Pollen as the link between floral phenotype and fitness

Recei ed: 8 May 2023 | Accep ed: 11 May 2023 DOI: 10.1002/ajb2.16200 SPECIAL ISSUE ARTICLE Pollen as he link be ween flo al pheno ype and fi ness Øys ein H. Opedal 1 |Rocío Pé ez‐Ba ales 2 |Vinícius L. G. B i o 3 | Na han Muchhala 4 |Miquel Capó 5 |Agnes Dellinge 6 1 Depa men o Biology, Lund Uni e si y, Söl ega an 37, Lund 22362, Sweden 2 Bo any Depa men , Uni e si y o G anada, G anada 18071, Spain 3 Ins i u o de Biologia, Uni e sidade Fede al de Ube lândia, Ube lândia 38405‐315, B azil 4 Depa men o Biology, Uni e si y o Missou i a Sain Louis, Sain Louis, MO, USA 5 Depa amen o de Sis emas y Recu sos Na u ales, Uni e sidad Poli écnica de Mad id, Mad id, Spain 6 Depa men o Bo any and Biodi e si y Resea ch, Uni e si y o Vienna, Vienna, Aus ia Co espondence Øys ein H. Opedal, Depa men o Biology, Lund Uni e si y, Söl ega an 37, Lund 22362, Sweden. Email: [email p o ec ed] Abs ac Pollen plays a key ole in plan ep oduc i e biology. Despi e he long his o y o esea ch on pollen and pollina ion, ecen ad ances in pollen‐ acking me hods and s a is ical app oaches o linking plan pheno ype, pollina ion pe o mance, and ep oduc i e fi ness yield a s eady flow o exci ing new insigh s. In his in oduc ion o he Special Issue “Pollen as he Link Be ween Pheno ype and Fi ness,”we s a by desc ibing a gene al concep ual model linking unc ional classes o flo al pheno ypic ai s o pollina ion‐ ela ed pe o mance me ics and ep oduc i e fi ness. We use his model as a amewo k o syn hesizing he ele an li e a u e, highligh ing he s udies included in he Special Issue, and iden i ying gaps in ou unde s anding and oppo uni ies o u he de elopmen o he field. The pape s ha ollow in his Special Issue p o ide new insigh s in o he ela ionships be ween pollen p oduc ion, p esen a ion, flowe mo phology, and pollina ion pe o mance (e.g., pollen deposi ion on o s igmas), he ole o pollina o s in pollen ans e , and he consequences o he e ospecific pollen deposi ion. Se e al o he s udies demons a e exci ing expe imen al and analy ical app oaches ha should pa e he way o con inued wo k add essing he in iguing ole o pollen in linking plan pheno ypes o ep oduc i e fi ness. KEYWORDS fi ness unc ion, flowe –pollina o fi , he e ospecific pollen ans e , pa h analysis, plan –pollina o in e ac ions, pollen pe o mance, pollen p esen a ion, pollen p oduc ion, pollen ans e , pollina o ‐ media ed selec ion Pollen plays a key ole in plan ep oduc i e biology and is s udied in a ange o fields including cell and molecula biology (Bedinge , 1992), biochemis y (S anley and Linskens, 1974), ecology (Olle on, 2021), sys ema ic biology (Ca dinal‐McTeague and Gillespie, 2016), and e olu iona y bo any (Williams and Maze , 2016). As male game ophy es, pollen sha e some aspec s o i s biology wi h ha o animal spe m, while o he aspec s a e undamen ally dis inc . Chie among hese is he in ol e- men o pollina o s in pollen ans e among flowe s in mos flowe ing plan s (Olle on, 2021). Pollina ion by animals has my iad consequences o plan ecology and e olu ion, and as ca ie s o genes and media o s o fi ness gains h ough pollen expo and eceip , pollen si s a he e y cen e o he pollina ion p ocess. Na u al selec ion a ises when pheno ypic ai s a e linked o indi idual pe o mance and, in u n, fi ness (Opedal, 2021). “Pe o mance”is used he e in he sense o measu able quan i ies linking a pa icula kind o pheno ypic ai o fi ness (A nold, 1983), and “fi ness”in he con ex o pollina ion usually e e s o ep oduc i e fi ness as measu ed by seed p oduc ion. The ele an pe o mance componen (s) can be defined wi h e e ence o he hypo hesized unc ion o he ai s unde s udy. Fo example, he pe o mance o indi idual pollen g ains (pollen pe o mance) can be measu ed as he success in eaching a s igma, ge mina ing, de eloping a pollen ube ha eaches an o a y, and e ilizing an o ule (Williams and Maze , 2016). In he con ex o animal pollina ion, howe e , pollina ion‐ ela ed pe o mance componen s (pollina ion pe o mance) a e bes unde s ood Am J Bo . 2023;110:e16200. wileyonlinelib a y.com/jou nal/AJB | 1o 10 h ps://doi.o g/10.1002/ajb2.16200 This is an open access a icle unde he e ms o he C ea i e Commons A ibu ion License, which pe mi s use, dis ibu ion and ep oduc ion in any medium, p o ided he o iginal wo k is p ope ly ci ed. © 2023 The Au ho s. Ame ican Jou nal o Bo any published by Wiley Pe iodicals LLC on behal o Bo anical Socie y o Ame ica. This a icle is pa o join special issues o he Ame ican Jou nal o Bo any and Applica ions in Plan Sciences:“Pollen as he Link Be ween Pheno ype and Fi ness.” om he pe spec i e o he pa en al plan and include me ics such as pollen pickup om pollina o s (a componen o emale pollina ion pe o mance), placemen on o pollina o s and subsequen deposi ion on o conspecific s igmas (compo- nen s o male pollina ion pe o mance). While hese pe spec i es a e ob iously ela ed, he pollina ion pe spec i e leads na u ally o ques ions abou flo al ai s unc ionally in ol ed in he pollina ion p ocess (pollina ion unc ional ai s), while he pollen pe spec i e leads o ques ions abou pollen ai s de e mining he a e o he indi idual game o- phy e (pollen unc ional ai s), such as pollen size and pollen‐ ube g ow h a es. This dis inc ion is pa ly, bu no comple ely, aligned wi h he con en ional dis inc ion be ween p e‐pollina ion and pos ‐pollina ion p ocesses (Minnaa e al., 2019; Ch is ophe e al., 2020). As eflec ed in he i le, his special issue ocuses on he ole o pollen in linking flo al pheno ypes o fi ness. This idea is summa ized g aphically in he gene al model ep esen ed in Figu e 1. While his model is on he one hand concep ual, we will see ha i also can unc ion as an empi ical oadmap and as a ep esen a ion o an analy ical amewo k allowing join analyses o many o he p ocesses discussed in he pape s ha ollow in his special issue. Ou discussion will cen e mo e on pollina ion pe o mance and pollina ion unc ional ai s han on pollen pe o mance and pollen unc ional ai s. This choice pa ly eflec s ou own esea ch a eas and expe ise and also he ac ha he pollen pe o mance pe spec i e was well co e ed in a p e ious special issue o he Ame ican Jou nal o Bo any (see Fig. 1o Williams and Maze , 2016). In hei in oduc o y pape , Williams and Maze (2016) also p o ide a b ie his o ical accoun o esea ch on pollen biology. Ou ocus is simila o ha o Minnaa e al. (2019), and hei discussion o “pa hways o pa e ni y” alls na u ally in o he pollen‐expo pa hway in ou model (Figu e 1). In he ollowing, we use ou g aphical model (Figu e 1) as a amewo k o ou lining some o he key opics ela ed o he ole o pollen in linking flo al pheno ypes o fi ness, including b ie summa ies o he pape s ha add ess hem in he cu en special issue. We end