Editing Damselfly (section)

===Life cycle===
Damselflies are [[Hemimetabolism|hemimetabolous]] insects that have no pupal stage in their development.<ref>{{cite book|title=A Dictionary of Entomology|url=https://books.google.com/books?id=9IcmCeAjp6cC&pg=PA679 |year=2011 |publisher=CABI |isbn=978-1-84593-542-9 |page=679}}</ref> The female inserts the eggs by means of her ovipositor into slits made in water plants or other underwater [[Substrate (biology)|substrates]] and the larvae, known as naiads or nymphs, are almost all completely aquatic.<ref name=Paulson2011/> Exceptions include the Hawaiian ''[[Megalagrion oahuense]]'' and an unidentified Megapodagrionid from New Caledonia,<ref>{{cite journal |journal=Psyche: A Journal of Entomology |volume=62 |issue=4 |year=1955 |title=A terrestrial damselfly nymph (Medapodarionidae) from New Caledonia |author=Willey, Ruth Lippitt |pages=137–144 |url=http://downloads.hindawi.com/journals/psyche/1955/039831.pdf |doi=10.1155/1955/39831|doi-access=free }}</ref> which are terrestrial in their early stages.<ref name=Carde/> The [[Lestidae|spreadwings]] lay eggs above the waterline late in the year and the eggs overwinter, often covered by snow. In spring they hatch out in the meltwater pools and the nymphs complete their development before these temporary pools dry up.<ref name=Acorn/>

The nymphs are voracious [[Predation|predators]] and feed by means of a flat [[Insect mouthparts#Labium|labium]] (a toothed mouthpart on the lower jaw) that forms the so-called mask; it is rapidly extended to seize and pierce the ''[[Daphnia]]'' (water fleas), [[mosquito]] larvae, and other small aquatic organisms on which damselfly nymphs feed. They breathe by means of three large external, fin-like gills on the tip of the abdomen, and these may also serve for locomotion in the same manner as a fish's tail.<ref name=Paulson2011/> Compared to dragonfly larvae, the nymphs show little variation in form. They tend to be slender and elongate, many having morphological adaptations for holding their position in fast flowing water. They are more sensitive than dragonfly nymphs to oxygen levels and suspended fine particulate matter, and do not bury themselves in the mud.<ref name=Heckman>{{cite book |author=Heckman, Charles W. |title=Encyclopedia of South American Aquatic Insects: Odonata - Zygoptera: Illustrated Keys to Known Families, Genera, and Species in South America |url=https://books.google.com/books?id=PG_td3hm7XoC&pg=PA17 |year=2008 |publisher=Springer |isbn=978-1-4020-8176-7 |pages=17, 31–33}}</ref>

The nymphs proceed through about a dozen moults as they grow. In the later stages, the wing pads become visible. When fully developed, the nymphs climb out of the water and take up a firm stance, the skin on the thorax splits and the adult form wriggles out. This has a soft body at first and hangs or stands on its empty larval case. It pumps haemolymph into its small limp wings, which expand to their full extent. The haemolymph is then pumped back into the abdomen, which also expands fully. The [[exoskeleton]] hardens and the colours become more vivid over the course of the next few days. Most damselflies emerge in daytime, and in cool conditions the process takes several hours. On a hot day, the cuticle hardens rapidly and the adult can be flying away within half an hour.<ref name=Paulson2011/>

<gallery widths="200" heights="200">
File:Blue-tailed damselfly (Ischnura elegans) nymph.jpg|Blue-tailed damselfly (''[[Ischnura elegans]]'') nymph, showing the three tail appendages
File:Damselfly emergence-Aralam-2016-10-29-001.jpg|''[[Prodasineura verticalis]]'' female emerging from the [[exuviae|split skin of the nymph]]
</gallery>