Diversity
Asterocampa
, commonly known as emperor butterflies, are a genus made up of four species, including
tawny emperor butterflies
,
hackberry emperor butterflies
,
cream-banded emperor butterflies
, and
empress leilia butterflies
. Each of these species contains up to four subspecies.
Geographic Range
Emperors are a Nearctic genus of butterflies. They are also found in Mexico and the
Antilles.
Habitat
Adults are typically found on their food plants. Some species of this genus, like
tawny emperors
, can be found in riparian forests, dry forests, and suburban areas.
Hackberry emperors
are found at river ends.
- Habitat Regions
- temperate
- Terrestrial Biomes
- forest
- Aquatic Biomes
- rivers and streams
Physical Description
Species of this genus are typically brown, tan, or orange with black patterns. Males
are smaller than females. One species,
hackberry emperors
, have black eyespots on their forewings. They also have a row of blue-green eyespots
on their hind wings.
Larvae are green with patterns that vary by species. All larvae of this genus have
spiky horns. Pupae are green on color. Eggs are white or pale yellow in color.
- Other Physical Features
- ectothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
Development
Depending on the species, eggs are laid in singly, in small batches, or in large batches.
Often found on the undersides of leaves or on the bark of trees. After hatching, larvae
move as a group to food sources. Each group of larvae lays down a trail of silk for
other larvae to follow. This allows larvae to safely reach new feeding areas. Early
instars of larva molt on the undersides of leaves or in leaf shelters. In some species,
third instar larvae overwinter on the undersides of leaves or in leave shelters.
- Development - Life Cycle
- metamorphosis
- diapause
Reproduction
Emperors breed seasonally. The reproduce sexually and lay eggs.
- Key Reproductive Features
- seasonal breeding
- sexual
- oviparous
Lifespan/Longevity
Depending on the species and location, there may between one and four generations
per year. Larvae create leaf shelters and undergo diapause during cold months.
Behavior
Emperors butterflies are able to fly and glide. They are active during the day. Staying mainly in one area, emperors do not travel long distances.
Communication and Perception
Emperor butterflies have compound eyes. Like other butterflies, they are able to see
ultraviolet light. Their antennae are sensory organs; they allow the butterflies to
sense odors, touch, and possibly sound. They have taste receptors in their mouths
and on the bottoms of their feet. Butterflies are able to perceive sound, though they
do not have a special organ dedicated to this sense as moths do.
- Other Communication Modes
- pheromones
Food Habits
Adults of this genus are rarely observed feeding on flowers. Instead, they feed on
rotting fruit, carrion, dung, and tree sap. They have been recorded feeding from the
snakewood trees
.
Caterpillars feed on their host plants. Larvae of both
hackberry butterflies
and
tawny emperors
feed on
hackberry trees
and
southern sugarberry trees
. Larvae of
hackberry butterflies
tend to feed on old foliage. Larvae of
tawny emperors
feed on new foliage. By feeding on different ages of foliage, these two species are
able to avoid competition with each other.
Predation
When they feel threatened, larvae of some species will swing their spiny, spiky heads
around. They will try to bite the threat with their mandibles. Larvae are preyed upon
by generalist predators. They are parasitized by at least one species of
tachinid fly
and
ichneumonid wasps
.
Ecosystem Roles
Emperors are parasitized by
tachinid flies
and
ichneumonid wasps
.
- ichneumonid wasps ( Microcharops tibialis )
- tachinid flies ( Chetogena edwardsii )
Economic Importance for Humans: Positive
Emperors have no known positive economic importance to humans.
Economic Importance for Humans: Negative
Although rare, larvae of
hackberry emperors
may cause complete defoliation of their host plants.
Tawny emperors
rarely have the numbers to impact their host plants.
Conservation Status
Some species of this genus are the target of conservation efforts. Most populations
are stable.
Additional Links
Contributors
Deena Hauze (author), Animal Diversity Web Staff.
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- metamorphosis
-
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
- diapause
-
a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- diurnal
-
- active during the day, 2. lasting for one day.
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- pheromones
-
chemicals released into air or water that are detected by and responded to by other animals of the same species
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- carnivore
-
an animal that mainly eats meat
- scavenger
-
an animal that mainly eats dead animals
- herbivore
-
An animal that eats mainly plants or parts of plants.
- folivore
-
an animal that mainly eats leaves.
- frugivore
-
an animal that mainly eats fruit
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
References
Hall, D., J. Butler. 2014. "Common name: hackberry emperor" (On-line). Featured Creatures. Accessed August 02, 2020 at http://entnemdept.ufl.edu/creatures/bfly/hackberry_emperor.htm .
Hall, D. 2019. "Common name: tawny emperor butterfly" (On-line). Featured Creatures. Accessed August 02, 2020 at http://entnemdept.ufl.edu/creatures/bfly/bfly2/tawny_emperor.htm .
Johnson, K. 1988. Reviewed Work: Taxonomy, Phylogeny, and Biogeography of Asterocampa Röber 1916 (Lepidoptera, Nymphalidae, Apaturinae). Journal of the New York Entomological Society , 96(4): 482-485. Accessed July 31, 2020 at https://www-jstor-org.ezproxy2.library.colostate.edu/stable/25009719 .
Neck, R. 1983. SIGNIFICANCE OF VISITS BY HACKBERRY BUTTERFLIES (NYMPHALIDAE: ASTEROCAMPA) TO FLOWERS. Journal of the Lepidopterists' Society , 37(4): 269-274. Accessed July 31, 2020 at https://images.peabody.yale.edu/lepsoc/jls/1980s/1983/1983-37(4)269-Neck.pdf .
Pelham, J. 2008. A catalogue of the butterflies of the United States and Canada with a complete bibliography of the descriptive and systematic literature. Journal of Research on the Lepidoptera , 40: 685.
Wernert, S. 1998. Reader's Digest North American Wildlife . New York: Readers Digest.