Editing Mysida (section)

==Behavior==
[[File:Mysis relicta..jpg|thumb|left|''Mysis relicta'']]
Some species are [[benthic]] (living on the seabed) and others [[pelagic]] (living in mid-water), but most are found close to, crawling on or burrowing into the mud or sand. Most marine species are benthic by day but leave the seabed at night to become [[plankton]]ic. Locomotion is mostly by swimming, the pleopods being used for this purpose. Some mysids live among [[algae]] and [[seagrass]]es, some are solitary while many form dense swarms. Mysids form an important part of the diet of such fish as [[shad]] and [[flounder]].<ref name=Ruppert/> In general, they are free-living, but a few species, mostly in the subfamily [[Heteromysinae]], are [[commensal]] and are associated with [[sea anemone]]s and [[hermit crab]]s.<ref name="Meland"/> Several [[taxon|taxa]] have also been described from different freshwater habitats and caves.<ref name="Meland"/> ''[[Mysis relicta]]'' and its close relatives inhabit cold, deep lakes and have a diurnal cycle of vertical migrations.<ref>{{cite journal |author1=Audzijonytė, Asta |author2=Väinölä, Risto |year=2005 |title=Diversity and distributions of circumpolar fresh- and brackish-water ''Mysis'' (Crustacea: Mysida): descriptions of ''M. relicta'' Lovén, 1862, ''M. salemaai'' n.sp., ''M. segerstralei'' n.sp. and ''M. diluviana'' n.sp., based on molecular and morphological characters |journal=Hydrobiologia |volume=544 |issue=1 |pages=89–141 |doi=10.1007/s10750-004-8337-7|s2cid=20925048 }}</ref> The species ''Mysidium integrum'' has a [[Mutualism (biology)|mutualistic]] relationship with [[longfin damselfish]], the shrimp providing nutrients for the algae farms the fish feed on and the fish providing protection from predators.<ref>{{cite web |url=https://theconversation.com/we-found-algae-farming-fish-that-domesticate-tiny-shrimp-to-help-run-their-farms-151615 |title=We found algae-farming fish that domesticate tiny shrimp to help run their farms |date=2020-12-08}}</ref><ref>{{cite journal |doi=10.1038/s41467-020-19958-5|title=Domestication via the commensal pathway in a fish-invertebrate mutualism|year=2020|last1=Brooker|first1=Rohan M.|last2=Casey|first2=Jordan M.|last3=Cowan|first3=Zara-Louise|last4=Sih|first4=Tiffany L.|last5=Dixson|first5=Danielle L.|last6=Manica|first6=Andrea|last7=Feeney|first7=William E.|journal=Nature Communications|volume=11|issue=1|page=6253|pmid=33288750|pmc=7721709|bibcode=2020NatCo..11.6253B |s2cid=227948531|doi-access=free}}</ref>

The majority of Mysida are [[omnivore]]s, feeding on algae, [[detritus]], and [[zooplankton]]. [[Scavenger|Scavenging]] and [[cannibalism]] are also common, with the adults sometimes preying on their young once they emerge from the marsupium.<ref name="Mauchline"/> The pelagic and most other species are [[filter feeder]]s, creating a feeding current with the exopods of their pereopods. This wafts food particles into a ventral food groove along which they are passed before being filtered by [[seta]]e (bristles) on the second maxillae. Larger planktonic prey can be caught in a trap composed of the endopods of the thoracic appendages.<ref name=Ruppert/> Some benthic species, especially members of the subfamily [[Erythropinae]], have been observed feeding on small particles which they collected by grooming the surfaces of their bodies and legs.<ref name="Meland"/>

[[File:Brackwasserkrebs, Spaltfußkrabbe (Mysis vulgaris).jpg|thumb|''[[Neomysis integer]]'']]
Individual mysids are either male or female, and fertilisation is external. The [[gonad]]s are in the thorax and are tubular in shape. Males have two [[gonopore]]s in the eighth thoracic segment and a pair of long penises. The female gonopores are in the sixth thoracic segment and the oostegites are attached to the first to seventh pereopods to form a brood pouch.<ref name=Ruppert/> Mating usually takes place at night and lasts only a few minutes.<ref name="Mauchline"/> During the process, the male inserts his penises into the marsupium and releases sperm. This stimulates the female and the eggs are usually released into the marsupium within an hour. Here they are fertilised and retained, development of the embryos in the brood pouch being [[Direct development|direct]] with the young hatching from the eggs as miniature adults.<ref name=Ruppert/> The size of a mysid brood generally correlates with body length and environmental factors such as density and food availability.<ref name="Dom 1999">{{cite journal |author1=Domingues, P. M. |author2=Turk, P. E. |author3=Andrade, J. P. |author4=Lee, P. G. |year=1999 |title=Culture of the mysid, ''Mysidopsis almyra'' (Bowman), (Crustacea: Mysidacea) in a static water system: effects of density and temperature on production, survival and growth |journal=[[Aquaculture Research]] |volume=30 |issue=2 |pages=135–143 |doi=10.1046/j.1365-2109.1999.00309.x|doi-access=free }}</ref> The age at which mysids reach [[sexual maturity]] depends on water temperature and food availability.<ref name="Dom 1999"/><ref name= "Sudo">{{cite journal |author=Sudo, H. |year=2003 |title=Effect of temperature on growth, sexual maturity and reproduction of ''Acanthomysis robusta'' (Crustacea: Mysidacea) reared in the laboratory |journal=[[Marine Biology (journal)|Marine Biology]] |volume=143 |issue=6 |pages=1095–1107 |doi=10.1007/s00227-003-1160-2|s2cid=83480469 }}</ref><ref name="EPA"/> For the species ''[[Americamysis bahia|Mysidopsis bahia]]'', this is normally at 12 to 20 days.<ref name="EPA">{{cite book |publisher=[[United States Environmental Protection Agency|Environmental Protection Agency]] |year=1990 |title=Culturing ''Mysidopsis bahia''. Supplemental Report. EPA 505/8-90-006b}}</ref> The young are released soon afterwards, and although their numbers are usually low, the short [[reproductive cycle]] of mysid adults means a new brood can be produced every four to seven days.<ref name="Mauchline"/><ref name="EPA"/><ref name="Dom 1998">{{cite journal |author1=Domingues, Pedro M. |author2=Turk, Philip E. |author3=Andrade, Jose P. |author4=Lee, Philip G. |year=1998 |title=Pilot-scale production of mysid shrimp in a static water system |journal=[[Aquaculture International]] |volume=6 |issue=5 |pages=387–402 |doi=10.1023/A:1009232921784|s2cid=37703503 }}</ref>