Viceroy butterfly
Encyclopedia
The Viceroy Butterfly is a North American butterfly
with a range from the Northwest Territories
along the eastern edges of the Cascade Range
and Sierra Nevada mountains, southwards into central Mexico
.
Its wings feature an orange and black pattern, and over most of its range it is a Müllerian mimic
with the Monarch
butterfly (Danaus plexippus). The viceroy's wingspan is between 53 and 81 mm. It can be distinguished from the Monarch by its smaller size and the postmedian black line that runs across the veins on the hindwing.
In Florida
, Georgia
, and the Southwest, Viceroys share the pattern of the Queen (Danaus gilippus) and in Mexico they share the pattern of the Soldier (Danaus eresimus). In all three areas, the local Danaus
population mimic the coloration of the Viceroy species. It was originally believed that the Viceroy was a Batesian mimic
of the three other species, and presumed edible or only mildly unpalatable to predators, but this has since proven not to be true.
The caterpillar
feeds on trees in the willow family Salicaceae
, including willow
s (Salix), and poplars and cottonwoods (Populus
). The caterpillars sequester the salicylic acid
in their bodies, which makes them bitter, and upsets predators' stomachs. As further protection, the caterpillars, as well as their chrysalis stage, resemble bird droppings. Adults are strictly diurnal, flying preferentially in the late morning and early afternoon.
The Viceroy was named the state butterfly of Kentucky
in 1990.
However, much evidence supports that a single event colonization is the best explanation. One theory of Nearctic colonization states that the reason for the colonization was a larvae host plant shift. The position of the Poplar admiral (L. populi), a Palearctic species, in a phylogenetic tree confirms that the Poplar is the closest existing relative of the Nearctic taxa and is consistent with the theory that the host plant had a large effect on the evolution of North American admirals. Just like the wing-pattern of the Palearctic butterflies has little evidence of divergence, the host plant use of these species also shows no sign of divergence. These species only feed on different species of honeysuckle (Lonicera ssp.) The exception is the Poplar that feeds exclusively on aspen (Salicaceae: Populus tremulus) All North American Limenitis feed on Salicaceae as well, suggesting that an (ancestral host plant shift) expansion of a novel host plant across the Bering land bridge could have driven the colonization of the Nearctic. Species level phylogenies based on the mitochondrial gene COI and the gene EFI-α of Nearctic and Palearctic species also indicate a single colonization of the Nearctic species The phylogenies produced indicate that a white-banded ancestor similar to the species L. arthemis established itself in North America and resulted in several major lineages, three of which involved mimicry independently of each other. Given the present monophyly of the Nearctic species, it is likely that a single migration and subsequent expansion of the population was the foundation of the Nearctic butterflies.
Determining what part of the butterfly genome controls wing color and pattern is also a major component that must be taken into account when trying to understand the evolution of mimicry. Each individual stripe or spot on a wing has a distinct identity that can be traced from species to species within a family A fascinating feature of pattern genetics is that the dramatic phenotypic changes are primarily due to small changes in the gene that determines the sizes positions of patter elements This discovery is in accord with the principal theory for the evolution of mimicry. The theory proposes that initial mimicry is achieved by a single mutation that has a large effect on the phenotype, which immediately gives the organism some protection, and is then refined by so-called modifier genes with lesser phenotypic effects Consequently, if the genes for wing pattern and color were normal functioning genes, a single mating would produce several phenyotypically different offspring, making the ability for mimicry to evolve very difficult.
This unique puzzle led to proposal of a possible supergene. A supergene is a tight cluster of loci that facilitate the co-segregation of adaptive variation, providing integrated control of complex adaptive phenotypes Different genomic rearrangements have tightened the genetic linkage between different color and pattern loci with complete suppression of recombination in experimental crosses in a 400,000 base section containing at least 18 genes This single supergene locus controls differences in a complex phenotype like wing coloration that can involve modifications of wing pattern, shape, and body color. Mimetic patterns have high fitness correlated to locally abundant wing patterns and low fitness when the offspring have recombinant, non-mimetic phenotypes This tight-linked area of wing pattern genes explains how mimetic phenotypes are not broken up during recombination during sexual reproduction.
