrating the monarch migration with a tagging demonstration and release. Monarch Butterfly and Pollinator Festival WHERE: Brackenridge Park — 3910 N. St. Mary’s, San Antonio WHEN: Saturday, Oct. 8, 10 a.m. – 2 p.m. PRICE: Free The Monarch Butterfly and Pollinator Festival takes flight in October as migrating monarch butterflies move through the state. The seventh annual festival starts with a parade, followed by tagging monarch butterflies in honor of loved ones, waggle dancing, and maneuvering a monarch migration obstacle course. If you’d like to tag a butterfly in honor of a friend, family member or loved one, details are provided online. Butterfly Flutterby WHERE: Grapevine Botanical Gardens at Heritage Park WHEN: Saturday, Oct. 15, 10 a.m. - 2 p.m. PRICE: Entrance is free. Some vendor activities or food services may have a fee. Bring your entire family to celebrate the monarch butterfly migration at the 25th Annual Butterfly Flutterby in Grapevine. It all starts with a parade, where prizes will be awarded to the kids and pets with the best costumes. You can also take part in a live monarch butterfly release, and learn about them with a hands-on exhibit and storytime. Stop by the arts and crafts station to make a pet bandana, pom pom caterpillar or handprinted butterfly on a stick. Lastly, browse an art gallery showcasing kindergarten through fifth grader artists from the Grapevine/Colleyville Independent School District, and a display with over 300 butterflies from around the world. Texas Butterfly Festival WHERE: National Butterfly Center — 3333 Butterfly Park, Mission WHEN: Oct. 29 to Nov. 1 PRICE: $355 per member and $395 for non-members The National Butterfly Center is a 100-acre native plant botanical garden and wildlife preserve established by the North American Butterfly Association to advance its mission of education and conservation. The center will be hosting the 26th Annual Texas Butterfly Festival, a three-day event where attendees can expect to see more than 60 butterfly species in a day. |
Monarch Migration
2022
Each fall, North American monarchs travel from their summer breeding grounds to overwintering locations. East of the Rocky Mountains, monarchs travel up to an astonishing 3,000 miles to central Mexico, whereas the shorter migration west of the Rockies is to the California coast. There is evidence of some interchange between the eastern and western populations, perhaps when individuals cross the Rocky Mountains, when butterflies fly from the western U.S. to the Mexican wintering sites, or butterflies from the Mexican sites fly into the western U.S
INTERACTIVE MONARCH MIGRATION
Go to full screen version This map was created in collaboration with the Center for Global Environmental Education at Hamline University with generous support from U.S. Forest Service - International Programs, U.S. Fish and Wildlife Service, and the Missouri Department of Conservation. Click on the seasons on the right for an interactive view of the monarchs' annual migration. When each animation is finished, click on the butterfly to learn more with videos and slide shows. EASTERN MONARCHS Decreasing day length and temperatures, along with aging milkweed and fewer nectar sources trigger a change in monarchs; this change signifies the beginning of the migratory generation. Unlike summer generations that live for two to six weeks as adults, adults in the migratory generation can live for up to nine months. Most monarch butterflies that emerge after about mid August in the eastern U.S. enter reproductive diapause (do not reproduce) and begin to migrate south in search of the overwintering grounds where they have never been before. From across the eastern U.S. and southern Canada, monarchs funnel toward Mexico. Along the way, they find refuge in stopover sites with abundant nectar sources and shelter from harsh weather. Upon reaching their destination in central Mexico beginning in early November, monarchs aggregate in oyamel fir trees on south-southwest facing mountain slopes. These locations provide cool temperatures, water, and adequate shelter to protect them from predators and allow them to conserve enough energy to survive winter. In March, this generation begins the journey north into Texas and southern states, laying eggs and nectaring as they migrate and breed. The first generation offspring from the overwintering population continue the journey from the southern U.S. to recolonize the eastern breeding grounds, migrating north through the central latitudes in approximately late April through May. Second and third generations populate the breeding grounds throughout the summer. It is generally the fourth generation that begins where we started this paragraph, migrating through the central and southern U.S. and northern Mexico to the wintering sites in central Mexico. WESTERN MONARCHS In any given year, adult monarchs west of the Rocky Mountains leave overwintering sites along the California coast (with a small number of sites in Baja California and Arizona) in February and March and head inland in search of milkweed on which to deposit their eggs. Once first-generation monarch eggs reach adulthood, they disperse east across the Central Valley and north across most of the western states. Second- and third-generation monarchs live and die throughout spring and summer, generally staying in the same areas where they hatched. The fourth generation (along with late bloomers from the third generation) emerges in late summer to fall. This migratory generation lives 6-9 months, compared to the 2-5 weeks of |
earlier generations. Western migratory monarchs also differ biologically from non-migratory generations; they are in a state of fourth to fifth generation of North American monarch migrates. Therefore, it is certain that monarchs rely on their instincts rather than learning to find overwintering sites. What kind of instincts might they rely on? Other animals use celestial cues (the sun, moon, or stars), the earth’s magnetic field, landmarks (mountain ranges or bodies of water), polarized light, infra-red energy perception, or some combination of these cues. Of these, the first two are considered to be the most likely cues that monarchs use, and consequently have been studied the most.
Sun Compass: Since monarchs migrate during the day, the sun is the celestial cue most likely to be useful in pointing the way to the overwintering sites. This proposed mechanism is called a sun compass. Monarchs may use the angle of the sun along the horizon in combination with an internal body clock (like a circadian rhythm) to maintain a southwesterly flight path. The way this would work is illustrated below. For example, if a monarch’s internal clock reads 10:00 AM, then the monarch will fly to the west of the sun to maintain a southern flight direction. When the monarch’s internal clock reads noon (12:00 PM), the monarch’s instincts tell it to fly straight toward the sun, while later in the day the monarch’s instincts tell it to fly to the east of the sun. |
However, this would have to be combined with the use of some other kind of cue. If all the monarchs in eastern and central North America maintained a southwesterly flight, they could never all end up in the same place. It has been proposed that mountain ranges are important landmarks used by monarchs during their migration. For example, when eastern monarchs encounter a mountain range, their instincts might tell them to turn south and follow the mountain range. This kind of instinct would serve to funnel monarchs from the entire eastern half of North America to a fairly small region in the mountains of central Mexico.
Magnetic Compass: Scientists have suggested that monarchs may use a magnetic compass to orient, possibly in addition to a sun compass or as a “back-up” orientation guide on cloudy days when they cannot see the sun. Studies of migratory birds have indicated that they register the angle made by the earth’s magnetic field and the surface of the earth. These angles point south in the Northern Hemisphere and north in the Southern Hemisphere. James Kanz (1977) conducted experiments to test the orientation of migratory monarchs held in cylindrical flight chambers. He reported that the monarchs flew in southwesterly directions on sunny days, but flew in random directions on cloudy days. He concluded that monarchs primarily use the sun to orient, and that magnetic orientation was unlikely, since the monarchs did not appear to be able to orient when they could not use the sun. However, Klaus Scmidt-Koenig (1985) reported conflicting evidence. He recorded the vanishing bearings (the direction in which a monarch disappears from sight) of wild, migratory monarchs, and found that even on cloudy days, most monarchs still flew in a southwesterly direction. Scientists attempted additional tests of magnetic orientation, but were not able to determine whether monarchs use the Earth’s magnetic field to orient. However, researchers from the Reppert Lab (2014) showed that migratory monarchs indeed possess a magnetic compass that aids |
in orienting migrants south towards their overwintering grounds during fall migration. Remarkably, the use of the magnetic compass requires short wave UV-light (previous magnetic compass experiments failed to account for light at this range). With UV-light being allowed to enter the flight simulator, eastern migratory monarchs consistently oriented themselves south. The light-sensitive magnetosensors reside in the adult monarch’s antennae. While the expert consensus remains that the sun compass is the monarch’s primary compass for navigation, the authors suggest migratory monarchs use the magnetic compass to augment their sun compass.
Genetics: Upon dispersal, the Central and South American, Atlantic, and Pacific populations lost the ability to migrate. This prompted researchers to identify the gene regions in North American monarchs that appeared highly differentiated from non-migratory populations. Kronforst et al. (2014) identified 536 genes significantly associated with migration. One single genomic segment appeared to be divergent in the non-migrating populations and was extremely different from the North American population. One gene, collagen IV alpha-1, showed high divergence between migrating and non-migrating populations. Collagen IV alpha-1 is an important gene for muscle function, and divergence of this gene implicates selection for different flight muscles between migrating and non-migrating populations. Surprisingly, Collagen IV alpha-1 was down regulated in migratory monarchs, perhaps preparing them for lengthy flights. Furthermore, migrating monarchs had low metabolic rates compared to non-migrants as a consequence of flight muscle performance, lowering energy expenditure in migrating monarchs muscles. This evidence led researchers to conclude that changes in muscle function afforded migrating monarchs the ability to fly farther and use their energy more efficiently. Dr. Kronforst used the analogy of a marathon runner vs. a sprinter, "Migrating butterflies are essentially endurance athletes, while others are sprinters. |
Monarch Life Cycle
ANNUAL LIFE CYCLE
The monarchs that spend the winter in the mountains of central Mexico are the final generation of a cycle that begins anew each year. Most of the butterflies in this final generation begin their lives in the northern US or southern Canada, and then migrate thousands of kilometers to mountaintops that neither they nor their parents (and likely their grandparents) have ever seen before.
After spending several months in Mexico they return north beginning in March, starting the cycle again as they lay eggs in northern Mexico and the southern US. Their parents, grandparents, and great-grandparents have very different lives. These summer monarchs live only about a month as adults and begin laying eggs when they are only a few days old.
In most years, the total number of monarchs probably increases with each generation. Because the winter generation must live for such a long time before reproducing, the entire population shrinks as some of these individuals die during the fall migration and overwintering period. The population then grows over the spring and summer.
The monarchs that spend the winter in the mountains of central Mexico are the final generation of a cycle that begins anew each year. Most of the butterflies in this final generation begin their lives in the northern US or southern Canada, and then migrate thousands of kilometers to mountaintops that neither they nor their parents (and likely their grandparents) have ever seen before.
After spending several months in Mexico they return north beginning in March, starting the cycle again as they lay eggs in northern Mexico and the southern US. Their parents, grandparents, and great-grandparents have very different lives. These summer monarchs live only about a month as adults and begin laying eggs when they are only a few days old.
In most years, the total number of monarchs probably increases with each generation. Because the winter generation must live for such a long time before reproducing, the entire population shrinks as some of these individuals die during the fall migration and overwintering period. The population then grows over the spring and summer.
GENERATION 1
Monarchs in Generation 1 are the offspring of the monarchs that overwinter. They are laid from late March through April in the southern United States and northern Mexico, and fly north as adults. They do not undergo reproductive diapause. Life Cycle Summary The first monarch generation of the year begins when females that have spent the winter in Mexico lay eggs in northern Mexico and the southern U.S. beginning in late March. The last eggs are laid in late April or early May, farther north. Since it is often cool when Generation 1 larvae are developing, it may take them up to 40 or 50 days, or even more, to develop from eggs to adults. Generation 1 adults emerge from late April to early June. They mate and begin to lay eggs about four days after emerging, and continue the journey north that their parents began, laying eggs along the way. They begin to arrive in the northern US and southern Canada in late May.
Like all monarchs, this generation begins life on plants in the genus Asclepias, these are species of milkweed. The most important host plants for Generation 1 monarchs in the southern US are Asclepias oenotheroides, A. viridis and A. asperula.
GENERATION 2 Monarchs in Generation 2 are the grandchildren of the overwintering monarchs. They are laid throughout much of eastern North America from late April through June. They do not undergo reproductive diapause. Life Cycle Summary Generation 2 larvae are widely distributed throughout the eastern United States, first beginning to appear in the south in early May, and in the north in mid to late May. Eggs that become generation 2 may be laid as late as July in the north. These larvae also eat milkweed species; a few of the main species that they use include A. syriaca (common milkweed), A. incarnata (swamp milkweed), and A. tuberosa (butterfly milkweed). Generation 2 adults emerge in June and July, and mate and lay eggs soon after emerging. Most of those that begin their lives in
the south move north as adults, since the southern summers are too hot and dry for their offspring. Those laid farther north probably do not move far, and can use all of their energy to produce as many offspring as possible. |
GENERATIONS 3 & 4
Monarchs in Generations 3 and 4 are the great- and great-great grandchildren of the overwintering monarchs. They are laid throughout the northern part of the range of eastern migratory monarchs from late May through July (Generation 3), and late June through August (Generation 4). Some generation 3 individuals emerge early enough to reproduce in the northern part of their breeding range or after moving south (see immature distribution map). However, Generation 3 individuals that emerge late in August will undergo diapause and migrate to Mexico, as will most Generation 4 individuals. Life Cycle Summary Generations 3 and 4 monarch eggs are laid throughout the northern part of their range in July and August. Some adults move south in late July and August, and may lay eggs as late as October in the southern part of the US. Some generation 3 monarchs emerge early enough to produce another summer generation. But those that emerge later are different from other monarchs in two important ways. First, they will migrate to and from the overwintering sites in Mexico. Second, they do not reproduce right after they emerge. In response to decreasing temperatures and shortening day lengths at the end of the summer, their reproductive organs remain in an immature state. Instead of mating and laying eggs, they spend their time drinking nectar and clustering together in nighttime roosts in preparation for their long journey south. This delayed maturity is called diapause. Most of the monarchs will remain in this condition until the following spring, when they begin to mate in the overwintering colonies.
During September, October, and early November, migratory adults fly to overwintering sites in central Mexico, where they remain from November to March. In March, they begin to journey north, laying the eggs that will become the new Generation 1 along the way.
