Recent Topics Posters
Shaw, Joshua P , Martin, Noland H. .
Mechanical pollinator isolation in Louisiana Iris: legitimacy and pollen transfer .
Many evolutionary forces work in concert to prevent the admixture of divergent lineages. In Louisiana Irises, a number of prezygotic and postzygotic barriers are thought to maintain the prevalence of the four species: Iris fulva, I. nelsonii, I. brevicaulis, and I. hexagona. One isolating mechanism, pollinator isolation, is believed to be one of the primary barriers preventing interspecific gene flow, yet the mechanics of pollinator isolation are poorly understood. Pollinator isolation can be broken down into both ethological and mechanical processes. Ethological isolation is important because there are two pollinator syndromes in the Louisiana Iris system. Iris fulva and I.nelsonii produce red flowers more attractive to and more conducive to hummingbird visitation. Iris brevicaulis and I. hexagona produce violet flowers which are preferred by bumblebees. While ethological isolation significantly inhibits gene flow, it is also an incomplete barrier. Mechanical isolation may further prevent hybrid formation, and has been divided into two categoriesólegitimate visitation and pollen transfer. The current study examines mechanical isolation in Louisiana Iris. Pollen transfer data were collected by utilizing powdered fluorescent dye as a pollen analogue to track the movement of pollen within and between the Iris species for bumblebees and ruby-throated hummingbirds. Iris anthers were dusted with the dye, and pollinator bouts were recorded. Presence/absence of the dye on the floral parts was recorded. Evidence supporting the significance of pollinator isolation through both legitimacy and pollen transfer has been found.
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1 - Texas State University, Biology, 401 N Fredericksburg #305, San Marcos, TX, 78666, United States
2 - Texas State University, Department of Biology, 601 University Drive, San Marcos, Texas, 78666, USA
Presentation Type: Recent Topics Poster
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM