Abstract Detail

Reproductive Processes

Degenhardt, Katrina [1], Karron, Jeffrey [2], Mitchell, Randall [3], Christopher, Dorothy [2], Rush, Richard [1].

Reproductive biology of buzz pollinated Primula meadia.

A major evolutionary trend in flowering plants is the evolution of strategies that limit pollen removal by inefficient or wasteful pollen foragers. One such strategy is the evolution of poricidal anthers, which restrict pollen removal to bees able to vibrate anthers at exceptionally high frequency (typically 300 – 500 hz). As the anthers are “buzz pollinated”, the pollen grains achieve sufficient velocity to come shooting out of the anther pores and onto the underside of the pollinator, a region where grooming by the pollinator is inefficient, allowing for greater pollen transfer among plants. Recently there has been increasing interest in studying the biomechanics of the buzz-pollination process. However, the reproductive ecology of buzz-pollinated species in natural populations remains largely unexplored. Buzz-pollination is a very complex learned foraging behavior, and bumble bees not familiar with the unusual floral morphology of buzz-pollinated species will often depart flowers without successfully extracting pollen. Thus we hypothesize that small or low density populations of buzz-pollinated species may disproportionately suffer from pollen limitation. To test this hypothesis, we are studying the ecology of Primula meadia (“shooting star”), a spring flowering wetland perennial native to prairies of central and eastern North America. This species is a member of a small North American clade of 15 species that represent a single origin of buzz pollination in the large genus Primula. All members of the “Dodecatheon” clade share similar floral morphology consistent with buzz pollination: pendant flowers with petals reflexed upward and enlarged anthers arranged in a cone around the protruding stigma. The anthers dehisce introrsely along longitudinal slits within the anther cone and pollen is ejected through the tips of the anthers when they are vibrated at sufficient velocity. Primula meadia is pollinated primarily by queens of several Bombus species as well as by solitary Augochloropsis (“sweat bees”). Through the use of caging experiments and “pollinator interviews”, we are quantifying the relative contributions of these different pollinator classes to Primula meadia reproductive success. Primula meadia does not set seed in the absence of pollinators, and self-pollination results in very high levels of early-acting inbreeding depression (> 50% seed abortion). We hypothesize that this may contribute to low levels of reproductive success in small population fragments.

1 - University of Wisconsin-Milwaukee, Biological Sciences, 3209 N Maryland Ave, Milwaukee, WI, 53211, USA
2 - University Of Wisconsin-Milwaukee, Department Of Biological Sciences, Po Box 413, Milwaukee, WI, 53201, United States
3 - University Of Akron, Department Of Biology, Dept Of Biology, Akron, OH, 44325, United States

buzz pollination
breeding system
pollinator foraging behavior.

Presentation Type: Oral Paper
Number: RP3007
Abstract ID:202
Candidate for Awards:None

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