Luna moth
Luna moth | |
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Male | |
Female | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Lepidoptera |
Family: | Saturniidae |
Genus: | Actias |
Species: | A. luna
|
Binomial name | |
Actias luna |
The luna moth (Actias luna), also called the American moon moth, is a
The moth has lime-green wings and a white body. Its caterpillars are also green. Its typical wingspan is roughly 114 mm (4.5 in), but wingspans can exceed 178 mm (7.0 in), ranking the species as one of the larger moths in North America.
Across Canada, it has one generation per year, with the winged adults appearing in late May or early June, whereas farther south it will have two or even three generations per year, the first appearance as early as March in southern parts of the United States.[2]
As
A parasitoid fly deliberately introduced to North America as a biological pest control for the invasive species spongy moth (formerly known as gypsy moth) appears to have had a negative impact on luna moths and other native moths.[6][7]
Description
Eggs, attached in small groups to undersides of leaves, are mottled white and brown, slightly oval, and roughly 1.5 millimeters in diameter.
The
There are some sex-determined and regional differences in appearance. Females will have a larger abdomen compared to males because it contains 200–400 eggs. Both sexes have antennae, but on the male, much longer and wider. Wing color is blue-green in the north and for the over-wintering generation in the central and southern states; second and third generation wing color has more of a yellow-green tint.[2]
Etymology
Described and named Phalena plumata caudata by James Petiver in 1700, this was the first North American saturniid to be reported in the insect literature.[2] The initial Latin name, which roughly translates to "brilliant, feather tail",[9] was replaced when Carl Linnaeus described the species in 1758 in the tenth edition of Systema Naturae, and renamed it Phalaena luna, later Actias luna, with luna derived from Luna, the Roman moon goddess. The common name became "Luna moth".[2] Several other North American giant silk moths were also given species names after Roman or Greek mythology.[10]
Distribution
The Luna moth is found in North America, from east of the Great Plains in the United States – Florida to Maine, and from Saskatchewan eastward through central Quebec to Nova Scotia in Canada.[2][8][11] Luna moths are also rarely found in Western Europe as vagrants.[12]
Life cycle
Based on the climate in which they live, Luna moths produce different numbers of generations per year. In Canada and northern regions of the United States they are univoltine, meaning one generation per year. Life stages are approximately 10 days as eggs, 6–7 weeks as larvae, 2–3 weeks as pupae, finishing with one week as winged adults appearing in late May or early June. In the mid-Atlantic states the species is bivoltine, and farther south trivoltine, meaning respectively two and three generations per year. In the central states the first generation appears in April, second in July. Even farther south, first generation appears as early as March, with second and third spaced eight to ten weeks later.[2]
Eggs
Females lay 200–400 eggs, singly or in small groups, on the underside of leaves of the tree species preferred by the larvae. Egg laying starts the evening after mating is completed and goes on for several days. Eggs hatch in about a week.[2][8]
Larvae
Each
Pupae
The Luna moth pupates after spinning a silk cocoon, which is thin and single layered. Shortly before pupation, the final, fifth-instar caterpillar will engage in a "gut dump" where any excess water and intestinal contents are expelled. As pupae, this species is more physically active than most moths. When disturbed, the moths will wiggle within their pupal cases, producing a noise. Pupation takes approximately two weeks unless the individual is in diapause over winter, in which case the pupal stage takes about nine months. The mechanisms triggering diapause are generally a mixture of genetic triggers, duration of sunlight and temperature. The pupae have chitinous spurs near the base of the forewings. By vigorously moving about within the cocoon, these spurs tear a circular opening from which the imago emerges, the silk of the cocoon having also been weakened by the secretion of cocoonase, a protein-digesting enzyme.[2][14]
Imago (winged)
Pupae transition to winged state after receiving external signals in the form of temperature change. When the adult Luna moths emerge from their pupae, their abdomens are swollen and their wings are small, soft and wet. The first few hours of adult life will be spent pumping
Mating
Giant silk moths have in common a mating process wherein the females, at night, release volatile sex pheromones, which the males, flying, detect via their large antennae. Males can detect these molecules at a distance of several miles, and then fly in the direction the wind is coming from until reaching the female. Luna moth females mate with the first males to find them, a process that typically starts after midnight and takes several hours.[2] Researchers extracted three chemical compounds from the pheromone gland of unmated Luna moth females and identified one major and two minor aldehyde compounds designated E6,Z11-18:Ald, E6-18:Ald and Z11-18:Ald. The same compounds were also synthesized. Field experiments with both unmated females and the synthesized compounds confirmed that E6, Z11-18:Ald was the major sex pheromone, attraction augmented by the addition of E6-18:Ald but not by Z11-18:Ald. The authors mentioned that no other moth species were attracted to either the unmated females or the synthesized products, confirming that the pheromone is species-specific, at least for the sites and dates where it was tested.[15]
Gallery of life cycle
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Eggs from female raised in captivity, laid on coarse paper
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Hatching larva
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4th-instar larva. Spots can also be yellow or magenta.
