Abstract Detail

Reproductive Processes

Rodriguez, Rosa [1], Wolfe, Andi [2], Kubatko, Laura [3].

Anther dehiscence time depends on anther morphology in Penstemon: implications for pollination.

The interaction between flowers and the animals that pollinate them is one of the major drivers of angiosperm (flowering plants) diversification because it promotes reproductive isolation between closely-related diverging species. Therefore, it is not surprising that approximately 85% of angiosperms are pollinated by animals. However, many plant species are also visited by pollen thieves that collect flower resources but do not pollinate. Pollen thieves not only reduce the reproductive output (fitness) of the populations from which they rob, they could also influence the amount of pollen made available. Therefore, the pollen presentation schedule should reflect adaptations toward successful pollination, so that populations frequented by pollen thieves should develop a staggered pollen presentation. The goal of this study was to determine whether anther dehiscence times vary across species with different anther morphologies and to evaluate the contribution of pollen thieves to any difference in anther dehiscence time. Five species of Penstemon (P. albidus, P. fruticosus, P. glandulosus, P. speciosus, and P. whippleanus) were used in this study. Our sampling covers the total distribution range of the five species in the U.S.A., and consisted of recording flower visitors, measuring anther dehiscence times, and measuring 21 morphological variables. The data were analyzed using R software. An ordered probit analysis was used to determine whether sites frequented by the same type of visitor (true pollinators, thieves, etc.) have similar morphology. Time-to-event (survival) analysis was used to estimate the mean anther dehiscence time. Our results indicated that anther dehiscence time is significantly different between all species. Additionally, anther dehiscence time was longer in species with anthers that dehisce from tip-to-tip, and across the connective (P. albidus and P. whippleanus), and shorter in species with anther that dehisce only at the distal tip (P. speciosus). Only P. albidus was highly frequented by pollen-collecting bees. However, it has shorter anther dehiscence time than P. whippleanus (211 minutes difference). Finally, our results suggest that staggered anther dehiscence is positively correlated with anthers that dehisce from tip-to-tip and across the connective. This mechanism may potentially have evolved to reduce the effect of pollen thieves.

1 - The Ohio State University, Evolution, Ecology and Organismal Biology, 318 W 12th Ave, Building 131, Columbus, OH, 43210, United States
2 - Ohio State University, Department Of Evolution, Ecology And Organismal Biology, 318 W. 12th Avenue, Columbus, OH, 43210, United States
3 - The Ohio State University, Departments of Statistics, Cockins Hall, 1958 Neil Ave, Columbus, Ohio, 43210, United States

Keywords:
Anther dehiscence
Pollination
Penstemon
pollen thieves
pollen presentation theory.

Presentation Type: Oral Paper
Session: REP2, Reproductive Processes 2
Location: San Luis 2/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 2:00 PM
Number: REP2003
Abstract ID:791
Candidate for Awards:None