Editing Chelicerata (section)

===Reproduction===
[[Image:Vaejovis cashi 222065762.jpg|200px|right|thumb| Female [[scorpion]] ''[[Vaejovis|Vaejovis cashi]]'' carrying its young (white)]]
[[Horseshoe crab]]s use [[external fertilization]]; the [[sperm]] and [[ovum|ova]] meet outside the parents' bodies. Despite being aquatic, they spawn on land in the [[intertidal zone]] on the beach.<ref>{{cite journal | url=https://www.jstor.org/stable/1542294 | jstor=1542294 | title=Nest-Site Selection in the Horseshoe Crab, Limulus polyphemus | last1=Penn | first1=Dustin | last2=Brockmann | first2=H. Jane | journal=Biological Bulletin | year=1994 | volume=187 | issue=3 | pages=373–384 | doi=10.2307/1542294 | pmid=29281397 }}</ref> The female digs a depression in the wet sand, where she will release her eggs. The male, usually more than one, then releases his sperm onto them.<ref>{{Cite news |last=Brown |first=David |date=2018-05-02 |title=Millions of horseshoe crabs spawn on the shores of Delaware Bay each year. Here's how to see them. |language=en-US |newspaper=Washington Post |url=https://www.washingtonpost.com/lifestyle/travel/millions-of-horseshoe-crabs-spawn-on-the-shores-of-delaware-bay-each-year-heres-how-to-see-them/2018/04/26/496a8efa-3daf-11e8-974f-aacd97698cef_story.html |access-date=2023-07-15}}</ref> Their [[trilobite]]-like [[larva]]e look rather like miniature adults as they have full sets of appendages and eyes, but initially they have only two pairs of book-gills and gain three more pairs as they [[molt]].<ref name="RuppertFoxBarnes2004Xiphosura" />

Also the sea spiders have external fertilization. The male and female release their sperm and eggs into the water where fertilization occurs. The male then collects the eggs and carries them around under his body.<ref>{{Cite journal |last=Fornshell |first=John A. |year=2015 |title=Larval stages of two deep sea pycnogonids |url=https://kmkjournals.com/upload/PDF/IZ/IZ%20Vol%2012/invert12_2_197_205_Fornshell.pdf |journal=Invertebrate Zoology |volume=12 |issue=2 |pages=197–205|doi=10.15298/invertzool.12.2.05 }}</ref>

