Tes$ngpollinatorsyndromesandcrosscompa$bilityineveningprimroses(Onagraceae)
TaylorTate1,2,EmilyLewis1,2,Dr.TaniaJogesh2,Dr.KrissaSkogen2
Northwestern1,ChicagoBotanicGarden2
Introduc$on
Methods:PollinatorObserva$ons
Angiosperms,orfloweringplants,appealtospecificpollinatorstheywishtoaNractby
exhibi$ngcertainfloralcolorsandscents,andbyopeningwhenthepollinatorisac$ve
(Doddetal.1999).Evolu$onaryadapta$onsincreasethechancesthatpollina$onbya
par$cularpollinatorwilloccur,thusincreasingthelikelihoodthatpollenfromthesame
specieswillcontacttheplant’ss$gmatoproduceaviableseed.
•  Pollina$onobserva$onvideosweretakenusingaGoProcamerasetupinthefield
duringthesummerof2014.Cameraswereplacedapproximatelyonefootawayfrom
newlyopenflowersduringthreeobserva$onalperiods:morning(5:00to11:00),
a`ernoon(11:00to17:00)andnight(17:00to20:00).
•  Videoswerescoredandthefollowingdatawererecorded:$meofday,asketchofthe
plantofinterest,numberofvisitsandiden$fica$onofthefloralvisitors.Visita$on
ratesperhourwerecalculatedforeachspecies.
Results:CrossCompa$bility
Species
Hawkmoth
O.cespitosa
subsp.
marginata
Photo
Anthesis Floral Floral
Size Color
PM
Nectar Lengthof
TimeOpen
Large White Yes
~15hours
PM
Large Yellow Yes
~15hours
Intermediate O.toumeyi
PM
Large Yellow Yes
~24hours
Bee
O.gayleana
AM
Small Yellow No
~12hours
Bee
O.tubicula
AM
Small Yellow No
~12hours
References
•  Dodd,M.E.,Silvertown,J.,&Chase,M.W.(1999).Evolu$on,53(3),732-744Friedman,W.2009.Themeaningof
Darwin’s“abominablemystery.”Am.J.Botany96(1):5-21
•  Emerson,Sterling."Thegene$csofself-incompa$bilityinOenotheraorganensis."Gene4cs23.2(1938):190.
•  Rousset,François."Gene$cdifferen$a$onandes$ma$onofgeneflowfromF-sta$s$csunderisola$onby
distance."Gene4cs145.4(1997):1219-1228.
Acknowledgements
SpecialthankstoDr.JeremieFantandDr.RickOverson.FundingwasprovidedbyNSFDEB1342873,DBI
1461007,andanUndergraduateResearchGrantfromNorthwesternUniversity.
Discussion
60
30
Maternal
Population
Trigg ranch
0
Yeso 1
Yeso 2
90
60
30
0
Autogamous
Geitonogamous
Sibling
Within population` Between population
90
Species
Cross Type
B
O. hartwegii subsp. filifolia
O. gayleana
60
30
Maternal
Population
Trigg ranch
0
Yeso 1
Yeso 2
90
60
30
0
Autogamous
Geitonogamous
Sibling
Within population` Between population
Autogamous
Geitonogamous
Sibling
Within population` Between population
CrossType
Type
Cross
Figure4.TotalnumberofseedsofO.hartwegiisubsp.filifoliaandO.gayleanaresul$ngfrom
handpollina$onsforeachofthefivetreatments.A.Bypopula$on,B.Allpopula$onspooled.
90
60
30
O. gayleana
Intermediate O.
lavandulifolia
A
O. hartwegii subsp. filifolia
Pollina'on
Sydrome
90
O. gayleana
Table1:Pollina$onsyndromeandfloraltraitsoffiveOenotheraspecies
•  Ourpollinatorobserva$ondataareinsupportofthehypothesisthatthedominantpollinator
canbepredictedbyfloraltraits.
•  Aspredicted,O.cespitosasubsp.marginatawasvisitedprimarilybyhawkmoths,O.tubicula
andO.gayleanawereprimarilyvisitedbybees,andO.toumeyiwasvisitedbyboth
hawkmothsandbees(Figure3).
•  Incontrasttoexpecta$ons,O.lavandulifolia,thoughttoalsovisitedbybothhawkmothsand
bees,wasdominantlyvisitedbyhawkmothsonlyinthestudysitesinves$gated(Figure3).
6.0
5.0
Hawkmoth visits
4.0
Bee visits
3.0
2.0
1.0
O. 0.0
cespitosa marginata O. lavandulifolia O. toumeyi
O. tubicula
O. gayleana
Figure3:Beeandhawkmothpollinatorvisita$onratesforfiveOenotheraspecies.
