Known scientifically as Danaus plexippus, this iconic pollinator should need no introduction. If anyone has heard of butterflies, chances are, they’ve heard of the monarch butterfly. And it’s no wonder this milkweed butterfly - part of the subfamily Danainae within the family Nymphalidae - has earned such a royal status in our culture.

It’s instantly recognizable for the bright orange coloring on its wings, overlain with black stripes with white spots along the fringes. The body is also black with white spots. These bold markings are a clear warning to potential predators of the toxins built up in its body from the milkweed they depend on in their larval stage. This relative safety from predators allows them to grow fairly large for butterflies, with a wingspan of 3.5 - 4 inches. Males tend to be slightly larger and have a pair of black spots, one on each hindwing along the first black stripe from their body. These spots produce pheromones used to help attract a mate.

Known only in the Americas until the mid-nineteenth century, monarch butterflies now have populations across the Atlantic and Pacific, from Australia to Africa. This change is most likely due to human activity, at least to some extent. The monarchs we’re familiar with here in Wisconsin belong to the eastern population of the migratory subspecies, which also happens to make up 90% of the total global population. Their range extends from southern Canada in the summer to central Mexico in the winter. They occupy and breed in our state from around late April to late September. They can be found just about anywhere there are flowering plants, and most importantly, milkweed.

Monarchs absolutely rely on milkweed for their survival. It is the only plant they’ll lay their eggs on and the only plant the caterpillars will eat. The substance that gives this plant its namesake is the milky white latex it produces. The latex contains cardiac glycosides, which are the compounds that make this insect toxic to most animals. Agriculture and urbanization, unfortunately, have made milkweed habitats fewer and farther apart, contributing significantly to the decline in monarch populations. Strangely enough, despite their reliance on this evolutionary relationship, monarchs aren’t particularly good at pollinating their host plants. They must then also rely on other pollinators like bumblebees, which have an easier time getting their legs in and out of the small, sticky flowers. The decline of bee populations may therefore mean further trouble for the butterflies. Nature weaves quite a tangled web indeed.

Past their striking appearance, monarch butterflies are best known for their two-way yearly migration from the mountains of central Mexico, to the open fields of northern Canada in spring, and back to Mexico in fall. Once the Monarchs return, they overwinter together in massive colonies that can measure in the tens of millions of individual butterflies. But there’s even more to the story than that! One of the things that makes their migratory lifestyle so fascinating is that no individual butterfly has ever actually been to its destination. This means they must rely on environmental cues - like shorter days, cooler temperatures, and the angle of the sun - acting on the migratory instincts programmed into their genes. All monarchs possess these genes, but they are only active in the one subspecies.

Monarch colonies huddle together for warmth at overwintering sites

It takes three generations for monarchs to reach their northernmost breeding grounds, but the fourth generation is particularly special. Instead of reaching reproductive maturity days after leaving the chrysalis, they emerge in diapause. Their development is literally put on hold in preparation for the flight back down south. While the first three generations may only live between two to six weeks, the fourth generation, also sometimes called the “super” or “Methuselah” generation, can live up to 8 months and complete the sometimes 3,000 mile journey on their own! They store as much fat as they can along the way and conserve energy by making use of air currents to soar like birds, as opposed to flapping the whole way there. They can travel up to 50 miles a day, given ideal conditions. When they finally arrive at their overwintering sites, they barely have an opportunity to eat and must rely on their fat reserves and the cooler temperatures of their mountain roosts to slow their metabolism. The monarchs rest until spring before finally beginning reproduction, starting the cycle all over again.

While monarchs themselves may not be the most efficient pollinators, their extensive range gives them a wide selection of flowers to nectar along their yearly journey. In Wisconsin, this includes, but is by no means limited to coneflowers, goldenrod, phlox, sunflowers, black-eyed Susans, asters, and so on. Their habitats are also vital to countless other pollinators, so what’s good for monarchs is good for the rest of the ecosystem. Sadly, this also works in the opposite direction. Monarch butterflies and many of their contemporaries are threatened by a host of troubles such as pesticides, breeding and overwintering habitat loss, disease, and climate change. The eastern population has suffered over an 80% loss in numbers since the late 90s. Within the last year alone, populations have decreased by 59% due to drought and human land use greatly reducing milkweed abundance. In 2020, the US Fish and Wildlife Service (FWS) announced the listing of monarch butterflies as an endangered species to be “warranted but precluded” by other species taking higher priority. So while they are recognized as a threatened species, they are not currently federally protected.