MONARCHS AND MILKWEED In early spring, as Monarchs move north through the Texas funnel, they need milkweed on which to lay the first generation of eggs. They continue to need milkweed through the summer as subsequent generations reproduce as they move north. Milkweeds including Common milkweed (Asclepius syriaca), Swamp milkweed (A. incarnata), Poke milkweed (A. exaltata), Purple milkweed (A. purpurascens), Butterfly milkweed (A. Tuberosa), Prairie milkweed (Asclepias hirtella), Whorled milkweed (Asclepias verticillata) and Short green milkweed (A. viridiflora) are some of the milkweed host plants Monarch butterfly depend upon. MONARCHS AND FLORAL NECTAR Monarch butterflies need floral nectar in the springtime to fuel migration and reproduction. The rate at which spring-blooming flowers develop is largely temperature-dependent; flowers bloom earlier in a spring with warmer temperatures. Because adult monarchs are generalists, they are able to eat nectar from a wide variety of spring flowers. This fact gives them some flexibility. In contrast, monarch larvae are specialists; they can only eat milkweed. The need for milkweed may determine when and where monarchs travel because even though adult butterflies don’t depend on milkweed, their offspring do. But in the fall when the monarchs are heading south, they don’t need milkweed since they enter their reproductive diapause, a temporary stage in which they postpone sexual activities and save their energy to migrate to Mexico. At this point, they need water, ample nectar sources, trees or other protection at night for roosting, and connected habitats. |
Conserving the Magic of the Monarch Migration
Conservando la Magia de la Migración Monarca
MONARCH FUN FACTS
Click HERE to download a 2 page sheet of fun facts about the monarchs that you can print double-sided and have a handout to share information about the monarchs with others. A more detailed description of the monarchs is found below and a video explaining monarch butterfly biology – life cycle, nutrition and habitat needs, and migration patterns – as well as the environmental threats faced by monarchs, and the conservation measures being taken to support their survival given by MBF board member and Director of the UW-Madison Arboretum, Dr. Karen Oberhauser, is found HERE. MONARCH LIFE CYCLE The life of a monarch begins when a female monarch lays an egg, usually on the underside of a milkweed leaf. The egg hatches after 3-5 days to reveal a very small larva (caterpillar). Over a period of 9-15 days, the larva increases its body mass about 2,000 times as it grows and molts (sheds its skin) five times to allow for the rapid increase in size. The period between each molt is called an instar; monarch larvae undergo five instars, so the largest caterpillars are fifth instar larvae. Each larva then pupates and spends another 9-14 days as a chrysalis or pupa. When fully developed, an adult butterfly emerges from the pupa casing. It pumps fluid from its abdomen into its wings, and in a short time the wings dry and harden. The new monarch then flies to nectar and soon mates. If it is a female it starts laying eggs.
Breeding monarchs may live two to five weeks. The development time of eggs, larvae, and pupae depend on temperature. Cool or very hot conditions result in longer development times. The survival rates of the immatures are low, with less than 5% surviving to become fifth instars. A variety of predators, including ants, spiders, true bugs, beetles, and lacewing larvae cause much of this mortality. THE JOURNEY NORTH Each spring, the first monarchs arrive in northern U.S. states and southern Canada shortly after milkweeds first appear. These first monarchs in the northern breeding range come from eggs laid by females who likely spent the winter in Mexico and flew to find milkweed in northern Mexico and the southeastern United States (like Texas, Louisiana, and Florida) and to a lesser extent the western United States. They use their last bit of energy after the long winter to begin the migration and reproduce. We often think of these first monarchs we see in late spring as the first summer generation of the new year. A similar spring migration occurs in the west from the California coastal overwintering sites.
SUMMER BREEDING The first summer generation monarchs mate, lay eggs, and die. Their eggs start the cycle over again, hatching, growing, pupating, emerging, mating, laying eggs, and dying, living up to 6 weeks. Each of three to four summer generations continues this cycle.
THE JOURNEY SOUTH Monarchs that emerge as adults at the end of the summer are different because they aren’t adapted to survive freezing temperatures. Instead, this generation of monarchs undergoes the same life cycle as the generations before them until they are adults. Then their life is different from all other broods. Instead of mating and laying eggs, they put all of their energy into migrating to a climate in which they can survive until springtime.
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We call these monarchs the migrating generation. Migration allows them to stay alive until the next spring when they can fly north and begin laying eggs.
The fall migration is key to the success of the monarchs’ annual life cycle. Fall monarchs look like other monarchs. They are physiologically different, however, emerging from the pupa in a state called reproductive diapause. Diapause is a period of suspended development produced by changes in their hormonal levels; fall individuals do not have the mature internal sex organs (testes and ovaries) that the summer generations have. A variety of signals from nature combine to induce this diapause condition, including shortening day length, changes in temperature between day and night, and even the age of the milkweed plants that they had eaten as larvae. Beginning in late August and continuing through September and October, these individual monarchs fly up to 2,000 miles south to the Transvolcanic mountain range of central Mexico. They drink nectar and conserve energy, catching warm air currents blowing to the south that allow them to soar instead of using powered flight as they go. WINTERING IN MEXICO In Mexico, monarchs find the south-facing slopes of high mountains and settle on branches and trunks of oyamel fir trees, forming dense clusters. The low temperatures allow them to go into torpor (very similar to hibernation, only not as deep as “sleep”). This way, they can conserve their energy until warmer spring weather returns.
Monarchs that pass the winter in the mountains of central Mexico are the final generation each year. After spending several months in Mexico (from early November until March), warm, lengthening days signal that it’s time to become active again. A NEW CYCLE BEGINS In late February and March, monarchs end reproductive diapause, becoming ready to mate and lay eggs as they move northward. Once they become reproductively active, they live only another few weeks. Their eggs then mark the start of another annual life cycle, as the first summer generation of monarchs is born again. Unlike the summer generations, which live for 2-6 weeks as adults, the overwintering generation of butterflies lives 7-9 months – surviving a long southward migration, several months in Mexico, and a northward migration back into the southern United States.
The first generation of monarchs, followed by three to four summer generations, and a final fall migrating/overwintering generation together comprise the annual life cycle of the monarch species. Monarch butterflies have evolved to live this way, with special adaptations that allow them to survive seasonal changes to their habitats. Nectar plants, milkweed, water, and the oyamel fir forests in Mexico are all crucial to continue this annual life cycle. Monarchs compete with human needs for land and resources wherever they are. Efforts to provide suitable habitat for monarchs are linked to supporting the needs of the local residents who have shared the same region with the butterflies for many generations. Supporting the monarch life cycle is difficult, but it can be done, and MBF works to meet this challenge. Much more information about monarch biology and conservation can be found in the 2016 Monarch Conservation Implementation Plan. |
Déjà Vu: Is 2022’s Dry Spring Setting Stage for Another Texas Drought like 2011
By Monika Maeckle
April 18th, 2022
April 18th, 2022
It’s feeling a lot like the spring of 2011. No rain, lots of wind, absent wildflowers, myriad wildfires and burn bans, and early enactment of landscape watering restrictions.
Many Texas cities, including San Antonio, utilize landscape watering restrictions to conserve water in hot, dry climates. The City of San Antonio announced Stage 2 watering restrictions effective April 13. That means homeowners can water their landscapes once a week between certain hours. “It has been extraordinarily dry, the start of 2022,” said Karen Guz, Director of Water Conservation at San Antonio Water System (SAWS). “It’s hard to say what comes next.”
She added that in San Antonio, residents are likely to remain in some level of watering restrictions throughout the summer. In the Texas Hill Country, the Llano River is flowing low. Some reports cite a stream flow of 35% below average. The following message greets callers to Llano River Region Adventures, a Hill Country paddling outfitter and guiding service: “The Llano River is currently on the low side. Canoeing has been curtailed. Kayaking is still possible, but there will be scraping and possibly some short drags.” Such conditions are not unusual in the peak of a Texas summer, but less common in the middle of spring. Away from the river, a parched, dry landscape results in a crunchy soundtrack when tread upon–brittle foliage rather than the swish of verdant green usually experienced this time of year. According to Texas A&M Forest Service, 149 of Texas 254 counties are under burn bans. The National Interagency Fire Center reports that 19,226 wildfires have burned 820,587 acres in the United States since January 1. That’s above the 10-year average of 13,166 wildfires and 610,287 acres burned. And monarch butterflies? They passed us by this year. Between the drier-than average-winter, a late Texas freeze in March, and temperatures that bolted into the 90s quickly thereafter, the Texas Funnel in 2022 was not exactly welcoming to migrating monarchs. |
Swamp milkweed, Asclepias incarnata, sprouts along the Llano’s river banks, but it’s too late–the monarchs have moved on. Queens, another milkweed feeding butterfly, haven’t shown up yet.
