Interactions between ants, treehoppers, flowers and flower visitors in cerrado vegetations: experimental study with Byrsonima intermedia A. Juss

Author(s)

Javier Eduardo Ibarra Isassi

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2016-02-23

Examining board members

Paulo Sergio Moreira Carvalho de Oliveira; André Victor Lucci Freitas; Rodrigo Cogni

• Advisor: Paulo Sergio Moreira Carvalho de Oliveira

Abstract

Ants and plants are dominant organisms in terrestrial ecosystems; as such, ants are commonly found visiting plants. Often, ant presence benefits plants, reducing the number of herbivores and/or contributing to seed dispersion, and in turn, benefiting themselves by feeding and sheltering in structures offered by plants. However, the presence of ants in flowers is commonly considered as antagonistic, because ants rarely pollinate but collect floral resources, modifying and reducing other insects¿ floral visitation frequency or efficiency. Ant-plant interactions are very common in the Cerrado. Although many studies have investigated the effects of the presence of ants on herbivore attacks or the relation between ants and the presence of Extrafloral Nectaries (EFNs), the effect of ant floral visitation in this biome remains understudied. Associations between ants and honeydew-producing insects present near inflorescences can modify the local abundance and behavior of ants, potentially disturbing pollinator-plant interactions. Byrsonima intermedia (known in Brazil as murici-do-campo) is commonly found in the Cerrado savanna. This plant has elaiophores (oil-producing glands) in the base of flowers. The oil produced is collected by bees, which in turn, pollinate this plant through buzz-pollination. Field observations allowed us to confirm that ants rarely visit B. intermedia inflorescences when there are no treehoppers. Considering this, the focus of this dissertation is to study the effects of the presence of the ant-treehopper association in the reproduction of B. intermedia. Direct observation and experimental manipulations of the presence of ants and ant-treehopper association in the field showed that the presence of ants in inflorescences reduce the duration of the visit of pollinators, which, in turn, reduces the fruit set of the plant. Furthermore, the results of our experiments suggest that the negative effects of the ant-treehopper association on plant reproduction are caused by the increased number of ants visiting inflorescences and not by the herbivory effect (AU)

• FAPESP's process: 14/12486-8 - Interactions between ants, flowers and flower visitors in cerrado vegetation: case study with Byrsonima intermedia A. Juss. (Malpighiaceae)
• Grantee: Javier Eduardo Ibarra Isassi
• Support Opportunities: Scholarships in Brazil - Master