Manduca sexta
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2008-07-16T14:34:33Z
Trfasulo
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added UF FC external link
{{Taxobox
| name = Tobacco Hornworm
| status = LC
| image = Tomato_Hornworm.jpg
| image_width = 250px
| regnum = [[Animal]]ia
| phylum = [[Arthropod]]a
| classis = [[Insect]]a
| ordo = [[Lepidoptera]]
| familia = [[Sphingidae]]
| genus = ''[[Manduca]]''
| species = '''''M. sexta'''''
| binomial = ''Manduca sexta''
| binomial_authority = [[Carolus Linnaeus|Linnaeus]], [[1763]]
}}
'''''Manduca sexta''''' [[Linneus#Linnaean_taxonomy|L.]] is a moth of the family [[Sphingidae]] present through much of the [[The Americas|American]] continent. Commonly known as the '''tobacco hornworm''', it is closely related to and often confused with the very similar [[tomato hornworm]] (''Manduca quinquemaculata''); the [[Larva|larvae]] of both feed on the foliage of various plants from the family [[Solanaceae]]. The tobacco hornworm can be distinguished by its seven diagonal lines on its sides; tomato hornworms have eight V-shaped markings <ref>{{cite web | url=http://creatures.ifas.ufl.edu/field/hornworm.htm | title=Tobacco Hornworm |accessdate=2006-10-21 |last=Villanueva |first=Raul |year=1998 |month=June }}</ref>. An easy way to remember the markings is tobacco hornworms have straight white lines like cigarettes, while tomato hornworms have V-shaped markings as in V8 juice. ''M. sexta'' has mechanisms for selectively sequestering and secreting the [[neurotoxin]] [[nicotine]] present in tobacco.
''M. sexta'' is a common [[model organism]], especially in [[neurobiology]], due to its easily accessible [[nervous system]] and short life cycle. It is used in a variety of biomedical and biological scientific experiments. It can be easily raised on a wheat-germ based diet. The larva is large and thus relatively easy to [[Dissection|dissect]] and isolate organs from.
== Life cycle ==
''M. sexta'' have a short life cycle, lasting about 30 to 50 days. In most areas, ''M. sexta'' have about two generations per year, but they can have about three or four generations per year in [[Florida]].<ref>{{cite web |url=http://bugs.clemson.edu/museum/moths/local/moth1.htm | title=Manduca sexta "Carolina sphinx" |accessdate=2006-10-21 |last=Eichman |first=Aaron |coauthors=Weston Tripp, Matt Edwards |year=2000 }}</ref>
=== Eggs ===
''M. sexta'' [[Egg (biology)|eggs]] are spherical, approximately 1 millimeter in diameter, and translucent green in color. They typically hatch 2–4 days after they are laid. Eggs are normally found on the underside of foliage, but can also be found on the upper surface.
=== Larvae ===
[[Image:Tobacco Hornworm.png|thumb|left|130px|''M. sexta'' larva]][[Image:Tomato Hornworm 1.JPG|thumb|A tobacco hornworm with parasitic wasp cocoons.]]
[[Image:TomatoHornworm feces.jpg|thumb|150px|Hornworm caterpillars and their fecal material]]
''M. sexta'' larvae are green in color and grow up to 70 millimeters in length. Under laboratory conditions, while fed a wheat-germ based diet, larvae are turqouise due to a lack of pigments in their diet. ''M. sexta'' blood contains the blue-colored protein insecticyanin. When the larva feeds on plants it ingests [[pigment|pigmentacious]] [[carotenoid]] proteins. Carotenoids are primarily yellow in hue. When bound together, the protein complex is green.
During the [[larva]]l stage, ''M. sexta'' caterpillars feed on plants of the family [[Solanaceae]], principally [[tobacco]]. Near the end of this stage, the caterpillar seeks a location for [[pupa]]tion, burrows underground, and pupates. The searching behaviour is known as "wandering." The instinct of wandering can be visually confirmed by spotting the heart (aorta) which is a long, pulsating vein running along the length of the caterpillar's dorsal side. The heart appears just as the caterpillar is reaching its final instar. ''M. sexta'' has five larval [[instar]]s which are separated by [[ecdysis]] (molting).
A common [[biological pest control|biological control]] for hornworms is the [[parasitism|parasitic]] [[Braconidae|braconid wasp]], ''[[Cotesia]]'', which lays its eggs in the bodies of tobacco hornworms. The wasp larvae feed internally, and emerge from the body to spin their [[Cocoon (silk)|cocoons]]. Parasitized tobacco hornworms are often seen covered with multiple white, [[cotton]]y wasp cocoons, which are often mistaken for large eggs.
=== Pre-pupae ===
[[Image:Manduca_Sexta_pre-pupa.JPG|thumb|left|150px|Tobacco hornworm pre-pupa]]
Before the larva pupates, it goes through a stage called the pre-pupa, where its shrinks considerably and prepares to pupate. Often, people mistake this stage as a dead, or dying, caterpillar.
=== Pupae ===
The pupal stage lasts approximately 18 days under laboratory conditions (17 hours light, 7 hours dark, 27°C). When reared on a short-day [[photoperiod]] (12 hours light, 12 hours dark), pupae enter a state of diapause that can last several months. During the pupal stage, structures of the adult moth form within the pupal case which is shed during [[eclosion]] (adult emergence).
=== Adults ===
Adult ''M. sexta'' are known as Carolina Sphinx moths. ''M. sexta'' moths are [[nectarivorous]] and feed on flowers, demonstrating a remarkable ability to hover.
Adult males and females are sexually dimorphic. Males are identifiable by their broader [[Antenna (biology)|antennae]]. Female moths are typically ready to mate one week after [[eclosion]], and do so only once. Males may mate many times. Mating generally occurs on a vertical surface at night, and can last several hours, with the male and female facing in opposite positions, their posterior ends touching. After mating, females deposit their fertilized eggs on foliage, usually on the underside of leaves.
<gallery>
Image:Manduca sexta female sjh.JPG | Tobacco hornworm adult female
Image:Manduca sexta male sjh.JPG | Tobacco hornworm adult male
Image:Manduca sexta diversity sjh.JPG | Tobacco hornworm diversity
<!-- Image with unknown copyright status removed: Image:Tobacco Hornworm moth 1.jpg| Tobacco hornworm adult -->
</gallery>
==References==
<references/>
==External links==
{{Commons|Manduca sexta}}
{{Wikispecies|Manduca sexta}}
*[http://www.superworm.ca Canadian Hornworm supplier]
*[http://www.colostate.edu/Depts/CoopExt/4DMG/Pests/tomato.htm Hornworm description at Colorado State]
*[http://ohioline.osu.edu/hyg-fact/2000/2113.html Nuisance Parasitic Wasps at Ohio State University Extension]
*[http://www.npwrc.usgs.gov/resource/distr/lepid/moths/usa/1081.htm Moths of North America]
*[http://creatures.ifas.ufl.edu/field/hornworm.htm tobacco hornworm] on the [[UF]] / [[IFAS]] Featured Creatures Web site
[[Category:Moths]]
[[Category:Pest insects]]
[[Category:Tomato pathogens and pests]]
[[de:Tabakschwärmer]]
[[fr:Sphinx du tabac]]
[[ja:タバコスズメガ]]
[[no:Tobakksvermer]]