by poin ing o gaps in ou cu en unde s anding and p opose ways o wa d o add essing hese gaps. FUNCTION AND PERFORMANCE IN POLLINATION, OR HOW POLLEN LINKS FLORAL PHENOTYPE TO FITNESS Ou concep ual model (Figu e 1) can be seen as a g aphical ep esen a ion o a pa h‐analy ical fi ness unc ion linking pheno ypic ai s h ough hypo hesized causal ela ionships o componen s o pe o mance and fi ness. This kind o model bo ows concep ual ideas om W igh ian pa h analysis (W igh , 1921;Shipley,2016) and can be o malized as a se ies o s a is ical models yielding es ima es o ai –pe o mance, pe o mance–fi ness, and ai –pe o mance–fi ness ela ion- ships. T ai –pe o mance ela ionships a e hose be ween a pe o mance componen and a ai (e.g., be ween s igma pollen load and flowe size), and pe o mance–fi ness FIGURE 1 G aphical model linking classes o pollina ion unc ional ai s (le ) o ep oduc i e fi ness on he igh (W=S ♀ +S ♂ ). T acing he a ows backwa d, he numbe o seeds p oduced as a ma e nal pa en (S ♀ ) is a unc ion o he numbe o pollen g ains (P) deposi ed on o s igmas h ough c oss‐(P CROSS ) and sel ‐pollina ion (P SELF ). Because c oss‐pollen eceip equi es pollina o isi a ion, he expec ed c oss‐pollen load can be w i en as a p oduc o he p obabili y o isi a ion (V) and pollen deposi ion condi ional on isi a ion (P C ), and he o al pollen load (P)asP=VP C +P S . Flo al ai s can indi ec ly inc ease he numbe o pollen g ains (P) by inc easing isi a ion o pollina o s esponding o ad e isemen o ewa d ai s, o di ec ly by imp o ing mechanical fi and hus he efficiency o pollen ans e . The a e o sel ‐pollina ion is also de e mined by flo al ai s affec ing wi hin‐flowe pollen ans e . The numbe o seeds si ed h ough pollen expo (S ♂ ) depends on he amoun o pollen deposi ed by pollina o s on o conspecific s igmas (P DEP ), which in u n depends on a ia ion in pollen placemen on o pollina o s (pollen pickup) as a unc ion o pollina o a ac ion, flowe –pollina o fi , and pollen p oduc ion. 2o 10 | POLLEN AS THE LINK BETWEEN FLORAL PHENOTYPE AND FITNESS 15372197, 2023, 6, Downloaded om h ps://bsapubs.onlinelib a y.wiley.com/doi/10.1002/ajb2.16200 by Uni e sidad De G anada, Wiley Online Lib a y on [19/07/2023]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License ela ionships a e hose be ween a fi ness componen and a pe o mance componen (e.g., how a ia ion in s igma pollen load ansla es in o seed p oduc ion) (A nold, 1983; Opedal, 2021). This and ela ed analy ical app oaches a e gaining inc easing popula i y in e olu iona y ecology (Shaw e al., 2008;Le check,2016; Henshaw e al., 2020)andp o ide se e al specific ad an ages in he s udy o pollina ion (S an on e al., 1991;Conne ,1996;Aigne ,2005; Bols ad e al., 2010; Opedal, 2021). Mos impo an ly, causal‐in e ence me hods such as pa h analysis equi e p io knowledge abou he (hypo hesized) causal ela ions be ween a iables, which is o en a ailable in pollina ion ecology. Rod íguez‐O e o e al. (2023)use he ypeo pa h–analy ical fi ness unc ion illus a ed by ou model o link flo al ai s o se e al pollina ion pe o mance componen s (pollina o isi a ion, pollen deposi- ion, pollina ium emo al), and one ep oduc i e fi ness componen (seed se ) in a se o ood‐decep i e o chids. I is impo an o keep in mind ha he model ep esen ed in Figu e 1is no fixed bu can be easily ailo ed o he biology o he s udy sys em and o he da a a ailable in a specific s udy. Fo example, in his special issue, Ga cía‐Muñoz e al. (2023) de eloped s uc u al equa ion models ha link flo al mo phology, ep oduc i e in es men (pollen and o ule p oduc ion), and fi ness (seed p oduc ion) in he sel e E ysimum incanum s.l. main ained in a pollina o ‐ ee g eenhouse en i on- men . S uc u al equa ion modeling is closely ela ed o he fi ness– unc ion app oach desc ibed abo e and allowed he au ho s o assess suppo o hypo hesized causal ela ion- ships among a iables. Because he analysis conce ned plan s kep in a g eenhouse, he fi ness unc ion could be simplified by omi ing c oss‐pollina ion. Simila ly, o sel ‐ incompa ible species, i would o en be na u al o omi sel ‐pollen deposi ion om he fi ness unc ion (al hough sexual in e e ence can ac also in sel ‐incompa ible species; Webb and Lloyd, 1986). Finally, o simplici y, ou model ea s sel ed and ou c ossed ma e nal seed p oduc ion join ly (Figu e 1,pollen‐ eceip pa hway), which co esponds o emale fi ness as ypically measu ed in field s udies. A simple ex ension would be o spli his fi ness componen in o sel ed andou c ossedcomponen s (e.g., B iscoe‐Runquis e al., 2017). T ai –pe o mance and pe o mance–fi ness ela ion- ships can be s udied independen ly (e.g., in field s. g eenhouse/lab s udies), and subsequen ly combined in o a comple e fi ness unc ion (A nold, 1983). Indeed, any s udy explo ing one o mo e links be ween pheno ype, pe o mance, and fi ness can be seen as es ima ing one componen ela ionship o a fi ness unc ion. In his sense, Figu e 1can be seen as an empi ical oadmap whe e he impo an ole o pollen in all links be ween componen s helps o cla i y he i le and ocus o his special issue. In he ollowing sec ions, we gi e se e al examples o how addi ional ai classes (e.g., pollen mo phology, flo al shape) and pe o mance componen s (e.g., he e ospecific pollen deposi ion) can be in eg a ed in o his gene al amewo k. Pollen p oduc ion and p esen a ion Building he kind o fi ness unc ion ep esen ed in Figu e 1 equi es ca e ul conside a ion o he expec ed causal ela ions among a iables. F om he male pe spec- i e, he fi s s ep in success ul c oss‐pollina ion is pollen placemen by an an he on o a pollina o (“pollen pickup”). The a e a which his occu s depends on he local abundance o (po en ial) pollina o s, he o aging p e e - ences o hese pollina o s, hei mechanical fi wi h he isi ed flowe s, and he amoun (and pe haps p ope ies) o pollen p esen ed (Minnaa e al., 2019). Pollen p oduc ion a ies g ea ly among animal‐ pollina ed plan s, and a long his o y o heo e ical and empi ical wo k has explo ed he causes and consequences o his a ia ion. C uden (1977) compiled es ima es o he a io o he numbe o pollen g ains o o ules (pollen:o ule a io) o assess and suppo he expec a ion ha he p oduc ion o pollen ela i e o o ules inc eases along a g adien om cleis ogamous o highly ou c ossing species o he ex en ha pollen:o ule a ios can be ea ed as a eliable p oxy o a ia ion in ma ing sys em. Recen me a‐analyses, including in his issue, ha e e ealed la ge‐ scale pa e ns and co ela es o pollen:o ule a ios. Fo example, Cunha and Aizen (2023) es ed and ound suppo o he expec a ion ha pe ‐flowe pollen p oduc ion will inc ease wi h flowe display size o compensa e o inc eased pollen discoun ing when pollina o s isi mul iple flowe s on he same plan (Ha de and Ba e , 1995). Also in his