nymph (biology)
{{Short description|Immature form of some invertebrates}}
File:Schistocerca gregaria (21530461886).jpg nymphs beside an adult]]
In biology, a nymph (from Ancient Greek νύμφα nūmphē meaning "bride") is the juvenile form of some invertebrates, particularly insects, which undergoes gradual metamorphosis (hemimetabolism) before reaching its adult stage.Encyclopedia of Entomology Ed. John L. Capinera. Dordrecht, London, Springer. 2008, 2nd Ed. {{ISBN|978-1-4020-6242-1}} (Print) 978-1-4020-6359-6 (Online) Unlike a typical larva, a nymph's overall form already resembles that of the adult, except for a lack of wings (in winged species) and the emergence of genitalia. In addition, while a nymph moults, it never enters a pupal stage. Instead, the final moult results in an adult insect.{{cite journal |last=Truman |first=James |title=The origins of insect metamorphosis |journal=Nature |year=1999 |volume=401 |issue=6752 |pages=447–52 |doi=10.1038/46737 |pmid=10519548 |bibcode=1999Natur.401..447T |s2cid=4327078 |url=https://scholar.google.com/ |url-status=dead |archive-url=https://web.archive.org/web/20140131002221/http://scholar.google.com/ |archive-date=2014-01-31 }} Nymphs undergo multiple stages of development called instars.
Taxa with nymph stages
File:28383-adult-nymph-i-scapularis.webp adult and nymph, left and right. ]]
File:Brown hawker dragonfly (Aeshna grandis) dragonfly nymph late instar.JPG nymphs are aquatic, unlike the adult form. (pictured: Aeshna grandis)]]
Many species of arthropods have nymph stages. This includes the insect orders such as Orthoptera (crickets, grasshoppers and locusts), Hemiptera (cicadas, shield bugs, whiteflies, aphids, leafhoppers, froghoppers, treehoppers), mayflies, termites, cockroaches, mantises, stoneflies and Odonata (dragonflies and damselflies).{{cite web |url=http://australianmuseum.net.au/metamorphosis-a-remarkable-change |title=Metamorphosis: a remarkable change |author=Britton, David |date=9 July 2009 |publisher=Australian Museum |access-date=13 July 2015}} Arachnids such as spiders, mites, and ticks also have nymphs.
Nymphs of aquatic insects, as in the Odonata, Ephemeroptera, and Plecoptera orders, are also called naiads, an Ancient Greek name for mythological water nymphs. Some entomologists have said that the terms larva, nymph and naiad{{Cite journal |last1=Bybee |first1=Seth M. |last2=Hansen |first2=Quinn |last3=Büsse |first3=Sebastian |last4=Cahill Wightman |first4=Haley M. |last5=Branham |first5=Marc A. |date=2015 |title=For consistency's sake: the precise use of larva, nymph and naiad within Insecta|journal=Systematic Entomology |language=en |volume=40 |issue=4 |pages=667–670 |doi=10.1111/syen.12136|s2cid=83922500 |doi-access=free }} should be used according to the developmental mode classification (hemimetabolous, paurometabolous or holometabolous) but others have pointed out that there is no real confusion.{{cite journal |last1=Redei |first1=David |last2=Stys |first2=Pavel |title=Larva, nymph and naiad - for accuracy's sake. |journal= Systematic Entomology|date=July 2016 |volume=41 |issue=3 |pages=505–510 |doi=10.1111/syen.12177 |s2cid=87053533 |issn=0307-6970|doi-access=free |bibcode=2016SysEn..41..505R }} In older literature, these were sometimes referred to as the heterometabolous insects, as their adult and immature stages live in different environments (terrestrial vs. aquatic).{{cite journal |last=Tutt |first=J. W.|title=The Nature of Metamorphosis|journal=Proceedings of the South London Entomological & Natural History Society |date=1897 |url=https://archive.org/details/proceedingsofsou18981900sout/page/n191/mode/2up |pages=20–27|access-date=17 August 2020}}
Second Egg Hypothesis
In 1628, English physician William Harvey published An Anatomical Disquisition on the Motion of the Heart and Blood in Animals. In his writing, Harvey hypothesized that the pupal stage in insects was the result of imperfect eggs. While some eggs produced smaller versions of fully-matured insects known as nymphs, others created intermediate forms. Thus, these intermediate forms must go through a second egg stage to reach their adult form. This hypothesis attempts to explain the developmental differences between hemimetabolous and holometabolous metamorphosis. Though there is little evidence supporting Harvey's hypothesis, it is still significant to modern research in nymphs.{{How|date=April 2024}}
Relationship with humans
File:Pheasant Tail Nymph.jpg attracts trout by imitating a brown aquatic insect larva.|left]]
In fly fishing with artificial flies, this stage of aquatic insects is the basis for an entire series of representative patterns for trout.{{cite web |last=Austin |first=Matthew |title=Nymph patterns of flies |year=2004 |publisher=theflystop.com |location=San Diego |url=http://www.theflystop.com/fly-fishing-flies-discount/nymphs}} They account for over half of the fishing fly patterns regularly used in the United States.
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References
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External links
- {{Commons category inline|Nymphs (biology)}}
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