---
title: "What the sources say about the Monarch Butterfly | AnimalTracks.wiki"
description: "44 claims from the Monarch Butterfly profile, each beside the words of the source that backs it."
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---

# What the sources say about the Monarch Butterfly (*Danaus plexippus*)

> 44 claims from the Monarch Butterfly profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Monarch Butterfly](https://animaltracks.wiki/animals/monarch-butterfly/)

## Walker et al. (2022). Danaus plexippus. The IUCN Red List of Threatened Species 2022: e.T159971A219149911.

https://doi.org/10.2305/iucn.uk.2022-1.rlts.t159971a219149911.en

| The page says | The source says |
| :--- | :--- |
| The IUCN Red List rates the species Least Concern | Least Concern (note: category via GBIF copy; assessment year not in cached text, so left out of the body) |

## Monarch (Danaus plexippus). U.S. Fish & Wildlife Service.

https://www.fws.gov/species/monarch-danaus-plexippus

| The page says | The source says |
| :--- | :--- |
| makes one of the longest known insect migrations in the world | The monarch's journey is one of the longest known insect migrations in the world. |
| A butterfly of about half a gram that wears milkweed poison as armor | On average, adult monarch butterflies weigh about half of a gram, which is less than the weight of a paperclip. (note: tagline; 'on average' per source) |
| Eastern monarchs migrate up to 3,000 miles using a sun compass | The eastern population of monarchs travel up to 3,000 miles during migration traveling from Canada, through the U.S. and down to Mexico (note: stats.superpower; compass in the next claim) |
| Fields, roadsides, wetlands and gardens with milkweed, across the Americas | Whether it’s a field, roadside area, open area, wet area or urban garden, milkweed and flowering plants are needed for monarch habitat. (note: stats.habitat; Americas from the range claim below) |
| Eastern North American monarchs fly up to 3,000 miles each fall, from Canada through the United States to Mexico | The eastern population of monarchs travel up to 3,000 miles during migration traveling from Canada, through the U.S. and down to Mexico |
| The trip may last more than two months | a trip that may last more than two months |
| the longest single-day flight recorded for a tagged eastern monarch is 265 miles | The longest single day flight of a tagged eastern North American monarch was recorded at 265 miles. |
| A monarch caterpillar eats milkweed | Monarch butterflies require healthy and abundant milkweed plants for both laying eggs on and as a food source for caterpillars. |
| By consuming it, monarchs obtain toxins called cardenolides that defend them against predators | By consuming milkweed plants, monarchs obtain toxins, called cardenolides, that provide a defense against predators. |
| The adult's bright orange wings with a black border act as a warning that eating one can be toxic | Adult monarch butterflies are large and conspicuous, with bright orange wings surrounded by a black border and covered with black veins. ... The bright coloring of a monarch serves as a warning to predators that eating them can be toxic. |
| An adult monarch has a wingspan of 3 to 4 inches (7 to 10 cm) | Wingspan: 3 to 4 inches (7 to 10 cm) |
| On average it weighs about half a gram, less than a paperclip | On average, adult monarch butterflies weigh about half of a gram, which is less than the weight of a paperclip. |
| Caterpillars have black, yellow and white stripes and reach 2 inches (5 cm) before they pupate | Monarch caterpillars, or larvae, have black, yellow and white stripes and reach lengths of two inches before metamorphosis. ... Larval length: 2 inches (5 cm) |
| or turn into a chrysalis | Monarch caterpillars then pupate into a green and gold chrysalis |
| Most breeding adults live about two to five weeks | Most breeding adult butterflies live approximately two to five weeks |
| Overwintering adults that enter reproductive diapause | overwintering adults that enter into reproductive diapause can live six to nine months |
| can live six to nine months | overwintering adults that enter into reproductive diapause can live six to nine months |
| a state of suspended reproduction | go into a state of suspended reproduction, known as diapause |
| Monarchs are native to North and South America and have spread to many other places, including Australia, New Zealand and parts of the Iberian Peninsula | Monarchs are native to North and South America but have since spread to many other locations where milkweed and suitable temperatures exist, including Australia, New Zealand and portions of the Iberian Peninsula. |
| North America's migratory monarchs form two populations | North American migratory monarchs are divided into eastern and western populations. |
| Most eastern monarchs winter in oyamel fir forests in the mountains of central Mexico | For the eastern North American population, most monarchs overwinter in oyamel fir tree roosts located in mountainous regions of central Mexico |
| western monarchs, west of the Rocky Mountains, winter mainly in California | Monarchs living west of the Rocky Mountains in North America primarily overwinter in California |
| Where milkweed grows all year and temperatures suit them, monarchs in many areas live and breed year round without migrating | With the year-round presence of milkweed and suitable temperatures, monarchs in many areas of the their worldwide range, including parts of North America, live and breed year round. Many of these non-migratory monarchs |
| In early spring the survivors end their pause in breeding, mate at the overwintering sites and then fly back through the breeding grounds | In early spring, surviving monarchs break diapause and mate at the overwintering sites before dispersing. The same individuals that undertook the initial southward migration begin flying back through the breeding grounds. |
| After several generations of offspring, a new generation makes the next fall trip for the first time | After several generations of monarch offspring in the spring and summer, a new generation begins the fall migration for the first time. |
| Females lay eggs on milkweed plants, the only food the caterpillars can eat | they lay eggs on milkweed plants as that is the only food the caterpillars can eat |
| Adults are less picky and sip nectar from many flowers | Adult monarchs feed on the nectar of many flowers during breeding and migration |