Beyond the river banks, nary a milkweed sprout is showing in the ranch’s usual haunts. Zizotes milkweed, Asclepias oenotheroides, planted several years ago, has failed to sprout. Antelope horns, Asclepias asperula, transplanted from a friend, remains absent. Nectar sources are equally unavailable. That usual harbinger of spring, the prickly, pervasive agarita bush with redolent yellow blooms that usually shows in late February and early March, was stymied by the freeze and then parching temperatures. The tangy red berries remain dried on the bush. Along the Llano and in many other parts of Texas, we’ve had no measurable rain in months. Conditions call to mind 2011’s historic drought, which resulted in the lowest population counts of monarch butterflies in recorded history. Those dismal numbers kickstarted mainstream monarch butterfly conservation in 2015. The dry conditions have residents of Mason, Texas, posing rain prayers.
“Lord, give me peace and assurance that You will bring the needed rains,” wrote Don Gray, administrator for the Mason County Texas Community page on Facebook. His April 14 post was followed by 99 comments, including dozens of “Amens” and praying hand emojis. The lack of rain provides stark contrast to the last two years, which have offered robust moisture and optimal conditions for monarchs, other butterflies, bees and wildflowers. Meanwhile, pockets of the state have enjoyed more typical rain conditions. As of April 14, U.S. Drought Monitor maps show 88% of Texas in a drought with another 9% classified as “abnormally dry.” Guz remains cautiously hopeful. “May is now our wettest month–it used to be June. Those are two of our wettest months, and if we get the rain we need, it won’t be like 2011. It’s all about what Mother Nature brings us in the next two months.” |
Monarch Butterfly
WWF WILDLIFE AND CLIMATE CHANGE SERIES
This assessment is one in a series resulting from a WWF study that assesses the vulnerability of numerous species to the effects of climate change. For each species, we also recommend climate adaptive management strategies.
MONARCH BUTTERFLIES (Danaus plexippus) range throughout the world, but this assessment focuses on North American populations. Monarchs have a high dispersal ability across a large geographic range. This, combined with their short generation time and high reproductive rate, suggests that monarchs may have a high capacity to adapt to longer term changes in climate. However, a number of traits make them vulnerable to a changing climate. Like most butterflies, monarchs are highly sensitive to weather and climate: They depend on environmental cues (temperature in particular) to trigger reproduction, migration, and hibernation. Their dependence on milkweed alone as a host plant is a further vulnerability, particularly as milkweed abundance is declining throughout the monarch range. They also face a decline in their overwinter habitat, and the effects of an increasing frequency of extreme weather events such as drought and severe storms, and extremes in hot and cold temperatures. Priorities for climate-informed monarch conservation should include restoring and increasing the extent of habitat with appropriate milkweed species and nectar sources. The public at large can contribute to this effort by planting backyard habitat. Increased monitoring of populations is also important, and citizen science efforts can contribute to this. It is also essential to maintain and restore overwinter habitat, reduce the use of herbicides and pesticides, and address issues related to land-use change. CLIMATE VULNERABILITY OF THE MONARCH BUTTERFLY Vulnerability Levels: H =High M =Medium L =Low U =Unknown 1. SENSITIVITY (L) IUCN Red List Status Near threatened. The eastern monarch migration, however, has been classified as an endangered phenomenon. (L) Geographic Range Large. The largest population is in North America, but populations of varying size occur in many other parts of the world. 2 The focus of this assessment is on North America, where there are three recognized populations. Two of these are migratory, and are found east and west of the Rocky Mountains. The eastern population travels up to 3,000 miles in a year to overwinter in Central Mexico. 3 The western population travels a shorter distance to overwinter on the California coast. 3,4 One smaller, nonmigratory population is found in southern Florida. 5 Over the past 20 years, monarchs may have lost more than 165 million acres of habitat, including nearly a third of their summer breeding grounds. 6 (M) Population Size Medium. The area of forest occupied by overwintering butterflies is used as an indirect indicator of abundance. 4 At the end of 2014, the eastern population occupied an overwinter habitat of 2.79 acres, representing the second-smallest area measured since monitoring began in 1993. 7 Current western monarch population estimates represent a 50% decline from the long-term average.8 (M) Temperature Tolerance Medium. For monarch caterpillars, temperatures above 29°C may retard growth, 9 and extended exposure to temperatures above 36°C can cause significant mortality10; the upper thermal limit appears to be 42°C.11 Long hot dry spells can reduce adult butterfly lifespan and the number of eggs females lay.12 Below-freezing temperatures can be lethal to overwintering adults, particularly when combined with moisture.13 Physiological acclimation may however help in coping with thermal extremes.11 Temperature influences annual population growth of monarchs and is crucial in determining range limits for butterflies in general.14,15 (H) Does the species rely on environmental cues for reproduction? Yes. Temperature influences reproductive development in adult male and female butterflies, with an optimal temperature of 28°C for both sexes.16 The rate of development across all life stages is temperature dependent.9 In many butterfly species, climatic conditions affect body temperature, which in turn is crucial for finding mates, increasing fecundity, and laying eggs.17 (H) Does the species rely on environmental cues for migration? Yes. Both temperature and precipitation influence migration phenology.14 If the weather is unfavorable, migrants accumulate in “staging areas” for several days.18 Monarchs overwintering in Mexico require prolonged exposure to cold overwintering temperatures in order to trigger the northward migration.19 (H) Does the species rely on environmental cues for hibernation? Yes. Hibernation is triggered by fluctuating fall temperatures, decreasing daylight, and aging milkweed.20 (H) Does the species have any strong or symbiotic relationships with other species? Yes. Monarch butterflies lay their eggs on milkweed, and the caterpillars need milkweed to grow and develop.3 (H) Diet Specialist. Caterpillars feed on milkweed only. There are over 100 species3 of milkweed; 72 of them are native to the USA and Canada, with the highest species diversity found in Texas and Arizona.21 (M) Abundance of Food Source Medium. Milkweed abundance in the eastern and western USA is decreasing.3 Milkweed quality for caterpillars diminishes at higher temperatures.22 (M) Freshwater Requirements Medium. Precipitation influences the annual population growth of monarchs.14 Very dry conditions keep eggs from hatching,23 and affect the availability and quality of milkweed and nectar sources.11,24 However, many milkweed species are drought-tolerant once established.21 (M) Habitat Specialization Specialist. Monarchs require a mix of nectar flowers and native milkweed throughout their flyway.3 Mexico’s high-elevation oyamel fir forest provides an ideal microclimate for overwintering butterflies,11 as do forest groves along the California coast. (M) Susceptibility to Disease Medium. Monarchs can be exposed to diseases caused by bacteria, viruses, and fungi,24 as well as affected by parasitoids (tachinid flies, braconid wasps).11 Changing temperature and precipitation could affect parasitoid abundance.11 Individuals staying in the southern USA rather than overwintering in Mexico are increasingly exposed to the protozoan parasite Ophryocystis elektroscirrha, particularly from year-round tropical milkweed (the parasite’s host).25 Parasite prevalence and load are lower in migratory populations.26 2. ADAPTIVE CAPACITY (L) Dispersal Ability High. The rapid expansion of monarch populations around the world suggests a very high dispersal ability and indicates there may be extensive gene flow between populations.27 The eastern migratory population migrates up to 3,000 miles in the fall to overwintering sites in Mexico.28 Generation Time (L) Short. The eastern migratory population typically has 3-5 generations in a year, depending on temperature.29 The overwintering generation lives for approximately 8-9 months, while the other generations live for approximately one month each.3 |
