Large yellow underwing moths (Noctua pronuba), also known as winter cutworms, are common across western Europe and were introduced to Nova Scotia, Canada in the 1970s. Since then, large yellow underwing moths have spread across North America, including the entirety of Canada, the United States, and northern Mexico. They are able to survive in North America partly because of their adaptations to cold weather. Populations of large yellow underwing moths in North America have been growing steadily since the early 2000s. There are also reports of large yellow underwing moths in Iceland, Scandinavia, northern Africa, and Asia. ("Invasive Species Comendium", 2021; Difonzo and Russell, 2010; "Large Yellow Underwing - Noctua pronuba", 2021)
Large yellow underwing moths are habitat generalists and can adapt to many different ecosystems. In general, they prefer open or shrubby areas, lawns, agricultural fields, and disturbed lands. However, they also occur in urban and suburban areas, especially as adults. There is currently not enough data available to assess the elevation range of large yellow underwing moths, though they have been reported higher than 1,500 m above sea level. ("Butterflies and Moths of North America", 2021)
Large yellow underwing caterpillars are green when they hatch and become reddish-brown as they age. They are patterned with a row of black dashes running down each side of their bodies. These black marks are more prominent on their posterior ends. In later instars, caterpillars develop a set of white or cream dashes directly next to the black dashes, towards their ventral sides. The presence of white or cream-colored dashes distinguishes large yellow underwing caterpillars from other species in the genus Noctua.
Large yellow underwing moth adults have light or dark brown forewings with darker markings across them, called reniform spots. These reniform spots come in 5 different patterns and vary between 3 different colors, making large yellow underwing moths a polymorphic species. Adults in European populations are also slightly sexually dimorphic: males tend to have a more mottled pattern and females tend to be lighter in color. The hindwings of large yellow underwing moths give them their common name, as they are a distinct orange-yellow color, with a black band at the posterior end of each hindwing. Wingspans range from 40 to 60 mm.
Large yellow underwing moths share physical similarities with other species in the genus, Noctua. However, lunar yellow underwing moths (Noctua orbona) and lesser yellow underwing moths (Noctua comes) are slightly smaller than large yellow underwing moths. Large yellow underwing moths are similar in size to broad-bordered yellow underwing moths (Noctua fimbriata), but the latter species is distinguished by a thicker black stripe on their hindwings. ("Invasive Species Comendium", 2021; Cook and Sarsam, 1981; Difonzo and Russell, 2010; "European Yellow Underwing", 2007; "Pacific Northwest Pest Management Handbooks", 2021)
Female large yellow underwing moths deposit groups of eggs in leaf litter or attach them to structures like leaves, stems, or fenceposts. In general, large yellow underwing caterpillars take between 2 and 4 weeks to hatch from eggs. They begin around 3 mm and grow to about 50 mm in their final instar. However, the timing of development in large yellow underwing moth caterpillars is determined by temperature. Studies show that they can hatch, pupate, and emerge as adults in as little as 32 days, provided temperatures remain around or above 25 °C. When temperatures are around 8 °C, complete metamorphosis can take up to 230 days. Caterpillars are typically active throughout winter and pupate in the soil or under forest debris in spring and summer. Chrysalids are reddish-brown, smooth and around 25 mm long. The amount of time that large yellow underwing moths spend in their pupal stage is also determined by environmental temperature. Large yellow underwing moth adults emerge throughout the spring and summer. Although adults hatch at different times, they are considered a univoltine species, with only one new generation per year. ("Invasive Species Comendium", 2021; J. Green, et al., 2016)
Although there is much yet to be studied about the mating habits of large yellow underwing moths, it is clear that they have one new generation per year, and adults live only a single season. It has also been observed that there is a period of egg maturation after mating has occurred, which lasts more than 30 days and averages 58 days. After this period, females lay their eggs on plants or in leaf litter on the ground. Based on similar species in the family Noctuidae, it is likely that large yellow underwing moths are polyandrous or polygynandrous, with females mating with multiple males and, possibly, males mating with multiple females. ("Invasive Species Comendium", 2021; Cook and Sarsam, 1981)
The reproductive cycle of large yellow underwing moths begins in the spring and summer, when newly emerged adults mate. Eggs develop internally for an average of 58 days, after which females oviposit around 100 to 300 eggs in clusters on vegetation or in detritus on the ground. Large yellow underwing caterpillars, commonly known as winter cutworms, hatch after 2 to 4 weeks and begin feeding, continuing to do so throughout winter. Large yellow underwing moths undergo complete metamorphosis. In spring, caterpillars burrow into the soil to pupate and form chrysalids. Adults emerge from their chrysalids in a matter of weeks, depending on temperature. Large yellow underwing moths often migrate before laying their eggs, giving hatchlings the potential to establish populations in new areas. ("Invasive Species Comendium", 2021; Cook and Sarsam, 1981)
Large yellow underwing moths exhibit no parental involvement beyond the acts of mating and egg-laying. Like many moth species, they lay large quantities of eggs and invest no time in the development of their offspring.
