Cycnia tenera

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Dogbane tiger moth
Cycnia teneraPCCP20030807-2447B.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Superfamily: Noctuoidea
Family: Erebidae
Subfamily: Arctiinae
Genus: Cycnia
Species:
C. tenera
Binomial name
Cycnia tenera
(Hübner, 1818)
Synonyms
  • Hypercombe terneraHubner, 1808
  • Tanada anticaWalker, 1856
  • Arctia sciurusBoisduval, 1869
  • Euchaetes yosemitaeH. Edwards, 1883

Cycnia tenera, the dogbane tiger moth or delicate cycnia, is a moth in the family Erebidae. It occurs throughout North America, from southern British Columbia to Nova Scotia southwards to Arizona and Florida. The species is distasteful and there is evidence that it emits aposematic ultrasound signals; these may also jam bat echolocation, as the functions are not mutually exclusive.

Contents

Ecology

It is a common feeder on Apocynum cannabinum (dogbane, Indian hemp) which produces a milky latex containing cardenolides, toxic cardiac glycoside that defend against herbivores. [1] It also feeds on milkweed species, Asclepias, at least in parts of its range, but is most commonly reported from dogbane. Its interactions with bats have been much studied, but are an area of dispute regarding whether the clicks emitted by adult moths are disruptive of bat echolocation, or merely aposematic warning signals. The two functions are not mutually exclusive, however, so it may not be possible to resolve the issue. The moth's coloration appears to be aposematic for insectivorous birds. [2] Chemical signals do not prevent bats from attacking, but do cause bats to release C. tenera they have caught. [2] [3]

Life cycle

Dogbane tiger moth larva Cycnia.JPG
Dogbane tiger moth larva

This moth has several generations per year through much of its range, so caterpillars may be found from June to November. [4]

Eggs are laid in clutches of 50–100. Larvae are reported to feed in aggregations of five to seven, at least in the early instars. [1] Caterpillars are covered all over in soft grey to whitish hairs. Larvae feed at night.

Dogbane tiger moth cocoon CycniaCocoon.JPG
Dogbane tiger moth cocoon

The cocoon is grayish and covered in hairs from the caterpillar's body.

Adults have white wings with a buttery yellow margin along the front of the forewing; the legs are black. The underside of the forewing may have a dusting of black. The body is yellow with a row of black spots. The wingspan is 30–40 millimetres (1.2–1.6 in).

Ultrasound calls

Bats refuse to eat either muted or intact moths of C. tenera. [2] Hawking bats, that is, those seeking moths in flight, attacked intact, clicking C. tenera less frequently than surgically muted (with tymbal organs destroyed) moths in experiments. Intact moths emitted calls when the hunting bats switched from search phase calls to approach phase calls. [5] In gleaning attacks, when bats attack moths perched on surfaces, bats use a different frequency of sound that these moths cannot hear, [6] and the moths do not respond until actually handled by bats. Then clicking moths were dropped more frequently than mute moths.

In a set of experiments using bats that had never been exposed to moths before, Hristov and Conner found the clicking signals helped the bats to learn which moths are distasteful, and so to avoid them. [7] They did not rule out a jamming function for the calls, however, and Ratcliffe and Fullard noted 20% of these native bats aborted attacks on the moth. [2]

The calls are additionally used by male moths to signal to female moths. [8] Like many Arctiinae, C. tenera flies all day and night, though preferentially some time after dusk. Its sense of hearing, on the other hand, is only moderately well-developed. Thus, the calls of Cycnia tenera have more of a defensive than a social function, and the aposematic role is likely to be significant. [9]

Subspecies

Related Research Articles

Animal echolocation Method used by several animal species to determine location using sound

Echolocation, also called bio sonar, is a biological sonar used by several animal species. Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation, foraging, and hunting in various environments.

Luna moth Species of insect

The Luna moth is a Nearctic moth in the family Saturniidae, subfamily Saturniinae, a group commonly known as giant silk moths. It has lime-green colored wings and a white body. The larvae (caterpillars) are also green. Typically, it has a wingspan of roughly 114 mm (4.5 in), but can exceed 178 mm (7.0 in), making it 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.

Arctiinae Subfamily of moths

The Arctiinae are a large and diverse subfamily of moths, with around 11,000 species found all over the world, including 6,000 neotropical species. This group includes the groups commonly known as tiger moths, which usually have bright colours, footmen, which are usually much drabber, lichen moths, and wasp moths. Many species have "hairy" caterpillars that are popularly known as woolly bears or woolly worms. The scientific name of this subfamily refers to this hairiness. Some species within the Arctiinae have the word tussock in their common name due to people misidentifying them as members of the Lymantriinae based on the characteristics of the larvae.