So, what can be done to help these dazzling pollinators? Due to being so recognizable and well loved, monarch butterflies are a perfect flagship species for conservation. There is an abundance of organizations, communities, and individuals working diligently to protect our fluttering friends. Steps you can take to make an impact can be as simple as sprinkling a few wildflower seeds in your yard and spreading awareness of this pollinator's plight. You can also be more active in the fight by planting larger butterfly gardens complete with native flowers and milkweeds. Otherwise, you can participate in citizen science communities like iNaturalist by simply recording your observations in their natural habitats to help researchers keep tabs on their numbers and inform conservation effort decision making. As of April 2024, there have been 4,457 observations of monarch butterflies through iNaturalist spread across the entire state, with 954 observations in 2023. There have been no Wisconsin observations so far this year, which is to be expected as they won’t be arriving until later in the month, so be ready to get out there and get looking.

Monarch butterflies are a delightful and ecologically important invertebrate that would be sorely missed across much of the continent. Their popularity helps to draw attention to pollinators as a whole, and conservation efforts for monarchs necessarily benefit a wide range of other species they share their habitats with. These vibrant insect travelers help to showcase just how wildly fascinating and interconnected nature can be, and will hopefully continue to draw our attention for many years to come.

Monarch nectaring on milkweed flowers

References:
Center for Biological Diversity. Search Results for "Monarch".
Wisconsin Department of Natural Resources. "How You Can Help Monarchs".
Davis, Adrian, et al. "Wing morphology and flight performance in the monarch butterfly." PLOS ONE, vol. 17, no. 3, 2022, e0286921. DOI: 10.1371/journal.pone.0286921.
Monarch Joint Venture. "Monarch Importance." monarchjointventure.org.
Monarch Joint Venture. "More Than Monarchs: Bumble Bees' Role in Milkweed Pollination." monarchjointventure.org.
Greenburgh Nature Center. "It's Complicated." greenburghnaturecenter.org.
The Butterfly Lady. "The Monarch Butterfly: Super Generation." butterfly-lady.com.
Monarch Joint Venture. "Overwintering." monarchjointventure.org.
Best Bees. "The Monarch Butterfly." bestbees.com.
Oberhauser, Karen, et al. "Monarch butterfly global distribution and migration." Frontiers in Ecology and Evolution, vol. 7, 2019, 362. DOI: 10.3389/fevo.2019.00362.
Center for Biological Diversity. "New Eastern Monarch Butterfly Count Indicates Pollinator Still Threatened." biologicaldiversity.org.
World Wildlife Fund. "Eastern Migratory Monarch Butterfly Populations Decrease by 59% in 2024." worldwildlife.org.
Photo Reference:
Court Whelan, Ph.D https://dailywildlifephoto.nathab.com/photography-guide/whats-in-my-camera-bag-monarch-butterfly-migration-adventure/
© Derek Ramsey / derekramsey.com / Used with permission

In the midst of a total solar eclipse, when the world plunges into an eerie darkness, humans aren't the only ones affected. Bees, also experience a dramatic shift in behavior. The total solar eclipse of August 21, 2017, provided scientists with a unique opportunity to delve into the foraging and homing habits of honey bees (Apis mellifera) during this celestial spectacle.

Traditionally, bees are known to be industrious creatures, buzzing from flower to flower in search of nectar and pollen from dawn till dusk. However, when the moon's shadow began its dance with the sun across North America, bee behavior took an unexpected turn. Researchers, including ecologist Candace Galen from the University of Missouri, embarked on a mission to understand how these tiny insects responded to the celestial event.

Armed with microphones strategically placed among flowers, the team captured the buzz of activity as the eclipse unfolded. What they discovered was remarkable: as totality, the phase where the sun is completely obscured by the moon, descended upon the landscape, the buzz of bees abruptly ceased. It was as if a switch had been flicked, plunging the bees into a sudden silence.

This swift transition puzzled researchers. Bees, unlike humans, aren't adapted to handle the sudden onset of darkness brought on by an eclipse. As Nicole Miller-Struttmann, an evolutionary ecologist at Webster University, notes, these insects lack a strong evolutionary history to guide their behavior during such events. Instead, they rely on other environmental cues, which may leave them ill-prepared for the unique conditions of an eclipse.

While the 2017 eclipse provided valuable insights into bee behavior, questions remain unanswered. With advancements in technology and a wealth of knowledge accumulated from previous studies, scientists are gearing up for an even more comprehensive investigation.

The 2024 solar eclipse offers a chance to further unravel the intricacies of bee behavior and shed light on lingering questions. Will bees exhibit similar patterns of activity as observed in 2017, or will new insights emerge? As the countdown to April' eclipse begins, scientists and citizen scientists alike eagerly await the opportunity to witness nature's spectacle and unlock the secrets hidden within the silent wings of bees.

