wing coupling
File:Lepidoptera Psychidae Oiketicus freno o frenulo.jpg spp. (family Psychidae). The frenulum can be seen at the top of the rear wing, which hooks onto the retinaculum, seen here as a small brush on the front wing, so that the wings travel together during flight. Magnification: 10x]]
Some four-winged insect orders, such as the Lepidoptera, have developed a wide variety of morphological wing coupling mechanisms in the imago which render these taxa as "functionally dipterous" (effectively two-winged) for efficient insect flight.{{cite book |title=The biomechanics of insect flight: form, function, evolution |last=Dudley |first=Robert |edition=Reprint, illustrated |year=2002 |publisher=Princeton University Press |isbn=978-0-691-09491-5 |pages=476 }} All but the most basal forms exhibit this wing coupling.{{cite book |last1=Stocks |first1=Ian|editor1-first=John L.|editor1-last=Capinera |title=Encyclopedia of Entomology|url=https://books.google.com/books?id=i9ITMiiohVQC |edition=2 |series=Gale virtual reference library|volume=4 |year=2008 |publisher=Springer Reference |isbn=978-1-4020-6242-1 |pages=4345 |chapter=Wing coupling |access-date=14 November 2010}}{{Rp|4266}}
The mechanisms are of three different types - jugal, frenulo-retinacular and amplexiform.{{cite book|title=The Lepidoptera: form, function and diversity |last=Scoble |first=M.J. |year=1995|publisher=Oxford University Press |edition= Reprint (illustrated) |isbn=978-0-19-854952-9 |pages=416 |url=https://books.google.com/books?id=gnpd_5iNTiwC |access-date=14 November 2010}} Subsec. "Wing coupling". Pp 56-60.
Jugal wing coupling
The more primitive groups of moth have an enlarged lobe-like area near the basal posterior margin, i.e. at the base of the forewing, called {{anchor|jugum}}jugum, that folds under the hindwing in flight.{{cite book |last1=Powell |first1=Jerry A.|editor2-last=Cardé |editor2-first=Ring T.|editor1-first=Vincent H. |editor1-last=Resh |title=Encyclopedia of Insects|url=https://books.google.com/books?id=wrMcPwAACAAJ|access-date=14 November 2010 |edition=2 (illustrated)|year=2009 |publisher=Academic Press|isbn=978-0-12-374144-8 |pages=1132|chapter=Lepidoptera }}{{rp|631-664}}
Frenulo-retinacular wing coupling
File:Frenulo-retinacular wing coupling in male and female moths.png
Other groups of moth have a frenulum on the hindwing that hooks under a retinaculum on the forewing. The {{anchor|retinaculum}}retinaculum is a hook or tuft on the underside of the forewing of some moths. Along with the {{anchor|frenulum}}frenulum, a spine at the base of the forward or costal edge of the hindwing, it forms a coupling mechanism for the front and rear wings of the moth.
Amplexiform wing coupling
In the butterflies{{efn|The male of one species of hesperiid (skipper) butterfly does have wing couplings.}} and in the Bombycoidea{{efn|The Sphingidae (hawk moths) however do have wing couplings.}}, there is no arrangement of frenulum and retinaculum to couple the wings. Instead, an enlarged humeral area of the hindwing is broadly overlapped by the forewing. Despite the absence of a specific mechanical connection, the wings overlap and operate in phase. The power stroke of the forewing pushes down the hindwing in unison. This type of coupling is a variation of frenate type but where the frenulum and retinaculum are completely lost.{{cite book |title=Attachment devices of insect cuticle |last=Gorb |first=Stanislav |chapter=Inter-locking of body parts |year=2001 |publisher=Springer |isbn=978-0-7923-7153-3 |pages=305 |url=https://books.google.com/books?id=aiSOCbk3LRsC |access-date=16 November 2010}}
Notes
{{notelist}}
References
{{reflist|28em}}
Sources
- Pinhey, E (1962). Hawk Moths of Central and Southern Africa. Longmans Southern Africa, Cape Town.