issue, Ha de and Johnson (2023) a gue ha some o he conclusions o p e ious me a‐analyses on his opic may be p ema u e because he analysis o a ios can obscu e effec s p esen o one o bo h unde lying a iables (he e pollen and o ule p oduc ion). Ins ead, Ha de and Johnson (2023) p opose ha pollen and o ule numbe s be analyzed join ly in a bi a ia e model, poin ing ou ha when he analysis is pe o med on a loga i hmic scale, he pollen:o ule a io can be di ec ly in e ed om he pa ame e s o such models (gi en ha log Pollen numbe –log O ule numbe = log [Pollen numbe /O ule numbe ]). Whe he and how his analy ical app oach will change he quali a i e esul s o p e ious analyses emains o be seen, bu his po en ial issue illus a es he impo ance in biology o ca e ul conside a ion o measu emen s and hei meaning (Houle e al., 2011). Ha de and Johnson (2023) also es ed and ound suppo o he hypo hesis ha pollen numbe pe flowe dec eases in axa wi h mo e efficien pollen ans e as measu ed by he p opo ion o pollen eaching s igmas, suppo ing a di ec link om pollen p oduc ion ia pollen ans e o fi ness, i.e., a ai –pe o mance–fi ness ela ionship (Figu e 1). In e ms o wi hin‐popula ion ai –pe o mance ela- ionships o pollen numbe (Figu e 1), we expec a ia ion in pollen numbe pe flowe o affec pollen placemen on o pollina o s and sel ‐pollen deposi ion on o s igmas. Es ima es o hese ela ionships in na u al popula ions a e a e, likely eflec ing he gene al ocus on selec ion h ough POLLEN AS THE LINK BETWEEN FLORAL PHENOTYPE AND FITNESS | 3o 10 15372197, 2023, 6, Downloaded om h ps://bsapubs.onlinelib a y.wiley.com/doi/10.1002/ajb2.16200 by Uni e sidad De G anada, Wiley Online Lib a y on [19/07/2023]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License emale unc ion (Minnaa e al., 2019; Ch is ophe e al., 2020). S an on e al. (1991), in an ea ly applica ion o pa h analysis in pollina ion ecology, ound ha g ea e pollen p oduc ion inc eased isi s by small na i e bees, which in u n led o g ea e si ing success. In one o he ew s udies quan i ying pheno ypic selec ion on pollen numbe h ough he male unc ion, Mo gan and Conne (2001) de ec ed posi i e selec ion. I we assume o now ha pollen placemen on o pollina o s and subsequen deposi ion on o s igmas a e co ela ed, his esul indi ec ly suppo s a posi i e ela ionship be ween pollen p oduc ion and placemen . This assump ion may no be jus ified, howe e . Fo example, in his issue, Pea son e al. (2023) epo posi i e ela ionships be ween indi idual pollen p oduc ion by Echinacea plan s and placemen on o a ange o pollina o s, bu his a ia ion was no associa ed wi h subsequen a ia ion in si ing success. This lack o a pe o mance–fi ness ela ionship can pe haps be explained by diffe ences in pollina o beha io and pollen‐ ans e p ocesses, as discussed below (and see S an on e al., 1991). In hei analysis o he selfing E ysimum incanum, Ga cía‐Muñoz e al. (2023) conside ed pa e ns o co a ia ion among pollen p oduc ion, o ule p oduc ion, flo al mo phology, and seed p oduc ion. Al hough pollen numbe had a limi ed di ec effec on seed p oduc ion in a g eenhouse, his s udy did show ha pollen numbe can co a y wi h flowe mo phology and wi h o ule p oduc ion, hus affec ing ep oduc i e fi ness. Beyond pollen numbe , he dynamics o pollen place- men on o pollina o s will also depend on he way in which pollen is p esen ed by flowe s. Fo example, aligning he daily pe iod o pollen p esen a ion o he ac i i y peak o pollina o s may bo h op imize pollen emo al and, o some ex en , educe ep oduc i e in e ac ions wi h co‐flowe ing species (S one e al., 1998). In his issue, Š enc e al. (2023) de ec ed alignmen be ween peaks in pollen p esen a ion and pollina o isi a ion o h ee co‐flowe ing species. Less is known abou wi hin‐popula ion a ia ion in daily pollen p esen a ion schedules (Eisen e al., 2017), which would be an in e es ing ai o include in pollina ion fi ness unc ions (Figu e 1). Simila ly, plan species diffe in he size o he pollen “packages” eleased pe pollina o isi . The op i- mum amoun o pollen eleased pe isi is expec ed o depend on se e al ac o s (Ha de and Thomson, 1989). When pollen is he p ima y ewa d, plan s ace he challenge o a oiding excessi e pollen loss due o g ooming while ensu ing a ac i eness o pollina o s. In his issue, Heiling e al. (2023) modeled pollen packaging s a egies unde he influence o hese cons ain s, confi ming he expec a ion ha op imum package size depends on he ela i e p e e ence o pollina o s o la ge packages, bu also addi ional ac o s such as o al pollen p oduc ion in he popula ion and possible ela ionships wi h pe ‐plan isi a ion a es. The ole o pollen as a ewa d in some species could be easily inco po a ed in o fi ness unc ions (Figu e 1) by including links om pollen p oduc ion (o daily p esen a ion) o pollina o isi a ion. Pollen ans e Once placed on o a pollina o , pollen can be los h ough a se ies o fil e s o ba ie s (Minnaa e al., 2019). Fo example, in he classic s udy o E y h onium g andiflo um by Thomson and Thomson (1989), less han 1% o he pollen emo ed om an he s eached a conspecific s igma. E en in unusually p ecise sys ems such as pollina ium‐ bea ing o chids, pollen is o en los du ing ans e (Capó e al., 2023; Ha de and Johnson, 2023). These esul s sugges ha he link om flo al pheno ype (affec ing pollen placemen ) o male ep oduc i e fi ness ia deposi ion on o conspecific s igmas may be highly a iable and ha d o de ec in analyses linking flo al ai s o pollen placemen (male pe o mance) and numbe o seeds si ed (male ep oduc i e fi ness, see Pea son e al., 2023). This a iabili y may be one eason why ela i ely ew s udies ha e de ec ed pheno ypic selec ion on flo al ai s h ough he male unc ion (Ashman and Mo gan, 2004; bu see e.g., B iscoe Runquis e al., 2017). Va ia ion in pollen ans e can a ise h ough many p ocesses, including in e ac ions on he body o he pollina o (Minnaa e al., 2019). In his special issue, Moi and Ande son (2023) p o ide empi ical e idence ha pollen o sequen ially isi ed flowe s can be deposi ed in laye s on o he pollina o 's body, and ha pollen deposi ion may decline om ea ly‐ o la e ‐ isi ed flowe s. Using he ecen ly de eloped fluo escen quan um‐do s echnique (Minnaa and Ande son, 2019) olabelpollen o indi idual flowe s, Moi and Ande son (2023)analyzed he laye s o pollen on he bodies o flypollina o s o labeled pollen and ound mo e labeled pollen in he op laye s. When a fly had isi ed wo labeled flowe s, i ca ied mo e pollen om he fi s flowe han om he second flowe , sugges ing ha exis ing pollen g ains om ea lie isi s inhibi addi ional pollen placemen . These esul s p o ide he fi s empi ical e idence o pollen laye ing as a mechanism media ing male–male compe i- ion du ing pollen ans e . How pollen laye ing affec s