Impact of distinct insect pollinators on gene flow

Authors: Brunet, Johanne; Holmquist, Karsten

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2007
Publication Date: 12/12/2007
Citation: Brunet, J., Holmquist, K.G. 2007. Impact of distinct insect pollinators on gene flow [abstract]. 62nd Annual North Central Weed Science Society (NCWSS) Meeting. Paper No. 131.

Interpretive Summary:

Technical Abstract: The vast majority of fruits and vegetables, together with some hay crops (alfalfa) and some oil-producing crops (canola) are pollinated by insects. However we have little information on how insect pollinators affect the movement of genes via pollen and even less on how distinct insect pollinators may differentially affect pollen flow. In this study we examined whether two types of insect pollinators, bumble bees and hawkmoths, differentially affected gene flow via pollen in the rocky mountain columbine, our model system. In one experiment, we used paternity analyses to contrast the movement of genes via pollen by bumble bees and hawkmoths within and between patches within a population. In a second experiment, we genotyped seeds from many target females located within a 40 km2 area, and used the Kindist module of Poldisp v.1.0 to fit the exponential power model to the haplotype data in order to calculate the average distance, axial variance and kurtosis of pollen dispersal for each pollination treatment. Results of our paternity analyses indicated that both pollinator types were as efficient via male function. Plants visited by hawkmoths and bumble bees had similar male reproductive success and sired the same number of outcrossed seeds. In addition pollen moved by either pollinator type sired seeds of similar genetic diversity on the same number of recipients. Moreover bumble bees did not limit pollen movement to nearest neighbor plants but frequently moved pollen between patches that were up to 150 meters apart. Fitting the exponential power model to examine dispersal on a larger geographical scale indicated that hawkmoths tended to move pollen 2-5 times as far as bumble bees. Pollen dispersal was fat tailed with relatively high kurtosis indicating the importance of long distance gene dispersal. While both hawkmoths and bumble bees were as efficient at moving pollen around, hawkmoths moved pollen further distances relative to bumble bees. Distinct pollinator types can differentially impact gene movement via pollen and thus differentially influence both seed purity and the spread of transgenes.