References:

1. Waiker, P., Baral, S., Kennedy, A., Bhatia, S., Rueppell, A., Le, K., Amiri, E., Tsuruda, J., & Rueppell, O. (2019). Foraging and homing behavior of honey bees (Apis mellifera) during a total solar eclipse. Naturwissenschaften, 106(1-2), 4. https://pubmed.ncbi.nlm.nih.gov/30617515/ PubMed
2. Chiu, Joanna. "Busy Bees Take a Break During Total Solar Eclipses." Smithsonian Magazine, 29 Jan. 2019, www.smithsonianmag.com

The Karner blue butterfly, scientifically known as Lycaeides melissa samuelis, belongs to the Lycaenidae family, commonly referred to as gossamer-winged butterflies. This delicate creature is a symbol of grace and beauty in Wisconsin's natural landscapes.

Measuring about the size of a nickel, with a wingspan of approximately one inch, the Karner blue butterfly bears distinctive features that aid in its identification. Its top side exhibits a sky blue hue in males, while females showcase a darker blue and brown palette, complemented by vibrant orange spots along the edges of both hind wings. Moreover, both genders flaunt bands of orange crescents on the undersides of their fore and hind wings, a unique trait that distinguishes them from other small blue butterflies.

Historically, the Karner blue butterfly inhabited a vast range spanning from Minnesota to Maine and into Canada. However, habitat loss, fragmentation, and destruction have significantly diminished its populations. Today, outside of Wisconsin, the Karner blue persists in small pockets across Indiana, Michigan, Minnesota, New Hampshire, and New York. Sadly, it has been extirpated in states like Massachusetts, Pennsylvania, Ohio, and Ontario. As of December 2023, 637 observations of the Karner Blue Butterfly exist on iNaturalist for Wisconsin. This is WPW’s call to action to increase observations to enhance our understanding of the butterfly's location, population, and habits, ultimately contributing to improved conservation efforts!

In Wisconsin, the Karner blue finds refuge in open barrens, savannas, and prairies where wild lupine thrives. These habitats, prevalent in central and northwest Wisconsin, serve as vital ecosystems for the butterfly's survival. Wild lupine, the primary food source for Karner blue caterpillars, is essential for sustaining their populations. Additionally, Karner blues may also inhabit areas like roadsides, utility right-of-ways, and other open early successional stages, providing crucial corridors for dispersal and genetic diversity.

Given its dwindling populations and restricted habitats, conservation efforts are paramount for the Karner blue butterfly's survival. Organizations and agencies in Wisconsin are actively involved in habitat restoration projects, including the preservation and enhancement of lupine-rich environments. These initiatives aim to safeguard not only the Karner blue but also other native species dependent on similar habitats.

References
"Wisconsin butterflies" Retrieved 2024-01-23 https://wisconsinbutterflies.org/butterfly/species
Photo reference https://www.iceagetrail.org/wp-content/uploads/Spring-2018-MT-pXX-XX-Land-Conservation-highlights-Photo-2-Steve-Apps-Karner-blue-butterfly.jpg

Swamp Metalmark

Our monthly pollinator spotlight shines brightly on the Swamp Metalmark (Calephelis muticum), an endangered butterfly known for its distinctive and visually appealing colors.

The upper side of its wings typically features a combination of metallic blue or green hues, giving it a striking and iridescent quality. The wingspan is usually small, ranging from 1 to 1.5 inches. On the underside, the wings of the Swamp Metalmark display a more subdued and earthy coloration, often with browns and grays. This serves as a form of camouflage when the butterfly rests on vegetation.

In the US, the Swamp Metalmark - along with all pollinators - face significant challenges, primarily stemming from habitat loss, degradation, and fragmentation. Urbanization, marked by replacing native vegetation with roadways, manicured lawns, and non-native gardens, threatens the essential food and nesting sites vital for the survival of these pollinators.

The life cycle of the Swamp Metalmark is intricately tied to its environment. The eggs are laid singly on the underside of the host plant. Fourth and fifth-stage caterpillars overwinter. In the Great Lakes region, there is only one brood between June and August, while in the southern regions, there are two broods between May and September. Given its weak flight and specific food plant requirements, the swamp metalmark rarely (if ever) leaves the streamside wetlands and grasslands where it occurs. Maximum individual dispersal distances are probably on the order of a few hundred yards, with the species generally regarded as rare and highly local in occurrence.

Typically found in wetland habitats like swamps and marshes, the Swamp Metalmark relies on areas where Swamp Thistle grows as their larval foods are usually Cirsium muticum and Cirsium altissimum. In the adult stage, sightings have been reported on the nectar flowers of Rudbeckia hirta, also known as brown-eyed susan or yellow ox-eye daisy.

Last year, the Wisconsin Department of Natural Resources (DNR) proposed to issue an authorization for the incidental taking of this rare butterfly, which is expected to affect roughly 7.5 acres of its habitat to be disturbed in Oconto County and Marinette County. More information about this notice along with updates can be found on WI DNR’s site.