DETERMINING SPECIES VULNERABILITY The study identified the key vulnerabilities of a species based on four factors: SENSITIVITY: the inability of the species to persist, as is, under changing climatic conditions. To assess sensitivity, we looked at IUCN Red List status, geographic range, population size, temperature tolerance, reliance on environmental cues (for reproduction, migration, hibernation), symbiotic interactions, diet, abundance of food sources, freshwater requirements, habitat specialization, and susceptibility to disease. ADAPTIVE CAPACITY: the ability of the species to respond to changes in climate. To assess adaptive capacity, we looked at dispersal ability, generation time, reproductive rate, and genetic variation. EXPOSURE: the extent of climatic change and variation that the species encounters and is projected to encounter. OTHER THREATS: any other relevant threats, such as habitat destruction, poaching, human-wildlife conflict and pollution, as well as the human responses to climate change that exacerbate these threats (L) Reproductive Rate High. On average, a female lays 300-400 eggs over her lifetime,24 though mortality rates are high. (M) Genetic Variation Medium. Studies suggest that there is gene flow between eastern and western populations, and that levels of genetic diversity within these populations are fairly high.27 3. EXPOSURE (M) What degree of climate variability is the species currently exposed to? Medium. Currently exposed to a variety of extreme weather and climatic events, including floods, strong winds, droughts, fires, severe rains, heat waves, and freezing temperatures.4 A few examples follow: A severe storm killed an estimated 2.5 million butterflies in January 1981.30 Drought and fires in Texas have led to a lack of nectar for butterflies headed south.11 Wet winters have left soggy butterflies in Mexico exposed to cold snaps31 (a severe storm in 2002 killed 80% of the overwintering population).24 In 2012, near-record heat sped up the northward migration, skewed migratory patterns, and limited reproduction; in 2013, the opposite happened when cold weather delayed the northward migration. (M) What level of change in temperature and precipitation is projected across the species’ range? Medium. North America is projected to get warmer throughout. The most warming is projected to take place at higher latitudes of the USA and Canada, as well as eastern Canada. The least warming is projected in parts of southern Mexico, the US Pacific Coast, and the southeastern US. Also projected are more frequent extreme heat events, more intense droughts, and increased precipitation variability. It is likely that the higher latitudes in North America will experience an increase in precipitation, while much of the southern half of North America will get drier.32 4. OTHER THREATS (H) Other Threats High. Habitat conversion and changes in land management practices, particularly in the corn belt region of the US.3 A surge in the use of glyphosate herbicide on crops (particularly corn and soybean), which has caused severe milkweed decline in the US Midwest.6 A decline in nectar plants. Deforestation and degradation of forests through illegal logging in Mexico.4 RECOMMENDED CLIMATE-ADAPTIVE MANAGEMENT STRATEGIES Based on the vulnerability assessment, we recommend these climate-adaptive management strategies for monarch butterflies:
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A BLOG ABOUT MONARCHS
The Science of Monarch Butterflies: A Blog about Monarchs, Written by a Monarch Scientist, for People Who Love Monarchs
Hello blog readers,
Today I need to once again veer into the contentious territory of tropical milkweed, which is always a topic that stirs emotions among monarch enthusiasts. I'm going to tell you about a brand new study that I just read (I had nothing to do with it and am only the messenger here), that was just published in a high-profile scientific journal. I found the paper to be quite interesting, since it focused on monarch physiology, which is one of my own areas of interest. Anyway, this is a paper that folks should know about, and I need to write down my thoughts on it while it is still fresh in my mind. The paper was published in the journal, Nature Communications Biology, and I think it is fully open access (link here). The authors were a number of folks from the department of entomology at Penn State, and the lead author was Tori Pocius (pictured below). Some readers may recall that Tori had done a Masters project in the lab of Chip Taylor some years ago. From a simple google search, I see she was a postdoc at the time of this project, working in the lab of Dr. Jared Ali, who is a fairly new professor in their entomology dept. I also see that Dr. Ali (pictured below, holding the laptop) appears to have a lively lab group which conducts research on milkweeds. Perhaps we'll be hearing more from his lab in the future. OK, lets get to this new study. As any monarch enthusiast knows, there are many different species of milkweeds in North America, and each of these have differences in their plant chemistry. This paper describes an experiment that was designed to test what happens to larvae that eat different milkweed species, and specifically, what is the effect of these milkweeds on the metabolism of adult monarchs. This is a very interesting question, which has not specifically been explored before, but |
has great importance for the long-distance migration of monarchs. From prior research, we know that monarchs from migratory populations appear to have a lower metabolism than those from non-migratory populations. And within the eastern migratory population, we also know that the migratory generation has a lower metabolism than those from the breeding generation. Combined, these both tell us that having a low metabolism is needed for the long-distance journey, presumably because this saves energy. Think of metabolism as the body's "idling speed", like in a car engine - if the engine is revving too high when you drive, it burns a lot of gas.
Anyway, the authors questioned if different milkweeds can affect metabolism, because of the differences in cardenolide content of the plants. Cardenolides are the substance that makes the milkweeds toxic, and when the monarch larvae eat the plants, they themselves become toxic. But, there is a catch - the cardenolides are hard on the monarchs too, and they can cause some key physiological changes during development, that we are only now beginning to learn. For example, we now know that different milkweeds can affect traits like larval survival, immunity, resistance to parasites, and adult wing morphology. In other words, monarchs that are grown on different species of milkweeds may look similar, but they may have vastly different physiologies. The researchers examined 8 different species of milkweeds in this experiment, including tropical milkweed. These were chosen because of their difference in cardenolide content, as well as their availability. I'm going to put a screenshot below of a table from the paper that describes the plants used. A lot of these should be familiar to monarch enthusiasts. From reading the methods of the paper, these plants were all grown from seed in temperature controlled plant growth chambers. |
You can see above, that tropical milkweed, Asclepias curassavica, has the highest cardenolide content of all of these commonly-found milkweeds. This is one of the reasons why this plant causes so many problems for monarch biology.