Temperate greatly impacts the lifespan of large yellow underwing moths. Larvae can take up to 230 days to pupate when temperatures are consistently low, or as little as 32 days when temperatures are consistently warm. Similarly, the time large yellow underwing moths spend as pupae is determined in part by temperature, with warmer weather allowing them to emerge more quickly, within days or weeks.
Large yellow underwing moth adults can be long-lived, relative to other moth species. Captive bred males live an average of 55 days, and captive bred females live an average of 75 days. ("Invasive Species Comendium", 2021; Cook and Sarsam, 1981)
Large yellow underwing caterpillars can be gregarious and are known to travel in large groups to feed, similar to armyworms in the family Spodoptera. However, there are also reports of solitary caterpillars and adults, and they are not a truly social species. Caterpillars forage for food nocturnally. During the day, they bury themselves up to 5 cm deep in soil, often in or around the root system of a host plant, to avoid predators. They are most active between 4 am and 4 pm, or on overcast days. Large yellow underwing caterpillars are highly tolerant of cold, and continue feeding and moving in sub-zero temperatures at very slow rates. When they feel threatened, they will curl up to form a c-shape with their body.
Large yellow underwing moths are strong fliers, and migrate distances that have not been exactly measured. Adults are also nocturnal and will commonly roost on manmade or natural structures during the day, flying in short sporadic bursts when disturbed. They are attracted to nectar and light and it is common to find both males and females in light traps, as opposed to other moth species where light traps yield a female bias. Large yellow underwing moths are typically active from June to September, often in large numbers. (Cook and Sarsam, 1981; "Magnetic Compass Sense in the Large Yellow Underwing Moth, Noctua pronuba L.", 1982; "Pacific Northwest Pest Management Handbooks", 2021)
The home range of large yellow underwing moths continues to grow as new generations of these habitat generalists migrate to new regions.
Adult European yellow underwings are attracted to light and nectar. They are known to orient themselves with the moon and stars for navigation, but can also rely on a magnetic sense to detect Earth's magnetic fields, which they use to navigate like a compass on overcast nights. ("Invasive Species Comendium", 2021; "Magnetic Compass Sense in the Large Yellow Underwing Moth, Noctua pronuba L.", 1982)
Large yellow underwing caterpillars are often gregarious and can cause damage to a wide range of plants they use as hosts. Caterpillars of the genus Noctua are commonly called "cutworms", for their habit of "cutting" plants down by feeding on their stems, leaves, foliage, and root systems. Furthermore, large yellow underwing caterpillars are known as "winter cutworms" because of their ability to withstand cold temperatures and feed throughout fall and winter. Large yellow underwing moth adults and caterpillars are primarily nocturnal, although caterpillars are also active on overcast days.
