Abstract Detail

Reproductive Processes

Zweck, Justin [1].

A comparison of divergent pollination strategies in co-blooming Dalea (Fabaceae) species.

The genus Dalea (Fabaceae) is a valuable system for studying shifts in pollination systems because it contains species with two different modes of floral presentation.  Species with papilionoid (bilaterally symmetrical) flowers enclose anthers and stigma within keel petals.  Non-papilionoid species’ flowers (radially symmetrical) expose their stamens and pistils on dense, compressed spikes.  In 2014 and 2015 I compared the pollination and breeding systems of 5 co-blooming papilionoid and non-papilionoid Dalea species in southeastern Arizona.  While the papilionoid species studied were exclusively bee-pollinated, the non-papilionoid species had a generalized pollination system, which including insects in 3 Orders. However, papilionoid species also showed automatic self-pollination in the absence of pollen vectors, which didn’t occur in non-papilionoid species.  Accordingly, the papilionoid species displayed significantly less flowers per inflorescence compared to non-papilionoid species.   These divergent pollination systems had different trade-offs.  For example, stigmas of papilionoid flowers were less likely to receive heterospecific pollen compared to non-papilionoid species, but papilionoid species were also more likely to be visited by nectar thieves. In addition to the tradeoffs detailed here, I predict that the papilionoid species studied have lower genetic diversity than non-papilionoid species, while conversion of pistils into viable fruits should be lower in non-papilionoid species when pollinators are scarce.

1 - UM Duluth, Biology, 207 SSB, 1035 Kirby Dr, Duluth, MN, 55805, United States


Presentation Type: Oral Paper
Number: 0013
Abstract ID:696
Candidate for Awards:None

Copyright © 2000-2019, Botanical Society of America. All rights reserved