The fruit dispersion of Adenostemma brasilianum (Asteraceae) by birds: an experimental approach

ABSTRACTThe pantropical genus Adenostemma (Asteraceae) includes mostly herbs which occur in wet forests and stream edges. They produce a large number of small fruits or cypselae, covered by glandular hairs and bearing a particular glandular pappus. These morphological characteristics of the fruits have been associated, but never tested, with dispersion by adhesion to birds’ feathers. We developed for the first time an experimental study to demonstrate the ability of the fruits of Adenostemma brasilianum (Pers.) Cass. to adhere to birds’ feathers. We performed three different experiments to test both the adherence and retention time of the fruits, with: 1) individual feathers, 2) taxidermied birds mounted in a life-like position, and 3) live captive birds. The fruits were effective in attaching to feather barbs under the three experiments and were able to remain attached for a period of time, supporting previous hypotheses that epiornithochory could be directly involved in the process of fruit dispersion. Our results are especially relevant in the understanding of biogeographic patterns in Adenostemma, given the importance of birds as fruit dispersion agents.KEYWORDS: Adenostemmadispersion by adhesionepiornithochoryEupatorieaepantropicalsticky fruits AcknowledgmentsWe thank R. Ramos, M. Grossi, E. Guerrero and T. Barea for helping us during field work, P. Altieri, M. Colombo, J. Crisci, and A. Jauregui for critical reading of the manuscript, and two anonymous reviewers for their helpful comments. We also thank K. Depot for carefully revising the English writing and Julio Milat from the Museo Ornitológico de Berisso for providing the taxidermied models to carry out the experiments. This study was conducted with research permits from the regional nature conservation authority (Res. 003/16; OPDS #17717, Dirección de Áreas Naturales Protegidas, Buenos Aires province, Argentina) and complies with the current laws of the country in which it was performed. This paper is the Scientific Contribution N° 1239 of the Institute of Limnology “Dr. Raúl A. Ringuelet” (ILPLA, CCT-La Plata CONICET, UNLP). Authors are CONICET Research Fellows.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingPartial financial support was received from Agencia Nacional de Promoción Científica y Tecnológica (PICT 2017–0965 and 2020–1529).