Batesian mimicry Bluffing imitation of a strongly defended species

Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both. It is named after the English naturalist Henry Walter Bates, after his work on butterflies in the rainforests of Brazil.

In evolutionary biology, an evolutionary arms race is a struggle between competing sets of co-evolving genes, traits, or species, that develop adaptations and counter-adaptations against each other, resembling an arms race. These are often described as examples of positive feedback. The co-evolving gene sets may be in different species, as in an evolutionary arms race between a predator species and its prey, or a parasite and its host. Alternatively, the arms race may be between members of the same species, as in the manipulation/sales resistance model of communication or as in runaway evolution or Red Queen effects. One example of an evolutionary arms race is in sexual conflict between the sexes, often described with the term Fisherian runaway. Thierry Lodé emphasized the role of such antagonistic interactions in evolution leading to character displacements and antagonistic coevolution.

Natterers bat

Natterer's bat is a European vespertilionid bat with pale wings. It has brown fur tending to greyish-white on its underside. It is found across most of the continent of Europe, parts of the Near East and North Africa. It feeds on insects and other invertebrates which it catches on the wing or pursues on the ground.

Aposematism Honest signalling of an animals powerful defences

Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or smell, sharp spines, or aggressive nature. Aposematism always involves advertising signals, which may take the form of conspicuous coloration, sounds, odours or other perceivable characteristics. Aposematic signals are beneficial for both predator and prey, since both avoid potential harm.

Crypsis

In ecology, crypsis is the ability of an animal to avoid observation or detection by other animals. It may be a predation strategy or an antipredator adaptation. Methods include camouflage, nocturnality, subterranean lifestyle and mimicry. Crypsis can involve visual, olfactory, or auditory concealment. When it is visual, the term cryptic coloration, effectively a synonym for animal camouflage, is sometimes used, but many different methods of camouflage are employed by animals.

Garden tiger moth Species of moth

The garden tiger moth or great tiger moth is a moth of the family Erebidae. Arctia caja is a northern species found in the US, Canada, and Europe. The moth prefers cold climates with temperate seasonality, as the larvae overwinter, and preferentially chooses host plants that produce pyrrolizidine alkaloids. However, garden tiger moths are generalists, and will pick many different plants to use as larval host plants.

Western barbastelle Species of bat

The western barbastelle, also known as the barbastelle or barbastelle bat, is a European bat in the genus Barbastella. This species is found from Portugal to Azerbaijan and from Sweden to Canary Islands, where a sub-species was identified. It has a short nose, small eyes and wide ears. The conservation status of B. barbastellus is assessed as "Near Threatened", "Vulnerable", "Critically Endangered" or "Extinct" in various parts of its range.

<i>Euchaetes egle</i> Species of moth

Euchaetes egle, the milkweed tiger moth or milkweed tussock moth, is a moth in the family Erebidae and the tribe Arctiini, the tiger moths. The species was first described by Dru Drury in 1773. It is a common mid- through late-summer feeder on milkweeds and dogbane. Like most species in this family, it has chemical defenses it acquires from its host plants, in this case, cardiac glycosides. These are retained in adults and deter bats, and presumably other predators, from feeding on them. Only very high cardiac glycoside concentrations deterred bats, however. Adults indicate their unpalatability with clicks from their tymbal organs.

<i>Halysidota tessellaris</i> Species of moth

Halysidota tessellaris, also called the pale tiger moth, banded tussock moth, and tessellated halisidota, is in the family Erebidae and the tribe Arctiini, the tiger moths. The species was first described by James Edward Smith in 1797. Like many related species, adult moths have chemical defenses acquired from its host plants, in this case, alkaloids. Larval behaviors suggest that they are chemically protected; they have not been analyzed for alkaloid content.

Whispering is an unvoiced mode of phonation in which the vocal folds are abducted so that they do not vibrate; air passes between the arytenoid cartilages to create audible turbulence during speech. Supralaryngeal articulation remains the same as in normal speech.

Aganainae Subfamily of moths

The Aganainae are a small subfamily of moths in the family Erebidae. The adults and caterpillars of this subfamily are typically large and brightly colored, like the related tiger moths. Many of the caterpillars feed on poisonous host plants and acquire toxic cardenolides that make them unpleasant to predators. Like the closely related litter moths, the adults have long, upturned labial palps, and the caterpillars have fully or mostly developed prolegs on the abdomen. The Aganainae are distributed across the tropics and subtropics of the Old World.

<i>Parasemia plantaginis</i> Species of moth

Parasemia plantaginis, the wood tiger, is a moth of the family Erebidae. Several subspecies are found in the Holarctic ecozone south to Anatolia, Transcaucasus, northern Iran, Kazakhstan, Mongolia, China, Korea and Japan. One subspecies is endemic to North America.

