Geographic Range
Eastern tent caterpillars,
Malacosoma americanum
, range throughout the eastern and central United States and are found as far west
as the Rocky Mountains.
Habitat
Eastern tent caterpillars are often found in forests and near human habitations. Between
early spring and early summer, they build silk tents where branches of small trees
meet. Preferred species of tree include peach (
Prunus persica
), cherry and plum (
Prunus
), hawthorne (
Crataegus
), and apple and crabapple (
Malus domestica
). They also build tents in other species of broadleaf trees and shrubs, such as ash
(
Fraxinus
), birch (
Betula
), willow (
Salix
), maple (
Acer
), oak (
Quercus
), and poplar (
Populus
). Eastern tent caterpillars are active as moths from late May to June, where they
can be found in a variety of habitats including landscaped properties, although they
are much more abundant in wooded areas.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- forest
- Other Habitat Features
- urban
- suburban
- agricultural
Physical Description
Adult (moth) Eastern tent caterpillars are reddish brown in color and have two creamy white stripes running obliquely across their front wings. Wingspan is approximately 2.5 cm. Adults have siphoning mouthparts, and females are generally larger than males.
As caterpillars, they can reach 4 to 5 cm in length, and their long setae give them a fuzzy appearance. Color varies, but most are black with a white dorsal stripe and brown and yellow lateral lines. Many also have blue spots along their sides. Caterpillars have chewing mouthparts, used to consume leaves.
Egg masses of Eastern tent caterpillars encircle branches and are covered with shiny,
black or dark grey varnish-like material. Tents of
Malacoso americanum
are among the largest of any tent caterpillar and are typically constructed where
two branches meet. Tents usually face southeast. Cocoons are white or yellow.
- Other Physical Features
- ectothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
Development
Eastern tent caterpillars mate soon after emergence. Females attach eggs to branches
in masses of about 150 to 400 eggs. Egg masses encircle small branches or twigs and
are covered with shiny, black or dark grey varnish-like material. In about 3 weeks,
embryos develop to first-stage larvae. Larvae enter diapause and spend summer, fall
and most of winter unhatched. Eggs begin to hatch late February and early March, just
as leaf development begins to occur. Newly hatched caterpillars feed on the egg mass
covering and then move to a nearby fork in the branches where they spin silk to form
a tent. Eastern tent caterpillars have 6 larval instars. After 4 to 6 weeks of feeding
on leaves, caterpillars reach about 5 cm in length and are fully grown. They then
leave the tent and spin a silk cocoon in a protected place such as under rocks, logs,
debris on the ground, or cracks of buildings. The pupal stage lasts 3 to 4 weeks.
Eastern tent caterpillars live about 5 days as adults.
- Development - Life Cycle
- metamorphosis
- diapause
Reproduction
Male Eastern tent caterpillars seek females even before females have left the cocoon,
flying from cocoon to cocoon waiting for females to emerge. There are generally a
higher number of males than females. Mating behavior of both males and females varies
with sex ratio and population abundance. Especially when competition is high, males
may attempt to mate with females that are already copulating. Increased male competition
allows females to select and reject potential mates. Males may or may not hold onto
the substrate while mating. Copulation generally ends shortly after a female begins
fanning her wings, although if competition is high, males may prolong copulation.
Females die soon after breeding. Eastern tent caterpillars are polygynangrous.
- Mating System
- polygynandrous (promiscuous)
Eastern tent caterpillars breed once a year, mating soon after emergence. After copulation,
females lay their eggs in a protected area in masses of 150 to 400 eggs. Eggs are
cylindrical and measure about 1 mm in length. Eggs are placed in rows on a twig, and
eggs and twig are wrapped with a frothy, shiny material called spumaline. Egg masses
of Eastern tent caterpillars are easy to recognize. Eggs hatch during late February
and early March, just as leaf development begins to occur.
- Key Reproductive Features
- seasonal breeding
- sexual
- fertilization
- oviparous
Female Eastern tent caterpillars cover egg masses with a protective substance, spumaline.
The spumaline coating also serves as the first meal for hatching caterpillars. Because
females die soon after breeding, they do not actively provide parental care after
eggs are laid.
- Parental Investment
- female parental care
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
Eastern tent caterpillars live about 10 months in total. Adults may live for 5 days.
Females usually die soon after laying eggs.
Behavior
Eastern tent caterpillars are social, and as caterpillars they live in “cohorts," which are initially formed from sibling groups. Typical sibling group size (third instar) is 50 to 200 individuals. Populations at a given time can contain sub-populations of multiple instar stages.
When not feeding, a cohort of Eastern tent caterpillars aggregates within their silken "tent." The size of the tent increases as the caterpillars grow. Tents are thought to provide shelter from parasites and from some predators as well. They also aid in thermoregulation, and tents often have zones of varying temperature, caused by effects of sun, air currents, and aggregations of caterpillars within it. Individuals within a tent have been observed to move to warmer or cooler sections of the enclosure as need for heating or cooling dictates. In situations of high ambient heat, caterpillars have been observed hanging by their prolegs from the lower surface of the tent.
