Editing Ctenophora (section)

=== Prey and predators ===

Almost all ctenophores are [[predator]]s – there are no vegetarians and only one genus that is partly [[parasitic]].<ref name=Haddock2007ComparativeFeeding/> If food is plentiful, they can eat ten times their own weight per day.<ref>{{cite journal |last1=Reeve |first1=M.R. |last2=Walter |first2=M.A. |last3=Ikeda |first3=T. |date=July 1978 |title=Laboratory studies of ingestion and food utilization in lobate and tentaculate ctenophores 1:&nbsp;Ctenophore food utilization |journal=[[Limnology and Oceanography]] |volume=23 |issue=4 |pages=740–751 |doi=10.4319/lo.1978.23.4.0740 |doi-access=free}}</ref> While ''Beroe'' preys mainly on other ctenophores, other surface-water species prey on [[zooplankton]] (planktonic animals) ranging in size from the microscopic, including mollusc and fish larvae, to small adult crustaceans such as [[copepod]]s, [[amphipod]]s, and even [[krill]]. Members of the genus ''[[Haeckelia]]'' prey on [[jellyfish]] and incorporate their prey's [[nematocyst]]s (stinging cells) into their own tentacles instead of [[colloblast]]s.<ref name=MillsNotesFromExpert/> Ctenophores have been compared to [[spider]]s in their wide range of techniques for capturing prey – some hang motionless in the water using their tentacles as "webs", some are ambush predators like Salticid [[jumping spider]]s, and some dangle a sticky droplet at the end of a fine thread, as [[bolas spider]]s do. This variety explains the wide range of body forms in a [[phylum]] with rather few species.<ref name=Haddock2007ComparativeFeeding>{{cite journal |last=Haddock |first=S.H.D. |author-link=Steven Haddock |date=December 2007 |title=Comparative feeding behavior of planktonic ctenophores |journal=[[Integrative and Comparative Biology]] |volume=47 |issue=6 |pages=847–853 |pmid=21669763 |doi=10.1093/icb/icm088 |doi-access=}}</ref> 

The two-tentacled "cydippid" ''Lampea'' feeds exclusively on [[salp]]s, close relatives of sea-squirts that form large chain-like floating colonies, and juveniles of ''Lampea'' attach themselves like parasites to salps that are too large for them to swallow.<ref name=Haddock2007ComparativeFeeding/> Members of the cydippid genus ''[[Pleurobrachia]]'' and the lobate ''[[Bolinopsis]]'' often reach high population densities at the same place and time because they specialize in different types of prey: ''[[Pleurobrachia]]''{{'}}s long tentacles mainly capture relatively strong swimmers such as adult copepods, while ''[[Bolinopsis]]'' generally feeds on smaller, weaker swimmers such as [[rotifer]]s and mollusc and [[crustacean larvae]].<ref>{{cite journal |last1=Costello |first1=J.H. |last2=Coverdale |first2=R. |date=October 1998 |title=Planktonic feeding and evolutionary significance of the lobate body plan within the Ctenophora |journal=[[The Biological Bulletin]] |volume=195 |issue=2 |pages=247–248 |doi=10.2307/1542863 |pmid=28570175 |jstor=1542863}}</ref>

It is often difficult to identify the remains of ctenophores in the guts of possible predators as they are broken down quickly, although the combs sometimes remain intact long enough to provide a clue. [[Chum salmon]], ''Oncorhynchus keta'', digest ctenophores 20 times as fast as an equal weight of [[shrimp]]s; ctenophores can provide the fish with a good diet if there are enough of them around. Some [[jellyfish]] and [[turtle]]s eat large quantities of ctenophores, and jellyfish may temporarily wipe out ctenophore populations. Since ctenophores and jellyfish often have large seasonal variations in population, most fish that prey on them are generalists and may have a greater effect on populations than specialist jelly-eaters. Herbivorous fishes deliberately feed on gelatinous zooplankton during blooms in the Red Sea.<ref>{{cite journal |last1=Bos |first1=A.R. |last2=Cruz-Rivera |first2=E. |last3=Sanad |first3=A.M. |year=2016 |title=Herbivorous fishes ''Siganus rivulatus'' (Siganidae) and ''Zebrasoma desjardinii'' (Acanthuridae) feed on Ctenophora and Scyphozoa in the Red Sea  |journal=[[Marine Biodiversity]] |volume=47 |pages=243–246 |doi=10.1007/s12526-016-0454-9 |s2cid=24694789}}</ref> The larvae of some [[sea anemone]]s are parasites on ctenophores, as are the larvae of some [[flatworm]]s that parasitize fish when they reach adulthood.<ref>{{cite journal |last=Arai |first=Mary Needler |date=June 2005 |title=Predation on pelagic coelenterates: A review |journal=[[Journal of the Marine Biological Association of the United Kingdom]] |volume=85 |issue=3 |pages=523–536 |doi=10.1017/S0025315405011458 |bibcode=2005JMBUK..85..523A |s2cid=86663092}}</ref>