LONG-TONGUED FLY POLLINATION AND EVOLUTION OF FLORAL SPUR LENGTH IN THE <i>DISA DRACONIS</i>
 COMPLEX (ORCHIDACEAE)

Johnson, Steven D.; Steiner, Kim E.

doi:10.1111/j.1558-5646.1997.tb02387.x

Cited by 227 publications

(110 citation statements)

References 37 publications

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“…Compared to related taxa in Ranunculaceae, DNA sequence divergence in Aquilegia is extremely low, a pattern suggestive of a rapid radiation (Hodges andArnold 1994a, 1995). There is considerable variation in spur length, color, and orientation among the approximately 70 species of Aquilegia, and functional studies in Aquilegia (Hodges and Arnold 1994b) and other groups (e.g., Nilsson 1988;Johnson and Steiner 1997) demonstrate the importance of spur characters in pollination and reproductive success. This has been put forth as evidence that speciation in Aquilegia has been driven by pollinatormediated natural selection for divergence in floral traits (Hodges 1997).…”

Section: An Empirical Example: Floral Nectar Spurs In Aquilegiamentioning

confidence: 99%

Detecting the Historical Signature of Key Innovations Using Stochastic Models of Character Evolution and Cladogenesis

Ree¹

2005

Evolution

132

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Abstract. Phylogenetic evidence for biological traits that increase the net diversification rate of lineages (key innovations) is most commonly drawn from comparisons of clade size. This can work well for ancient, unreversed traits and for correlating multiple trait origins with higher diversification rates, but it is less suitable for unique events, recently evolved innovations, and traits that exhibit homoplasy. Here I present a new method for detecting the phylogenetic signature of key innovations that tests whether the evolutionary history of the candidate trait is associated with shorter waiting times between cladogenesis events. The method employs stochastic models of character evolution and cladogenesis and integrates well into a Bayesian framework in which uncertainty in historical inferences (such as phylogenetic relationships) is allowed. Applied to a well-known example in plants, nectar spurs in columbines, the method gives much stronger support to the key innovation hypothesis than previous tests. The tempo of evolution is a subject of general interest to evolutionary biologists, from nucleotide mutation rates within populations to the proliferation of branches on the tree of life. At the macroevolutionary level, key innovation hypotheses (Sanderson and Donoghue 1994) have been put forth to explain unusual disparities in species number between clades. A key innovation is commonly regarded as a biological trait that promotes lineage diversification via mechanisms that increase the rate of speciation and/or decrease the rate of extinction (e.g., Hodges and Arnold 1995). (Hereafter, ''diversification'' will be used to convey the net change in clade diversity as a result of speciation and extinction.) Changes in the rate of lineage diversification are expected to leave an imprint in the phylogeny of the affected species, underscoring the importance of historical inference in studies of evolutionary innovations.Key innovation hypotheses are most frequently studied by correlation, which measures the degree to which multiple origins of a trait are associated with clades of unusual size. Correlations are appealing because they use phylogenetically independent datapoints, typically comparisons of sister clades, to demonstrate a general, repeatable effect on diversity by the candidate trait. Increasing the sample size in this way reduces the potential impact of other factors that affect diversification rate. A popular approach has been to compare the relative sizes of sister groups using nonparametric sign tests, for example, in studies of insect phytophagy (Mitter et al. 1988), plant latex and resin canals (Farrell et al. 1991), floral nectar spurs (Hodges 1997), and flower symmetry (Sargent 2004). Alternatively, parametric approaches make it possible to identify unusually large clades by fitting data to predictions of null models of stochastic cladogenesis, and this can increase the statistical power associated with trait correlations (Slowinski and Guyer 1993;Sims and McConway 2003;McConway and Sims 2004).I...