Pollinator visits per hour
Results:PollinatorObserva$ons
O. hartwegii subsp. filifolia
2.  OenotheragayleanaandO.hartwegiifilifoliaareself-incompa$blespecies.Crosses
ofleastrela$on(betweenpopula$on)willproducethegreatestseedset,followed
bycrossesofpossiblerela$on(withinpopula$on),andlastlycrossesofdefinite
rela$on(siblingsofthesamematernalline).
Figure2.Beepollina$onsyndrome.Bee
visi$ngO.gayleana.PhotoCredit:Jogesh
•  Bothspeciesappeartobecompletelyself-incompa$bleasnoseedswereproducedin
eitherofthetwoselfcrosstreatments,autogamousandgeitonogamous(Figure4AandB).
•  Nosignificantdifferenceswereobservedbetweenthethreeoutcrosstreatments(sibling,
withinpopula$onandbetweenpopula$on)ineitherspecies(Figure4A).
•  Oenotheragayleanadidnotdifferamongthethreepopula$ons(Figure4B)whileinO.
hartwegiisubsp.filifoliapopula$onYBproducedsignificantlymoreseedsthantheother
twopopula$ons(Figure4B).
Total number of seeds
Hypotheses
Figure1.Hawkmothpollina$onsyndrome.Hyles
lineatavisi$ngO.harringtonii.PhotoCredit:Skogen
1.  Flowersexhibi$nghawkmothpollina$onsyndromecharacteris$cswillbeprimarily
visitedbyhawkmoths,flowersexhibi$ngbeepollina$onsyndromecharacteris$cs
willbeprimarilyexhibitedbybees,andflowerswithanintermediatesuiteof
characteris$cswillbevisitedbyboth.
•  Handpollina$ontreatmentswereperformedatanthesisonO.gayleanaandO.hartwegii
subsp.filifoliagrownfromwild-collectedseedsfrom4differentpopula$onsingrowth
chambercondi$ons.Thefivetreatmentswere:autogamous,geitonogamous,sibling,within
popula$on,andbetweenpopula$on.
•  Theiden$$esofthematernalandpaternalparentplantsandthedateofthecrosswere
recordedonajeweler'stagwhichwasthenaNachedtothedevelopingfruit.
•  Fruitswerecollectedeightweeksa`ercrosseswereconductedorassoonastheydetached.
•  Thefollowingdatawerecollectedonatotalof240fruitsfromthreepopula$ons(120per
species,40perpopula$on):fruitweight(g),length(mm),width(mm),andseedcount.
•  DatawasanalyzedusingtheprogramRversion3.2.1toiden$fyrela$onshipsbetweenseed
countandspecies,crosstype,andoriginalpopula$onofthematernalplant.Differences
weretestedwithanega$vebinomialgeneralizedlinearmodel.
number
of seeds
TotalTotal
number
of seeds
Crosscompa$bilityofthemaleandfemalegameteisalsoimportantforreproduc$ve
success.Oenotherahartwegiisubsp.filifoliaandO.gayleanaaresuspectedtobeself
incompa$blemembersoftheeveningprimrosefamily,Onagraceae.Themechanism
fortheirself-incompa$bilityisthoughttobeasuiteofalleles(SIalleles)preven$ng
pollentubeforma$on(Emerson1938).Ifso,acrossbetweensiblingsorbetween
plantsinthesamepopula$onmayexhibitreducedreproduc$vesuccesswhen
comparedwithcrossesmadebetweenpopula$ons,becausetheyhaveahigher
likelihoodofhavingthesameSIallelesduetotheprincipleofisola$onbydistance
(Rousset1997).Bothsuccessfulpollina$onandtheforma$onofaviableseediscrucial
forreproduc$on.Studyingtheseprocessescanprovidevaluableinsightintothe
evolu$onaryrela$onshipbetweendifferentplantsandpollinators.
Methods:CrossCompa$bility
0
Differencesbetweencrosstypes:Chi-sq=658.78,df=4,p<0.001**;species:Chi-sq=180.31,df=1,p=0.51ns;maternal
popula$on:Chi-sq=186.77,df=2,p=0.03*
•  Ourfindingsdemonstratethatpollinatorsyndromesarecapableofaccuratelypredic$ngdominantpollinatorsinwildpopula$onsof
severalspeciesofOenothera.
•  AsiscommoninmanymembersofOnagraceae,O.gayleanaandO.hartwegiisubsp.filifoliaweredeterminedtobeselfincompa$blebut
thattherewasnodifferenceinseedproduc$onamongdifferentoutcrossestypesinthepopula$onsinves$gated.
•  FutureworkshouldassesswhetherthepaNernsfoundherearefoundthroughouttherangeofeachspecies.