Large yellow underwing caterpillars are dietary generalists and herbivores. They feed on a variety of wild plants, cultivated crops, and ornamentals spanning 17 plant families. Crops particularly susceptible to large yellow underwing moths include beets (Beta vulgaris), cabbage and Brussels sprouts (Brassica oleracea), lettuce (Lactuca sativa), potatoes (Solanum tuberosum) and tomatoes (Solanum lycopersicum), carrots (Daucus carota), squashes (genus Cucurbita), grapes (genus Vitis), strawberries (genus Fragaria), alfalfa (Medicago sativa), yellow oat grass (Trisetum flavescens), ryegrasses (genus Lolium), tobacco (Nicotiana tabacum), and hops (Humulus lupulus). Additionally, they feed on ornamental asters (family Asteraceae) such as marigolds, dahlias, and daisies, as well as ornamental carnations (family Caryophyllaceae) and primroses (family Primulaceae). Large yellow underwing moth adults feed on nectar, often from flowers such as butterfly bushes (genus Buddleia) and valerians (genus Valeriana). ("Invasive Species Comendium", 2021; "Pacific Northwest Pest Management Handbooks", 2021)
Large yellow underwing caterpillars are hosts for a number of insect parasitoids, including ichneumon wasps (Amblyteles quadriguttorius), and tachinid flies such as (Blondelia nigripes), (Compsilura concinnata, Eurithia caesia), (Pales pavida), (Phryxe vulgaris), (Ramonda spathulata), and (Wagneria dilatata). Common predators of large yellow underwings moth adults include bats such as greater horseshoe bats (Rhinolophus ferrumequinum), lesser horseshoe bats (Rhinolophus hipposideros), and brown long-eared bats (Plecotus auritus). Other predators of both caterpillars and adult large yellow underwing moths include boxelder bugs (Boisea trivittata), birds, squirrels (genus Sciurus), and domestic animals. When disturbed, adults fly quickly and erratically for short distances, flashing their bright yellow or orange hindwings as a warning. Large yellow underwing caterpillars hide during the day and feed at night to avoid predation. Another potential defense mechanism used by caterpillars is to make certain potential predators sick. Although more research is required to establish whether large yellow underwing caterpillars are truly toxic, there are reports of domestic cats and dogs consuming large quantities of caterpillars and becoming ill. ("Invasive Species Comendium", 2021; Difonzo and Russell, 2010)
Large yellow underwing caterpillars are an important food source for many predators and parasitoids in their home ranges. They are also a generalist herbivore that can use a variety of plants as hosts. As populations grow in North America, time and research will indicate their impacts on native flora and fauna.
Because large yellow underwing moths were relatively recently introduced in North America, more studies need to be done to reveal any positive economic importance for humans in these areas. In their native range and introduced areas where they are well established, large yellow underwing moths are not considered to be of significant economic value.
Large yellow underwing caterpillars eat many common crop plants, particularly during fall and winter. This can lead to economic losses for farmers. Large yellow underwing moths are listed as minor crop pests of strawberries (genus Fragaria), potatoes (Solanum tuberosum), hops (Humulus lupulus), grasses (family Poaceae), and certain species of sapling trees in nurseries. They also feed on ornamental plants that are common in urban and suburban gardens, causing aesthetic damage or damage to protected species such as carnations and pinks (genus Dianthus).
Large yellow underwing moths pose a potential risk to domestic cats and dogs, as there are multiple documented cases of illness following mass consumption of caterpillars. However, this illness has not been linked to a disease of any kind, and more research into the toxicity of large yellow underwing moths is needed. ("Invasive Species Comendium", 2021; Difonzo and Russell, 2010; "Pacific Northwest Pest Management Handbooks", 2021)
Due to the overall success and large numbers of large yellow underwing moths throughout their native and introduced ranges, they currently have no special status on the IUCN Red List, CITES appendices, U.S. Federal List, or State of Michigan List.
Galen Burrell (editor), Special Projects.
Claire Walther (author), Special Projects.
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.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
living in landscapes dominated by human agriculture.
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.
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.
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
an animal that mainly eats leaves.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
An animal that eats mainly plants or parts of plants.
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
(as perception channel keyword). This animal has a special ability to detect the Earth's magnetic fields.
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.
makes seasonal movements between breeding and wintering grounds
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
chemicals released into air or water that are detected by and responded to by other animals of the same species
"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.
scrub forests develop in areas that experience dry seasons.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.
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).
Living on the ground.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.
living in cities and large towns, landscapes dominated by human structures and activity.
uses sight to communicate
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CABI. 2021. "Invasive Species Comendium" (On-line). Noctua pronuba (common yellow underwing moth). Accessed August 27, 2021 at https://www.cabi.org/isc/datasheet/36417.
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Copley, C., R. Cannings. 2005. Notes on the status of the Eurasia moths Noctua pronuba and Noctua comes (Lepidoptera: Noctuidae) on Vancouver Island, British Columbia. Journal of the Entomological Society British Columbia, 102: 83-84.
J. Green, , B. McDonald, E. Peachey, A. Dreves. 2016. "Oregon State University Extension Service" (On-line). Winter Cutworm: A New Pest Threat in Oregon. Accessed August 27, 2021 at https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9139.pdf.