Papilio butterfly vs. hawkmoth pollination explains floral syndrome dichotomy in a clade of Lilium

This dataset contains data described in the paper recently accepted by Botanical Journal of the Linnean Society:“ Liu C-Q, Niu Y, Lu Q-B, Chen Z, Cai B, Fang Y, Gao Y-D. (2021) Papilio butterfly vs. hawkmoth pollination explains floral syndrome dichotomy in a clade of Lilium".

The Leucolirion  clade of Lilium contains species with either tepal-recurved or trumpet-shaped flowers. We hypothesized that the tepal-recurved flowers  might be pollinated by butterflies and/or birds while the trumpet-shaped flowers might permit visitation by a variety of hawkmoths. Lilium leucanthum has trumpet shaped flowers, and some populations of this species show dark coloration on the floral outer surface, suggesting pollination by mammals. We examined the dependence of reproduction on pollinators by pollen load analysis and pollination experiments. We also analysed floral traits to contrast the two floral syndromes involving different lepidopteran groups.

The tepal-recurved lilies delivered pollen by Papilio butterflies with pollen predominantly attached to the hindwings. The trumpet-shaped flowers attracted diverse species with proboscises of different lengths. Self-incompatibility prevails throughout the clade. Exclusion of lepidopteran visitors resulted in very low seed set. The butterfly- and hawkmoth-pollinated species display contrasting floral syndromes. Thus, the dichotomy in floral syndrome, including nectar, color, and morphology in the Leucolirion clade is associated with Papilio butterfly vs. hawkmoth pollination. Intraspecific variation in colour of the floral outer surface of L. leucanthum  was also confirmed by our measurements.

These data can be used in further research on the floral ecology and evolution of Lilium and may also be needed in reviews of flower-hawkmoth interactions and hawkmoth biology.

Methods
Flower visitor observations were conducted directly by researchers working in the field. Pollination treatments were conducted in the field using randomly chosen individuals. Floral morphology and moth proboscises were measured by plastic rulers or digital callipers. Pollen load analysis were investigated by capturing flower visitors. Floral colour in terms of reflectance spectra was measured using a spectrometer (Flame), equipped with a UV-visble light source (DH-2000, both by Ocean Optics Inc., Dunedin, FL, USA). See the text of the article for more details.