subsequen deposi ion on o s igmas emains an open ques ion. Ano he impo an sou ce o a ia ion in pollen‐ ans e efficiency is he iden i y o pollina o s. These diffe ences a e clea om a small bu g owing body o s udies assessing landscape‐scale effec s o pollina o mobili y on popula ion diffe en ia ion (Dellinge e al., 2022; Feigs e al., 2022; Gamba and Muchhala, 2023). In his issue, Lewis e al. (2023) used popula ion gene ics o es whe he diffe ences in he mobili y o hawkmo h and bee pollina o s explain popula ion diffe en ia ion in wo species o Oeno he a.As expec ed, hey ound inc eased popula ion diffe en ia ion wi h less‐mobile pollina o s (bees in hei case), bu li le effec s on popula ion diffe en ia ion h ough (ballis ic sho ‐dis ance) seed dispe sal (see also Gamba and Muchhala, 2020). Fu he mul ispecies s udies assessing he ela i e impo ance o pollen e sus seed‐media ed gene dispe sal a e needed o be e unde s and he impac o 4o 10 | POLLEN AS THE LINK BETWEEN FLORAL PHENOTYPE AND FITNESS 15372197, 2023, 6, Downloaded om h ps://bsapubs.onlinelib a y.wiley.com/doi/10.1002/ajb2.16200 by Uni e sidad De G anada, Wiley Online Lib a y on [19/07/2023]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License pollina o declines and changes in pollina o assemblages on he pe sis ence and e olu ion o plan popula ions. Besides landscape‐scale effec s o pollina o mobili y, diffe ences in pollina o o aging pa e ns and beha io may also affec small‐scale pollen‐ ans e efficiency and si ing success wi hin popula ions (Minnaa e al., 2019; Ke n e al., 2023). In wo s udies in his issue, aspec s o pollina ion efficiency we e compa ed ac oss diffe en bee species. Pea son e al. (2023) combined field obse a ions, single‐ isi pollina ion expe imen s and pa e ni y analyses o show ha bee species diffe en ially influence si ing success and ha hese diffe ences a e no always cap u ed by measu es o isi a ion a e o pollen emo al. Simila ly, Weinman e al. (2023) s udied he composi ion o he pollen loads ha bees ca y on hei bodies and in hei scopae and ound ha pollen o many plan species we e packed in bee scopae (and hus no a ailable o ans e o s igmas) wi hou occu ing on bee bodies. These wo s udies accen ua e he alue o combining molecula app oaches wi h efined pollina ion expe imen s ha go beyond he me e documen a ion o isi a ion and o s udying bee o aging s a egies o deciphe sub le p e‐and pos ‐ pollina ion pheno ype–pe o mance–fi ness ela ionships (Ch is ophe e al., 2020). Pollina o a ac ion F om he pe spec i e o he ma e nal plan , he fi s s ep in success ul c oss‐pollina ion is o a ac a leas one pollina o indi idual. T ai –pe o mance ela ionships o pollina o a ac ion ai s a ise when pollina o s make o aging decisions based on di ec assessmen o ewa d a ailabili y (Bols ad e al., 2010)o onflo al o plan ‐le el ad e isemen s ac ing as “hones signals”(e.g., plan heigh , Lo ie and Aa ssen, 1999;flowe size, A mb us e e al., 2005). In his issue, ai ‐pe o mance ela ionships o a ac ion ai s a e demons a ed in wo s udies o e es ial o chids. Capó e al. (2023)quan ified he ela ionships be ween plan heigh , flo al display size, pollina ium emo al, and ui se o fi e species. Al hough plan size also eflec s o e all igo , which leads o a ia ion in ep oduc i e success independen ly o polli- na o s (e.g., T unschke e al., 2017), he posi i e ela ion- ships be ween pollina ium emo al and hese “ igo ” ai s also suppo a ole o pollina o ‐media edselec ionin hei e olu ion. Rod íguez‐O e o e al. (2023) ook heanalysis o ai –pe o mance–fi ness ela ionships one s ep u he by de eloping a comple e fi ness unc ion and using i o es ima e selec ion g adien s. These au ho s also de ec ed o e all posi i e ai –pe o mance– ela ionships and selec ion on ad e isemen ai s. In e es ingly, he ai –pe o mance ela ionships we e compa able be ween emale (pollen deposi ion) and male pollina ion pe o m- ance (pollina ium emo al), sugges ing a leas some connec ion be ween he pollen‐ eceip and pollen‐expo pa hways o fi ness (Figu e 1). Flowe –pollina o fi While he ini ial s ep o he ma e nal plan in ol es a ac ion o he pollina o , ecei ing pollen hen depends on he p esence o pollen on he pollina o 's body and on whe he pa s o he pollina o 's body ca ying pollen make con ac wi h a ecep i e s igma. To he ex en ha flo al ai s de e mine he p obabili y o con ac and posi ion o con ac wi h pollina o bodies, hese flowe –pollina o fi ai s will hen link flo al pheno ype o pollina ion pe o mance (Opedal, 2021). Rod íguez‐O e o e al. (2023) included spu leng h and flowe size as a fi ai in hei o chid fi ness unc ion and showed ha ai –pe o mance ela ionships and selec ion on fi ai s end o fluc ua e d ama ically in bo h s eng h and di ec ion, p esumably in esponse o a ia ion in flowe –pollina o fi ac oss popula ions and species isi ed by diffe en pollina o s (Opedal, 2021). While mos p e ious s udies ha e ocused on indi idual fi ai s, Dellinge e al. (2023) ook on he challenge o linking complex flo al shape a ia ion as de ec ed by mo phome ic echniques o pollen emo al om an he s and deposi ion on o s igmas. They used a dimension‐ educ ion echnique, he wo‐block pa ial leas squa es me hod (Rohl and Co i, 2000), o combine a la ge se o measu emen s (he e landma ks) in o a single axis ela ed o a ia ion in pollina ion pe o mance. This app oach e ealed a de ec able ai –pe o mance ela ion- ship o pollen emo al om an he s, bu no o pollen deposi ion on o s igmas. Dellinge e al. (2023) also p o ide a gene al oadmap o u he wo k along his line. Pollen placemen on pollina o s is pe haps bes unde - s ood h ough he lens o pollina ion accu acy (A mb us e e al., 2009). Fo example, S ewa e al. (2022) compa ed he p ecision o pollen placemen (one componen o pollina- ion accu acy) ac oss a di e se se o plan species in Thailand and ound ha pollen placemen on pollina o s was mos p ecise in pheno ypically mo e specialized flowe s, as indica ed (among o he ai s) by bila e al flowe symme y and used co ollas. In his issue, Pé ez‐Ba ales and A mb us e (2023) compa ed pa e ns o pollina ion accu acy ac oss si es whe e Linum species occu ei he alone o wi h congene s o assess, and o some ex en suppo , di e gence in fi ai s among co‐flowe ing species. When a plan species is isi ed by mo e han one pollina o species (o unc ional g oup), ai –pe o mance ela ionships a e likely o diffe among hem. In his issue, Fu ado e al. (2023) compa ed he pollina ion efficiency o bee and hummingbi d pollina o s o Palicou ea igida, le e aging he pollen‐size dimo phism o hei dis ylous flowe s o assess pollen placemen on pollina o s and single‐ isi deposi ion on o s igmas. They ound ha he wo pollina o unc ional g oups diffe ed in pe ‐ isi pollen deposi ion, especially o he sho ‐ s yled mo ph. Also in his