Banca de QUALIFICAÇÃO: TALES MARTINS DE ALENCAR PAIVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : TALES MARTINS DE ALENCAR PAIVA
DATE: 12/07/2023
TIME: 09:00
LOCAL: Laboratório Didático I - DECOL
TITLE:

Sexual selection and evolution of floral capitulum in family Asteraceae

KEY WORDS:

Male-male competition; maleness; floral capitulum; heterogamy; sex allocation.

PAGES: 50
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Sexual selection benefits traits that increase reproductive success and often determines differential resource allocation between male and female sex components. In plants, competition between males leads to increased investment in male function, and may even result in disinvestment in female function. The Asteraceae family has specialized inflorescences, the floral chapters. In these structures, small flowers are condensed together sharing the same receptacle. The number of flowers present in the floral chapter can vary widely among species. Additionally, some groups have evolved chapters with morphological and functional dimorphism among flowers, which may result in distinct sexual roles. In this thesis, our goal was to understand the history and evolutionary significance of variation in the number of flowers per chapter, as well as to estimate its importance in determining inflorescence architecture and masculinization. The thesis is divided into three chapters. In the first, we reconstruct the ancestral states of flower number and chapter architecture along a calibrated phylogeny. We find strong evidence that the common ancestor for the entire family possessed homogamous inflorescence with few flowers (~ 12). Heterogamy evolved several times independently, although a larger number of reversions to the homogamous condition were observed in the phylogeny. The number of flowers per chapter is an extremely plastic and poorly conserved trait. Chapters with more flowers are more likely to be heterogamous. In the second chapter, we found that chapters with higher flower numbers invest more in male function by increasing pollen production per chapter. We found no evidence of disinvestment in egg production in more flowered chapters. Therefore, we can conclude that in the family Asteraceae, chapters with more flowers are not merely more numerous copies than those with fewer flowers. Finally, in the third chapter we will test the influence of herbivory pressure on flower chapter masculinization. We expect that species with higher numbers of associated herbivores will exhibit more masculinized chapters, as expected by the red queen hypothesis.

COMMITTEE MEMBERS:
Externa ao Programa - 1813882 - ALICE DE MORAES CALVENTE VERSIEUX - nullPresidente - 1678202 - CARLOS ROBERTO SORENSEN DUTRA DA FONSECA
Externo à Instituição - GUSTAVO BRANT DE CARVALHO PATERNO