Document Type

Journal Article

Publication Title

Annals of Botany

Publisher

Oxford Academic

School

Centre for Ecosystem Management / School of Science

Funders

Edith Cowan University - Open Access Support Scheme

Comments

Delnevo, N., van Etten, E. J., Clemente, N., Fogu, L., Pavarani, E., Byrne, M., & Stock, W. D. (2020). Pollen adaptation to ant pollination–a case study from the Proteaceae. Annals of Botany. Article mcaa058. https://doi.org/10.1093/aob/mcaa058

Abstract

Background and aims

Ant-plant associations are widely diverse and distributed throughout the world, leading to antagonistic and/or mutualistic interactions. Ant pollination is a rare mutualistic association and reports of ants as effective pollinators are limited to a few studies. Conospermum (Proteaceae) is an insect-pollinated genus well represented in the south-western Australia biodiversity hotspot, and here we aimed to evaluate the role of ants as pollinators of C. undulatum.

Methods

Pollen germination after contact with several species of ants and bees was tested for C. undulatum and five co-flowering species for comparison. We then sampled the pollen load of floral visitors of C. undulatum to assess whether ants carried a pollen load sufficient to enable pollination. Lastly, we performed exclusion treatments to assess the relative effect of flying- and non-flying-invertebrate floral visitors on the reproduction of C. undulatum. For this, we measured the seed set under different conditions: ants exclusion, flying-insects exclusion and control.

Key results

Pollen of C. undulatum, along with the other Conospermum species, had a germination rate after contact with ants of ~80% which did not differ from the effect of bees; in contrast, the other plant species tested showed a drop in the germination rate to ~10% following ant treatments. Although ants were generalist visitors, they carried a pollen load with 68% to 86% of suitable grains. Moreover, ants significantly contributed to the seed set of C. undulatum.

Conclusions

Our study highlights the complexity of ant-flower interactions and suggests that generalizations neglecting the importance of ants as pollinators cannot be made. Conospermum undulatum has evolved pollen with resistance to the negative effect of ant secretions on pollen grains, with ants providing effective pollination services to this threatened species.

DOI

10.1093/aob/mcaa058

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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