Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and longproboscid flies

The Proteaceae are renowned for their floral diversity but surprisingly the role of pollinators in driving evolutionary divergence in this family has been underexplored. Here we focus on recently diverged taxa to gain insight into the processes that generate diversity by testing whether two varietie...

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Main Authors: Johnson, C., He, Tianhua, Pauw, A.
Format: Journal Article
Published: Kluwer Academic Publishers 2014
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/9806
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author Johnson, C.
He, Tianhua
Pauw, A.
author_facet Johnson, C.
He, Tianhua
Pauw, A.
author_sort Johnson, C.
building Curtin Institutional Repository
collection Online Access
description The Proteaceae are renowned for their floral diversity but surprisingly the role of pollinators in driving evolutionary divergence in this family has been underexplored. Here we focus on recently diverged taxa to gain insight into the processes that generate diversity by testing whether two varieties of Leucospermum tottum might have originated by pollinator mediated adaptive divergence. L. tottum var. tottum has pale salmon-coloured horizontally-oriented flowers, long nectar tubes, and small volumes of concentrated nectar. L. tottum var. glabrum has red and yellow vertically oriented flowers, short nectar tubes, and large volumes of dilute nectar. Despite the morphological divergence, the varieties are indistinguishable using eight molecular markers, indicating a very early stage of differentiation. Consistent with their morphologies, L. tottum var. tottum is pollinated by long-proboscid flies (Philoliche rostrata and Philoliche gulosa), Cape sugarbirds (Promerops cafer), and, to a lesser extent, by Orange-breasted sunbirds (Anthobaphes violacea), whereas, L. tottum var. glabrum is pollinated only by Orange-breasted sunbirds. A. violacea visits both varieties, but makes more frequent contact with pollen presenters when foraging on L. tottum var. glabrum. The exclusion of birds caused a steeper reduction in seed production in L. tottum var. glabrum than in L. tottum var. tottum, consistent with specialization for bird-pollination in this variety. Additionally, L. tottum var. glabrum exhibits autogamy, whereas L. tottum var. tottum does not. Floral divergence between the two L. tottum varieties corresponds with divergence in pollinator use.
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spelling curtin-20.500.11937-98062017-09-13T14:53:17Z Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and longproboscid flies Johnson, C. He, Tianhua Pauw, A. Bird-pollination Pollinator driven speciation Long-proboscid fly pollination Leucospermum tottum Reproductive assurance Pollinator shifts Adaptive divergence The Proteaceae are renowned for their floral diversity but surprisingly the role of pollinators in driving evolutionary divergence in this family has been underexplored. Here we focus on recently diverged taxa to gain insight into the processes that generate diversity by testing whether two varieties of Leucospermum tottum might have originated by pollinator mediated adaptive divergence. L. tottum var. tottum has pale salmon-coloured horizontally-oriented flowers, long nectar tubes, and small volumes of concentrated nectar. L. tottum var. glabrum has red and yellow vertically oriented flowers, short nectar tubes, and large volumes of dilute nectar. Despite the morphological divergence, the varieties are indistinguishable using eight molecular markers, indicating a very early stage of differentiation. Consistent with their morphologies, L. tottum var. tottum is pollinated by long-proboscid flies (Philoliche rostrata and Philoliche gulosa), Cape sugarbirds (Promerops cafer), and, to a lesser extent, by Orange-breasted sunbirds (Anthobaphes violacea), whereas, L. tottum var. glabrum is pollinated only by Orange-breasted sunbirds. A. violacea visits both varieties, but makes more frequent contact with pollen presenters when foraging on L. tottum var. glabrum. The exclusion of birds caused a steeper reduction in seed production in L. tottum var. glabrum than in L. tottum var. tottum, consistent with specialization for bird-pollination in this variety. Additionally, L. tottum var. glabrum exhibits autogamy, whereas L. tottum var. tottum does not. Floral divergence between the two L. tottum varieties corresponds with divergence in pollinator use. 2014 Journal Article http://hdl.handle.net/20.500.11937/9806 10.1007/s10682-014-9712-0 Kluwer Academic Publishers restricted
spellingShingle Bird-pollination
Pollinator driven speciation
Long-proboscid fly pollination
Leucospermum tottum
Reproductive assurance
Pollinator shifts
Adaptive divergence
Johnson, C.
He, Tianhua
Pauw, A.
Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and longproboscid flies
title Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and longproboscid flies
title_full Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and longproboscid flies
title_fullStr Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and longproboscid flies
title_full_unstemmed Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and longproboscid flies
title_short Floral divergence in closely related Leucospermum tottum (Proteaceae) varieties pollinated by birds and longproboscid flies
title_sort floral divergence in closely related leucospermum tottum (proteaceae) varieties pollinated by birds and longproboscid flies
topic Bird-pollination
Pollinator driven speciation
Long-proboscid fly pollination
Leucospermum tottum
Reproductive assurance
Pollinator shifts
Adaptive divergence
url http://hdl.handle.net/20.500.11937/9806