issue, Pea son e al. (2023)and Weinman e al. (2023)documen diffe ences in pollina- ion efficiency among bee pollina o axa. These kinds o diffe ences could be inco po a ed in o fi ness unc ions POLLEN AS THE LINK BETWEEN FLORAL PHENOTYPE AND FITNESS | 5o 10 15372197, 2023, 6, Downloaded om h ps://bsapubs.onlinelib a y.wiley.com/doi/10.1002/ajb2.16200 by Uni e sidad De G anada, Wiley Online Lib a y on [19/07/2023]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License by spli ing he pollen‐deposi ion pe o mance compo- nen in o pollina o ‐specific con ibu ions (c . Schemske and Ho i z, 1988). He e ospecific pollen ans e Whene e coflowe ing plan s sha e pollina o s, pollen loads deposi ed on o s igmas may con ain pollen o se e al species. He e ospecific pollen deposi ion is gene ally hough o ha e nega i e effec s on seed p oduc ion h ough mechanisms such as s igma clogging, in e e ence in he s yle, o conspecific pollen loss (Ashman and A ceo‐ Gómez, 2013; Mo ei a‐He nández and Muchhala, 2019). In p ac ice, howe e , i pollina o s also end o deposi mo e conspecific pollen when hey deposi mo e he e ospecific pollen, inc eased he e ospecific pollen deposi ion may ac ually co espond o g ea e seed se (e.g., Lopes e al., 2021), especially i he ecipien species has e ol ed a deg ee o ole ance o he e ospecific pollen. Fo example, in his issue, Hao e al. (2023) s udied pa e ns and consequences o he e ospecific pollen deposi ion on o s igmas in h ee Silene species and ound ha s igmas ecei ing mo e he e ospecific pollen also ended o ecei e mo e conspecific pollen and ha hand‐pollina ion wi h mix u es o conspecific and he e ospecific pollen did no usually educe seed p oduc ion compa ed o hose wi h only conspecific pollen. Such ole ance likely e ol es in esponse o na u al exposu e o he e ospecific pollen. Fo example, Mo ei a‐He nández e al. (2023) s udied pollen ans e wi hin and be ween sympa ic Bu meis e a and compa ed he effec o expe imen al pollen mix u es among se e al species ha diffe in he amoun o he e ospecific pollen hey ypically ecei e in he wild. As p edic ed, a species ha ecei es mo e he e ospecific pollina ion in he wild appea s o ha e e ol ed g ea e ole ance o i . How ole ance o he e ospecific pollen e ol es is no en i ely clea , bu likely ela es o changes in pollen–pis il in e ac ions and incompa ibili y sys ems (B oz and Bedinge , 2021). Analy ically, he e ospecific pollen deposi ion can eadily be included in o pollina ion fi ness unc ions as a pe o m- ance componen wi h logical links o pollina o isi a ion and ad e isemen , ewa d, and flowe ‐pollina o fi ai s (Figu e 1). As we ha e jus seen, he pe o mance–fi ness ela ionship (how he e ospecific pollen deposi ion affec s seed se and he ela ionship be ween conspecific pollen deposi ion and seed se ) has been well s udied (e.g., Hao e al., 2023; Mo ei a‐He nández e al., 2023; Pé ez‐Ba ales and A mb us e , 2023 [all in his issue]) and could easily be included by modelling seed se as a unc ion o conspecific pollen deposi ion, he e ospecific pollen deposi ion, and, p esumably, hei in e ac ion. T ai –pe o mance ela ionships o he e ospecific pol- len deposi ion ha e been less well s udied, al hough analyses o popula ion means sugges ha such ela ionships may occu a leas occasionally (Peuke e al., 2020; Lopes e al., 2021). The posi i e ela ionships o en obse ed be ween conspecific and he e ospecific pollen loads (e.g., Tu e al., 2016) also sugges ha he ai –pe o mance ela ionships migh be simila in shape. Simila ai –pe o mance ela ionships would mos likely occu i conspecific and he e ospecific pollen g ains a e placed, on a e age, on he same pa o he pollina o (Muchhala and Thomson, 2012). This assump ion may be jus ified in sys ems wi h sca e ed pollen placemen (e.g., in buzz‐ pollina ion), while in sys ems wi h mo e p ecise pollen placemen , he e is inc easing e idence o ep oduc i e cha ac e displacemen ac ing o educe he e ospecific pollen ans e (A mb us e e al., 1994; G ossenbache and Whi all, 2011; Eisen and Gebe , 2018). Pé ez‐Ba ales and A mb us e (2023) s udied he e ospecific pollina ion in he ligh o local assemblage s uc u e and po en ial e olu ion o ep oduc i e cha ac e displacemen in co‐ flowe ing Linum species. Thei ocal species, Linum suff u icosum, occu s in si es wi hou o he Linum species and in si es wi h co‐flowe ing and pollina o ‐sha ing congene s. In his sys em, he e ospecific pollen deposi ion nega i ely affec ed conspecific pollen ube o ma ion, bu diffe en Linum species we e only pa ially diffe en ia ed in hei pollina o assemblages and in flo al ai s affec ing pollen placemen on sha ed pollina o s a sympa ic si es. Pe o mance–fi ness ela ionships: om pollen deposi ion o seed se While male ep oduc i e success equi es pollen expo o conspecific s igmas, such pollen expo does no necessa ily gua an ee ha o ules will be e ilized. The ela ionship be ween conspecific pollen deposi ion and seed p oduc ion (i.e., he pe o mance–fi ness ela ionship o ou gene al fi ness unc ion; Figu e 1) is usually asymp o ic, wi h he asymp o e eflec ing he numbe o o ules and/o he uppe limi o esou ces a ailable o seed ma u a ion (Ashman e al., 2004). In e ms o building a fi ness unc ion, he pollen‐ o‐seeds cu e can be es ima ed ei he in he field o in a con olled g eenhouse en i onmen , hough he exac shape may diffe due o he influences o en i onmen al ac o s in he field (Hildesheim e al., 2019). One sou ce o a ia ion in pollen‐ o‐seed cu es is he na u e o pollen compe i ion. A la ge body o wo k has explo ed he consequences and e olu iona y impo ance o pollen compe i ion, and we e e eade s o Williams and Maze (2016) and e e ences he ein. Pollen unc ional ai s Beyond pollen numbe , many pollen unc ional ai s could affec he p obabili y o placemen on o pollina o bodies, deposi ion on o conspecifics igmas,andcompe i- i e abili y. T ai s such as pollen size, pollen nu ien con en , and pollen‐ ube g ow h a e would be s aigh o - wa d o in eg a e in o a fi ness unc ion (Figu e 1). Pollen 6o 10 | POLLEN AS THE LINK BETWEEN FLORAL PHENOTYPE AND FITNESS 15372197, 2023, 6, Downloaded om h ps://bsapubs.onlinelib a y.wiley.com/doi/10.1002/ajb2.16200 by Uni e sidad De G anada, Wiley Online Lib a y on [19/07/2023]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License ai s can also se e o a ac pollina o s when pollen unc ions as a flo al ewa d. In his issue, Nebaue e al. (2023) s udied he ole o pollen s e ols in he o aging decisions, nu i ion, and fi ness o bumble bees. Su p is- ingly, hey ound ha while bumble bees could de ec pu e s e ols, hey did no disc imina e be ween diffe en s e ols o be weenpollenwi hdiffe en s e ol concen a ions. Analy ically, including pollen nu ien composi ion in o a fi ness unc ion would likely benefi omdimension‐ educ ion app oaches such as he wo‐block pa ial leas squa e app oach used by Dellinge e al. (2023)o he educed‐ ank eg ession app oach ecen ly de eloped o analyzing ai –pe o mance ela ionships and selec ion on flo al scen chemis y (Opedal e al., 2022). Along wi h mo ing game es be ween indi iduals, pollen can also mo e a hos o diffe en pa hogens. In his issue, Fe e s and Ashman (2023) e iewed i al plan in ec ions associa ed wi h pollen, summa izing he cha ac e is ics o he pollen i ome and i s ansmission, wi h pa icula a en ion o plan , pollen, pollina o , and landscape ai s likely o be associa ed wi h a ia ion in i us ansmission. While he effec o ungal an he pa hogens on pollina ion has been s udied (Jenne s en, 1988; An ono ics and Alexande , 1992), oo li le is known abou he effec o pollen i uses on plan ai s and fi ness o be able o make clea p edic ions abou i us effec s on pollina ion. In ec- ions could po en ially affec plan s in ways ha would al e pollen ans e , c ea ing oppo uni ies o selec ion on flo al ai s (Giles e al., 2006). In p inciple, such effec s could be in eg a ed in o a pollina ion fi ness unc ion (Figu e 1). TECHNICAL ADVANCES IN POLLEN IDENTIFICATION AND QUANTIFICATION S udies o ai –pe o mance–fi ness ela ionships o he kind discussed abo e o en equi e quan ifica ion and iden ifica ion o pollen on s igmas o on pollina o s. Recen ly, me hods o au oma ed pollen iden ifica ion ha e ad anced conside ably, including machine‐lea ning algo- i hms o analyzing pollen pho os (Olsson e al., 2021) and pipelines o me a‐ba coding o pollen samples om bees (Bell e al., 2016) and he en i onmen (Polling e al., 2022). A pape in Applica ions in Plan Sciences o ms pa o he cu en special issue and p esen s a new pollen quan ifica- ion echnique. Bailey e al. (2023) e alua ed he use o high‐ ene gy iole ligh o pollen g ain classifica ion. The au ho s sampled pollen pelle s om 16 Apis melli e a hi es and compa ed iden ifica ion me hods based on high‐ene gy iole ligh and isible ligh o assess he ela ionship be ween pollen composi ion and colo . The p o ocol was able o diffe en ia e 35 pollen pelle colo s and aided in dis inguishing hei composi ion e en wi hin he same colo class. This me hod is low‐cos , easy o s anda dize, and highly ep oducible because pollen colo s can be iden ified by hei nume ical composi ion (RGB o hexadecimal). CONCLUSIONS AND PERSPECTIVES The pape s ha ollow in his special issue a es o he key ole o pollen in linking flo al pheno ypic a ia ion o pollina ion pe o mance and ep oduc i e fi ness. We hope ha ou discussion o he di e se insigh s and esul s om hese s udies in he ligh o a gene al pa h‐analy ical concep ual amewo k helps o illus a e he connec ions be ween opics ha a e o en s udied sepa a ely. We highligh he alue o a pa h‐analy ical amewo k o concep ualizing s udies o plan –pollina o in e ac ions and flo al e olu ion. In s udies ocusing on one o mo e indi idual ai –pe o mance, ai –fi ness, o pe o mance–fi ness ela ionship, de eloping a hypo he ical fi ness unc ion (causal diag am) can aid in e p e a ions by cla i ying he expec ed links o o he componen s o pe o mance and fi ness. Because he app oach is modula , indi idual ai –pe o mance and pe o mance–fi ness ela- ionships can be s udied in isola ion and la e linked oge he . Fo example, se e al s udies included in his special issue es ima e ai –pe o mance ela ionships by ela ing flo al pheno ype o pollen placemen o deposi ion in he field (e.g., Capó e al., 2023;Dellinge e al.,2023; Pé ez‐Ba ales and A mb us e , 2023;Rod íguez‐O e o e al., 2023). The co esponding pe o mance–fi ness ela ionship can be s udied h ough expe imen al manipula ion o pollen loads in he field o g eenhouse o in e pollen‐ o‐seed cu es o he influence o he e ospecific pollen deposi ion on he ela ionship be ween conspecific pollen deposi ion and seed se (e.g., Hao e al., 2023; Mo ei a‐He nández e al., 2023; Pé ez‐Ba ales and A mb us e , 2023). While hese kinds o esul s a e inc easingly a ailable, i is s ill a e o see hem combined in o a comple e fi ness unc ion o he kind illus a ed in Figu e 1, and we hope ha his special issue will inspi e u he wo k along his line. Two key poin s ha a ise when designing s udies o ai –pe o mance–fi ness ela ionships a e o conside (1) he (hypo hesized) unc ion o each kind o pheno ypic ai , and (2) he in e media e pe o mance componen s ha link hese ai classes o ep oduc i e fi ness. I he pollina ion componen is made only implici by going s aigh om pheno ype o fi ness, as is o en he case in s udies o pollina o ‐media ed selec ion (Opedal, 2021), we isk missing impo an mechanisms such as hose associa ed wi h pollen loss and male–male in e ac ions du ing pollen ans e (Minnaa e al., 2019). On his no e, i is common o see s a emen s abou pollina ion pe o mance compo- nen s being poo su oga es o p oxies o fi ness. Howe e , pollina ion pe o mance componen s a e no necessa ily s udied because hey a e “p oxies”o ep oduc i e fi ness, bu because hey in hemsel es a e in o ma i e abou pollina ion unc ion, which is cen al o unde s anding he e olu ion o flowe s and plan ep oduc ion. In ac , weak pe o mance–fi ness ela ionships equally means ha male ep oduc i e fi ness may be a poo p oxy o pollina ion pe o mance, highligh ing he impo ance o s udying bo h componen s. POLLEN AS THE LINK BETWEEN FLORAL PHENOTYPE AND FITNESS | 7o 10 15372197, 2023, 6, Downloaded om h ps://bsapubs.onlinelib a y.wiley.com/doi/10.1002/ajb2.16200 by Uni e sidad De G anada, Wiley Online Lib a y on [19/07/2023]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License Pe spec i es One gene al insigh om he s udies included in his special issue and he gene al li e a u e is ha diffe en pollina o axa may media e diffe en ai –pe o mance–fi ness ela ionships (e.g., Aigne , 2005; Sahli and Conne , 2011;Fu adoe al.,2023; Nakazawa and Kishi, 2023; Pea son e al., 2023). One way o see hisis ha eachpollina o axon media es a unique pollina ion fi ness unc ion ha can, in p inciple, be es ima ed. Es ima ing such efined, axon‐specificfi ness unc ions will equi e c ea i e, mul i‐me hod s udy designs ha d aw on bo h classical pollina ion–ecological obse a ions, expe imen s, and molecula echniques (Cas illa e al., 2017). As a s ep in his di ec ion, i seems impo an o a leas conside pollina o ‐specific esponses oflo al ad e isemen s and pa e ns o pollen deposi ion (Schemske and Ho i z, 1988; S an on e al., 1991). The de elopmen o new pollen‐labeling echniques such as quan um do s has opened new oppo uni ies o quan i ying he a es o pollen g ains a e pollen placemen on o a pollina o (Minnaa and Ande son, 2019), bu hei empi ical implemen a ion has been ela i ely slow. We a e con inced ha such pollen‐labeling me hods will acili a e s udies o pollen