Banca de DEFESA: AMANDA VIEIRA DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : AMANDA VIEIRA DA SILVA
DATA : 16/06/2025
HORA: 14:00
LOCAL: Híbrida- SBC
TÍTULO:

The dark side of mutualisms: the cost of partnership among plants, floral visitors and ant bodyguards

PÁGINAS: 150
RESUMO:

Mutualisms are ecological interactions characterized by its positive outcome for partners involved in the interaction. However, the magnitude of this outcome depends not only on the benefits but also on the costs involved in this interaction. In nature, organisms often engage in multiple mutualisms, sometimes simultaneously, to obtain resources that are costly and/or impossible to obtain by themselves. By engaging in multiple mutualisms simultaneously, organisms can pay significant ecological costs due to negative interactions between partners of different mutualisms. However, studies evaluating the effects of ecological costs in dynamics and functioning of mutualisms are still scarce, especially in evolutionary times. This dissertation aims to fulfil this knowledge gap. This dissertation is structured in three chapters, each of them with specific questions, hypotheses and distinct methods. We used plants involved in protection mutualisms with ants via extrafloral nectar secretion and pollination mutualisms via production of attractive flowers to animal pollinators as our model study. Ants protect these plants against herbivores, but they can also repel pollinators, negatively affecting pollination efficiency, which could represent an ecological cost of protection mutualism. In the first chapter, we used a meta-analytical approach to estimate the magnitude of the ecological costs imposed by ants on pollination of EFN-bearing plants. We found that ants impose a low but highly variable cost on pollination of EFN-bearing plants. Besides, ants have a stronger negative effect on patterns of floral visitation, especially by bees, than on plant reproductive success. Given that the cost of ants on bee-visitation is high, it is expected that natural selection does not favor the simultaneous occurrence of traits directly related to ant attraction (EFNs) and exclusively bee-pollination (poricidal anthers) on the same lineages. This is what we investigated in the second chapter. We found a negative evolutionary correlation between these two traits across angiosperm phylogeny, indicating that these traits rarely occur together on the same lineages. However, more than 40 genera present both traits, which led us to the third chapter, in which we evaluated whether EFN-bearing species from a hiperdiverse legume genus in Brazil have floral traits that could reduce ant access to flowers or the ant effects on pre- and post- pollination when compared to species lacking EFNs. To our surprise, we did not find any evidence of the effect of EFNs on the evolution of floral traits. Overall, our results show that the ecological costs of mutualisms are modulated by different factors at the ecological scale and it could have important consequences for the evolutionary trajectory of traits mediating mutualisms, including the ones not directly related to ant-plant interaction. Thus, we highlight the importance of considering the ecological costs of mutualism in future studies evaluating the functioning of these interactions in ecological time and the evolutionary trajectory of traits mediating these interactions.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 058.701.134-31 - LAURA CAROLINA LEAL DE SOUSA - NENHUMA
Membro Titular - Examinador(a) Externo à Instituição - FLÁVIA DELGADO SANTANA - INPA
Membro Titular - Examinador(a) Externo à Instituição - GUSTAVO BURIN FERREIRA
Membro Titular - Examinador(a) Externo à Instituição - PEDRO JOAQUIM BERGAMO - UNESP
Membro Titular - Examinador(a) Externo à Instituição - MARTIN FRANCISCO PAREJA PIAGGIO - UNICAMP
Membro Suplente - Examinador(a) Externo à Instituição - LORENA BUENO VALADÃO MENDES
Membro Suplente - Examinador(a) Externo à Instituição - PAULO ENRIQUE CARDOSO PEIXOTO - UFMG
Membro Suplente - Examinador(a) Externo à Instituição - ALEXANDRE VARASCHIN PALAORO