Tymbal

The tymbal is the corrugated exoskeletal structure used to produce sounds in insects. In male cicadas, the tymbals are membranes in the abdomen, responsible for the characteristic sound produced by the insect. In tiger moths, the tymbals are modified regions of the thorax, and produce high-frequency clicks. In lesser wax moths the left and right tymbals emit high frequency pulses that are used as mating calls.

<i>Utetheisa ornatrix</i> Species of moth

Utetheisa ornatrix, also called the bella moth, ornate moth or rattlebox moth is a moth of the subfamily Arctiinae. It is aposematically colored ranging from pink, red, orange and yellow to white coloration with black markings arranged in varying patterns on its wings. It has a wingspan of 33–46 mm. Moths reside in temperate midwestern and eastern North America as well as throughout Mexico and other parts of Central America. Unlike most moths, the bella moth is diurnal. Formerly, the bella moth or beautiful utetheisa of temperate eastern North America was separated as Utetheisa bella. Now it is united with the bella moth in Utetheisa ornatrix.

Ultrasound avoidance is an escape or avoidance reflex displayed by certain animal species that are preyed upon by echolocating predators. Ultrasound avoidance is known for several groups of insects that have independently evolved mechanisms for ultrasonic hearing. Insects have evolved a variety of ultrasound-sensitive ears based upon a vibrating tympanic membrane tuned to sense the bat's echolocating calls. The ultrasonic hearing is coupled to a motor response that causes evasion of the bat during flight.

Deimatic behaviour

Deimatic behaviour or startle display means any pattern of bluffing behaviour in an animal that lacks strong defences, such as suddenly displaying conspicuous eyespots, to scare off or momentarily distract a predator, thus giving the prey animal an opportunity to escape. The term deimatic or dymantic originates from the Greek δειματόω (deimatόo), meaning "to frighten".

Echolocation systems of animals, like human radar systems, are susceptible to interference known as echolocation jamming or sonar jamming. Jamming occurs when non-target sounds interfere with target echoes. Jamming can be purposeful or inadvertent, and can be caused by the echolocation system itself, other echolocating animals, prey, or humans. Echolocating animals have evolved to minimize jamming; however, echolocation avoidance behaviors are not always successful.

References

  1. 1 2 James A. Cohen & Lincoln P. Brower (1983). "Cardenolide sequestration by the dogbane tiger moth". Journal of Chemical Ecology . 9 (4): 521–531. doi:10.1007/BF00990224.
  2. 1 2 3 4 John M. Ratcliffe & James H. Fullard (2005). "The adaptive function of tiger moth clicks against echolocating bats: an experimental and synthetic approach". Journal of Experimental Biology . 208 (24): 4689–4698. doi: 10.1242/jeb.01927 . PMID   16326950.
  3. Barber, J. R.; Conner, W. E. (2007). "Acoustic mimicry in a predator prey interaction". Proceedings of the National Academy of Sciences of the United States of America. 104 (22): 9331–9334. Bibcode:2007PNAS..104.9331B. doi:10.1073/pnas.0703627104. PMC   1890494 . PMID   17517637.
  4. David L. Wagner (2005). Caterpillars of Eastern North America: a Guide to Identification and Natural History. Princeton University Press. ISBN   978-0-691-12144-4.
  5. James H. Fullard, James A. Simmons & Prestor A. Saillant (1994). "Jamming bat echolocation: the dogbane tiger moth times its clicks to the terminal attack calls of the big brown bat Eptesicus fuscus" (PDF). Journal of Experimental Biology . 194: 285–298. PMID   7964403.
  6. James H. Fullard (1979). "Behavioral analyses of auditory sensitivity in Cycnia tenera (Lepidoptera: Arctiidae)". Journal of Comparative Physiology . 129 (1): 79–83. doi:10.1007/BF00679914.
  7. Nickolay I. Hristov & William E. Conner (2005). "Sound strategy: acoustic aposematism in the bat–tiger moth arms race". Naturwissenschaften . 92 (4): 164–169. Bibcode:2005NW.....92..164H. doi:10.1007/s00114-005-0611-7. PMID   15772807.
  8. W. E. Conner (1987). "Ultrasound: its role in the courtship of the arctiid moth, Cycnia tenera". Experientia . 43 (9): 1029–1031. doi:10.1007/BF01952230.
  9. James H. Fullard & Nadia Napoleone (2001). "Diel flight periodicity and the evolution of auditory defences in the Macrolepidoptera" (PDF). Animal Behaviour . 62 (2): 349–368. doi:10.1006/anbe.2001.1753. Archived from the original (PDF) on 2007-06-15.

Further reading