Editing Arachnid (section)

==Diet and digestive system==

Arachnids are mostly [[carnivore|carnivorous]], feeding on the pre-digested bodies of insects and other small animals. But ticks, and many mites, are parasites, some of which are carriers of disease. The diet of [[mite]]s also include tiny animals, fungi, plant juices and decomposing matter.<ref>{{cite journal | doi=10.1111/brv.12832 | title=Feeding habits and multifunctional classification of soil-associated consumers from protists to vertebrates | year=2022 | last1=Potapov | first1=Anton M. | last2=Beaulieu | first2=Frédéric | last3=Birkhofer | first3=Klaus | last4=Bluhm | first4=Sarah L. | last5=Degtyarev | first5=Maxim I. | last6=Devetter | first6=Miloslav | last7=Goncharov | first7=Anton A. | last8=Gongalsky | first8=Konstantin B. | last9=Klarner | first9=Bernhard | last10=Korobushkin | first10=Daniil I. | last11=Liebke | first11=Dana F. | last12=Maraun | first12=Mark | last13=Mc Donnell | first13=Rory J. | last14=Pollierer | first14=Melanie M. | last15=Schaefer | first15=Ina | last16=Shrubovych | first16=Julia | last17=Semenyuk | first17=Irina I. | last18=Sendra | first18=Alberto | last19=Tuma | first19=Jiri | last20=Tůmová | first20=Michala | last21=Vassilieva | first21=Anna B. | last22=Chen | first22=Ting-Wen | last23=Geisen | first23=Stefan | last24=Schmidt | first24=Olaf | last25=Tiunov | first25=Alexei V. | last26=Scheu | first26=Stefan | journal=Biological Reviews | volume=97 | issue=3 | pages=1057–1117 | pmid=35060265 | s2cid=246078291 | doi-access=free }}</ref> Almost as varied is the diet of [[Opiliones|harvestmen]], where we will find predators, decomposers and omnivores feeding on decaying plant and animal matter, droppings, animals and mushrooms.<ref>{{cite journal | doi=10.1636/JoA-S-20-002 | title=Diet, predators, and defensive behaviors of New Zealand harvestmen (Opiliones: Neopilionidae) | year=2021 | last1=Powell | first1=Erin C. | last2=Painting | first2=Christina J. | last3=Hickey | first3=Anthony J. | last4=Machado | first4=Glauco | last5=Holwell | first5=Gregory I. | journal=The Journal of Arachnology | volume=49 | s2cid=234364795 | doi-access=free }}</ref><ref>[https://www.wildlifetrusts.org/wildlife-explorer/invertebrates/spiders/common-harvestman Common harvestman | The Wildlife Trusts]</ref><ref>[https://www.discoverwildlife.com/animal-facts/insects-invertebrates/how-do-harvestmen-hunt/ How do harvestmen hunt? - BBC Wildlife Magazine]</ref> The [[harvestmen]] and some mites, such as the [[house dust mite]], are also the only arachnids able to ingest solid food, which exposes them to internal parasites,<ref name=pinto2007>{{cite book |last1=Machado |first1=Glauco |last2=Pinto-da-Rocha |first2=Ricardo |last3=Giribet |first3=Gonzalo |editor1-last=Pinto-da-Rocha |editor1-first=Ricardo |editor2-last=Machado |editor2-first=Glauco |editor3-last=Giribet |editor3-first=Gonzalo |date=2007 |title=Harvestmen: the Biology of Opiliones |publisher=[[Harvard University Press]] |isbn=978-0-674-02343-7 |name-list-style=amp}}</ref> although it is not unusual for spiders to eat their own silk. And [[Bagheera kiplingi|one species]] of spider is mostly herbivorous.<ref>[https://www.livescience.com/5759-rare-vegetarian-spider-discovered.html Rare Vegetarian Spider Discovered]</ref> Scorpions, spiders and pseudoscorpions secrete [[venom]] from specialized [[gland]]s to kill prey or defend themselves.