ans e (Ke n e al., 2023) and he sys em‐ specific pe o mance–fi ness ela ionships associa ed wi h pollen loss du ing ans e (Minnaa and Ande son, 2021). De ailed pollen acking me hods may also allow us o link pollina ion pe o mance mo e closely o pollen pe o mance and hence gain a mo e holis ic unde s anding o when and why specific pollen g ains a e mo e compe i i ely success ul han o he s. Combining such app oaches wi h pa e ni y assessmen s and popula ion gene ics holds u he p omise o ealis ically es ima ing ai –pe o mance–fi ness ela- ionships unde he influence o bo h s ochas ic and de e minis ic componen s o pollen ans e . Finally,weconcludeby epo ingonaninciden ha occu ed du ing he p ocess o pu ing oge he his special issue, which is o ele ance o he b oade scien ific communi y. Two yea s ago, one o us was app oached by a o ‐p ofi jou nal wi h he in i a ion o gues edi a special issue and in i ed he es o us o con ibu e. In ou p oposal, we explici ly s a ed ou goal o eaching b oadly ac oss he pollina ion biology communi y, including young esea che s and esea che s om he global sou h. A e sending ou in i a ions o colleagues, we lea ned o he exo bi an p ocessing cha ges and open‐access publica ion ees ha each au ho wouldneed oco e ;anamoun ha wouldse e o exclude he e y g oups we we e ying o each. A e discussions among ou sel es, some o he au ho s con ibu ing o his special issue and o he colleagues, we decided o e ac he special issue om he o iginal jou nal and ins ead we app oached he edi o ial boa d o he Ame ican Jou nal o Bo any (AJB) wi h ou special issue p oposal. A yea and a hal la e , we a e ex emely happy oha e aken hiss ep.Webelie e ha d awing b oad a en ion o publica ion bias in o ‐p ofi jou nals, and he alue o p o essional socie ies and he powe hey ha e in suppo ing a mo e di e se and inclusi e scien ific communi y is as impo an as assessing he ole o pollen in plan ep oduc ion. We hank he edi o s o AJB o he oppo uni y o publish his special issue and hei suppo and us h oughou he p ocess. ACKNOWLEDGMENTS We hank he mee ing o ganize s and pa icipan s a he symposium “Towa ds a concep ual ame o s udy flo al o m and unc ion in pollina ion”o ganized by R.P.B., A.S.D., and Ø.H.O. a Ecoflo 2021. Ø.H.O. acknowledges suppo om he Swedish Resea ch Council (g an n . 2021‐ 04777), R.P.B. om he Spanish Minis y o Science and Inno a ion (g an PID2021‐127264NB‐I00), V.L.G.B. om Conselho Nacional de Desen ol imen o Cien ífico e Tecnológico (CNPq, g an n . 308107/2021‐7), and A.S.D. om he Aus ian Science Fund (g an n . T‐1186). ORCID Øys ein H. Opedal h p://o cid.o g/0000-0002-7841-6933 REFERENCES Aigne , P. A. 2005. Va ia ion in pollina ion pe o mance g adien s in aDudleya species complex: Can gene aliza ion p omo e flo al di e gence? Func ional Ecology 19: 681–689. An ono ics, J., and H. M. Alexande . 1992. Epidemiology o an he ‐smu in ec ion o Silene alba (=S. la i olia) caused by Us ilago iolacea: pa e ns o spo e deposi ion in expe imen al popula ions. P oceedings o he Royal Socie y, B,Biological Sciences 250: 157–163. A mb us e , W. S., M. E. Edwa ds, and E. M. Debe ec. 1994. Flo al cha ac e displacemen gene a es assemblage s uc u e o wes e n Aus alian igge plan s (S ylidium). Ecology 75: 315–329. A mb us e , W. S., L. An onsen, and C. Pélabon. 2005. Pheno ypic selec ion on Dalechampia blossoms: hones signaling affec s pollina ion success. Ecology 86: 3323–3333. A mb us e , W. S., T. F. Hansen, C. Pélabon, R. Pe ez‐Ba ales, and J. Maad. 2009. The adap i e accu acy o flowe s: measu emen and mic oe olu iona y pa e ns. Annals o Bo any 103: 1529–1545. A nold, S. J. 1983. Mo phology, pe o mance and fi ness. Ame ican Zoologis 23: 347–361. Ashman, T. L., and M. T. Mo gan. 2004. Explaining pheno ypic selec ion on plan a ac i e cha ac e s: Male unc ion, gende balance o ecological con ex ? P oceedings o he Royal Socie y, B, Biological Sciences 271: 553–559. Ashman, T. L., and G. A ceo‐Gómez. 2013. Towa d a p edic i e unde s anding o he fi ness cos s o he e ospecific pollen eceip and i s impo ance in co‐flowe ing communi ies. Ame ican Jou nal o Bo any 100: 1061–1070. Ashman, T. L., T. M. Knigh , J. A. S ee s, P. Ama aseka e, M. Bu d, D. R. Campbell, M. R. Dudash, e al. 2004. Pollen limi a ion o plan ep oduc ion: ecological and e olu iona y causes and consequences. Ecology 85: 2408–2421. Bailey, C. P., C. A. Son e , J. L. Jones, S. Pandey, S. Habe le, K. San os, M. L. Absy, and R. Rade . 2023. Does so ing by colo using isible and high‐ene gy iole ligh imp o e classifica ion o axa in honey bee pollen pelle s? Applica ions in Plan Sciences 11: e11514. Bedinge , P. 1992. The ema kable biology o pollen. Plan Cell 4: 879–887. Bell, K. L., N. de Ve e, A. Kelle , R. T. Richa dson, A. Gous, K. S. Bu gess, and B. J. B osi. 2016. Pollen DNA ba coding: cu en applica ions and u u e p ospec s. Genome 59: 629–640. Bols ad, G. H., W. S. A mb us e , C. Pélabon, R. Pé ez‐Ba ales, and T. F. Hansen. 2010. Di ec selec ion a he blossom le el on flo al 8o 10 | POLLEN AS THE LINK BETWEEN FLORAL PHENOTYPE AND FITNESS 15372197, 2023, 6, Downloaded om h ps://bsapubs.onlinelib a y.wiley.com/doi/10.1002/ajb2.16200 by Uni e sidad De G anada, Wiley Online Lib a y on [19/07/2023]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License ewa d by pollina o s in a na u al popula ion o Dalechampia scho ii: ull‐disclosu e hones y? New Phy ologis 188: 370–384. B iscoe Runquis , R. D., M. A. Gebe , M. Picke ‐Leona d, D. A. Moelle , C. G. Ecke , and A. A. Winn. 2017. Ma ing sys em e olu ion unde s ong pollen limi a ion: e idence o dis up i e selec ion h ough male and emale fi ness in Cla kia xan iana.Ame ican Na u alis 189: 549–563. B oz, A. K., and P. A. Bedinge . 2021. Pollen–pis il in e ac ions as ep oduc i e ba ie s. Annual Re iew o Plan Biology 72: 615–639. Capó, M., J. Bo às, S. Pe elló‐Suau, J. Ri a, and J. Cu sach. 2023. Pheno ype–fi ness ela ionships and pollen‐ ans e efficiency o fi e o chid species wi h diffe en pollina ion s a egies. Ame ican Jou nal o Bo any 110: e16198. Ca dinal‐McTeague, W. M., and L. J. Gillespie. 2016. Molecula phylogeny and pollen e olu ion o Eupho biaceae ibe Plukene ieae. Sys ema ic Bo any 41: 329–347. Cas illa, A. R., N. S. Pope, M. O'Connell, M. F. Rod iguez, L. T e ino, A. San os, and S. Jha. 2017. Adding landscape gene ics and indi idual ai s o he ecosys em unc ion pa adigm e eals he impo ance o species unc ional b ead h. P oceedings o he Na ional Academy o Sciences, USA 114: 12761–12766. Ch is ophe , D. A., R. J. Mi chell, and J. D. Ka on. 2020. Pollina ion in ensi y and pa e ni y in flowe ing plan s. Annals o Bo any 125: 1–9. Conne , J. K. 1996. Unde s anding na u al selec ion: an app oach in eg a ing selec ion g adien s, mul iplica i e fi ness componen s, and pa h analysis. E hology Ecology & E olu ion 8: 387–397. C uden, R. W. 1977. Pollen–o ule a ios: a conse a i e indica o o b eeding sys ems in flowe ing plan s. E olu ion 31: 32–46. Cunha, N. L. d., and M. A. Aizen. 