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Incolonialrotifers,colonymemberswereobservedtocooperateinfoodcol-
lection;theprocesswastestedexperimentallyusingcarmine.Adultmembersof
aSinantherinasocialiscolonyturntheircoronasinthesamedirectiontoproduce
awatercurrentheadingtowardsthecolony.Theycontrolthewaythecurrent
movesaroundthecolonyandfromwhereitflowsaway(WALLACE1987).
Respiration.Therotiferrespirationisage-dependent:theegg-layingfemales
takeupmoreoxygenthantheyoungestforms.Studiesonrotiferrespirationat
differentfoodconcentrationsandconstanttemperature(20oC)showedtheaver-
agedailyrespirationtobe13610-6;16310-6;20110-6;and265×10-6cal/ind.in
theyoungestindividuals,thoseaged13-24h,femalesolderthan25h,andrepro-
ducingfemales(regardlessoftheireggtype),respectively(PILARSKA1977b,c).
WhenstudyingrespirationinBrachionusplicatilis,EPPandLEWIS(1980)
foundrespirationrateat20-28oCtobeindicativeofthespecies’abilitytomain-
tainstablemetabolismwithinthattemperaturerange.However,therespiration
rateincreasesaboveandbelowthetemperaturerangeindicated,mostprobably
duetothermalstressthatexceedsthespecies’homeostaticpotential.
Reproductionanddevelopment.Environmentalfactorsmostimportantfor
rotifersurvivalandreproductionincludewatertemperatureaswellasthequality
andquantityoffood.Thegenotypeisimportantaswell,asisthemodeofre-
production:amictic(notinvolvingfertilisation)ormictic(withfertilisation).An
increaseinwatertemperaturereducessurvivorship.
Rotiferlongevitymaybemeasuredinculturesonly.Suchstudieswerecon-
ductedonrepresentativesofthegeneraBrachionusandAsplanchnaandonsome
bdelloidspecies.Rotiferlongevitywasfoundtobetemperature-dependent:50%
ofthelaboratorypopulationofBrachionuscalycifloruswerefoundtosurviveup
to16daysat15oC,11daysat20oC,and5daysat25oC(HALBACH1970).Important
forsurvivalisfooddensity.ThehighestsurvivalrateofBrachionuscalyciflorus
wasobservedtoaccompanytheChlorelladensityrangefrom0.5×106to1.0×106
cells/ml(HALBACHandHALBACH-KEUP1974).Inaddition,SNELLandKING(1977)
foundthelifespanofthehighlyfertileAsplanchnabrightwelliifemalestobe
shorter(2.5days),comparedtothatofthelessfertilefemaleswhichlivedforan
averageof4.5days.
Rotiferreproductionisverycomplexandproceedsdifferentlyineachof
thethreeclasses:theSeisonidea,Bdelloidea,andMonogononta.TheSeisonidea
aremarineepi-andectoparasitesoncrustaceans.Theirreproductionisexclusively
bisexual;femalesandmalesareverysimilartoeachotherandco-occur(RIC-
CI1992).TheBdelloideaarefreshwaterrotifersoccurringasmembersoftheben-
thosordwellinginmoist,periodicallydryhabitats.Theirreproductionisexclu-
sivelyparthenogeneticandinvolvesamicticfemales;thesehavepairedovaries.
TheMonogontaaremostwidelydistributedinfreshwaterhabitatsandes-
tuaries.Amonogonontfemalefeaturesasingleovary;theoogenyproceedsvia
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