Color signals of bee‐pollinated flowers: the significance of natural leaf background

Abstract

Flower color is a primary pollinator attractant and generally adjusted to the cognitive system of the pollinators. The perception of flower color depends on the visual system of pollinators and also on environmental factors such as light conditions and the background against which flowers are displayed. METHODS:Using bee-pollinated Fabaceae species as a model, we analyzed flower color diversity and compared flower color signals considering both the standard green and the natural leaf background of two tropical seasonally dry vegetations-a mountain rupestrian grassland (campo rupestre) and a woody savanna (cerrado)-compared to a nontropical Mediterranean shrubland. RESULTS: By using natural background, bees discriminated color for 58% of the flowers in the campo rupestre and for only 43% in cerrado. Both vegetations were surpassed by 75% of bee color discrimination in Mediterranean vegetation. Chromatic contrast and purity were similar among the three vegetation types. Green contrast and brightness were similar between the tropical vegetations but differed from the Mediterranean shrubland. Green contrast differences were lost when using a standard green background, and most variables (purity, green contrast, and brightness) differed according to the background (natural or standard green) in all vegetations. CONCLUSIONS:The natural background influenced bee perception of flower color regardless of vegetation. The background of the campo rupestre promoted green contrast for flowers, ensuring flower detection by pollinators and, along with bees, may also act as a selective pressure driving the diversity of flower colors in Fabaceae species. We highlight the importance of considering the natural background coloration when analyzing flower color signals.

Hybrid Mimulus flowers attract a new pollinator

“…We used 347, 424, and 539 nm for UV, blue, and green receptors to model the color hexagon model (Skorupski & Chittka, 2010). For the color hexagon model, we followed (Martins et al ., 2021) to calculate the green contrast and brightness: the green contrast was calculated by subtracting 0.5 from the green photoreceptor excitation, and the brightness was calculated as the sum of the three photoreceptors excitations. For the receptor noise model, we used Apis mellifera noise parameters, with the receptor density ratio 0.85 : 4 : 1 and the weber fraction of 0.12 (Vorobyev et al ., 2001).…”

HybridMimulusflowers attract a new pollinator

“…We used 347, 424 and 539 nm for UV, blue and green receptors to model the color hexagon model (Skorupski and Chittka 2010). For the color hexagon model, we followed (Martins et al 2021) to calculate the green contrast and brightness: the green contrast was calculated by subtracting 0.5 from the green photoreceptor excitation and the brightness was calculated as the sum of the three photoreceptors excitations. For the receptor noise model, we used Apis mellifera noise parameters, with the receptor density ratio 0.85:4:1 and the weber fraction of 0.12 (Vorobyev et al 2001).…”

Polinização por formigas em Microstachys serrulata (Mart. & Zucc.) Müll. Arg. (Euphorbiaceae) no Cerrado

“…Estatística circular e testes de Rayleigh Observar se a polinização de Microstachys serrulata é dependente de animais ou não h5: A polinização biótica ou zoofilia é necessária para a frutificação da espécie, já que a inflorescência amarelo-esbranquiçada contrasta com as folhas verdes e fica facilmente visível para insetos próximos (Martins et al 2021). Além disso, foram encontrados grãos de pólen viáveis em observações prévias no laboratório, e a apomixia é descrita apenas em poucas espécies da família Euforbiaceae (Moog et al 2002;Bressan et al 2013).…”

“…As pequenas flores de M. serrulata foram visitadas por insetos pequenos, o que caracteriza uma amostragem de visitantes generalista como proposta por Bawa et al, (1985). Além disso, embora as flores de M. serrulata apresentem flores de coloração pálida, é importante ressaltar que as flores possuem um tom contrastante com o resto da planta, característica importante para a atração de polinizadores (Martins et al 2021).…”