Epizoochory in Parrots as an Overlooked Yet Widespread Plant-Animal Mutualism.

Dailos Hernández-Brito,Pedro Romero-Vidal,Fernando Hiraldo,Craig Symes,Jomar Barbosa,José Díaz-Luque,Martina Carrete,José Tella,Erica Pacífico,Thomas White,Guillermo Blanco,Esther Sebastián-González

doi:10.3390/plants10040760

Abstract

Plant–animal interactions are key to sustaining whole communities and ecosystem function. However, their complexity may limit our understanding of the underlying mechanisms and the species involved. The ecological effects of epizoochory remain little known compared to other seed dispersal mechanisms given the few vectors identified. In addition, epizoochory is mostly considered non-mutualistic since dispersers do not obtain nutritional rewards. Here, we show a widespread but unknown mutualistic interaction between parrots and plants through epizoochory. Combining our observations with photos from web-sources, we recorded nearly 2000 epizoochory events in 48 countries across five continents, involving 116 parrot species and nearly 100 plant species from 35 families, including both native and non-native species. The viscid pulp of fleshy fruits and anemochorous structures facilitate the adherence of tiny seeds (mean 3.7 × 2.56 mm) on the surface of parrots while feeding, allowing the dispersion of these seeds over long distances (mean = 118.5 m). This parrot–plant mutualism could be important in ecosystem functioning across a wide diversity of environments, also facilitating the spread of exotic plants. Future studies should include parrots for a better understanding of plant dispersal processes and for developing effective conservation actions against habitat loss and biological invasions.

Highlights

The knowledge of biotic interactions is critical to understand the structure of communities and ecosystem function [1,2], as well as to develop effective conservation actions against increasing habitat loss worldwide [3,4]
Epizoochory is generally considered infrequent compared to other zoochory mechanisms such as endozoochory, as it is mostly caused by the eventual attachment of propagules to the body of mammals or some bird species [11,16,17,34]
Epizoochory in mammals occurs thanks to specialized fruit structures of some plants that allow their attachment to fur [11,12], suggesting an epizoochorous dispersal syndrome for these plants

Summary

Introduction

The knowledge of biotic interactions is critical to understand the structure of communities and ecosystem function [1,2], as well as to develop effective conservation actions against increasing habitat loss worldwide [3,4]. Once seeds adhere to the animal surface, their detachment can be facilitated by certain behaviors of the dispersers, such as grooming and bill-wiping [18,19] and conspecific social interactions, which could even assist secondary seed dispersal events after seed transference between individuals [13,20]. These seeds, in general, attach inadvertently to the animal’s body without a clear benefit to the transporter [11,13]. Previous studies have shown that epizoochory in certain groups such as terrestrial birds is anecdotic [21,22,23] and largely skewed to waterbirds, probably because plants exploited by terrestrial birds are rarely epizoochorous [21,23]

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Results

Conclusion