Instar: Difference between revisions
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An '''instar''' (from the Latin "form", "likeness") is a developmental stage of [[arthropods]], such as [[insects]], between each [[ecdysis|molt]] (''ecdysis''), until [[sexual maturity]] is reached.<ref>Allaby, Michael: ''A Dictionary of Ecology'', page 234. Oxford University Press, USA, 2006.</ref> Arthropods must shed the [[exoskeleton]] in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or changes in the number of body segments. Some arthropods can continue to molt after sexual maturity, but these subsequent molts are generally not called instars. |
An '''instar''' (from the Latin "form", "likeness") is a developmental stage of [[arthropods]], such as [[insects]], between each [[ecdysis|molt]] (''ecdysis''), until [[sexual maturity]] is reached.<ref>Allaby, Michael: ''A Dictionary of Ecology'', page 234. Oxford University Press, USA, 2006.</ref> Arthropods must shed the [[exoskeleton]] in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or changes in the number of body segments. Some arthropods can continue to molt after sexual maturity, but these subsequent molts are generally not called instars. |
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For most insect species the term ''instar'' is used to denote the developmental stage of the [[larva]]l or [[Nymph (biology)|nymph]]al forms of [[holometabolous]] (complete metamorphism) or [[hemimetabolous]] (incomplete metamorphism) insects, but the term can be used to describe any developmental stage including [[pupa]] or [[imago]] (the adult, which does not molt in insects). |
For most insect species, the term ''instar'' is used to denote the developmental stage of the [[larva]]l or [[Nymph (biology)|nymph]]al forms of [[holometabolous]] (complete metamorphism) or [[hemimetabolous]] (incomplete metamorphism) insects, but the term can be used to describe any developmental stage including [[pupa]] or [[imago]] (the adult, which does not molt in insects). |
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[[Image:Common_mormon_(Papilio_Polyetes)_catapillars.jpg|thumb|300px|Two instars of a caterpillar of ''[[Papilio polytes]]'']] |
[[Image:Common_mormon_(Papilio_Polyetes)_catapillars.jpg|thumb|300px|Two instars of a caterpillar of ''[[Papilio polytes]]'']] |
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The number of instars an insect undergoes depends on the species and the environmental conditions. Lower temperatures and humidity often slow the rate of development. |
The number of instars an insect undergoes depends on the species and the environmental conditions. Lower temperatures and humidity often slow the rate of development. |
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Revision as of 03:15, 6 January 2014
An instar (from the Latin "form", "likeness") is a developmental stage of arthropods, such as insects, between each molt (ecdysis), until sexual maturity is reached.[1] Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or changes in the number of body segments. Some arthropods can continue to molt after sexual maturity, but these subsequent molts are generally not called instars.
For most insect species, the term instar is used to denote the developmental stage of the larval or nymphal forms of holometabolous (complete metamorphism) or hemimetabolous (incomplete metamorphism) insects, but the term can be used to describe any developmental stage including pupa or imago (the adult, which does not molt in insects).
_catapillars.jpg)
The number of instars an insect undergoes depends on the species and the environmental conditions. Lower temperatures and humidity often slow the rate of development.
References
The dictionary definition of instar at Wiktionary
- ^ Allaby, Michael: A Dictionary of Ecology, page 234. Oxford University Press, USA, 2006.
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