Instar

From Free net encyclopedia

Image:Eposlarvae.jpgAn instar is a developmental stage of arthropods, such as insects, between each molt. Arthropods must shed the exoskeleton in order to grow or assume a new form. For most insect species the term "instar" is used to denote the developmental stage of the larval or nymphal forms of holometabolous or hemimetabolous insects, however the term can be used to describe any developmental stage including pupa or imago. Differences between instars can often be seen in altered body proportions or changes in the number of body segments. The number of instars an insect completes depends on the species and the environmental conditions with cooler temperatures and lower humidity often slowing developmental rates.