Editing Damselfly (section)

===Reproduction===
Mating in damselflies, as in dragonflies, is a complex, precisely choreographed process involving both indirect insemination and delayed fertilisation.{{sfn|Dijkstra|2006|pages=8–9}}<ref name=Battin>{{cite journal|last1=Battin |first1=Tom |title=The odonate mating system, communication, and sexual selection: A review |journal= Bolletino di Zoologia|date=1993 |volume=60 |issue=4 |pages=353–360 |doi=10.1080/11250009309355839 |doi-access=free }}</ref> The male first has to attract a female to his territory, continually driving off rival males. When he is ready to mate, he transfers a packet of sperm from his primary genital opening on segment 9, near the end of his abdomen, to his secondary genitalia on segments 2–3, near the base of his abdomen. The male then grasps the female by the head with the claspers at the end of his abdomen; the structure of the claspers varies between species, and may help to prevent interspecific mating.<ref name=Battin/><ref name=Cordero>{{cite book |last1=Cordero-Rivera |first1=Adolfo |last2=Cordoba-Aguilar |first2=Alex |chapter=Selective Forces Propelling Genitalic Evolution in Odonata |year=2010 |page=343 |chapter-url=http://ecoevo.uvigo.es/pdf/2010/2010-Genital%20evolution%20odonata-lq.pdf |title=The Evolution of Primary Sexual Characters in Animals |editor=Leonard, Janet |editor2=Alex Córdoba-Aguilar |publisher=Oxford University Press |access-date=2015-03-16 |archive-date=2015-02-25 |archive-url=https://web.archive.org/web/20150225124220/http://ecoevo.uvigo.es/pdf/2010/2010-Genital%20evolution%20odonata-lq.pdf |url-status=dead }}</ref> The pair fly in tandem with the male in front, typically perching on a twig or plant stem. The female then curls her abdomen downwards and forwards under her body to pick up the sperm from the male's secondary genitalia, while the male uses his "tail" claspers to grip the female behind the head: this distinctive posture is called the "heart" or "wheel";{{sfn|Dijkstra|2006|pages=8–9}}{{sfn|Trueman|Rowe|2009|page=Life Cycle and Behavior}} the pair may also be described as being "in cop".{{sfn|Berger|2004|p=39|ps=: <q>Romantic souls are pleased to note that at the climactic moment, the two slender bodies form a delicate heart shape. Experts say the pair is now 'in cop'.</q>}} Males may transfer the sperm to their secondary genitalia either before a female is held, in the early stage when the female is held by the legs or after the female is held between the terminal claspers. This can lead to variations in the tandem postures.<ref>{{cite journal|doi=10.1093/aesa/58.4.592|pmid=5834678|title=Sperm Transfer in Damselflies (Odonata: Zygoptera)|journal=Annals of the Entomological Society of America|volume=58|issue=4|pages=592|year=1965|last1=Bick|first1=G. H.|last2=Bick|first2=J. C.}}</ref> The spermatophore may also have nutrition in addition to sperms as a "[[nuptial gift]]".<ref>{{cite book|last1=Cordero Rivera |first1= A|last2=Cordoba-Aguilar |first2=A |year=2010| chapter=Selective forces propelling genitalic evolution in Odonata|editor1=  Leonard J|editor2=Cordoba-Aguilar, A |title=  The evolution of primary characters in animals|publisher= Oxford University Press|place= New York|pages= 332–352}}</ref> Some cases of [[sexual cannibalism]] exist where females (of ''[[Ischnura graellsii]]'') eat males while in copula.<ref>{{cite journal|doi=10.1127/entom.gen/17/1992/17|url=http://ecoevo.uvigo.es/PDF/Entomol_Gener_vol_17_pp_17-20_(1992).pdf|journal=Entomologia Generalis|volume=17|issue=1|year=1992|pages=17–20|title=Sexual Cannibalism in the Damselfly Species Ischnura graellsii (Odonata: Coenagrionidae)|author=Cordero, Adolfo|access-date=2017-04-28|archive-url=https://web.archive.org/web/20130613025042/http://ecoevo.uvigo.es/PDF/Entomol_Gener_vol_17_pp_17-20_%281992%29.pdf|archive-date=2013-06-13|url-status=dead}}</ref>

[[Parthenogenesis]] (reproduction from unfertilised eggs) is exceptional, and has only been recorded in nature in female ''[[Ischnura hastata]]'' on the [[Azores Islands]].<ref name=diversity /><ref>{{cite journal |journal= Heredity |volume=103|issue=5|pages=377–384 |doi=10.1038/hdy.2009.65 |pmid=19513091|year= 2009 |title=Thelytokous parthenogenesis in the damselfly ''Ischnura hastata'' (Odonata, Coenagrionidae): genetic mechanisms and lack of bacterial infection |first1=M. O. |last1=Lorenzo-Carballa |first2= A. |last2=Cordero-Rivera|doi-access=free|bibcode=2009Hered.103..377L }}</ref>

