Testing for apomixis in an obligate pollination mutualism

Authors

  • Jonathan TD Finch Hawkesbury Institute for the Environment, Western Sydney University
  • Sally A Power Hawkesbury Institute for the Environment, Western Sydney University
  • Justin A Welbergen Hawkesbury Institute for the Environment, Western Sydney University
  • James M Cook Hawkesbury Institute for the Environment, Western Sydney University

DOI:

https://doi.org/10.26786/1920-7603(2021)644

Keywords:

Breynia, Epicephala, Phyllanthaceae, apomixis, delayed fruit production, dormant pollinated flowers

Abstract

Plants with a small number of specific pollinators may be vulnerable to fluctuations in the availability of those pollinators, which could limit plant reproductive success and even result in extinction. Plants can develop mechanisms to mitigate this risk, such as apomixis. Reproductive assurance mechanisms have been largely ignored in obligate pollination mutualisms (OPMs), that are some of the most specialised of plant-pollinator interactions. Furthermore, although OPMs are often referred to as obligate, this is rarely tested. We performed a flower-bagging experiment to test if the unisexual flowers of Breynia oblongifolia could set fruit in the absence of its highly specialised seed-eating moth pollinators. Surprisingly, many bagged female flowers developed fruits, suggesting apomixis. We therefore conducted a second series of experiments in which we 1) added or excluded pollinators from caged plants; and 2) surveyed a wild population for apomictic reproduction using mother-offspring genotyping. In the absence of pollinators, no fruits developed. In addition, we detected no genetic evidence for apomixis when comparing between mothers and their offspring or between adults in a wild population. We explain the production of fruits in bagged branches by our discovery that B. oblongifolia can retain pollinated female flowers over the winter period. These flowers develop to fruits in the spring in the absence of male flowers or pollinators. Our study thus shows that B. oblongifolia is unable to produce fruit in the absence of its specialist moth pollinators. Thus, the highly specific interaction between plant and pollinators appears to be truly obligate.

Author Biography

Jonathan TD Finch, Hawkesbury Institute for the Environment, Western Sydney University

 

Published

2021-09-17

How to Cite

Finch, J. T., Power, S. A., Welbergen, J. A., & Cook, J. M. (2021). Testing for apomixis in an obligate pollination mutualism. Journal of Pollination Ecology, 28, 167–178. https://doi.org/10.26786/1920-7603(2021)644