2023. Pollen p oduc ion pe flowe inc eases wi h flo al display size ac oss animal‐pollina ed flowe ing plan s. Ame ican Jou nal o Bo any 110: e16180. Dellinge , A. S., D. Hanusch, M. Oswald, D. Fe nández‐Fe nández, and J. Schönenbe ge . 2023. Using geome ic mo phome ics o de e mine he “fi es ”flo al shape: a case s udy in la ge‐flowe ed, buzz‐pollina ed Me iania he nandoi.Ame ican Jou nal o Bo any 110: e16183. Dellinge , A. S., O. Paun, J. Baa , E. M. Temsch, D. Fe nández‐Fe nández, and J. Schönenbe ge . 2022. Popula ion s uc u e in Neo opical plan s: in eg a ing pollina ion biology, opog aphy and clima ic niches. Molecula Ecology 31: 2264–2280. Eisen, K., A. L. Case, and C. M. Ca uso. 2017. Va ia ion in pollen‐ dispensing schedules o Lobelia siphili ica.In e na ional Jou nal o Plan Sciences 178: 79–84. Eisen, K. E., and M. A. Gebe . 2018. Ecological so ing and cha ac e displacemen con ibu e o he s uc u e o communi ies o Cla kia species. Jou nal o E olu iona y Biology 31: 1440–1458. Feigs, J. T., S. I. J. Holzhaue , S. Huang, J. B une , M. Diekmann, P.‐O. Hedwall, K. K amp, and T. Naa . 2022. Pollina o mo emen ac i i y influences gene ic di e si y and diffe en ia ion o spa ially isola ed popula ions o clonal o es he bs. F on ie s in Ecology and E olu ion 10: 908258. Fe e s, A. M., and T. L. Ashman. 2023. The pollen i ome: a e iew o pollen‐associa ed i uses and consequences o plan s and hei in e ac ions wi h pollina o s. Ame ican Jou nal o Bo any 110: e16144. Fu ado, M. T., R. Ma ias, R. Pé ez‐Ba ales, and H. Consola o. 2023. Complemen a y oles o hummingbi ds and bees: pollen pickup, pollen deposi ion, and ui p oduc ion in he dis ylous Palicou ea igida.Ame ican Jou nal o Bo any 110: e16194. Gamba, D., and N. Muchhala. 2020. Global pa e ns o popula ion gene ic diffe en ia ion in seed plan s. Molecula Ecology 29: 3413–3428. Gamba, D., and N. Muchhala. 2023. Pollina o ype s ongly impac s gene flow wi hin and among plan popula ions o six Neo opical species. Ecology 104: e3845. Ga cía‐Muñoz, A., C. Fe ón, C. Vaca‐Beni o, J. Lou ei o, S. Cas o, A. J. Muñoz‐Paja es, and M. Abdelaziz. 2023. Ploidy effec s on he ela ionship be ween flo al pheno ype, ep oduc i e in es men and fi ness exhibi ed by an au ogamous species complex. Ame ican Jou nal o Bo any 110: e16197. Giles, B. E., T. M. Pe e sson, U. Ca lsson‐G ane , and P. K. Ing a sson. 2006. Na u al selec ion on flo al ai s o emale Silene dioica by a sexually ansmi ed disease. New Phy ologis 169: 729–739. G ossenbache , D. L., and J. B. Whi all. 2011. Inc eased flo al di e gence in sympa ic monkeyflowe s. E olu ion 65: 2712–2718. Hao, K., Q. Fang, and S.‐Q. Huang. 2023. Do Silene species wi h exposed s igmas ole a e in e e ence by he e ospecific pollen? Ame ican Jou nal o Bo any 110: e16147. Ha de , L. D., and J. D. Thomson. 1989. E olu iona y op ions o maximizing pollen dispe sal o animal‐pollina ed plan s. Ame ican Na u alis 133: 323–344. Ha de , L. D., and S. C. H. Ba e . 1995. Ma ing cos o la ge flo al displays in he maph odi e plan s. Na u e 373: 512–515. Ha de , L. D., and S. D. Johnson. 2023. Beyond pollen:o ule a ios: e olu iona y consequences o pollina o dependence and pollina ion efficiency o pollen and o ule p oduc ion in angiospe ms. Ame ican Jou nal o Bo any 110: e16177. Heiling, J. M., R. E. I win, and W. F. Mo is. 2023. Conflic ing cons ain s on male ma ing success shape ewa d size in pollen‐ ewa ding plan s. Ame ican Jou nal o Bo any 110: e16158. Henshaw, J. M., M. B. Mo issey, and A. G. Jones. 2020. Quan i ying he causal pa hways con ibu ing o na u al selec ion. E olu ion 74: 2560–2574. Hildesheim, L. S., Ø. H. Opedal, W. S. A mb us e , and C. Pelabon. 2019. Quan i a i e and quali a i e consequences o educed pollen loads in a mixed‐ma ing plan . Ecology and E olu ion 9: 14253–14260. Houle, D., C. Pélabon, G. P. Wagne , and T. F. Hansen. 2011. Measu emen and meaning in biology. Qua e ly Re iew o Biology 86: 3–34. Jenne s en, O. 1988. Insec dispe sal o ungal disease: effec s o Us ilago in ec ion on pollina o a ac ion in Visca ia ulga is.Oikos 51: 163–170. Ke n, B. R., Ca ley L. N., and Moelle D. A. 2023. Di ec acking o pollen wi h quan um do s e eals su p ising uni o mi y in dispe sal dis ance ac oss ele en popula ions o an annual plan . Ame ican Jou nal o Bo any h ps://doi.o g/10.1002/ajb2.16201[in p ess]. Le check, J. S. 2016. piecewiseSEM: Piecewise s uc u al equa ion modelling in R o ecology, e olu ion, and sys ema ics. Me hods in Ecology and E olu ion 7: 573–579. Lewis, E. M., J. B. Fan , M. J. Moo e, and K. A. Skogen. 2023. Hawkmo h and bee pollina o s impac pollen dispe sal a he landscape bu no local scales in wo species o Oeno he a.Ame ican Jou nal o Bo any 110: e16156. Lopes, S. A., P. J. Be gamo, S. Naja a Pinho Quei oz, J. Olle on, T. San os, and A. R. Rech. 2021. He e ospecific pollen deposi ion is posi i ely associa ed wi h ep oduc i e success in a di e se hummingbi d‐ pollina ed plan communi y. Oikos 2022; e08714. Lo ie, C. J., and L. W. Aa ssen. 1999. The ad an age o being all: highe flowe s ecei e mo e pollen in Ve bascum hapsus L. (Sc ophula - iaceae). Ecoscience 6: 68–71. Minnaa , C., and B. Ande son. 2019. Using quan um do s as pollen labels o ack he a es o indi idual pollen g ains. Me hods in Ecology and E olu ion 10: 604–614. Minnaa , C., and B. Ande son. 2021. A combina ion o pollen mosaics on pollina o s and flo al handedness acili a es he inc ease o ou c oss pollen mo emen . Cu en Biology 31: 3180–3184.e3. Minnaa , C., B. Ande son, M. L. de Jage , and J. D. Ka on. 2019. Plan –pollina o in e ac ions along he pa hway o pa e ni y. Annals o Bo any 123: 225–245. Moi , M., and B. Ande son. 2023. Pollen laye ing and male–male compe i ion: Quan um do s demons a e ha pollen g ains compe e o space on pollina o s. Ame ican Jou nal o Bo any 110: e16184. Mo ei a‐He nández, J., H. Ghai, N. Te zich, R. Zamb ano‐Ce allos, N. H. Oleas, and N. Muchhala. 2023. Limi ed ep oduc i e in e e ence despi e high a es o he e ospecific pollen ans e among co‐occu ing ba ‐pollina ed Bu meis e a.Ame ican Jou nal o Bo any 110: e16199. Mo ei a‐He nández, J. I., and N. Muchhala. 2019. Impo ance o pollina o ‐media ed in e specific pollen ans e o angiospe m e olu ion. Annual Re iew o Ecology, E olu ion, and Sys ema ics 50: 191–217. POLLEN AS THE LINK BETWEEN FLORAL PHENOTYPE AND FITNESS | 9o 10 15372197, 2023, 6, Downloaded om h ps://bsapubs.onlinelib a y.wiley.com/doi/10.1002/ajb2.16200 by Uni e sidad De G anada, Wiley Online Lib a y on [19/07/2023]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License