Effects of Fire and Pollinator Visitation on the Reproductive Success of Asimina reticulata (Annonaceae), the Netted Pawpaw


Louise K. Barton

Additional Authors:

Eric S. Menges


Sept 2018


Annonaceae, endemic, geitonogamy, pollination ecology, prescribed fire

ABSTRACT The netted pawpaw (Annonaceae, Asimina reticulata) is a widespread Florida endemic plant that produces relatively few fruits. To understand its distribution and reproductive success, we posed three questions: (a) how do time-since-fire (TSF) and pollinator visitation influence reproductive success, (b) is it pollinator dependent, and (c) does outcrossing increase reproductive success? In 2016, we studied 157 plants in three flatwoods burn units (last burned, 2015, 2012, or 2001) and one grazed pasture at Archbold Biological Station in south-central Florida. Plants in pasture and recently burned flatwoods exhibited greater flower, fruit, and seed output, suggesting that habitat openness may promote competitive release or increased pollinator visitation. Pollinator visitation was greatest on plants within the 1-yr TSF, and the hairy flower scarab (Trichiotinus viridans) was the most prevalent visitor across all sites. Autogamously crossed flowers produced no fruit, confirming that seed production is pollinator dependent. Although fruit retention (10.0%) and seed germination (27.8%) were low after geitonogamous crossing, close and far outcrossing increased retention (30.8% and 39.6%) and germination success (41.6% and 46.4%). This research suggests that A. reticulata reaches its maximum reproductive potential in open areas after outcrossing events, and that low fruit set may be due to the lack of an effective pollinator, resulting in inbreeding depression. Additionally, an investigation into raccoons (Procyon lotor) as fruit consumers and potential seed dispersers suggests that seeds may benefit from gut scarification.