Pollinator identity and spatial isolation influence multiple paternity in an annual plant.
The occurrence and extent of multiple paternity is an important component of variation in plant mating dynamics. However, links between pollinator activity and multiple paternity are generally lacking, especially for plant species that attract functionally diverse floral visitors. In this study, we separated the influence of two functionally distinct floral visitors (hawkmoths and solitary bees) and characterized their impacts on multiple paternity in a self-incompatible, annual forb, Oenothera harringtonii (Onagraceae). We also situated pollinator-mediated effects in a spatial context by linking variation in multiple paternity to variation in plant spatial isolation. We documented pronounced differences in the number of paternal sires as function of pollinator identity: on average, the primary pollinator (hawkmoths) facilitated mating with nearly twice as many pollen donors relative to the secondary pollinator (solitary bees). This effect was consistent for both isolated and nonisolated individuals, but spatial isolation imposed pronounced reductions on multiple paternity regardless of pollinator identity. Considering that pollinator abundance and pollen dispersal distance did not vary significantly with pollinator identity, we attribute variation in realized mating dynamics primarily to differences in pollinator morphology and behaviour as opposed to pollinator abundance or mating incompatibility arising from underlying spatial genetic structure. Our findings demonstrate that functionally distinct pollinators can have strongly divergent effects on polyandry in plants and further suggest that both pollinator identity and spatial heterogeneity have important roles in plant mating dynamics.
Division of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA.|Program in Plant Biology and Conservation, Northwestern University, 2205 Tech Drive, O.T. Hogan Hall, Room 2-144, Evanston, IL, 60208, USA.
Matthew K
http://orcid.org/0000-0002-5134-5936
MK
Rhodes
Division of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA.
Jeremie B
http://orcid.org/0000-0001-9276-1111
JB
Fant
Division of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA.
Krissa A
http://orcid.org/0000-0002-7868-9632
KA
Skogen
D000818:Animals; D001516:Bees; D035264:Flowers; D009036:Moths; D029594:Onagraceae / Q000235:genetics*; D011058:Pollen / Q000235:genetics; D054817:Pollination; D060436:Self-Incompatibility in Flowering Plants

Hyles
; 
Oenothera
; hawkmoth; multiple paternity; pollination; solitary bee