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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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Temporal shifts in reproductive phenology of cycads: a comparative study in Ceratozamia
The reproductive phenology in plants consists of successive life cycle phases leading to reproductive success. In seed plants, cycads and other dioecious groups have complex reproductive systems, where individuals require synchronizations among two sexes and populations of the same species. Here, we analyzed phenology between populations of three geographically close species in the cycad genus Ceratozamia Brongn. We described the lifespan of pollen and ovulate strobili and their morphological changes throughout ontogeny and evaluated synchrony among reproductive events, focusing on the timing and abundance of the receptivity and open pollen phases. Our results showed that the reproductive timing in the three species was highly synchronous, and that the overlap between the receptivity and open pollen phases could point to gene flow among populations of different species. We identified a correlation between the reproductive patterns and the temperature and precipitation regimes. Pollen and ovulate strobili were produced during the rainy season, whereas the period of synchrony between receptivity and pollen occurred during the dry season. The seed release occurred during the rainy season, which could contribute to keep the seed moist and prevent the embryo from drying out. Finally, we highlight the utility of studies in wild populations for the ecological and evolutionary understanding of phenological patterns in cycads.
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- Award ID(s):
- 0629817
- PAR ID:
- 10417362
- Date Published:
- Journal Name:
- Botany
- Volume:
- 100
- Issue:
- 11
- ISSN:
- 1916-2790
- Page Range / eLocation ID:
- 827 to 838
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1139/cjb-2022-0053