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...
with a range from the Northwest Territories
Northwest Territories
The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...
along the eastern edges of the Cascade Range
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
and Sierra Nevada mountains, southwards into central Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
.
Its wings feature an orange and black pattern, and over most of its range it is a Müllerian mimic
Müllerian mimicry
Müllerian mimicry is a natural phenomenon when two or more harmful species, that may or may not be closely related and share one or more common predators, have come to mimic each other's warning signals...
with the Monarch
Monarch butterfly
The Monarch butterfly is a milkweed butterfly , in the family Nymphalidae. It is perhaps the best known of all North American butterflies. Since the 19th century, it has been found in New Zealand, and in Australia since 1871 where it is called the Wanderer...
butterfly (Danaus plexippus). The viceroy's wingspan is between 53 and 81 mm. It can be distinguished from the Monarch by its smaller size and the postmedian black line that runs across the veins on the hindwing.
In Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
, and the Southwest, Viceroys share the pattern of the Queen (Danaus gilippus) and in Mexico they share the pattern of the Soldier (Danaus eresimus). In all three areas, the local Danaus
Danaus (genus)
Danaus, commonly called Tigers, Milkweeds, Monarchs, and Queens, is a genus of butterflies in the tiger butterfly tribe. They are found worldwide, including North America, South America, Africa, Asia, Indonesia and Australia...
population mimic the coloration of the Viceroy species. It was originally believed that the Viceroy was a Batesian mimic
Batesian mimicry
Batesian mimicry is a form of mimicry typified by a situation where a harmless species has evolved to imitate the warning signals of a harmful species directed at a common predator...
of the three other species, and presumed edible or only mildly unpalatable to predators, but this has since proven not to be true.
The caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
feeds on trees in the willow family Salicaceae
Salicaceae
Salicaceae are a family of flowering plants. Recent genetic studies summarized by the Angiosperm Phylogeny Group has greatly expanded the circumscription of the family to contain 55 genera....
, including willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...
s (Salix), and poplars and cottonwoods (Populus
Poplar
Populus is a genus of 25–35 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar , aspen, and cottonwood....
). The caterpillars sequester the salicylic acid
Salicylic acid
Salicylic acid is a monohydroxybenzoic acid, a type of phenolic acid and a beta hydroxy acid. This colorless crystalline organic acid is widely used in organic synthesis and functions as a plant hormone. It is derived from the metabolism of salicin...
in their bodies, which makes them bitter, and upsets predators' stomachs. As further protection, the caterpillars, as well as their chrysalis stage, resemble bird droppings. Adults are strictly diurnal, flying preferentially in the late morning and early afternoon.
The Viceroy was named the state butterfly of Kentucky
Kentucky
The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...
in 1990.