It sounds like the monarch eggs were obtained from a breeding colony maintained at Iowa State University, and shipped to the lab at Penn State (more on this later). The researchers grew the eggs until the caterpillars hatched, then placed the caterpillars onto these different milkweeds in their greenhouse (plants were in mesh cages). They allowed the caterpillars to eat and grow on these plants until they metamorphosed into adults, then they conducted a series of measurements on the adults, including their metabolism. Measuring metabolism in insects is something I do in my lab, so I can help to explain what they did here. The researchers placed an adult monarch in a glass jar (like a large mason jar), which had a tight-fitting lid. The lid had an air hose going from it to a machine that measured the amount of carbon dioxide in the jar. Monarchs, like humans and other animals, breathe, and in so doing, emit carbon dioxide. The amount of carbon dioxide they emit is directly related to their internal metabolism. Therefore, by measuring how much CO2 is being produced in the jar, the researchers can measure the monarch's metabolic rate. In my lab, I have a similar device, but mine measures oxygen, and so I measure metabolic rate of insects (and spiders!) by assessing how much oxygen is used by the critter in question over time. It sounds like the researchers placed the jar with the monarch in a temperature controlled incubator (with the air hose still connected) and they then measured the "resting" metabolic |
rate, and the "flight" metabolic rate of the monarch. For the resting state, they simply covered the jar with a black cloth, which more or less kept the monarch calm. They did this for 5 minutes. Then, they removed the cloth, and apparently, the monarch in the jar
then flapped around, which more or less simulates "flight." This is an approach I have seen used before. It doesn't really simulate actual migratory flight, but it does simulate "flapping", which is a good proxy for flight. Anyway, the researchers repeated this for all of the monarchs that had been reared on the different milkweed species. They then used the data they gathered on each monarch's CO2 emission to compare across the milkweed species. Now let's get to what they found. First, they reported that there were some overall differences on larval survival across the different milkweed species, which I won't get into here (this has been reported many times in other studies), and there were some differences in adult size (also not getting into). Interestingly, the authors also reported the size of the flight muscles of these monarchs - apparently, they had dissected the monarchs after the experiment to determine this. They found that flight muscles of monarchs reared on tropical milkweed were larger than those reared on 6 of the 7 other species. They spent a fair amount of time on this part, though I don't think it is as important as the metabolism parts (next). I'm pasting another screenshot below, of one of the key figures from the paper, that shows the "flight" metabolism of monarchs, and how the milkweed type affects this trait. They use abbreviations for the different milkweed species, which you can probably figure out. |
migratory monarchs. Interestingly, I don't think there is evidence that migratory monarchs require larger flight muscles than non-The key thing to see here, is that monarchs reared on tropical milkweed as larvae (CUR, above), have a very high metabolic rate during flight compared to other milkweeds. There was another graph given that showed the resting metabolic rate, which essentially showed the same thing as this one - monarchs have a higher metabolism when grown on tropical milkweed. Recall that for long-distance migration, we know that lower is better.
So in other words, monarchs reared on tropical milkweed would be burning a lot of energy trying to make the trip to Mexico in the fall. Next, let me ruminate a bit over this finding. While the implications are pretty clear (in terms of the migration), it is less clear why this was found. The authors did not really have a good explanation for why tropical milkweed produced monarchs with high metabolism, other than some discussion over the cardenolides. In general, I think the high metabolism is probably linked with the aforementioned larger flight muscle mass of these monarchs. The unusually large muscle size probably requires more energy to fuel, and during periods when energy is not critical, this is probably not a problem. But during the migration, this would be a problem. At first glance, one might think that having large flight muscles would be beneficial for |
migrants, even though it sounds logical they would. Thus, I can't see how this larger flight muscle would benefit the migratory journey, especially if it requires more energy. I guess an over-arching question here is why the high cardenolides cause monarchs to have overly-developed flight muscles in the first place. I can see from the paper that the authors also had these same thoughts.
Now, let me circle back to something that gave me some pause while reading this paper, and if any of the authors are reading this, perhaps they could keep it in mind for the future. I mentioned that the eggs for the project were obtained from a "breeding colony" at Iowa State University. The paper states that the colony had been maintained for 18 generations, but with some wild stock introduced occasionally to prevent inbreeding. There was no indication that these eggs were infected or anything like that, but what concerns me is that the monarchs were all on the small side, which is one consequence of a long-term breeding colony, especially one that has been ongoing for 18 generations. In other words, without the annual impact of the migration to remove any small-winged monarchs, you eventually end up with lots of small-winged monarchs in your breeding stock. I'll paste below another table from the supplemental file of the paper, which shows the morphological measurements of these monarchs. Look specifically at the forewing lengths (FWL), which are all in the mid-40s. Typically, migratory monarchs in the east have lengths over 50mm. |
This table tells me that the monarchs used in this experiment may or may not be truly representative of the "migratory" monarch generation. In fact, these wing sizes are similar to those from non-migratory monarchs in Florida, Costa Rica, etc. So does this mean the experiment is flawed? Not at all. By my read, the experiment was done quite well. This is really just me being picky I guess. And really, the issue of small-winged monarchs does not negate the findings regarding tropical milkweed, since all of the monarchs in the study were small. But I think if I had been a reviewer of this manuscript, I might have asked the authors to discuss this limitation.
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So, I guess these are my thoughts on this interesting new paper. For those who have followed this blog for a while, you may recall that in a prior post I had put together a list of all of the research surrounding tropical milkweed, which all show how it negatively affects migration in various ways. I guess I'll have to add this one to that list: the paper that shows how tropical milkweed produces monarchs with the wrong metabolism for migration!
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Monarch Butterflies Facing Battle Royal for Survival: Pollinators Placed on International Conservation Organization’s Red List as Endangered
August 1, 2022
Monarch butterflies have long graced the skies of Texas during their annual migration. However, their population has been in steady decline, and recently the International Union for the Conservation of Nature, IUCN, placed the monarch butterfly on its Red List of threatened species, classifying it as endangered.
The monarch butterfly has been placed on the International Union for the Conservation of Nature’s Red List as endangered. (Texas A&M AgriLife photo by Laura McKenzie
The IUNC’s Red List is a comprehensive information source on the global conservation status of animal, fungi and plant species. It is a tool for promoting the biodiversity conservation and policy change needed to protect the world’s flora and fauna. Texas A&M AgriLife entomologists are concerned about the decline in monarch butterfly populations and want Texans and others to understand why these “regal” insects are important to agriculture and the environment. ABOUT THE MONARCH According to IUCN estimates, the eastern monarch population in the U.S. has declined by anywhere from 22% to 72% over the past decade, with the western U.S. monarch population declining by anywhere from 66% to 91%. Habitat loss, climate change, pesticides and disease were cited as some of the major factors in the species’ decline. Monarch butterflies migrate from overwintering locations, the largest of which is in Mexico, to more temperate regions that can be thousands of miles from the overwintering areas. Depending on the region, multiple generations of monarch butterflies can be seen before the fall migration to overwintering sites. The monarch butterfly’s annual spring and summer migration from its overwintering sites to more northern sites overlaps with most of Texas. Many eastern migrating monarchs will pass through Central Texas before spreading northwards to Canada. In the fall, monarch butterflies begin their trek from northern locations across the U.S. and Canada to their overwintering sites in Mexico. As they move southward, most of these butterflies will converge in north Central Texas and continue their flight south into Mexico. FACTORS AFFECTING MONARCH POPULATIONS
“Monarchs are very susceptible to environmental changes, especially during the times in their annual cycle when millions of them collect in the same general location,” said James Tracy, Ph.D., a postdoctoral research associate in the Department of Entomology of Texas A&M’s College of Agriculture and Life Sciences. Tracy said temperature and precipitation can influence the monarchs’ spring and fall migrations and breeding season success. “A sudden winter storm in Mexico can kill millions of monarchs overwintering there,” Tracy said. “There is also a significant amount of habitat loss from logging. Habitat loss and climate change are two major factors in the monarch’s population decline.” Another factor affecting monarch populations is the huge reduction in supplies of one of its main sources of nutrition – milkweed. “Monarch caterpillars need milkweed for nourishment so they may grow and develop, but the increased use of herbicides and pesticides, habitat conversion and adverse land management |
have all taken a toll on this important food source,” said Robert Coulson, Ph.D., professor and director of the Knowledge Engineering Laboratory in the Department of Entomology.
