Interactive effects between donor and recipient species mediate fitness costs of heterospecific pollen receipt in a co-flowering community
Evaluation of pollen transfer in wild plant communities revealing heterospecific pollen receipt is common, yet experimental hand pollinations have revealed high among-species variation in the magnitude of its effect on recipient fitness. The causes of this among-species variation are unknown, however, prompting the investigation of underlying factors. Here, we conducted a hand-pollination experiment with ten co-flowering species to determine whether the effects of heterospecific pollen receipt are mediated by the pollen donor or recipient species alone, or whether the effects are determined by the interaction between them. We further assessed species traits potentially mediating interactive effects in heterospecific pollen receipt by evaluating the relationship between heterospecific pollen effect size and three different predictors reflecting a unique combination of pollen donor and recipient characteristics. Our results show, for the first time, that the magnitude of the heterospecific pollen receipt effect is determined by the specific combination of donor and recipient species (i.e., interactive effects). However, we were unable to uncover the specific combination of traits mediating these effects. Overall, our study provides strong evidence that an understanding of heterospecific pollen receipt effects based on recipient or donor characteristics alone may be insufficient. This study is an important step toward an understanding of consequences of heterospecific pollen receipt in co-flowering communities.
KeywordsCo-flowering Pollen transfer Pollination Pollen size Stigma area
We thank Rebecca Hayes, Elizabeth O’Neill, Kiera Doleski, Abigail Rothrauff and Jesse Daniels for their assistance collecting data, UPitt greenhouse staff for plant care. This work was funded by NSF DEB1452386 to TLA. CP was supported by an ETSU student–faculty collaborative grant. UPitt and ETSU provided logistical support.
Author contribution statement
TLA and GAG conceived and designed the experiments. RLK and GAG performed the experiments. CP and RLK processed samples and collected data. GAG and CP analyzed the data. GAG and RLK wrote the manuscript; all authors provided editorial advice.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Arceo-Gómez G, Abdala-Roberts L, Jankowiak A, Kohler C, Meindl GA, Navarro-Fernández CM, Parra-Tabla V, Ashman TL, Alonso C (2016) Patterns of among-and within-species variation in heterospecific pollen receipt: the importance of ecological generalization. Am J Bot 103:396–407. https://doi.org/10.3732/ajb.1500155 CrossRefPubMedGoogle Scholar
- Bascompte J, Jordano P (2007) Plant-animal mutualistic networks: the architecture of biodiversity. Annu Rev Ecol Evol Syst 38:567–593. https://doi.org/10.1146/annurev.ecolsys.38.091206.095818 CrossRefGoogle Scholar
- Cruden RW, Miller-Ward S (1981) Pollen-ovule ratio, pollen size, and the ratio of stigmatic area to the pollen-bearing area of the pollinator: an hypothesis. Evolution 35:964–974. https://doi.org/10.1111/j.1558-5646.1981.tb04962.x CrossRefPubMedGoogle Scholar
- Dafni A (1992) Pollination ecology: a practical approach. Oxford University Press, OxfordGoogle Scholar
- Freestone AL, Inouye BD (2006) Dispersal limitation and environmental heterogeneity shape scale-dependent diversity patterns in plant communities. Ecology 87:2425–2432. https://doi.org/10.1890/0012-9658(2006)87%5b2425:DLAEHS%5d2.0.CO;2 CrossRefPubMedGoogle Scholar
- Hedges L, Olkin I (1985) Statistical models for meta-analysis. Academic Press, New YorkGoogle Scholar
- Heslop-Harrison Y (1981) Stigma characteristics and angiosperm taxonomy. Nord J Bot 1:401–420. https://doi.org/10.1111/j.1756-1051.1981.tb00707.x CrossRefGoogle Scholar
- Murphy SD, Aarssen LW (1989) Pollen allelopathy among sympatric grassland species: in vitro evidence in Phleum pratense L. New Phytol 112:295–305. https://doi.org/10.1111/j.1469-8137.1989.tb02385.x CrossRefGoogle Scholar
- Olesen JM, Jordano P (2002) Geographic patterns in plant–pollinator mutualistic networks. Ecology 83:2416–2424Google Scholar
- Rasband WS (1997) ImageJ. US National Institutes of Health, BethesdaGoogle Scholar
- SAS Institute (2010) SAS/IML software, version 9.2. SAS Institute, Cary, North Carolina, USAGoogle Scholar
- Spira TP (1980) Floral parameters, breeding system and pollinator type in Trichostema (Labiatae). Am J Bot 67:278–284. https://doi.org/10.1002/j.1537-2197.1980.tb07652.x CrossRefGoogle Scholar