How flower colour signals allure bees and hummingbirds: a community-level test of the bee avoidance hypothesis

Author(s)

Gutierrez de Camargo, Maria Gabriela ^[1] ; Lunau, Klaus ^[2] ; Batalha, Marco Antonio ^[3] ; Brings, Sebastian ^[2] ; Garcia de Brito, Vinicius Lourenco ^[4] ; Cerdeira Morellato, Leonor Patricia ^[1]

Affiliation

^[1] UNESP Univ Estadual Paulista, Inst Biociencias, Dept Bot, Lab Fenol, BR-13506900 Sao Paulo - Brazil

^[2] Heinrich Heine Univ Dusseldorf, Inst Sensory Ecol, Dept Biol, D-40225 Dusseldorf - Germany

^[3] Univ Fed Sao Carlos, Dept Bot, BR-13565905 Sao Paulo - Brazil

^[4] Univ Fed Uberlandia, Inst Biol, BR-38400902 Uberlandia, MG - Brazil

• Document type: Journal article
• Source: NEW PHYTOLOGIST; v. 222, n. 2, p. 1112-1122, APR 2019.
• Web of Science Citations: 2

Abstract

Colour signals are the main floral trait for plant-pollinator communication. Owing to visual specificities, flower visitors exert different selective pressures on flower colour signals of plant communities. Although they evolved to attract pollinators, matching their visual sensitivity and colour preferences, floral signals may also evolve to avoid less efficient pollinators and antagonistic flower visitors. We evaluated evidence for the bee avoidance hypothesis in a Neotropical community pollinated mainly by bees and hummingbirds, the campo rupestre. We analysed flower reflectance spectra, compared colour variables of bee-pollinated flowers (bee-flowers; 244 species) and hummingbird-pollinated flowers (hummingbird-flowers; 39 species), and looked for evidence of bee sensorial exclusion in hummingbird-flowers. Flowers were equally contrasting for hummingbirds. Hummingbird-flowers were less conspicuous to bees, reflecting mainly long wavelengths and avoiding red-blind visitors. Bee-flowers reflected more short wavelengths, were more conspicuous to bees (higher contrasts and spectral purity) than hummingbird-flowers and displayed floral guides more frequently, favouring flower attractiveness, discrimination and handling by bees. Along with no phylogenetic signal, the differences in colour signal strategies between bee- and hummingbird-flowers are the first evidence of the bee avoidance hypothesis at a community level and reinforce the role of pollinators as a selective pressure driving flower colour diversity. (AU)

• FAPESP's process: 09/54208-6 - Multi-User Centralized Laboratory at the São Paulo State University Center for Biodiversity Studies
• Grantee: Célio Fernando Baptista Haddad
• Support type: Multi-user Equipment Program
• FAPESP's process: 13/50155-0 - Combining new technologies to monitor phenology from leaves to ecosystems
• Grantee: Leonor Patricia Cerdeira Morellato
• Support type: Research Program on Global Climate Change - University-Industry Cooperative Research (PITE)
• FAPESP's process: 17/01663-4 - Analysis of flowers colors in a rupestrian grassland community according to pollinators' visual system
• Grantee: Maria Gabriela Gutierrez de Camargo
• Support type: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 10/51307-0 - Floristic diversity and seasonal patterns of rupestrian fields and cerrado
• Grantee: Leonor Patricia Cerdeira Morellato
• Support type: Research Grants - Research Partnership for Technological Innovation - PITE
• FAPESP's process: 15/10754-8 - Spatio-temporal variations in the flower-color spectra according to the pollinators' visual systems
• Grantee: Maria Gabriela Gutierrez de Camargo
• Support type: Scholarships in Brazil - Post-Doctorate