Abstract
In landscape studies conducted in 2002 and 2003, Lantana camara (L.) ‘New Gold’ and ‘Radiation’ were visited by native butterflies to a greater extent than the remaining eight lantana in the studies. Other lantana visited preferentially but not as consistently included L. camara ‘White Doves’, ‘Firewagon’, ‘Confetti’, and Lantana montevidensis (Spreng.) ‘Weeping Lavender’. In general, the lowest visitation was experienced by L. camara ‘Cherry’ and ‘Carlos’. Total visit duration by one randomly selected butterfly was greater for ‘New Gold’, ‘Radiation’, ‘Firewagon’, and ‘White Doves’ than the remaining lantana. Plant characteristics including inflorescence number, number of flowers per inflorescence, percentage of yellow flowers per inflorescence, growth index, flower morphology, and flower color characteristics differed among cultivars. Cultivar differences that consistently correlated with visitation preferences were inflorescence number in 2002 and 2003, flower number per inflorescence in 2003, percentage of yellow flowers per inflorescence in 2002 and 2003, and growth index in 2003. Flower lightness and flower chroma correlated sporadically with visitation in late September and October 2002 and 2003. Percentage light reflectance of flowers for the wavelengths of green, yellow, orange, and red correlated with visitation in 2003. Based on correlation analysis, the cultivar characteristics that did not contribute to visitation differences included inflorescence width, corolla width, and corolla tube length.
In a separate study conducted in 2003 using the same lantana as in the visitation study, nectar volume, carbohydrate composition, and sucrose and fructose concentrations differed among inflorescences. Of ten Lantana evaluated, ‘Carlos’ and ‘Confetti had the largest inflorescence nectar volumes combined from nine flowers while ‘New Gold’, ‘White Doves’, and ‘Weeping Lavender’ had the smallest. The ratio of sucrose to hexose (fructose and glucose) in nectar from ‘Weeping Lavender’, ‘White Doves’, and ‘New Gold’ was greater than that of the remaining Lantana. The lowest ratios of sucrose to hexose were found for ‘Irene’, ‘Hot Country’, and ‘Carlos’, while similar to ‘Cherry’ and ‘Radiation’. The sucrose to hexose ratio for recently opened inner flowers was double that of middle and outer flowers. Sucrose and total sugar concentrations were greatest in recently opened inner flowers compared to middle and outer flowers. While direct comparison to the 2002 and 2003 studies of butterfly visitation preferences was not possible due to experimental design, data trends suggest a possible relationship between sugar composition, inflorescence nectar production and visitation from native butterfly species.
A Risk-Based Approach to Assess the Operational Resilience of Transmission Grids