Banca de DEFESA: GUSTAVO BRANT DE CARVALHO PATERNO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : GUSTAVO BRANT DE CARVALHO PATERNO
DATA : 30/07/2018
HORA: 08:00
LOCAL: Anfiteatro das Aves
TÍTULO:

Sex, herbivores and flower evolution

PALAVRAS-CHAVES:

good genes, parasites, biomass, coevolution, natural enemies, phylogeny, macroevolution, stoichiometry, cost

PÁGINAS: 233
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

Parasites represent a strong evolutionary force driving the evolution and maintenance of sex in different organisms. Species with a higher range of parasites should invest more in outcrossing and show more developed secondary sexual characters. In the last decades, many studies found support for this theory in different groups of animals. Nonetheless, a more general test of this theory to plants still poorly explored. Angiosperms show the most diverse range of reproductive strategies among organisms, representing an interesting model for the study of evolutionary forces shaping reproductive strategies. Sexual reproduction in angiosperms happens in flowers which can be divided into four basic components: androecium (male function); gynoecium (female function); corolla (pollinators attraction) and calyx (ovary defense). Surprisingly, comparative studies evaluating resource partition between these flower components remain overlooked. The study of flower allometry in a global scale offer great potential to unveil new macro-evolutionary patterns in plant sex strategy. This thesis is organized in four chapters that investigate patterns of sex allocation in angiosperms and the role of herbivores in the evolution of flower sexual strategies. In the first chapter, flower biomass data was collected across four continents (South America, North America, Europe and Oceania) to test the existence of a general allometric pattern in flower sex allocation of Angiosperms. It was shown that resource allocation to flowers follow a general allometric rule in which species with large flowers invest more in the male and petals components. In the second chapter, I tested the hypothesis that a higher pressure of herbivores at the evolutionary scale favors the evolution of reproductive strategies with higher investment in outcrossing. These results provide strong evidence that the parasite-mediated sex evolution theory (Red Queen Hypothesis) also applies to the plant kingdom. In the third chapter, It was estimated the stoichiometric cost of flowers and leaves for 56 Angiosperm species from the european flora. Its demonstrated that flowers are costly structures, representing a honest signal of quality in the competition for pollinators (Zahavi’s handicap). Flowers are phosphorus rich organs and have a distinct stoichiometric signature showing much higher P:C and P:N ratios than leaves. In the fourth chapter, I present the sensiPhy software which was developed (R package) to perform sensitivity analyses considering multiple types of uncertainties in phylogenetic comparative methods (phylogenetic, intra-specific and sampling uncertainty). With this thesis, I expect to contribute with a more solid and general understanding of the factors driving the evolution of plant sexual strategies at the macroevolutionary scale.

MEMBROS DA BANCA:
Presidente - 1678202 - CARLOS ROBERTO SORENSEN DUTRA DA FONSECA
Externo à Instituição - HARRY OLDE VENTERINK - VUB
Externo à Instituição - JOHANNES KOLLMANN - TUM
Externo à Instituição - MARK WESTOBY - MQ
Externo à Instituição - VANESSA GRAZIELE STAGGEMEIER - UNESP