ABSTRACT Most Papilionoideae species exhibit specialized flowers with the standard petal placed i... more ABSTRACT Most Papilionoideae species exhibit specialized flowers with the standard petal placed in the upper position and the keel and surrounding wings acting as the landing platform for bee visitors. For some groups, however, flowers became resupinate so that bees land at the standard petal. In this upside-down morphology, the pollen is deposited onto the dorsal side of visitors, instead of the ventral side as in most keel flowers. To understand how these inverted keel flowers work and their differences from normal keel flowers, we studied the resupinate species Canavalia brasiliensis, Centrosema pascuorum and Clitoria fairchildiana, and compared with the normal keel Lathyrus pubescens, Crotalaria micans and Dioclea violacea. Both the behavior and morphology of bee visitors were observed and compared to the flower morphology. We observed that most features of the mechanism exhibited by inverted keel flower are found at keel flowers, except for three key innovations: a thickening at wings’ margin in contact with the visitors’ body, tighter interlocking between petals and strengthening of the vexillum structure. Most visitors are adapted to flower characteristics in their morphology and behavior, although some act as thieves due to some of their morphological features, such as mouthpart length. In spite of their differences, bees behave almost in the same way when visiting both normal and inverted keel morphologies. Compared to keel flowers, inverted keel flowers evolved toward more restrictive structures that require large-bodied bees to operate them. Finally, we discuss possible selective pressures that might have led to the evolution of inverted keel flowers.
Flora - Morphology, Distribution, Functional Ecology of Plants, 2006
In spite of their tiny dimensions (3 Â 5 mm 2), the strongly honey-scented flowers of Guazuma ulm... more In spite of their tiny dimensions (3 Â 5 mm 2), the strongly honey-scented flowers of Guazuma ulmifolia (Malvaceae-Byttnerioideae) provide six sexual chambers. A central female unit is surrounded by five interconnected male compartments. At the onset of anthesis the strap-shaped odoriferous petal appendages form an open star with the female chamber in the centre. Hereafter, they wilt, intermingle and finally lock access to the stigma. Meanwhile, wilting sepals liberate new entrances from the back between the petal claws. They give way to nectar-offering male chambers. In each of them a well-lit (but closed) window lures the visitor into a standard position for passive pollen uptake. Finally, the insects have to back out of one of the rear entrances. It remains unknown how the minute visitors (maximum height ca. 0.5 mm)-if ever-overcome the distance to another Guazuma tree.
Colour is one of the most obvious advertisements of flowers and occurs in a huge diversity among ... more Colour is one of the most obvious advertisements of flowers and occurs in a huge diversity among the angiosperms. Flower colour is responsible for the attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower-visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower-visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV-reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UV-absorbing. In choice experiments we found that bees did not show consistent preferences for any colour- or pattern-types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower irrespective of its spatial position within the flower. The appearance of UV-patterns within flowers is the main difference in spectral reflectance between yellow bee- and bird-pollinated flowers, and affects the foraging behaviour of flower-visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other. This article is protected by copyright. All rights reserved.
Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among... more Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among the angiosperms. Flower colour is responsible for attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UV-absorbing. In choice experiments we found that bees did not show consistent preferences for any colour or pattern types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower, irrespective of its spatial position within the flower. The appearance of UV patterns within flowers is the main difference in spectral reflectance between yellow bee-and bird-pol-linated flowers, and affects the foraging behaviour of flower visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other.
Most Papilionoideae species exhibit specialized flowers with the standard petal placed in the upp... more Most Papilionoideae species exhibit specialized flowers with the standard petal placed in the upper position and the keel and surrounding wings acting as the landing platform for bee visitors. For some groups, however, flowers became resupinate so that bees land at the standard petal. In this upside-down morphology, the pollen is deposited onto the dorsal side of visitors, instead of the ventral side as in most keel flowers. To understand how these inverted keel flowers work and their differences from normal keel flowers, we studied the resupinate species Canavalia brasiliensis, Centrosema pascuorum and Clitoria fairchildiana, and compared with the normal keel Lathyrus pubescens, Crotalaria micans and Dioclea violacea. Both the behavior and morphology of bee visitors were observed and compared to the flower morphology. We observed that most features of the mechanism exhibited by inverted keel flower are found at keel flowers, except for three key innovations: a thickening at wings' margin in contact with the visitors' body, tighter interlocking between petals and strengthening of the vexillum structure. Most visitors are adapted to flower characteristics in their morphology and behavior, although some act as thieves due to some of their morphological features, such as mouthpart length. In spite of their differences, bees behave almost in the same way when visiting both normal and inverted keel morphologies. Compared to keel flowers, inverted keel flowers evolved toward more restrictive structures that require large-bodied bees to operate them. Finally, we discuss possible selective pressures that might have led to the evolution of inverted keel flowers.
Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among... more Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among the angiosperms. Flower colour is responsible for attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UVabsorbing. In choice experiments we found that bees did not show consistent preferences for any colour or pattern types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower, irrespective of its spatial position within the flower. The appearance of UV patterns within flowers is the main difference in spectral reflectance between yellow bee-and bird-pollinated flowers, and affects the foraging behaviour of flower visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other.
Os organizadores desta obra envidaram os seus melhores esforços para referenciar todas as fontes ... more Os organizadores desta obra envidaram os seus melhores esforços para referenciar todas as fontes bibliográficas e virtuais consultadas, bem como creditar todas as fotografias e ilustrações utilizadas e, colocam-se a disposição para corrigir quaisquer eventualidades em uma próxima edição.
