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Lophocampa maculata

By Claire Walther

Geographic Range

Spotted tussock moths (Lophocampa maculata) are found throughout southern Canada, from British Columbia to Newfoundland, though they are uncommon through most of this range. They are also wide-spread through the United States, though there are considerably fewer populations present in the Midwest. Denser populations occur in the northeastern Adirondacks and from the Rocky Mountains to the Pacific coast. ("Lophocampa maculata Harris, 1841", 2021; "Spotted Tussock Moth or Yellow-Spotted Tiger Moth Lophocampa maculata Harris, 1841", 2021; "Butterflies and Moths of the Adirondacks: Spotted Tussock Moth (Lophocampa maculata)", 2021)

Habitat

Spotted tussock moths range from 0 to 2600 m above sea level, and inhabit a variety of deciduous forests across North America. Their distribution depends on the distribution of their host trees. Specific elevation, humidity, and other environmental conditions are less important than the presence of host trees. ("Lepidoptera of the Pacific Northwest: Caterpillars and Adults", 2003; "Lophocampa maculata Harris, 1841", 2021; "Butterflies and Moths of the Adirondacks: Spotted Tussock Moth (Lophocampa maculata)", 2021)

  • Range elevation
    0 to 2600 m
    0.00 to 8530.18 ft
  • Average elevation
    1800 m
    5905.51 ft

Physical Description

Spotted tussock moths are a species of tiger moth (family Arctiidae), named for their alternating striped pattern of dark and light colors. However, both as adults and larvae, spotted tussock moths are polymorphic, meaning they come in many color variations. Adults have tan or yellow forewings, between 20 and 45 mm, often with brown stripes. The veins in their wings are also brown, giving them a spotted appearance. Their hindwings are not spotted, are a pale cream or yellow color, and are nearly translucent. Spotted tussock moths have relatively long antennae, slightly smaller than the length of their bodies, which are covered in hairlike structures. Males have antennae that are much wider than those of females. This sexual dimorphism makes the sexes easily distinguishable.

Spotted tussock moth caterpillars are completely covered in long hairs. This gives them a fuzzy appearance, resembling tussock grass, thus their common name. Late instar caterpillars are about 40 mm long and have a thick orange or yellow band of hair in the middle of their bodies. They have black hairs covering each end of their bodies, with white tufts jutting from the black patches. Spotted tussock moths are also called "yellow wooly bears", because of their coloration and fuzzy appearance. In earlier instars, their black bands are much less pronounced, with the majority of their bodies being covered in yellow, orange, or white hairs, and with small black spots forming lateral lines along each of their sides. Spotted tussock moth caterpillars have different color variations depending on their geographic location. ("Species Lophocampa maculata - Spotted Tussock Moth - Hodges#8214", 2021; "Lophocampa maculata Harris, 1841", 2021; "Spotted Tussock Moth or Yellow-Spotted Tiger Moth Lophocampa maculata Harris, 1841", 2021; Philip, 2021; Strothkamp, 2015; "Butterflies and Moths of the Adirondacks: Spotted Tussock Moth (Lophocampa maculata)", 2021)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    2 to 40 mm
    0.08 to 1.57 in
  • Range wingspan
    20 to 45 mm
    0.79 to 1.77 in

Development

Spotted tussock moths typically have an univoltine life cycle, meaning they have one generation per year. However, one distinct population in California is known to be bivoltine, meaning there are two generations per year. No other instances of this have been recorded, meaning the bivoltine lifecycle is specific to this population.

The majority of spotted tussock moths adhere to certain developmental steps. Firstly, females lay around 100 to 200 eggs in clusters of roughly 5 to 15. Eggs are around 1 mm long and pearly white to opaque when laid. As eggs develop, they become significantly darker. Caterpillars hatch from their eggs after about 1 week. Newly hatched caterpillars are an average of 2 mm in length with pale bodies, black heads, and long black hairs. Caterpillars develop through complete metamorphosis, which includes 5 caterpillar instars. In their final instars, caterpillars are roughly 40 mm in length and with bold saddles of red or yellow hairs in the center of their bodies and black hair with white tufts at each end. Caterpillars pupate approximately 2 months after hatching, depending on food availability and temperature. They pupate on leaves, forming a brown silk cocoon where they overwinter and emerge as adults in the spring.