<ref>{{cite journal | pmc=5983263 | year=2018 | last1=Santibáñez-López | first1=C. E. | last2=Ontano | first2=A. Z. | last3=Harvey | first3=M. S. | last4=Sharma | first4=P. P. | title=Transcriptomic Analysis of Pseudoscorpion Venom Reveals a Unique Cocktail Dominated by Enzymes and Protease Inhibitors | journal=Toxins | volume=10 | issue=5 | page=207 | doi=10.3390/toxins10050207 | pmid=29783636 | doi-access=free }}</ref> Their venom also contains pre-digestive enzymes that helps breaking down the prey.<ref>{{cite journal | pmc=3337657 | year=2012 | last1=Zeh | first1=J. A. | last2=Bonilla | first2=M. M. | last3=Adrian | first3=A. J. | last4=Mesfin | first4=S. | last5=Zeh | first5=D. W. | title=From father to son: Transgenerational effect of tetracycline on sperm viability | journal=Scientific Reports | volume=2 | page=375 | doi=10.1038/srep00375 | pmid=22540028 | bibcode=2012NatSR...2..375Z }}</ref><ref>{{cite journal | pmc=9030722 | year=2022 | last1=Delgado-Prudencio | first1=G. | last2=Cid-Uribe | first2=J. I. | last3=Morales | first3=J. A. | last4=Possani | first4=L. D. | last5=Ortiz | first5=E. | last6=Romero-Gutiérrez | first6=T. | title=The Enzymatic Core of Scorpion Venoms | journal=Toxins | volume=14 | issue=4 | page=248 | doi=10.3390/toxins14040248 | pmid=35448857 | doi-access=free }}</ref><ref>{{cite journal | pmc=5553785 | year=2017 | last1=Walter | first1=A. | last2=Bechsgaard | first2=J. | last3=Scavenius | first3=C. | last4=Dyrlund | first4=T. S. | last5=Sanggaard | first5=K. W. | last6=Enghild | first6=J. J. | last7=Bilde | first7=T. | title=Characterisation of protein families in spider digestive fluids and their role in extra-oral digestion | journal=BMC Genomics | volume=18 | issue=1 | page=600 | doi=10.1186/s12864-017-3987-9 | pmid=28797246 | doi-access=free }}</ref> The saliva of ticks contains anticoagulants and anticomplements, and several species produce a [[neurotoxin]].<ref>{{cite journal | pmc=8294578 | year=2021 | last1=Denisov | first1=S. S. | last2=Ippel | first2=J. H. | last3=Castoldi | first3=E. | last4=Mans | first4=B. J. | last5=Hackeng | first5=T. M. | last6=Dijkgraaf | first6=I. | title=Molecular basis of anticoagulant and anticomplement activity of the tick salivary protein Salp14 and its homologs | journal=The Journal of Biological Chemistry | volume=297 | issue=1 | page=100865 | doi=10.1016/j.jbc.2021.100865 | pmid=34118237 | doi-access=free }}</ref><ref>[https://www.ncbi.nlm.nih.gov/books/NBK470478/ Tick Paralysis - StatPearls - NCBI Bookshelf]</ref>

Arachnids produce digestive enzymes in their stomachs, and use their pedipalps and chelicerae to pour them over their dead prey. The digestive juices rapidly turn the prey into a broth of nutrients, which the arachnid sucks into a pre-buccal cavity located immediately in front of the mouth. Behind the mouth is a muscular, sclerotised [[pharynx]], which acts as a pump, sucking the food through the mouth and on into the [[oesophagus]] and [[stomach]]. In some arachnids, the oesophagus also acts as an additional pump.{{citation needed|date=March 2025}}

The stomach is tubular in shape, with multiple [[diverticula]] extending throughout the body. The stomach and its diverticula both produce digestive enzymes and absorb nutrients from the food. It extends through most of the body, and connects to a short sclerotised [[intestine]] and [[anus]] in the hind part of the abdomen.<ref name=IZ>{{cite book |first=Robert D. |last=Barnes |date=1982 |title=Invertebrate Zoology |publisher=Holt-Saunders International |location=Philadelphia, PA |pages=596–604 |isbn=978-0-03-056747-6}}</ref>