Editing Dragonfly (section)

=== Life cycle ===

[[File:Larve d'Anax empereur.JPG|thumb|left|Nymph of emperor dragonfly, ''[[Anax imperator]]'']]
[[File:Dragonfly naiad mask.jpg|thumb|Illustration of a naiad with mask extended]]

Dragonflies are [[Hemimetabolism|hemimetabolous]] insects; they do not have a [[pupa]]l stage and undergo an incomplete [[metamorphosis]] with a series of nymphal stages from which the adult emerges.<ref name=IFAS>{{cite web |url=http://entomology.ifas.ufl.edu/creatures/misc/odonata/odonata.htm |title=Dragonflies and damselflies: Odonata |author=Bybee, Seth |date=1 May 2012 |work=Featured Creatures |publisher=University of Florida: Entomology and Nematology |access-date=1 March 2015}}</ref> Eggs laid inside plant tissues are usually shaped like grains of rice, while other eggs are the size of a pinhead, ellipsoidal, or nearly spherical. A clutch may have as many as 1500 eggs, and they take about a week to hatch into aquatic [[Nymph (biology)|nymphs]] or naiads which moult between six and 15 times (depending on species) as they grow.<ref name=diversity /> Most of a dragonfly's life is spent as a nymph, beneath the water's surface. The nymph extends its hinged labium (a toothed mouthpart similar to a lower mandible, which is sometimes termed as a "mask" as it is normally folded and held before the face) that can extend forward and retract rapidly to capture prey such as [[mosquito]] larvae, [[tadpole]]s, and small fish.<ref name=IFAS/> They breathe through gills in their [[rectum]], and can rapidly propel themselves by suddenly expelling water through the anus.<ref>{{cite journal |last1=Mill |first1=P. J. |last2=Pickard |first2=R. S. |year=1975 |title=Jet-propulsion in anisopteran dragonfly nymphs |journal=Journal of Comparative Physiology A |volume=97 |issue=4 |pages=329–338 |doi=10.1007/BF00631969|s2cid=45066664 }}</ref> Some naiads, such as the later stages of ''[[Antipodophlebia asthenes]]'', hunt on land.<ref>{{cite journal |title=Biology of odonata |journal=Annual Review of Entomology |year=1980 |volume=25 |pages=189–217 |last=Corbet |first=Philip S. |doi=10.1146/annurev.en.25.010180.001201}}</ref>

[[File:Anax Imperator 2(loz).JPG|thumb|upright|[[Ecdysis]]: [[Emperor (dragonfly)|Emperor dragonfly]], ''[[Anax imperator]]'', newly emerged and still soft, holding on to its dry [[exuvia]], and expanding its wings]]

The nymph stage of dragonflies lasts up to five years in large species, and between two months and three years in smaller species. When the naiad is ready to metamorphose into an adult, it stops feeding and makes its way to the surface, generally at night. It remains stationary with its head out of the water, while its respiration system adapts to breathing air, then climbs up a [[Phragmites|reed]] or other emergent plant, and moults ([[ecdysis]]). Anchoring itself firmly in a vertical position with its claws, its [[exoskeleton]] begins to split at a weak spot behind the head. The adult dragonfly crawls out of its nymph [[exoskeleton]], the [[exuvia]], arching backwards when all but the tip of its abdomen is free, to allow its exoskeleton to harden. Curling back upwards, it completes its emergence, swallowing air, which plumps out its body, and pumping [[haemolymph]] into its wings, which causes them to expand to their full extent.{{sfn|Berger|2004|pp=10–11}}

Dragonflies in temperate areas can be categorized into two groups: an early group and a later one. In any one area, individuals of a particular "spring species" emerge within a few days of each other. The [[Basiaeschna|springtime darner]] (''Basiaeschna janata''), for example, is suddenly very common in the spring, but disappears a few weeks later and is not seen again until the following year. By contrast, a "summer species" emerges over a period of weeks or months, later in the year. They may be seen on the wing for several months, but this may represent a whole series of individuals, with new adults hatching out as earlier ones complete their lifespans.{{sfn|Berger|2004|p=9}}