Editing Chelicerata (section)

===Feeding and digestion===
The guts of most modern chelicerates are too narrow to take solid food.<ref name="RuppertFoxBarnes2004ArachnidaGen" /> All [[scorpion]]s and almost all [[spider]]s are [[predator]]s that "pre-process" food in preoral cavities formed by the [[chelicera]]e and the bases of the [[pedipalp]]s.<ref name="RuppertFoxBarnes2004Spiders" /><ref name="RuppertFoxBarnes2004Scorpions" /> However, one predominantly [[herbivore]] spider species is known,<ref name="MeehanOlsonCurry2008VegetarianJumpingSpider">{{cite conference |author1=Meehan, C.J. |author2=Olson, E.J. |author3=Curry, R.L. |date=21 August 2008 |title=Exploitation of the Pseudomyrmex–Acacia mutualism by a predominantly vegetarian jumping spider (''Bagheera kiplingi'') |conference=93rd ESA Annual Meeting |url=http://eco.confex.com/eco/2008/techprogram/P12401.HTM |access-date=2008-10-10 |df=dmy-all |archive-date=2019-12-01 |archive-url=https://web.archive.org/web/20191201153140/https://eco.confex.com/eco/2008/techprogram/P12401.HTM |url-status=dead }}</ref> and many supplement their diets with [[nectar]] and [[pollen]].<ref name="Jackson2001">{{citation |author=Jackson, R.R. |year=2001 |title=Jumping spiders (Araneae: Salticidae) that feed on nectar |journal=[[Journal of Zoology]] |volume=255 |pages=25–29 |url=http://xnelson.googlepages.com/Jacksonetal2001.pdf |doi=10.1017/S095283690100108X |display-authors=etal |access-date=2008-10-23 |archive-date=2009-03-18 |archive-url=https://web.archive.org/web/20090318020505/http://xnelson.googlepages.com/Jacksonetal2001.pdf |url-status=dead }}</ref> Many of the [[Acari]] (ticks and mites) are blood-sucking [[parasite]]s, but there are many predatory, herbivore and [[scavenger]] sub-groups. All the Acari have a retractable feeding assembly that consists of the chelicerae, pedipalps and parts of the [[exoskeleton]], and which forms a preoral cavity for pre-processing food.<ref name="RuppertFoxBarnes2004Acari">{{harvnb|Ruppert|Fox|Barnes|2004|pp=591–595}}</ref>

[[Harvestmen]] are among the minority of living chelicerates that can take solid food, and the group includes predators, herbivores and scavengers.<ref name="RuppertFoxBarnes2004Opiliones">{{harvnb|Ruppert|Fox|Barnes|2004|pp=588–590}}</ref> [[Horseshoe crab]]s are also capable of processing solid food, and use a distinctive feeding system. Claws at the tips of their legs grab small invertebrates and pass them to a food groove that runs from between the rearmost legs to the mouth, which is on the underside of the head and faces slightly backwards. The bases of the legs form toothed [[gnathobase]]s that both grind the food and push it towards the mouth.<ref name="RuppertFoxBarnes2004Xiphosura" /> This is how the earliest [[arthropod]]s are thought to have fed.<ref name="WonderfulLifeP105">{{cite book |title=Wonderful Life: The Burgess Shale and the Nature of History |location=New York, NY |publisher=W.W. Norton; Hutchinson Radius |page=105 |author=Gould, S.J. |author-link=Stephen Jay Gould |year=1990 |isbn=978-0-09-174271-3 |bibcode=1989wlbs.book.....G }}</ref>