Cycnia tenera

From Wikipedia, the free encyclopedia

iDogbane Tiger-moth

Image:Cycnia teneraPCCP20030807-2447B.jpg

Scientific classification

Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Superfamily:	Noctuoidea
Family:	Arctiidae
Subfamily:	Arctiinae
Genus:	Cycnia
Species:	C. tenera Hubner, 1818

Cycnia tenera, the Dogbane tiger-moth or Delicate Cycnia is a moth in the family Arctiidae.

It is a common feeder on dogbane or Indian hemp, Apocynum cannabinum which produces a milky latex containing cardenolide (cardiac glycoside) toxins that are used for anti-predator defense (Cohen and Brower, 1983). It also feeds on milkweed species, Asclepias (Cohen and Brower 1983), 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 that it may not be possible to resolve the issue.

1 Range
2 Life cycle
3 Ultrasound calls
4 References
5 External links

[edit] Range

Throughout North America, from southern British Columbia to Nova Scotia southwards to Arizona to Florida. Range map: [1].

[edit] Life cycle

Several generations per year through much of its range, so that caterpillars may be found from June to November (Wagner 2005).

Image:Cycnia.JPG

[edit] Larvae

Eggs are laid in clutches fo 50-100. Larvae are reported to feed in aggregations of 5 to 7, at least in the early instars (Cohen and Brower, 1983). Caterpillars are covered all over in soft grey to whitish hairs. Larvae feed at night.

Image:CycniaCocoon.JPG

[edit] Pupae

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

[edit] Adults

Wings are white with a buttery yellow margin along the front of the forewing and black legs. The underside of the forewing may have a dusting of black. The body is yellow with a row of black spots. Wingspan 30-40 mm.

[edit] Ultrasound calls

Bats refuse to eat either muted or intact moths of C. tenera (Ratcliffe and Fullard, 2005). 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 (Fullard et al., 1994). In gleaning attacks, when bats attack moths perched on surfaces, bats use a different frequency of sound that moths cannot hear (Fullard 1979), 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 (2005) found that the clicking signals helped the bats to learn which moths are distasteful, and so to avoid them. They did not rule out a jamming function for the calls, however, and Ratcliffe and Fullard noted that 20% of these naive bats aborted attacks on the moth.

The calls are additionally used by male moths to signal to female moths (Conner 1987).

[edit] References

Cohen, JA and LP Brower (1983). Cardenolide sequestration by the dogbane tiger moth. J. Chem. Ecol. 9, 521-531.

Conner WE (1987) Ultrasound: its role in the courtship of the arctiid moth, Cycnia tenera. Experientia 43: 1029–1031.

Fullard, JH (1979) Behavioral analyses of auditory sensitivity in Cycnia tenera (Lepidoptera: Arctiidae). J. Comp. Physiol. 129, 79-83.

Fullard, JH (1984) Listening for bats: pulse repetition rate as a cue for a defensive behavior in Cycnia tenera Hübner (Lepidoptera: Arctiidae). J. Comp. Physiol. A 154, 249-252.

Fullard, JH, JA Simmons and PA Saillant (1994) Jamming bat echolocation: the dogbane tiger moth times its clicks to the terminal attack calls of the big brown bat Eptesicus fuscus. J. Exp. Biol. 194, 285-298.

Hristov, NI, and WE Conner (2005). Sound strategy: acoustic aposematism in the bat-moth arms race. Naturwissenschaften 92, 164-169.

Scoble, MJ. (1995) The Lepidoptera: Form, Function and Diversity. Second ed. Oxford University Press.

Wagner, DL, (2005) Caterpillars of Eastern North America. Princeton University Press.

Waters, D. A. (2003) Bats and moths: what is there left to learn? Physiol. Entomol. 28, 237-250.

Weller, SJ, NL Jacobson and WE Connor (1999) The evolution of chemical defenses and mating systems in tiger moths (Lepidoptera: Arctiidae). Biol. J. Linn. Soc. 68, 557-578.