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5th-instar larva starting to create a cocoon (note silk strands to leaves)
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Pupa, removed from cocoon. Eyes visible at head end (left)
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Wings drying and enlarging after emergence from pupa
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Mating imagoes (winged adults). Male, with larger antennae, on left
Close-up images
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Antennae (male)
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Eye-spot on hindwing
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Eye-spot on forewing
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Extreme close-up of scales in eye-spot
Predators and parasites
Some species of giant silk moth larvae are known to make clicking noises when attacked by rubbing their serrated mandibles together. These clicks are audible to humans and extend into ultrasound frequencies audible to predators. Clicks are thought to be a form of aposematic warning signaling, made prior to predator-deterring regurgitation of intestinal contents. Luna moth larvae click and regurgitate, with the regurgitated material confirmed as being a predator deterrent against several species.[3]
Imagos (winged adults) of this and related night-flying Actias species collectively referred to as "moon moths" have long hindwing tails. A "false target" hypothesis holds that the tails evolved as a means of reducing risk of predation by bats which use echolocation to locate prey.[4] The moths use the spinning hindwing tails to fool bats into attacking nonessential appendages, with success occurring over 55% of the time.[16] Experiments were conducted with Luna moths with intact wings and with the tails removed. With intact wings, a majority of the attacking bats contacted the hindwing tails rather than the body of the moth; only 35% of intact moths were caught versus 81% for those with clipped tails. The results of this experiment support echolocation distortion as an effective countermeasure.[5]
The parasitoid fly Compsilura concinnata native to Europe was deliberately introduced to the United States throughout much of the 20th century as a biological control for spongy moths. Due to its flexible life cycle, it can parasitize more than 150 species of butterflies and moths in North America.[6][17] Researchers reported that when Luna moth larvae were placed outside for about a week and then collected and returned to the laboratory, four parasitic species emerged, the most common being C. concinnata. The researchers concluded that this parasitoid fly causes collateral damage to Luna moth populations.[7]
Luna moth larvae have displayed defenses against predators in late instars by developing spines once they reach about 3 cm in length. Unlike other species such as Automeris io, which have chemical defenses much earlier in the larval stage, the Luna moth larvae are left largely defenseless until it reaches this length. However, the absence of a chemical defense allows for the shortening of the larval stage. Automeris io has a larval stage at least twice as long on average as Actias luna, leaving it vulnerable to parasitism.[18]
Host plants
The larvae of Luna moths feed on several different species of
In popular culture
The Luna moth appeared on a first class United States postage stamp issued in June 1987. Although more than two dozen butterflies have been so honored,[20] as of 2019 this is the only moth.[21]
The band Big Thief references the Luna moth on their song "Strange" from the 2019 album U.F.O.F.[22]
References
- ^ "NatureServe Explorer 2.0". explorer.natureserve.org. Retrieved 20 June 2022.
- ^ ISBN 978-0801431302, retrieved 30 July 2018.
- ^ PMID 17337712.
- ^ PMID 27250152.
- ^ PMID 25730869.
- ^ a b Elkinton JS, Boettner GH (2004). "Chapter 2: The effects of Compsilura concinnata, an introduced generalist tachinid, on non-target species in North America: a cautionary tale. IN: Assessing Host Ranges of Parasitoids and Predators used for Classical Biological Control" (PDF). Forest Health Technology Enterprise Team, U.S. Dept. Agriculture. Retrieved 4 August 2018.
- ^ PMID 23425197.
- ^ a b c d e f g Hall, DW. "Luna moth – Actias luna (Linnaeus)". Featured Creatures, Entomology & Nematology Department, University of Florida. Retrieved 30 July 2018.
- ^ "Five Facts About the Luna Moth". The Infinite Spider - A Science and Nature Blog for Naturalists and Educators. 24 June 2017. Retrieved 2 August 2018.
- ^ "Our Giant Silk Moths and Ancient Mythology". National Moth Week. 2014. Retrieved 2 August 2018.
- ^ "North American map of Actias Luna". Discovery Life. Retrieved 28 July 2018.
- ^ "Rare Luna moth found in Devon... after travelling 4,000 miles from its". Evening Standard. 2008-06-11. Retrieved 2019-02-09.
- ^ Hall, D. W. (October 2019). "Common name: luna moth: scientific name: Actias (=Tropaea) luna (Linnaeus) (Insecta: Lepidoptera: Saturniidae: Saturniinae)". Featured Creatures, University of Florida. Retrieved December 6, 2021.
- ^ Hall, DW. "Polyphemus moth". Featured Creatures, Entomology & Nematology Department, University of Florida. Retrieved 8 August 2018.
- S2CID 44327978.
- PMID 25730869.
- PMID 17089674.
- S2CID 90239933.
- ^ S2CID 24487403.
- ^ "Butterflies". U.S. Stamp Gallery. Retrieved 1 August 2018.
- ^ "Luna moth". U.S. Stamp Gallery. Retrieved 1 August 2018.
- ^ "Big Thief - Strange Lyrics". Genius: Song Lyrics & Knowledge.