Egg-laying (ovipositing) involves not only the female darting over floating or waterside vegetation to deposit eggs on a suitable substrate, but the male hovering above her, mate-guarding, or in some species continuing to clasp her and flying in tandem. The male attempts to prevent rivals from removing his sperm and inserting their own,<ref name=Carde>{{cite book |author1=Cardé, Ring T. |author2= Resh, Vincent H. |title=A World of Insects: The Harvard University Press Reader |url=https://books.google.com/books?id=g28jXs3CVC8C&pg=PA195 |year=2012 |publisher=[[Harvard University Press]] |isbn=978-0-674-04619-1 |pages=195–197}}</ref> a form of [[sperm competition]] (the sperms of the last mated male have the greatest chance of fertilizing the eggs, also known as sperm precedence<ref name=reshcarde>{{cite book|chapter=Odonata (Dragonflies, Damselflies)|author=Tennessen, K.J.|pages=721–729|title=Encyclopedia of Insects|edition=2|editor=Resh, Vincent H. |editor2=Ring T. Cardé|year=2009|publisher=Academic Press}}</ref>) made possible by delayed fertilisation{{sfn|Dijkstra|2006|pages=8–9}}{{sfn|Trueman|Rowe|2009|page=Life Cycle and Behavior}} and driven by [[sexual selection]].<ref name=Battin/><ref name=Cordero/> If successful, a rival male uses his penis to compress or scrape out the sperm inserted previously; this activity takes up much of the time that a copulating pair remain in the heart posture.{{sfn|Berger|2004|p=39|ps=: <q>Romantic souls are pleased to note that at the climactic moment, the two slender bodies form a delicate heart shape. Experts say the pair is now 'in cop'.</q>}} Flying in tandem has the advantage that less effort is needed by the female for flight and more can be expended on egg-laying, and when the female submerges to deposit eggs, the male may help to pull her out of the water.<ref name=Carde/>

<gallery widths="200" heights="175">
File:Ceriagrion cerinorubellum-Kadavoor-2016-04-11-002.jpg|alt=Damselflies holding each other|First stage: ''[[Ceriagrion cerinorubellum]]'' pair with male transferring sperm from the primary to the secondary sex organs
File:Ceriagrion cerinorubellum-Kadavoor-2016-04-11-003.jpg|alt=Mating damselflies in heart position|Second stage: "heart" or "wheel" position, the female receiving sperm from the male secondary sex organ
File:Pseudagrion indicum ovipositing at Kadavoor.jpg|Yellow-striped blue dart, ''[[Pseudagrion indicum]]'', laying eggs; the male (above) continues to hold the female with his claspers.
Hetaerina americana-mating.webm|''[[Hetaerina americana]]'' mating: sperm removal
File:Chalcolestes viridis laying eggs into slits in twig.jpg|Willow emerald, ''[[Chalcolestes viridis]]'', still in tandem, laying eggs into a series of slits in a twig
</gallery>

All damselflies lay their eggs inside plant tissues; those that lay eggs underwater may submerge themselves for 30 minutes at a time, climbing along the stems of aquatic plants and laying eggs at intervals.<ref name=Lawlor>{{cite book |author=Lawlor, Elizabeth P. |title=Discover Nature in Water & Wetlands: Things to Know and Things to Do |url=https://books.google.com/books?id=Xo83huW7O6YC&pg=PA94 |year=1999 |publisher=Stackpole Books |isbn=978-0-8117-2731-0 |pages=88, 94–96}}</ref> For example, the red-eyed damselfly ''[[Erythromma najas]]'' lays eggs, in tandem, into leaves or stems of floating or sometimes emergent plants; in contrast, the scarce bluetail ''[[Ischnura pumilio]]'' oviposits alone, the female choosing mostly emergent grasses and rushes, and laying her eggs in their stems either above or just below the waterline.<ref name="SmallshireSwash2014">{{cite book |last1=Smallshire |first1=Dave |last2=Swash |first2=Andy |title=Britain's Dragonflies: A Field Guide to the Damselflies and Dragonflies of Britain and Ireland: A Field Guide to the Damselflies and Dragonflies of Britain and Ireland |url=https://books.google.com/books?id=jG9UAwAAQBAJ&pg=PA96 |year=2014 |publisher=Princeton University Press |isbn=978-1-4008-5186-7 |pages=94–96}}</ref> The willow emerald ''[[Chalcolestes viridis]]'' (a spreadwing) is unusual in laying eggs only in woody plant tissue, choosing thin twigs of trees that hang over water, and scarring the bark in the process.{{sfn|Dijkstra|2006|page=84}} A possible exception is an apparent instance of [[viviparity|ovo-viviparity]], in which ''[[Heliocypha perforata]]'' was filmed in western China depositing young larvae (presumably hatched from eggs inside the female's body) onto a partly submerged branch of a tree.<ref name=Salindra>{{cite journal|last1=Salindra |first1=H. G. |last2=Dayananda|first2=K. |last3=Kitching |first3=Roger L. |title=Ovo-viviparity in the Odonata? The case of Heliocypha perforata (Zygoptera: Chlorocyphidae) |journal=International Journal of Odonatology|year=2014 |volume=17 |issue=4 |pages=181–185 |doi=10.1080/13887890.2014.959076 |bibcode=2014IJOdo..17..181D |s2cid=83520585 |doi-access=free }}</ref>

Many damselflies are able to produce more than one brood per year ([[voltinism]]); this is negatively correlated with [[latitude]], becoming more common towards the equator, except in the Lestidae.<ref name=Corbet2006>{{cite journal |last1=Corbet |first1=Philip S. |last2=Suhling |first2=Frank |last3=Soendgerath |first3=Dagmar |title=Voltinism of Odonata: a review |journal=International Journal of Odonatology|date=2006|volume=9 |issue=1 |pages=1–44 |url=https://www.researchgate.net/publication/228369286 |doi=10.1080/13887890.2006.9748261|bibcode=2006IJOdo...9....1C |s2cid=55299239 |doi-access=free }}</ref>