ABSTRACT Most Papilionoideae species exhibit specialized flowers with the standard petal placed i... more ABSTRACT Most Papilionoideae species exhibit specialized flowers with the standard petal placed in the upper position and the keel and surrounding wings acting as the landing platform for bee visitors. For some groups, however, flowers became resupinate so that bees land at the standard petal. In this upside-down morphology, the pollen is deposited onto the dorsal side of visitors, instead of the ventral side as in most keel flowers. To understand how these inverted keel flowers work and their differences from normal keel flowers, we studied the resupinate species Canavalia brasiliensis, Centrosema pascuorum and Clitoria fairchildiana, and compared with the normal keel Lathyrus pubescens, Crotalaria micans and Dioclea violacea. Both the behavior and morphology of bee visitors were observed and compared to the flower morphology. We observed that most features of the mechanism exhibited by inverted keel flower are found at keel flowers, except for three key innovations: a thickening at wings’ margin in contact with the visitors’ body, tighter interlocking between petals and strengthening of the vexillum structure. Most visitors are adapted to flower characteristics in their morphology and behavior, although some act as thieves due to some of their morphological features, such as mouthpart length. In spite of their differences, bees behave almost in the same way when visiting both normal and inverted keel morphologies. Compared to keel flowers, inverted keel flowers evolved toward more restrictive structures that require large-bodied bees to operate them. Finally, we discuss possible selective pressures that might have led to the evolution of inverted keel flowers.
Flora - Morphology, Distribution, Functional Ecology of Plants, 2006
In spite of their tiny dimensions (3 Â 5 mm 2), the strongly honey-scented flowers of Guazuma ulm... more In spite of their tiny dimensions (3 Â 5 mm 2), the strongly honey-scented flowers of Guazuma ulmifolia (Malvaceae-Byttnerioideae) provide six sexual chambers. A central female unit is surrounded by five interconnected male compartments. At the onset of anthesis the strap-shaped odoriferous petal appendages form an open star with the female chamber in the centre. Hereafter, they wilt, intermingle and finally lock access to the stigma. Meanwhile, wilting sepals liberate new entrances from the back between the petal claws. They give way to nectar-offering male chambers. In each of them a well-lit (but closed) window lures the visitor into a standard position for passive pollen uptake. Finally, the insects have to back out of one of the rear entrances. It remains unknown how the minute visitors (maximum height ca. 0.5 mm)-if ever-overcome the distance to another Guazuma tree.
Colour is one of the most obvious advertisements of flowers and occurs in a huge diversity among ... more Colour is one of the most obvious advertisements of flowers and occurs in a huge diversity among the angiosperms. Flower colour is responsible for the attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower-visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower-visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV-reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UV-absorbing. In choice experiments we found that bees did not show consistent preferences for any colour- or pattern-types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower irrespective of its spatial position within the flower. The appearance of UV-patterns within flowers is the main difference in spectral reflectance between yellow bee- and bird-pollinated flowers, and affects the foraging behaviour of flower-visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other. This article is protected by copyright. All rights reserved.
Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among... more Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among the angiosperms. Flower colour is responsible for attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UV-absorbing. In choice experiments we found that bees did not show consistent preferences for any colour or pattern types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower, irrespective of its spatial position within the flower. The appearance of UV patterns within flowers is the main difference in spectral reflectance between yellow bee-and bird-pol-linated flowers, and affects the foraging behaviour of flower visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other.
Most Papilionoideae species exhibit specialized flowers with the standard petal placed in the upp... more Most Papilionoideae species exhibit specialized flowers with the standard petal placed in the upper position and the keel and surrounding wings acting as the landing platform for bee visitors. For some groups, however, flowers became resupinate so that bees land at the standard petal. In this upside-down morphology, the pollen is deposited onto the dorsal side of visitors, instead of the ventral side as in most keel flowers. To understand how these inverted keel flowers work and their differences from normal keel flowers, we studied the resupinate species Canavalia brasiliensis, Centrosema pascuorum and Clitoria fairchildiana, and compared with the normal keel Lathyrus pubescens, Crotalaria micans and Dioclea violacea. Both the behavior and morphology of bee visitors were observed and compared to the flower morphology. We observed that most features of the mechanism exhibited by inverted keel flower are found at keel flowers, except for three key innovations: a thickening at wings' margin in contact with the visitors' body, tighter interlocking between petals and strengthening of the vexillum structure. Most visitors are adapted to flower characteristics in their morphology and behavior, although some act as thieves due to some of their morphological features, such as mouthpart length. In spite of their differences, bees behave almost in the same way when visiting both normal and inverted keel morphologies. Compared to keel flowers, inverted keel flowers evolved toward more restrictive structures that require large-bodied bees to operate them. Finally, we discuss possible selective pressures that might have led to the evolution of inverted keel flowers.
Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among... more Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among the angiosperms. Flower colour is responsible for attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UVabsorbing. In choice experiments we found that bees did not show consistent preferences for any colour or pattern types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower, irrespective of its spatial position within the flower. The appearance of UV patterns within flowers is the main difference in spectral reflectance between yellow bee-and bird-pollinated flowers, and affects the foraging behaviour of flower visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other.
Os organizadores desta obra envidaram os seus melhores esforços para referenciar todas as fontes ... more Os organizadores desta obra envidaram os seus melhores esforços para referenciar todas as fontes bibliográficas e virtuais consultadas, bem como creditar todas as fotografias e ilustrações utilizadas e, colocam-se a disposição para corrigir quaisquer eventualidades em uma próxima edição.
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