Being air-breathing animals, although many mites have become secondarily aquatic,<ref>{{Cite book |last1=Resh |first1=Vincent H. |url=https://books.google.com/books?id=Ip57QSMCRk4C&dq=5000+species+of+arachnid+mites+adopt+a+secondary+aquatic+existence&pg=PA62 |title=Encyclopedia of Insects |last2=Cardé |first2=Ring T. |date=2003-04-04 |publisher=Elsevier |isbn=978-0-08-054605-6 |language=en|page=62|access-date=11 March 2025|via=Google Books}}</ref> the [[arachnid]]s use [[internal fertilization]]. Except for [[Opiliones]] and some mites, where the male has a penis used for direct fertilization,<ref>{{Cite book |last1=Watling |first1=Les |url=https://books.google.com/books?id=yqWkmpmE2twC&dq=exception+harvestmen+(Opiliones)+mites+(Acari)+males+copulate&pg=PA369 |title=Functional Morphology and Diversity |last2=Thiel |first2=Martin |date=2013-01-16 |publisher=OUP USA |isbn=978-0-19-539803-8 |language=en|pages=368–369|via=Google Books|access-date=11 March 2025}}</ref> fertilization in arachnids is indirect. Indirect fertilization happens in two ways: the male deposit his [[spermatophore]] (package of sperm) on the ground, which is then picked up by the female, or the male stores his sperm in appendages modified into sperm transfer organs, such as the [[pedipalp]]s in male spiders, which are inserted into the female genital openings during copulation.<ref name="RuppertFoxBarnes2004Spiders" /> [[Courtship display|Courtship]] rituals are common, especially in species where the male risks being eaten before mating. Most arachnids lay eggs, but all scorpions and some [[mite]]s are [[Viviparity|viviparous]], giving birth to live young (even more mites are ovoviviparous, but most are oviparous).<ref>{{cite journal | url=https://www.jstor.org/stable/4534928 | jstor=4534928 | last1=Benton | first1=T. G. | title=Reproduction and Parental Care in the Scorpion, Euscorpius flavicaudis | journal=Behaviour | year=1991 | volume=117 | issue=1/2 | pages=20–28 | doi=10.1163/156853991X00102 | url-access=subscription }}</ref><ref>{{cite book | url=https://books.google.com/books?id=QRvLBAAAQBAJ&dq=%22viviparous+mites%22&pg=PA365 | title=Embryology and Phylogeny in Annelids and Arthropods: International Series of Monographs in Pure and Applied Biology Zoology | isbn=9781483187020 | last1=Anderson | first1=D. T. | date=22 October 2013 | publisher=Elsevier }}</ref><ref>{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S1467803916301086 | doi=10.1016/j.asd.2016.09.001 | title=Scorpion katoikogenic ovariuterus – Much more alike to apoikogenic type than it seemed to be | year=2016 | last1=Jędrzejowska | first1=Izabela | last2=Szymusiak | first2=Kamil | last3=Mazurkiewicz-Kania | first3=Marta | last4=Garbiec | first4=Arnold | journal=Arthropod Structure & Development | volume=45 | issue=5 | pages=488–495 | pmid=27645113 | bibcode=2016ArtSD..45..488J | url-access=subscription }}</ref><ref>{{Cite book |last1=Auerbach |first1=Paul S. |url=https://books.google.com/books?id=O2EgDQAAQBAJ&dq=mites+oviparous,+some+are+ovoviviparous,+and+a+few+are+viviparous&pg=PA963 |edition=7th |title=Auerbach's Wilderness Medicine E-Book |last2=Cushing |first2=Tracy A. |last3=Harris |first3=N. Stuart |date=2016-09-21 |publisher=Elsevier Health Sciences |isbn=978-0-323-39609-7 |language=en}}</ref> Female pseudoscorpions carry their eggs in a brood pouch on the belly, where the growing embryos feeds on a nutritive fluid provided by the mother during development, and are therefore [[Matrotrophy|matrotrophic]].<ref>{{cite journal | pmc=9018881 | year=2022 | last1=Garbiec | first1=A. | last2=Christophoryová | first2=J. | last3=Jędrzejowska | first3=I. | title=Spectacular alterations in the female reproductive system during the ovarian cycle and adaptations for matrotrophy in chernetid pseudoscorpions (Pseudoscorpiones: Chernetidae) | journal=Scientific Reports | volume=12 | issue=1 | page=6447 | doi=10.1038/s41598-022-10283-z | pmid=35440674 | bibcode=2022NatSR..12.6447G }}</ref>

Levels of parental care for the young range from zero to prolonged. Scorpions carry their young on their backs until the first [[molt]], and in a few semi-social species the young remain with their mother.<ref>{{cite book |author=Lourenço, W.R. |contribution=Reproduction in scorpions, with special reference to parthenogenesis |title=European Arachnology 2000 |editor1=Toft, S. |editor2=Scharff, N. |pages=71–85 |publisher=Aarhus University Press |year=2002 |isbn=978-87-7934-001-5 |url=http://www.european-arachnology.org/proceedings/19th/Lourenco.PDF |access-date=2008-09-28 |df=dmy-all |archive-date=2008-10-03 |archive-url=https://web.archive.org/web/20081003122816/http://www.european-arachnology.org/proceedings/19th/Lourenco.PDF |url-status=dead }}</ref> Some spiders care for their young, for example a [[wolf spider]]'s brood cling to rough bristles on the mother's back,<ref name="RuppertFoxBarnes2004Spiders" /> and females of some species respond to the "begging" behavior of their young by giving them their prey, provided it is no longer struggling, or even [[Regurgitation (digestion)|regurgitate]] food.<ref name="Foelix1996SpidersReproduction">{{cite book |title=Biology of Spiders |author=Foelix, R.F. |publisher=Oxford University Press US |year=1996 |isbn=978-0-19-509594-4 |chapter=Reproduction |pages=[https://archive.org/details/biologyofspiders00foel_0/page/176 176–212] |via=Google Books |chapter-url=https://books.google.com/books?id=XUgyqxNKhyAC&q=%22Biology+of+Spiders%22+Foelix&pg=PP1 |access-date=2008-10-08 |df=dmy-all |url=https://archive.org/details/biologyofspiders00foel_0/page/176 }}</ref>