Coulson also noted that “roadkill” of the monarch butterfly in Texas, primarily during the fall migration, is responsible for a 2% to 3% annual decline in the population. He said he and others in the entomology department are working with the Texas Department of Transportation to find ways to keep butterflies away from highly traveled roadways and highways. “Our research and that of many “citizen scientists” watching their migration have shown monarchs are attracted to certain particular locations due to abundant food and water,” he said. “The use of flight diversion netting has helped protect migrating Asian purple crow milkweed butterflies from roadkill on a riverine bridge in Taiwan. We are collaborating with the Texas Department of Transportation to see if something like that may work here.” THE IMPACT OF FEWER MONARCHS “Monarch butterflies are visually stunning insects that help us learn to appreciate pollinators as important parts of our ecosystem and agriculture,” said Molly Keck, Texas A&M AgriLife Extension Service entomologist for Bexar County. “They are a type of environmental canary in the coal mine to show our environmental stewardship hasn’t been strong enough, and declining monarch populations parallel a decline in other pollinator populations.” Keck said monarch butterflies are also a symbol of the need to reduce deforestation and urbanization and better preserve natural areas. The monarch migration is a natural marvel that inspires great interest in the natural world. “These insects that travel for thousands of miles and across multiple generations to arrive at an unknown destination are a well-known sight in Texas, and that’s part of the reason they are our state insect,” Keck said. “While that alone is reason enough to be interested in them and to want to protect them, they also provide important lessons for young people wanting to know about natural science and the environment. It would be terribly sad to see such a beautiful and unique insect start to approach the point of extinction.” HOW TO HELP INCREASE MONARCH POPULATIONS
“Nectar from flowers provides the fuel monarchs need to fly, so if there are not any blooming plants to collect nectar from during the stops in their migration, the butterflies will not have the energy to continue,” Coulson said. “Planting flowers that attract monarchs as they pass through on their migration will help them reach their destination. In addition, creating more monarch habitats will help reverse their decline. Include butterfly or pollinator plants in your garden and avoid using pesticides.” Monarch caterpillar on a milkweed plant. (Texas A&M AgriLife photo courtesy of Aggie Horticulture.)Coulson also reiterated the importance of there being adequate milkweed for the monarchs. “We noted there are four particular types of milkweed the monarchs prefer as they travel through Texas during springtime,” he said. “You can learn what species of milkweed grow best in your region of Texas or the rest of the U.S. and learn how to plant it so the monarch caterpillars can have food to grow into butterflies.” Keck suggested planting a variety of flowering plants so adult monarchs have numerous food sources as they make their way to and from Mexico. “Here in Texas, you want to be sure to cut your milkweed down in October,” she said. “Otherwise, the monarchs will lay eggs before making it to Mexico. Those eggs usually hatch and then die because the food dries up, or we get a freeze before they complete their lifecycle. This is especially true when we have warm late falls or early winters, and milkweed doesn’t die back.” More information on what can be done to help restore monarch populations can be found at: www.monarchwatch.org. |
Migratory monarch butterfly now Endangered - IUCN Red List
July 21, 2022
Gland, Switzerland (IUCN) – The migratory monarch butterfly (Danaus plexippus plexippus), known for its spectacular annual journey of up to 4,000 kilometres across the Americas, has entered the IUCN Red List of Threatened SpeciesTM as Endangered, threatened by habitat destruction and climate change. All surviving sturgeon species – also migratory, found across the northern hemisphere – are now at risk of extinction due to dams and poaching, pushing the world’s most Critically Endangered group of animals yet closer to the brink. The tiger (Panthera tigris) has been reassessed, revealing new population figures.
The IUCN Red List now includes 147,517 species, of which 41,459 are threatened with extinction. “Today’s Red List update highlights the fragility of nature’s wonders, such as the unique spectacle of monarch butterflies migrating across thousands of kilometres,” said Dr Bruno Oberle, IUCN Director General. “To preserve the rich diversity of nature we need effective, fairly governed protected and conserved areas, alongside decisive action to tackle climate change and restore ecosystems. In turn, conserving biodiversity supports communities by providing essential services such as food, water and sustainable jobs.” The Endangered migratory monarch butterfly is a subspecies of the monarch butterfly (Danaus plexippus). The native population, known for its migrations from Mexico and California in the winter to summer breeding grounds throughout the United States and Canada, has shrunk by between 22% and 72% over the past decade. Legal and illegal logging and deforestation to make space for agriculture and urban development has already destroyed substantial areas of the butterflies’ winter shelter in Mexico and California, while pesticides and herbicides used in intensive agriculture across the range kill butterflies and milkweed, the host plant that the larvae of the monarch butterfly feed on. Climate change has significantly impacted the migratory monarch butterfly and is a fast-growing threat; drought limits the growth of milkweed and increases the frequency of catastrophic wildfires, temperature extremes trigger earlier migrations before milkweed is available, while severe weather has killed millions of butterflies. The western population is at greatest risk of extinction, having declined by an estimated 99.9%, from as many as 10 million to 1,914 butterflies between the 1980s and 2021. The larger eastern population also shrunk by 84% from 1996 to 2014. Concern remains as to whether enough butterflies survive to maintain the populations and prevent extinction. “It is difficult to watch monarch butterflies and their extraordinary migration teeter on the edge of collapse, but there are signs of hope. So many people and organisations have come together to try and protect this butterfly and its habitats. From planting native milkweed and reducing pesticide use to supporting the protection of overwintering sites and contributing to community science, we all have a role to play in making sure this iconic insect makes a full recovery,” said Anna Walker, member of the IUCN SSC Butterfly and Moth Specialist Group and Species Survival Officer at the New Mexico BioPark Society, who led the monarch butterfly assessment. The global sturgeon reassessment published today reveals that 100% of the world’s remaining 26 sturgeon species are now at risk of extinction, up from 85% in 2009. The assessments are based on refined calculations which show their decline over the past three generations to be steeper than previously thought. The Yangtze Sturgeon (Acipenser dabryanus) has moved from Critically Endangered to Extinct in the Wild, 17 species are now Critically Endangered, three are Endangered and five are Vulnerable on the IUCN Red List. The reassessment has also confirmed the extinction of the Chinese Paddlefish (Psephurus gladius). Renowned for their size, with the Critically Endangered Beluga (Huso huso) growing up to eight metres and 1,700 kilograms, sturgeons have been overfished for their meat and caviar for centuries. Despite being protected under international law, poaching continues to affect more than half of these species; stronger enforcement of regulations on the illegal sale of |
sturgeon meat and caviar is critical to stop further declines. Dams affect all sturgeon species migrating to their breeding grounds, while rivers warming due to climate change further disrupts sturgeon reproduction. Freshwater ecosystem restoration and building effective fish passages, together with restocking, which has already proven effective for species such as the Critically Endangered Adriatic sturgeon (Acipenser naccarii), are key measures to support the long-term survival of the world’s sturgeons.
