Prevalence, causes and consequences of interspecific pollen transfer in the subalpine plant communities of Polemonium brandegeei
| dc.contributor.author | Grey, Jacalyn | |
| dc.contributor.examiningcommittee | Bobiwash, Kyle (Entomology) | |
| dc.contributor.examiningcommittee | Klymiuk, Az (Biological Sciences) | |
| dc.contributor.examiningcommittee | Markham, John (Biological Sciences) | |
| dc.contributor.supervisor | Worley, Anne | |
| dc.date.accessioned | 2024-09-04T21:14:37Z | |
| dc.date.available | 2024-09-04T21:14:37Z | |
| dc.date.issued | 2024-08-27 | |
| dc.date.submitted | 2024-08-27T23:29:37Z | en_US |
| dc.degree.discipline | Biological Sciences | |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | Many pollinators visit multiple plant species, causing pollinators to carry and deposit diverse pollen loads. Although interspecific pollen transfer is ubiquitous, few studies have tested how pollen load composition and donor identity affect plant fitness. First, pollen from close relatives may decrease reproductive success due to their ability to germinate, clog pistils and usurp ovules, whereas pollen from distantly related donors may have negligible effects. Second, when pollen receipt is low, flowering neighbours may enhance pollinator visitation and cause a positive relationship between conspecific and heterospecific pollen deposition. I investigated the fitness consequences of pollen donor-recipient relatedness and pollinator sharing in two populations of a subalpine herb with diverse pollinators, Polemonium brandegeei, and its co-flowering communities. First, I collected open pollinated stigmas from all abundant co-flowering species in the communities. To test the prediction that pollinator sharing would be common in my study communities I used pollen transfer networks and floral visitor networks. Pollinator sharing was common between co-flowering species at CO-DM and WY-VD in 2022. All sampled species received or donated heterospecific pollen; most species, however, received little heterospecific pollen in each pollen load. Partial exclusion experiments revealed that both large pollinators (hummingbirds and hawkmoths) and small pollinators (bees and flies) contributed to outcrossed conspecific pollen and heterospecific pollen deposition. Second, I explored the fitness consequences of pollinator sharing and interspecific pollen transfer. Type II regressions between heterospecific pollen and conspecific pollen number and germination revealed that only neutral and facilitative relationships occurred between co-flowering species. To test the prediction that congeneric donors decrease P. brandegeei pollen germination and seed set, I conducted experimental hand pollinations including mixes of conspecific pollen and heterospecific pollen from a closely and distantly related species. General linear mixed models indicated that distantly related donors had no effect on P. brandegeei reproduction, although closely related donors decreased pollen germination and seed set. This study suggests that pollinator sharing between native co-flowering species can be common and beneficial in plant communities; competition, however, may occur if closely related species begin to co-flower due to range changes or phenological shifts. | |
| dc.description.note | October 2024 | |
| dc.description.sponsorship | University of Manitoba Graduate Fellowship, Manitoba Association of Plant Biologists Fellowship, GETS (Graduate Enhancement of Tri-Council Stipends) and Anne Worley’s NSERC Discovery grant | |
| dc.identifier.uri | http://hdl.handle.net/1993/38510 | |
| dc.language.iso | eng | |
| dc.subject | Pollinator sharing | |
| dc.subject | Interspecific pollen transfer | |
| dc.subject | Competition | |
| dc.subject | Facilitation | |
| dc.subject | Plant-pollinator interactions | |
| dc.title | Prevalence, causes and consequences of interspecific pollen transfer in the subalpine plant communities of Polemonium brandegeei | |
| local.subject.manitoba | no | |
| oaire.awardTitle | CGS-M | |
| oaire.awardURI | https://www.nserc-crsng.gc.ca/ResearchPortal-PortailDeRecherche/Instructions-Instructions/CGS_M-BESC_M_eng.asp | |
| project.funder.identifier | https://doi.org/10.13039/501100000038 | |
| project.funder.name | Natural Sciences and Engineering Research Council of Canada |