## Monarch Butterfly. San Diego Zoo Wildlife Alliance.

https://animals.sandiegozoo.org/animals/monarch-butterfly

| The page says | The source says |
| :--- | :--- |
| Milkweed as a caterpillar, flower nectar as an adult | As caterpillars, monarchs rely on native milkweed species to survive. Once they transform into adult butterflies, monarchs feed on nectar from flowering plants. (note: stats.diet) |
| A year brings four to five generations, and the late-summer and fall ones are the ones that migrate | Monarchs are multigenerational, cycling through four to five generations ... The later generations, which emerge in the late summer or fall, migrate north or south. |
| The monarch's two main bird predators, black-backed orioles and grosbeaks, seem immune to the toxins and eat monarchs in large numbers, though that may be because the toxins decay during migration and overwintering | Their two main avian predators, black-backed orioles and grosbeaks, seem to be immune to monarch toxins and consume the insects in large numbers; however, this may be due to the decay of monarch toxins during their migration and overwintering. |
| tags: pollinator | Along with other pollinators like bees, monarchs play an important role in the ecosystem, dispersing flower pollen as they flutter from plant to plant. (note: #998) |

## Taylor (2017). Biology of the Monarch Butterfly. Kansas School Naturalist 62(2), Monarch Watch.

https://monarchwatch.org/biology/

| The page says | The source says |
| :--- | :--- |
| In early studies a blue jay that ate a monarch vomited shortly afterwards because of the cardenolides, and that bird learned never to eat another | Early studies of Monarchs showed that when a blue jay ate a Monarch butterfly, it vomited shortly afterwards due to the cardenolides. That bird also learned to never eat another Monarch butterfly. (note: one bird in early studies; not generalised) |

## Merlin, Gegear & Reppert (2009). Antennal Circadian Clocks Coordinate Sun Compass Orientation in Migratory Monarch Butterflies. Science.

https://doi.org/10.1126/science.1176221

| The page says | The source says |
| :--- | :--- |
| whose eastern migrants steer by the sun | Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated Sun compass to aid navigation to their overwintering grounds in central Mexico. (note: tagline; eastern population) |
| Eastern monarchs migrate up to 3,000 miles using a sun compass | Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated Sun compass to aid navigation to their overwintering grounds in central Mexico. (note: stats.superpower; the 3,000 miles is covered by the fws-monarch entry above) |
| Migrating eastern monarchs use a time-compensated sun compass to find their overwintering grounds in central Mexico | Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated Sun compass to aid navigation to their overwintering grounds in central Mexico. |
| A 2009 study found that the antennae are necessary for proper sun compass orientation, that antennal clocks exist in monarchs, and that they likely provide the primary timing mechanism | we show that the antennae are necessary for proper time-compensated Sun compass orientation in migratory monarch butterflies, that antennal clocks exist in monarchs, and that they likely provide the primary timing mechanism for Sun compass orientation. (note: 2009 is the reference year (merlin-2009)) |
| The time compensation comes from a circadian clock, an internal body clock | It has been assumed that the circadian clock that provides time compensation resides in the brain |
| Scientists had assumed it sat in the brain, although nobody had tested that directly, and the authors called their antennae findings unexpected | It has been assumed that the circadian clock that provides time compensation resides in the brain, although this assumption has never been examined directly. ... These unexpected findings pose a novel function for the antennae |
| Migrating eastern monarchs steer by a time-compensated sun compass | Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated Sun compass to aid navigation to their overwintering grounds in central Mexico. (note: vibe.reason animal clause, same source as the body claim "Migrating eastern monarchs use a time-compensated sun compas") |
| clocks in their antennae likely provide the timing | we show that the antennae are necessary for proper time-compensated Sun compass orientation in migratory monarch butterflies, that antennal clocks exist in monarchs, and that they likely provide the primary timing mechanism for Sun compass orientation. (note: vibe.reason animal clause, same source as the body claim "A 2009 study found that the antennae are necessary for prope") |

## Karageorgi et al. (2019). Genome editing retraces the evolution of toxin resistance in the monarch butterfly. Nature.

https://doi.org/10.1038/s41586-019-1610-8

| The page says | The source says |
| :--- | :--- |
| Many insects that colonized cardiac glycoside plants, monarchs among them, evolved changes in the sodium pump, the cell protein those toxins attack | insects from six orders, including the monarch butterfly (Danaus plexippus), that have independently evolved to colonize plants that produce cardiac glycoside toxins 6-11 . Many of these insects evolved parallel amino acid substitutions in the α-subunit (ATPα) of the sodium pump (Na + /K + -ATPase) 7-11 , the physiological target of cardiac glycosides |
| In 2019 scientists used CRISPR gene editing to rebuild the monarch's changes in fruit flies | We then performed CRISPR-Cas9 base editing on the native Atpα gene in Drosophila melanogaster flies and retraced the mutational path taken across the monarch lineage (note: 2019 is the reference year (karageorgi-2019)) |
| Their triple-mutant "monarch flies" were as insensitive to the toxins as monarch butterflies | culminating in triple mutant 'monarch flies' that were as insensitive to cardiac glycosides as monarch butterflies. |