Nectar production in Louisiana iris hybrids

Nectar is an important attractant for pollinators, and a plant's success in sexual reproduction can be influenced by the amount and concentration of n ectar produced by its flowers. We studied nectar production over flower lif etime in Iris fulva, Iris brevicaulis, and four classes of hybrids - recipr ocal F-1's and backcrosses - between these species. Iris fulva produced les s concentrated nectar than did I. brevicaulis, whereas I. brevicaulis flowe rs had a shorter life span. Hybrids were not intermediate, but they had the high nectar concentration of I. brevicaulis combined with the long life sp an of I. fulva flowers. Nectar production and concentration declined after the first day in all classes, but flowers continued to produce nectar until they were completely wilted. Backcrosses did not show a shift in mean or i ncreased variation for the characters that distinguished the parental speci es; backcrosses toward I. fulva retained the high nectar concentration of I . brevicaulis, and backcrosses toward I. brevicaulis did not have a reduced flower life span. Overall, F-1 hybrid flowers produced the highest amounts of nectar and nectar sugar over their life spans. These results, together with previously obtained data on pollinator choice in mixed arrays of the s ame flower classes, show that F-1 hybrids between these species do not suff er from reduced attractiveness to pollinators. F-1 individuals produced mor e nectar and nectar sugar than did their parents, and thus, they are possib ly even more attractive to pollinators that forage for nectar.