Based on research on other species of tiger moths (family Arctiidae), spotted tussock moth adults likely live between 5 and 10 days, during which time they search for mates. ("Species Lophocampa maculata - Spotted Tussock Moth - Hodges#8214", 2021; Philip, 2021; Strothkamp, 2015)

Reproduction

There is little information on the mating systems of spotted tussock moths. However, based on research on similar species, they are likely polygynandrous. This means that both females and males may have multiple mates before they die. ("Lepidoptera of the Pacific Northwest: Caterpillars and Adults", 2003; Strothkamp, 2015)

Spotted tussock moths reproduce sexually and lay eggs in large batches once in their lifetime, making them oviparous and semelparous. Females have been recorded to lay multiple clutches of eggs, totalling around 150 eggs. Adults reach sexual maturity upon emerging from their cocoons. (Philip, 2021; Strothkamp, 2015)

  • Breeding interval
    Most populations breed once a year, between May and July. One population on the coast of California has two generations per year, and has a longer mating period.
  • Breeding season
    May to July
  • Average eggs per season
    150

Spotted tussock moths do not provide any parental investment beyond the acts of mating and egg-laying.

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

Eggs laid in early spring typically emerge as adults in early spring of the following year, and adults typically live between 5 and 10 days. Therefore, they complete their lifecycle in approximately 1 year. (Strothkamp, 2015)

  • Average lifespan
    Status: wild
    1 years

Behavior

Spotted tussock moth adults are nocturnal and volant. They are active between May and July, while caterpillars are usually observed between July and September. Adults are typically found in deciduous forests near host trees. They may also be collected in light traps. ("Species Lophocampa maculata - Spotted Tussock Moth - Hodges#8214", 2021; "Lepidoptera of the Pacific Northwest: Caterpillars and Adults", 2003; Strothkamp, 2015; "Butterflies and Moths of the Adirondacks: Spotted Tussock Moth (Lophocampa maculata)", 2021)

Home Range

There is little information on home range sizes of spotted tussock moths. As caterpillars, their home range is likely restricted to the tree or stand of trees where they hatched. Spotted tussock moths are not known to be territorial.

Communication and Perception

THere is little information on the specific communication and perception methods of spotted tussock moths. They use pheromones to communicate their position, which is especially important for adults when searching for mates. Spotted tussock moths are also phototropic, meaning they are attracted to natural light sources, such as the moon, as a means of orientation. As a result, spotted tussock moths - particularly females - are caught in light traps or are found near artificial light sources. (Strothkamp, 2015)

Food Habits

Spotted tussock moth caterpillars feed on the leaves of broad-leafed deciduous trees. Although they prefer leaves of willows (family Salicaceae) and poplars (genus Populus), spotted tussock moths also feed on birches (genus Betula), alders (genus Alnus), basswoods (genus Tilia), maples (genus Acer), and oaks (genus Quercus). In some geographic regions, populations of spotted tussock moths show strong preferences for certain host tree species. In other populations, they are more generalistic. Spotted tussock moth caterpillars were successfully reared in lab conditions using vine maple (Acer circinatum), pacific willow (Salix lasiandra), and dune willow (Salix hookeriana) as host plants. (Strothkamp, 2015; "Butterflies and Moths of the Adirondacks: Spotted Tussock Moth (Lophocampa maculata)", 2021)

  • Plant Foods
  • leaves

Predation

Little is known about the specific predators of spotted tussock moths. Likely predators include birds, bats, parasitoid wasps, and predatory insects.

To defend themselves, spotted tussock moth caterpillars use Batesian mimicry, matching the coloration of sympatric species that have stinging glands such as American dagger moths (Acronicta americana). Predators often associate bright orange or yellow colors with toxicity, and thus avoid eating animals with such aposematic coloration. Additionally, the long, brittle hairs covering their bodies likely protect spotted tussock moth caterpillars against potential predators. ("Spotted Tussock Moth (Lophocampa maculata)", 2021)

Ecosystem Roles

There is little information on the ecosystem roles of spotted tussock moths. Caterpillars eat the leaves of several types of broad-leaf, deciduous trees throughout North America. They likely serve as prey for birds, bats, and predatory arthropods. Furthermore, they likely serve as hosts for the larvae of parasitoid wasp species.

Economic Importance for Humans: Positive

Spotted tussock moths have no known positive economic impacts.

Economic Importance for Humans: Negative

Spotted tussock moths have no known negative economic impacts. Researchers have determined that known populations of spotted tussock moths are not dense enough to be considered pests.