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Section: An Empirical Example: Floral Nectar Spurs In Aquilegiamentioning

confidence: 99%

Detecting the Historical Signature of Key Innovations Using Stochastic Models of Character Evolution and Cladogenesis

Ree¹

2005

Evolution

132

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“…S tudies of plant-animal mutualisms have traditionally focused on highly specific interactions among a few species, such as a plant and its pollinators or seed dispersers (1,2). On the other hand, some systems seem to involve a much larger number of species, and some authors have used the term ''diffuse coevolution'' to describe the coevolutionary process in such communities (3)(4)(5).…”

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The nested assembly of plant–animal mutualistic networks

Bascompte

Jordano

Melián

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

2,007

2,610

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Most studies of plant-animal mutualisms involve a small number of species. There is almost no information on the structural organization of species-rich mutualistic networks despite its potential importance for the maintenance of diversity. Here we analyze 52 mutualistic networks and show that they are highly nested; that is, the more specialist species interact only with proper subsets of those species interacting with the more generalists. This assembly pattern generates highly asymmetrical interactions and organizes the community cohesively around a central core of interactions. Thus, mutualistic networks are neither randomly assembled nor organized in compartments arising from tight, parallel specialization. Furthermore, nestedness increases with the complexity (number of interactions) of the network: for a given number of species, communities with more interactions are significantly more nested. Our results indicate a nonrandom pattern of community organization that may be relevant for our understanding of the organization and persistence of biodiversity.

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“…Exemplos elegantes e bem ilustrativos ocorrem entre flores de Orchidaceae e seus polinizadores (Nilsson et al 1985;Johnson & Steiner 1997;Singer & Sazima 1999;Pauw 2006;Pansarin 2003), onde a planta "arrisca" todo o conteúdo polínico de uma só vez na polínia, que adere ao corpo dos visitantes no local que irá contatar o estigma (Fig. 4c).…”

Section: Local De Adesão Dos Grãos De Pólen No Corpo Dos Visitantesunclassified

Quando um visitante floral é um polinizador?

et al. 2016

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ResumoOs visitantes florais são animais que buscam, nas flores, recursos para si ou para sua prole. Às vezes uma mesma planta pode receber um espectro grande de visitantes, como é o caso de espécies cujas flores oferecem muito néctar. Porém, nem todo visitante floral realiza a polinização. Para ser um polinizador efetivo é necessário cumprir alguns requisitos, como: contato com a antera e o estigma, frequência de visita suficiente, fidelidade floral e a realização de uma rota adequada de visitação. Em muitos trabalhos sobre a estrutura de comunidades e, principalmente, sobre a rede trófica (ex. animal-planta), os autores adotam o termo polinizador para todo e qualquer visitante floral, categorizando-os com o mesmo papel e função para a planta. Neste trabalho, relatamos casos de visitantes florais que são polinizadores legítimos e efetivos, dos quais a planta depende de seu serviço para produção de frutos e sementes, distinguindo-os daqueles visitantes que não efetuam a polinização, ou não se tem certeza que o façam. Assim, espera-se ilustrar as diferenças, dando à devida importância e o peso correto para os muitos visitantes. Utilizamos abelhas como modelo, mas a idéia pode ser extrapolada para qualquer outro grupo de polinizador. Palavras-chave: flores, rede de interação mutualista, reprodução vegetal, transferência de pólen, visita legítima. AbstractFlower visitors are animals that generally seek resources in flowers for themselves or their offspring. Sometimes the same plant may receive a broad spectrum of visitors, such as nectar species. However not all floral visitors complete pollination. To be an effective pollinator is necessary to fulfill some requirements, such as: contact with the anther and stigma, enough frequency of visits, fidelity to the plant, and the realization of a suitable route of visitation. In many works on the structure of communities and especially of food webs (animal-plant), the authors adopt the term pollinator for each and every flower visitor categorizing them with the same role and function for the plant. In this work we report cases of floral visitors who are legitimate and effective pollinators of which the plant depends on its service for the production of fruits and seeds, distinguishing them from those visitors who do not pollinate, or are not sure to do so. Thus, it is expected to illustrate the differences, giving due importance and the correct weight for the many visitors. We used bees as a model, but the idea can be extrapolated to any other pollinator group.

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LONG-TONGUED FLY POLLINATION AND EVOLUTION OF FLORAL SPUR LENGTH IN THE DISA DRACONIS COMPLEX (ORCHIDACEAE)

Cited by 227 publications

References 37 publications

Detecting the Historical Signature of Key Innovations Using Stochastic Models of Character Evolution and Cladogenesis

Detecting the Historical Signature of Key Innovations Using Stochastic Models of Character Evolution and Cladogenesis

The nested assembly of plant–animal mutualistic networks

Quando um visitante floral é um polinizador?

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