Eastern tent caterpillars are among the first leaf-eaters to appear in the spring, and their emergence is synchronized with the appearance of early leaves on host trees. They typically remain in the tree on which they emerged as long as sufficient food resources are available. If supply of suitable leaves becomes marginal, or if density becomes very high, caterpillars migrate to other trees.
As Eastern tent caterpillars forage, they leave an "exploratory" trail of silk secreted
from spinnerets. When they follow exploratory trails back to their tent, they may
overmark the trail, creating "recruitment trails." They leave behind pheromones, deposited
by dragging their abdomens, indicating where high quality food has been found. A single
individual can even recruit the entire colony to a food source through this method.
Movement of Eastern tent caterpillars is largely confined to trails and frequently
used trails become conspicuously marked.
- Key Behaviors
- arboreal
- flies
- crepuscular
- motile
- social
- colonial
Home Range
Little information is currently available regarding the home range of Eastern tent caterpillars.
Communication and Perception
Eastern tent caterpillars have a well-developed system for making chemical trails, perceiving trails made by others, and reinforcing trails according to the feeding experience associated with them. An initial "exploratory" trail made by a foraging individual is recognizable by others; if the foraging path proves fruitful, reinforcing pheromones will be added to it by the original forager and subsequent trail followers, thereby recruiting others to benefit from quality food sources (a "recruitment trail"). Individuals choose a trail reinforced by more foragers over one that has had fewer reinforcers.
Caterpillars are also sensitive to light and can perceive images in at least a crude
manner. Experimentation has demonstrated capability to perceive a tree-like vertical
shape from modest distances as well as capability to discern a difference between
objects of different reflectivity. They are also able to sense the direction of the
sun. When presented experimentally with an undifferentiated barren field (an extensive
asphalt surface), they move in directions that are strongly correlated with sun orientation
at the time of the experiment.
- Communication Channels
- chemical
- Other Communication Modes
- pheromones
Food Habits
Newly hatched Eastern tent caterpillars initially consume the coating that surrounded
the egg mass. After constructing a tent, they typically leave the tent prior to dawn,
evening and night to feed on leaves. They retreat to the tent between feeding bouts
and to avoid midday heat or rain. Eastern tent caterpillars prefer leaves of peach
(
Prunus persica
), plum (
Prunus
), hawthorne (
Crataegus
), apple and crabapple (
Malus domestica
) and cherry trees such as black cherry (
Prunus serotina
), pin cherry (
Prunus pensylvanica
), and choke cherry (
Prunus virginiana
). Their favored host plants are black cherry trees (
Prunus serotina
). If resources are limited, they may also consume leaves of other species of broadleaf
trees and shrubs, such as maple (
Acer
), and oak (
Quercus
). Eastern tent caterpillars can quickly damage sections of a tree. Adults do not
feed.
- Plant Foods
- leaves
Predation
Predation is the most significant cause of mortality in Eastern tent caterpillars. Colonies between the first and second instars are the most preyed upon, and as instar number increases, so does their survival rate. Birds are their most common predators and often destroy the tent and consume the better part of the colony. Avian predators prefer younger larvae and pupae, and final instar caterpillars are rarely attacked, presumably due to setae and toxicity. Eastern tent caterpillars also have a variety of invertebrate predators, although they generally do not destroy the entire colony.
Eastern tent caterpillars are aposematic, resting together in groups on the surface
of their tent. They also thrash the anterior part of their body when predators are
detected. Other caterpillars in the colony also begin to trash, which deters timid
predators such as
stink bugs
.
- Anti-predator Adaptations
- aposematic
Ecosystem Roles
Eastern tent caterpillars build their tents on and consume the leaves of a variety
of trees and shrubs, particularly members of the family
Rosaceae
such as apple and crabapple (
Malus domestica
) and cherry (
Prunus
). Their favored host plant are black cherry trees (
Prunus serotina
). They also have a variety of avian and invertebrate predators. Attacks of an
avian
predators often increase the likelihood of an invertebrate attack due to damages
sustained to the tent. Eastern tent caterpillars also host a number of parasites,
like
Tachinid
flies. Eastern tent caterpillars may fall victim to a variety of pathogens, including
the viruses
Clostridium
and
Bacillus
. Disease mortality does not often parallel predation mortality, but severe outbreaks
have been known to occur.
- Tachinid flies Tachinidae
Economic Importance for Humans: Positive
There are no known direct positive effects of Eastern tent caterpillars on humans. As prey for birds and invertebrates, however, they help maintain a forest ecosystem.
Economic Importance for Humans: Negative
A single colony of Eastern tent caterpillars can completely defoliate small ornamental
trees, and heavy infestations can cause serious damage to larger trees. Damage to
already weakened trees can be fatal. Tents are considered unsightly and are thus
removed by land owners. For aesthetic reasons, this species can be considered a pest,
particularly to outdoor recreational areas. Eastern tent caterpillars are also serious
pests in apple orchards, and many pest-management programs have considerably reduced
their presence in orchards. Additionally, Eastern tent caterpillars are associated
with Mare Reproductive Loss Syndrome (MRLS). MRLS caused approximately 330 million
US dollars in losses in 2001.
- Negative Impacts
- causes or carries domestic animal disease
Conservation Status
Although pest-management programs are in place in many orchards and sunburn recreational areas, Eastern tent caterpillars are not threatened. This species has not been evaluated by the ICUN or the US Fish & Wildlife Service.
Additional Links
Contributors
Yami Martinez (author), Rutgers University, John McDermott (author), Rutgers University, Jennifer Oberle (author), Rutgers University, Jay Parikh (author), Rutgers University, David V. Howe (editor), Rutgers University, Gail McCormick (editor), 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).
- terrestrial
-
Living on the ground.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- urban
-
living in cities and large towns, landscapes dominated by human structures and activity.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- agricultural
-
living in landscapes dominated by human agriculture.
- 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.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- 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
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- female parental care
-
parental care is carried out by females
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- crepuscular
-
active at dawn and dusk
- motile
-
having the capacity to move from one place to another.
- social
-
associates with others of its species; forms social groups.
- colonial
-
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
- chemical
-
uses smells or other chemicals to communicate
- 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
- chemical
-
uses smells or other chemicals to communicate
- aposematic
-
having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.
- causes or carries domestic animal disease
-
either directly causes, or indirectly transmits, a disease to a domestic animal
- herbivore
-
An animal that eats mainly plants or parts of plants.
- folivore
-
an animal that mainly eats leaves.
- 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
Bieman, B., J. Witter. 1983. Mating Behavior of Malacosoma disstria at Two Levels of Mate Competition. The Florida Entomologist , 66(2): 272-279. Accessed January 21, 2007 at http://links.jstor.org/sici?sici=0015-4040%28198306%2966%3A2%3C272%3AMBOMDA%3E2.0.CO%3B2-K .
Choate, B., L. Rieske. 2005. Life History and Age-Specific Mortality of Eastern Tent Caterpillar (Lepidoptera: Lasiocampidae). Ecology and Population Biology , 98(4): 496-502.
Costa, J. 1998. Larval Ontogeny and Survivorship of Eastern Tent Caterpillar Colonies. Journal of Research on the Lepidoptera , 32: 89-98.
Drees, B., J. Jackman. 1999. "Texas Cooperative Extension" (On-line). Eastern Tent Caterpillar. Accessed December 08, 2007 at http://insects.tamu.edu/fieldguide/cimg294.html .
Fitzgerald, T. 2007. "The eastern tent caterpillar (Malacosoma americanum) (Lasiocampidae)" (On-line). Social Caterpillars. Accessed January 22, 2007 at http://web.cortland.edu/fitzgerald/Easterntent.htm .
Hyche, L. 1996. "The Eastern Tent Caterpillar: A Guide to Recognition and Habits in Alabama" (On-line). Accessed December 09, 2006 at http://www.ag.auburn.edu/enpl/bulletins/easterntentcaterpillar/easterntentcaterpillar.htm .
Mahr, S. 2005. "Eastern Tent Caterpillar, Malacosoma americanum" (On-line). Wisconsin Master Gardener Program. Accessed December 09, 2006 at http://www.hort.wisc.edu/mastergardener/Features/insects/ETC/etc.htm .
Reiske, L., L. Townsend. 2005. Orientation and dispersal Patterns of the Eastern Tent Caterpillar, Malacosoma americanum. Journal of Insect Behavior , 18(2): 193-207.
Shetlar, D. 2000. "Eastern and Forest Tent Caterpillars and their Control" (On-line). The Ohio State University Extension Factsheet. Insect and Pest Series.. Accessed December 09, 2006 at http://ohioline.osu.edu/hyg-fact/2000/2022.html .
Travis, H. 2004. The Effect of Eastern Tent Caterpillar (Malacosoma americanum) on Fall Webworm (Hyphantria cunea) Selection of Black Cherry (Prunus serotina) as a Host Tree. American Midland Naturalist , 153: 270-275.
Wagner, D. 2005. Caterpillars of Eastern North America . Princeton, NJ: Princeton University Press.
Webb, B., W. Barney, D. Dahlman, S. DeBorde, C. Weer, N. Williams, J. Donahue, K. McDowell. 2004. Eastern tent caterpillars (Malacosoma americanum) cause mare reproductive loss syndrome. Journal of Insect Physiology , 50(2-3): 185-193.