Handling spotted tussock moth caterpillars can result in mild skin irritation. (DuGar, et al., 2014; "Spotted Tussock Moth Caterpillar", 2021)

Conservation Status

Spotted tussock moths have no special status on the IUCN Red List, CITES, U.S. Federal List, or State of Michigan List. However, their historic range is known to have been slightly different than their range is today. More research is needed to confirm that the present conservation status of spotted tussock moths is accurate. ("Spotted Tussock Moth or Yellow-Spotted Tiger Moth Lophocampa maculata Harris, 1841", 2021)

Other Comments

Spotted tussock moths are often also referred to as "yellow-spotted tiger moths" or "mottled tiger moths". Caterpillars are frequently misidentified, as there are many species with similar patterning in the family Erebidae, subfamily Arctiinae, and genus Lophocampa. Many of the species that resemble s potted tussock moths have urticating (stinging or barbed) hairs or poison glands as defense mechanisms, which can cause irritation if handled and sickness if ingested. As a general caution, do not attempt to handle caterpillars, particularly those with tufts of "hair". However, true tiger moths typically lack stinging hairs, though they may still cause mild irritation, as is the case with spotted tussock moths. Because they are not toxic, spotted tussock moths are considered a type of tiger moth, not a type of tussock moth. Regardless, the most widely used common name is "spotted tussock moth".

Although spotted tussock moth caterpillars are not documented to have stinging hairs, there has been one incident involving an extreme allergic reaction (presumably to the caterpillar). More research is needed to evaluate the toxicity of spotted tussock moths. (DuGar, et al., 2014; "Species Lophocampa maculata - Spotted Tussock Moth - Hodges#8214", 2021; "Lepidoptera of the Pacific Northwest: Caterpillars and Adults", 2003)

Contributors

Claire Walther (author), Special Projects, Galen Burrell (editor), Special Projects.

Glossary

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.

World Map

acoustic

uses sound 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.

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.

chemical

uses smells or other chemicals to communicate

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.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

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.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scrub forest

scrub forests develop in areas that experience dry seasons.

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

tactile

uses touch to communicate

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.

visual

uses sight to communicate

References

Wild Adirondacks. 2021. "Butterflies and Moths of the Adirondacks: Spotted Tussock Moth (Lophocampa maculata)" (On-line). Adirondacks Forever Wild. Accessed October 03, 2021 at https://wildadirondacks.org/adirondack-moths-spotted-tussock-moth-lophocampa-maculata.html.

USDA. Lepidoptera of the Pacific Northwest: Caterpillars and Adults. FHTET-03-11. Morgantown, WV: USDA Forest Service. 2003. Accessed October 03, 2021 at https://www.fs.fed.us/foresthealth/technology/pdfs/FHTET_03_11.pdf.

2021. "Lophocampa maculata Harris, 1841" (On-line). Pacific Northwest Moths. Accessed October 01, 2021 at http://pnwmoths.biol.wwu.edu/browse/family-erebidae/subfamily-arctiinae/tribe-arctiini/lophocampa/lophocampa-maculata/.

Iowa State University Department of Entomology. 2021. "Species Lophocampa maculata - Spotted Tussock Moth - Hodges#8214" (On-line). BugGuide. Accessed October 03, 2021 at https://bugguide.net/node/view/5241.

2021. "Spotted Tussock Moth (Lophocampa maculata)" (On-line). Insect Identification. Accessed October 04, 2021 at https://www.insectidentification.org/insect-description.php?identification=Spotted-Tussock-Moth.

2021. "Spotted Tussock Moth Caterpillar" (On-line). Project Noah. Accessed October 04, 2021 at https://www.projectnoah.org/spottings/6284741.

Metalmark Web and Data. 2021. "Spotted Tussock Moth or Yellow-Spotted Tiger Moth Lophocampa maculata Harris, 1841" (On-line). Butterflies and Moths of North America. Accessed October 03, 2021 at https://www.butterfliesandmoths.org/species/Lophocampa-maculata.

DuGar, B., J. Sterbank, H. Tcheurekdijan, R. Hostoffer. 2014. Beware of the caterpillar: Anaphylaxis to the spotted tussock moth caterpillar, Lophocampa maculata. Allergy Rhinol, v. 5(2): all. Accessed October 03, 2021 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4124577/.

Philip, H. 2021. "Lophocampa maculata" (On-line). Where Art Meets the Heart. Accessed October 04, 2021 at http://www.whereartmeetstheheart.com/dghmaculatacats.shtml.

Strothkamp, K. 2015. Geographic Variation in Adult and Larval Lophocampa maculata Harris 1841. Journal of the Lepidopterists Society, 69(3): 197-208. Accessed October 03, 2021 at https://www.researchgate.net/publication/285206872_Geographic_Variation_in_Adult_and_Larval_Lophocampa_maculata_Harris_1841.

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