Pollinator visitation preference on native and non-native congeneric plants

Minimal research has been done looking at the ways in which non-native plants may be affecting native North American pollinators. I did a pollinator preference study on seven congeneric plant pairs in order to determine whether pollinators prefer native or non-native plants as food sources.; Honey bees had strong preferences for non-native species. There were significant differences in their number of visits to four out of five congeneric pairs in 2003 and five out of seven congeneric pairs visited in 2004.; Native pollinators did not show significant preferences for all of the native plant species, but they did significantly prefer native species more often than they preferred non-native species. When all of the native pollinator groups were considered as a whole, they visited native plant species significantly more in 31 of 70 congeneric pairings over the course of both field seasons. Native pollinators visited a non-native species significantly more often in one congener comparison.; I also conducted nectar comparison experiments using artificial flowers filled with native and non-native nectars. There was no significant difference in native pollinator visitation to the native and non-native nectars in the artificial flowers. There was also no significant difference in the amount of nectar remaining in the flowers once the experiments were concluded. I conclude that flower morphology or scent may be more important in determining visitation preferences than nectar chemistry.