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Abstract Premise Many tropical plants are bat‐pollinated, but these mammals often carry copious, multispecific pollen loads making bat‐pollinated plants susceptible to heterospecific pollen deposition and reproductive interference. We investigated pollen transfer between sympatric bat‐pollinated Burmeistera species and their response to heterospecific pollen deposition from each other. Methods We quantified conspecific and heterospecific pollen deposition for two populations of B. ceratocarpa , a recipient species in heterospecific pollen transfer interactions, that co‐occur with different donor relatives ( B. borjensis and B. glabrata ). We then used a cross‐pollination scheme using pollen mixtures to assess the species' responses to heterospecific pollen deposition in terms of fruit abortion and seed production. Results Burmeistera ceratocarpa received significantly more heterospecific pollen from its relatives at both sites than its own pollen was deposited on its relatives. However, heterospecific pollen deposition only affected seed production by B. borjensis and B. glabrata , but not by B. ceratocarpa , suggesting that early acting post‐pollination barriers buffer the latter against reproductive interference. Crosses between sympatric and allopatric populations suggest that the study species are fully isolated in sympatry, while isolation between allopatric populations is strong but incomplete. Conclusions We did not observe evidence of reproductive interference among our study species, because either heterospecific pollen deposition did not affect their seed production ( B. ceratocarpa ) or they receive heterospecific pollen only rarely ( B. borjensis and B. glabrata ). Frequent heterospecific pollen deposition might favor the evolution of barriers against foreign pollen (as in B. ceratocarpa ) that alleviate the competitive costs of sharing low fidelity pollinators with co‐occurring species.
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Cannabis pollen dispersal across the United States
For the recently legalized US hemp industry (Cannabis sativa), cross-pollination between neighboring fields has become a significant challenge, leading to contaminated seeds, reduced oil yields, and in some cases, mandated crop destruction. As a step towards assessing hemp cross-pollination risk, this study characterizes the seasonal and spatial patterns in windborne hemp pollen dispersal spanning the conterminous United States (CONUS). By leveraging meteorological data obtained through mesoscale model simulations, we have driven Lagrangian Stochastic models to simulate wind-borne hemp pollen dispersion across CONUS on a county-by-county basis for five months from July to November, encompassing the potential flowering season for industrial hemp. Our findings reveal that pollen deposition rates escalate from summer to autumn due to the reduction in convective activity during daytime and the increase in wind shear at night as the season progresses. We find diurnal variations in pollen dispersion: nighttime conditions favor deposition in proximity to the source, while daytime conditions facilitate broader dispersal albeit with reduced deposition rates. These shifting weather patterns give rise to specific regions of CONUS more vulnerable to hemp cross-pollination.
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- Award ID(s):
- 1922516
- PAR ID:
- 10571303
- Publisher / Repository:
- Nature Portfolio
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 14
- Issue:
- 1
- ISSN:
- 2045-2322
- Subject(s) / Keyword(s):
- Cannabis pollen dispersal Hemp cross-pollination pollen cross-pollination Windborne pollen transport Lagrangian Stochastic models LS models Mesoscale meteorological modeling Nonlinear dispersion modeling Convective and shear-driven turbulence Diurnal and seasonal pollen transport Environmental impact of hemp cultivation Agricultural risk assessment cross-pollination vulnerability risk assessment
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s41598-024-70633-x