As of December 2023, only ten observations of the Swamp Metalmark exist on iNaturalist for Wisconsin, predominantly in the southeastern regions between Fond du Lac and Sheboygan. Notably, there were no recorded sightings in 2023. Recognizing the importance of citizen science, this is WPW’s call to action to increase observations to enhance our understanding of the butterfly's location, population, and habits, ultimately contributing to improved conservation efforts! We will put out an additional “be on the lookout” notice in early June, along with a list of counties where the Metalmark has been reported in previous years.

References
"Wisconsin butterflies" Retrieved 2024-01-23 https://wisconsinbutterflies.org/butterfly/species/60-swamp-metalmark
Conservation Assessment for "The Swamp Metalmark" Retrieved 2024-01-23 https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsm91_054247.pdf
^ "Swamp Metalmark Calephelis muticum McAlpine, 1937 | Butterflies and Moths of North America". www.butterfliesandmoths.org. Retrieved 2022-01-25.
^ Illinois Endangered Species Protection Board (16 August 2019). "Summary of all ESPB preliminary listing decisions for the Illinois List review and revision ending in 2020" (PDF). Illinois Department of Natural Resources. pp. 1–15. Archived from the original (PDF) on 9 January 2020. Retrieved 9 January 2020.
^ "NatureServe Explorer 2.0". explorer.natureserve.org. Retrieved 2022-01-25.
"Swamp Metalmark". Butterflies and Moths of North America. Archived from the original on 2009-05-05. Retrieved 2008-10-11.
Photo Credit to: "https://alabama.butterflyatlas.usf.edu/species/details/27/swamp-metalmark"

What do bees do during winter? It’s a common question, and the answer varies wildly between bee species. Bees have unique adaptation methods to help them survive from year to year. Wisconsin's native bees have developed ingenious strategies to withstand the harsh winter conditions, whereas honeybees form perennial colonies and hibernate as a group. Some species of bumblebee employ a similar communal approach by clustering together within their nests to generate warmth. This spectrum of adaptations exemplifies the resourcefulness of native bees in navigating the challenges posed by winter.

Native Bees:
Many native bee species are solitary, with each female constructing her own nest. To endure the temperatures, these solitary bees often seek refuge in underground burrows or natural cavities, creating a protective environment insulated from the cold. Native bees undergo physiological changes to endure the winter months by entering a state of dormancy known as diapause, slowing down their metabolic activity to conserve energy.

Bumble Bees:
In the United States, there are approximately 49 species of bumblebee. Their biology differs depending on the climate and habitat of their endemic range. In general, bumbles have an annual life cycle. Bumblebees do not dig their nests or cause property damage like wasps and carpenter bees (that are known to eat/chew wood). Bumbles will often nest in pre-existing cavities that provide insulation and protection from the elements. Things like old rodent burrows, grass bunches, compost piles, hollow logs, or large roots provide them shelter during the winter, along with man-made structures like birdhouses.

Understanding their life cycle helps us understand how they can survive winter. Bumblebees have a social structure with overlapping generations and cooperative care for the brood. Queens are the only survivors during winter. The queens will emerge from hibernation each spring and spend the next few weeks foraging and looking for a new home. The next several weeks are spent gathering resources to fuel their egg-laying process. Like caterpillars, bumblebees undergo a complete metamorphosis from larva to fuzzy adulthood in 4-5 weeks. Colonies reach their peak size in summer. When there are enough workers to take over foraging responsibilities, the queen focuses on creating males and queens for the following year. Males and young queens leave the nest to mate, with only the queen returning. This is why we can often find male bumblebees sleeping on vegetation in late summer. Young queens that have mated will spend the rest of the year preparing for diapause- foraging to build up fat reserves while looking for a safe place to overwinter. Once a suitable location is found, they hunker down and enter a hibernation-like state and will remain there until spring to repeat the cycle.

Honeybees:
Honeybees have a completely different strategy for overwintering. They must provide their own heat source and maintain a food supply inside the hive to make it to spring. Honeybees will huddle up around the queen, creating a tight cluster inside the hive. The worker bees will vibrate their bodies to generate heat. Their communal goal is to keep the hive warm enough for the queen and colony to survive. The combined heat of all the workers can create a core temperature of 90 degrees! The cluster has two parts: a much denser outer mantle and a looser inner core. It takes an immense amount of energy to vibrate all winter long, so they must build up a large reserve of honey to keep them energized enough to ensure the colony survives. Because the hive is not growing throughout winter, male drones are a needless drain on winter resources and are kicked out in late fall. New males will be created the following year. On warm winter days (55 degrees or warmer), honeybees may forage from nearby bird feeders for tiny bits of protein.