Evolution of Admiral Butterflies (Nymphalidae: Limenitis)
The world is divided into eight biogeographic areas called ecozones: Palearctic, Nearctic, Afrotropic, Neotropic, Australasia, Indo-malaya, Oceania, and Antarctica. Palearctic includes most of Eurasia and North Africa while Nearctic includes most of North America. Limenitis butterfly wing patterns are much more diverse in the Nearctic than the Palearctic. Three lineages of mimetic butterflies occur in North America and the evolution of mimicry may have played a large role in the diversification of this group . In order for butterflies to travel from the Palearctic region to the Nearctic region of the world, the migration must have occurred during a time period when Beringia, the land bridge between Eurasia and North America, was still above water Based off crude divergence rate calculations , the colonization of the Nearctic Leminitis dates back approximately four million years Whether the migration event was a single or multiple occurrence event has a significant effect on how we look at the evolution of mimicry. A history of multiple migrations would suggest that speciation occurred before the evolution of mimicry, meaning mimicry was the result of speciation instead of the driver of speciation.However, much evidence supports that a single event colonization is the best explanation. One theory of Nearctic colonization states that the reason for the colonization was a larvae host plant shift. The position of the Poplar admiral (L. populi), a Palearctic species, in a phylogenetic tree confirms that the Poplar is the closest existing relative of the Nearctic taxa and is consistent with the theory that the host plant had a large effect on the evolution of North American admirals. Just like the wing-pattern of the Palearctic butterflies has little evidence of divergence, the host plant use of these species also shows no sign of divergence. These species only feed on different species of honeysuckle (Lonicera ssp.) The exception is the Poplar that feeds exclusively on aspen (Salicaceae: Populus tremulus) All North American Limenitis feed on Salicaceae as well, suggesting that an (ancestral host plant shift) expansion of a novel host plant across the Bering land bridge could have driven the colonization of the Nearctic. Species level phylogenies based on the mitochondrial gene COI and the gene EFI-α of Nearctic and Palearctic species also indicate a single colonization of the Nearctic species The phylogenies produced indicate that a white-banded ancestor similar to the species L. arthemis established itself in North America and resulted in several major lineages, three of which involved mimicry independently of each other. Given the present monophyly of the Nearctic species, it is likely that a single migration and subsequent expansion of the population was the foundation of the Nearctic butterflies.
Evolution of Viceroy Mimicry
Based on phylogenic evidence we know that mimicry in the North American admirals was a driver of speciation. An essential condition for the evolution of mimicry was the presence and abundance of unpalatable models. Mimetic evolution also involved direct selection with the model acting as a “starting block” for the mimic to evolve against The drive behind this type of evolution must be predation. Eventually, the mimetic population undergoes phenotypic fixation, usually at a point where the wing pattern and colors of the mimic have reached the closest superficial resemblance of its model As these processes continued, the subspecies divergences began occurring as the mimetic species expanded their geographical range and began mimicking other species of butterfly.Determining what part of the butterfly genome controls wing color and pattern is also a major component that must be taken into account when trying to understand the evolution of mimicry. Each individual stripe or spot on a wing has a distinct identity that can be traced from species to species within a family A fascinating feature of pattern genetics is that the dramatic phenotypic changes are primarily due to small changes in the gene that determines the sizes positions of patter elements This discovery is in accord with the principal theory for the evolution of mimicry. The theory proposes that initial mimicry is achieved by a single mutation that has a large effect on the phenotype, which immediately gives the organism some protection, and is then refined by so-called modifier genes with lesser phenotypic effects Consequently, if the genes for wing pattern and color were normal functioning genes, a single mating would produce several phenyotypically different offspring, making the ability for mimicry to evolve very difficult.
This unique puzzle led to proposal of a possible supergene. A supergene is a tight cluster of loci that facilitate the co-segregation of adaptive variation, providing integrated control of complex adaptive phenotypes Different genomic rearrangements have tightened the genetic linkage between different color and pattern loci with complete suppression of recombination in experimental crosses in a 400,000 base section containing at least 18 genes This single supergene locus controls differences in a complex phenotype like wing coloration that can involve modifications of wing pattern, shape, and body color. Mimetic patterns have high fitness correlated to locally abundant wing patterns and low fitness when the offspring have recombinant, non-mimetic phenotypes This tight-linked area of wing pattern genes explains how mimetic phenotypes are not broken up during recombination during sexual reproduction.
External links
- Viceroy, Butterflies of North Carolina
- Description of Viceroy on Butterflies and Moths website
- A Bitter Plant Becomes a Bitter Butterfly
- viceroy butterfly on the UFUniversity of FloridaThe University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
/ IFASInstitute of Food and Agricultural SciencesThe University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
Featured Creatures Web site - Viceroy, Butterflies of Canada