The tiger has been reassessed, with new figures revealing that there are currently between 3,726 and 5,578 tigers in the wild worldwide. The 40% increase since the last tiger assessment in 2015 is the result of improvements in monitoring, showing that there are more tigers than previously thought, and the number of tigers globally appears to be stable or increasing. While this reassessment confirms that the tiger remains Endangered on the IUCN Red List, the population trend indicates that projects such as the IUCN Integrated Tiger Habitat Conservation Programme are succeeding and recovery is possible as long as conservation efforts continue. Major threats include poaching of tigers, poaching and hunting of their prey, and habitat fragmentation and destruction due to the growing pressures of agriculture and human settlement. Expanding and connecting protected areas, ensuring they are effectively managed, and working with local communities living in and around tiger habitats, are critical to protect the species. SUPPORTING QUOTES “We are grateful to the IUCN network of experts for their state-of-the-art assessments, and their contributions to the development of the CITES Dalbergia Checklist in coordination with the Royal Botanic Gardens, Kew. Science underpins the decisions that CITES makes, and it is through these strategic partnerships that we are able to thrive and continue to make a significant contribution to the long-term conservation of rosewoods of the genus Dalbergia and other keystone forest species," said Ivonne Higuero, CITES Secretary-General. “Few species evoke the awe and wonder that the migratory monarch butterfly commands,” said Dr Sean T. O’Brien, President and CEO of Nature Serve. “While efforts to protect this species are encouraging, much is still needed to ensure its long-term survival. Never has there been a more pressing time to collect data, like that provided by the NatureServe Network, on our nation’s biodiversity.” "The diversity of freshwater species underpins the health of our freshwater ecosystems and our planet as a whole," said Harmony Patricio, Re:wild freshwater fish conservation manager. "The news out today on the status of the world’s sturgeons should act as a red alert about the declining health of the lakes and rivers sturgeons live in. Re:wild is proud to be working with Synchronicity Earth via Shoal on urgently bolstering the conservation of freshwater species throughout the world, to the benefit of all life on Earth." “The oldest reported beluga was 118 years old. They reach reproductive age at 2 m in length, about one fourth of their maximum size. The primary threat of these giant migratory fish is overexploitation. Freshwater ecosystems are among the most threatened in the world, as we not only use water to drink, clean, irrigate and fish, but also to dispose of our waste. Decline of monarchs is similar. Although they are not used directly by humans, their threats are decentralised, diffuse and multiple. Tiger population recovery, however, shows us that solving complex conservation challenges is possible, and within our reach. Although tigers are still Endangered, their populations appear to be stable or increasing. We need to learn from these conservation successes, share them with the public, and increase our investment in evidence-based conservation action,” said Dr Jon Paul Rodríguez, Chair of the IUCN Species Survival Commission. “It is tragic to see one of the world’s most well-known butterfly species, with remarkable migratory behaviours and local cultural significance, threatened with extinction. Assessments like these provide us with the foundations for conservation actions to try and help protect a species and avert further loss,” said Sophie Ledger, ZSL (Zoological Society of London) Indicators & Assessments Unit researcher and member of the IUCN SSC Butterfly and Moth Specialist Group. “Here at ZSL, we are collaborating with global experts to shed light on the status of a wide range of species, including butterflies. Considering the current global biodiversity crisis, it is critical to uncover what is happening with diverse and functionally important species such as these before it’s too late.” |
Recent IUCN “endangered” listing creates confusion for monarch butterfly fans
By Monika Maeckle
July 26, 2022
July 26, 2022
A recent designation of the monarch butterfly as “endangered” by the International Union for the Conservation of Nature (IUCN) had monarch aficionados’ heads spinning last week.
The organization, composed of government agencies and NGOs from around the world, issued a press release July 21 adding the monarch butterfly to its Red List of Threatened Species, citing habitat destruction and climate change. And yet in May, news broke that the eastern migratory monarch population enjoyed a 35% increase this year over last. In January, conservationists announced that the number of California’s monarchs, which move up and down the Pacific Coast, vaulted more than 12,000% in 2021. Given such robust monarch numbers over the past two years, the IUCN “endangered” designation came as a surprise. “Can we still tag monarchs?” wondered Drake White, chief docent for San Antonio’s Monarch Butterfly and Pollinator Festival. White oversees a team of trained docents that conduct one-on-one tagging demos at the the celebration that takes flight each October in the nation’s first Monarch Butterfly Champion City, so named by the National Wildlife Federation. The short answer is YES, we an still tag monarch butterflies. While the Geneva-based IUCN is considered one of the most comprehensive sources on the conservation status of animals, plants and fungi, it has zero jurisdiction nor governing authority. |
“The term ‘endangered’ captures people’s attention, but it doesn’t mean what people think it does,” said Ross Winton, an invertebrate biologist for Texas Parks and Wildlife.
Winton recalled the decision in 2020 by U.S. Fish and Wildlife on listing monarch butterflies as “threatened” under the Endangered Species Act. The federal agency determined the listing was “warranted but precluded” but failed to list them due to a lack of resources to protect them, moving them into the queue behind 161 other species. The issue is expected to be revisited in 2024. The iconic orange-and-black butterflies are widely known for their unique, multi-generation migration that takes them each spring from their overwintering habitat in the mountains of Mexico through Texas to Canada and back. San Antonio sits in the so-called Texas Funnel, a migratory pathway that sees large numbers of the insects each year. The Alamo City, like much of Texas, is also home to a fairly stable monarch butterfly population, according to Winton. Texas Parks and Wildlife recently conducted its own statewide monarch butterfly assessment. “It came back that it’s secure, but that’s using different data sets than IUCN,” Winton said. Monarch Joint Venture, a monarch butterfly conservation organization, clarified in a statement that the IUCN designation does not provide any protections or regulatory authority like an Endangered Species Act listing in the U.S. would. |
“This is another loud call to action that we need all hands on deck for monarch and pollinator conservation,” said Wendy Caldwell, the organization’s executive director.
Another source of confusion: in their press release, the IUCN referred to the “eastern migratory monarch butterfly” as a “subspecies of the monarch butterfly Danaus plexippus.” Scientists have debated if migrating and nonmigrating monarchs and those that live east or west of the Rocky Mountains have innately different DNA for years. A recent study, titled “Are eastern and western monarch butterflies distinct populations?” seems to have put that argument to rest. As the study’s lead author Micah Freedman told the MonarchScience blog, “The evidence pretty strongly suggests that they (western monarchs) are genetically indistinguishable from eastern monarchs, and the (relatively minor) differences that do exist between wild eastern and western monarchs are likely environmentally determined.” Andy Davis, author of the MonarchScience blog and editor of the Migration Studies Journal, went so far as to suggest that the IUCN listing was a PR stunt meant to fuel the dogma of doom surrounding monarchs. “The public ‘narrative’ around the |
monarch…is becoming more and more divorced from reality,” said Davis in a recent post about the listing.
In his own recent study, Davis makes compelling science-based arguments that the monarch butterfly itself is not endangered. Drawing on butterfly survey data pulled from 130,000 observations over 25 years in two countries, he concludes that there’s been “no overall decline in numbers of monarchs seen in the past 25 years, going back to the mid 1990s. In fact, there was an overall positive trend of 1.3% per year. Over 25 years, that’s about a 30% increase!” Read about the study here. “It’s hard to sort it out,” said Cathy Downs, referring to the mixed messages. Downs propagates milkweed, the monarch butterfly’s host plant, in her yard in Comfort in the Texas Hill Country. She also works as a monarch conservation specialist for Monarch Watch, a citizen science initiative based at the University of Kansas at Lawrence that tracks the monarchs’ migration each fall by tagging the creatures. “I’m glad they issued the statement and brought monarch conservation back to the forefront,” she said |
When the Endangered Species Act listing was being debated, those who tag monarch butterflies raised concerns that they would no longer be able to participate in the initiative to track the migrating insects via tiny stickers placed strategically on their wings, as the listing would likely prohibit such interactions with a protected species.
But that’s not a worry here, said Chip Taylor, founder of Monarch Watch. “The IUCN has absolutely no jurisdiction in the United States,” said Taylor. “It’s a wake-up call.”
But that’s not a worry here, said Chip Taylor, founder of Monarch Watch. “The IUCN has absolutely no jurisdiction in the United States,” said Taylor. “It’s a wake-up call.”