Ant nest distribution and richness have opposite effects on a Neotropical plant with extrafloral nectaries

Abstract

Studies assessing the effects of the spatial distribution of ant nests on ant‐plant mutualisms are rare, even though they could be decisive to the outcomes of such interactions. Here, we investigated how ant nest abundance and richness affected a Neotropical plant with extrafloral nectaries (EFN), Smilax polyantha (Smilacaceae). We used baits to sample all nests of mutualistic ants within a 12 m radius of each plant. All neighbouring plants with EFN within 10 m of each tagged plant were also sampled. We measured foliar herbivory and fruit production of each S. polyantha. We hypothesized that (i) high numbers of ant nests near S. polyantha individuals would reduce foliar herbivory and increase fruit production, and that (ii) high ant nest richness would increase foliar herbivory and reduce fruit production. Results showed that plants surrounded by more ant nests had lower foliar herbivory and higher fruit production. However, ant nest richness was associated with higher foliar herbivory. Furthermore, plants producing more leaves and those surrounded by more neighbouring plants with EFN had reduced herbivory. Despite this, S. polyantha had low numbers of ant nests and reduced fruit production when surrounded by high numbers of neighbours with EFN. We suggest that the spatial distribution of ant nests and resources (plants with EFN) play an important role in ant‐mediated mutualisms, where both ants and plants are likely competing for each other's services. Thus, incorporating these two variables in ecological models should provide insights into how protective mutualisms are structured.

Dear neighbor: Trees with extrafloral nectaries facilitate defense and growth of adjacent undefended trees

“…If the density of ant nests is higher near EFN plants, this could further contribute to facilitation by increasing soil fertility (Wagner & Nicklen, 2010). In addition to the spatial arrangement of ant nests (Moura et al, 2022), the outcome of the interaction between EFN plants and ants also depends on ant identity, as species attracted to nectar differ in their defense ability (Fagundes et al, 2017).…”

Extrafloral Nectary-Bearing Plants Recover Ant Association Benefits Faster and More Effectively after Frost-Fire Events Than Frost

“…This same pattern has been reported in other studies [91,92], where the authors suggest that resource, space, or time limitations may reduce the interaction capacity of some species. Moura et al (2022) [93] also found negative associations between ant nest richness and the herbivory rate of EFNs' bearing plants. These authors suggest that intensified competition due to high nest richness may distract visiting ants from the presence of herbivores on the plants.…”

Fabaceae and Cerrado savanna: Two descriptors of Brazilian extrafloral nectary plants

“…Areas where C . brasiliense was sampled sustains several other EFN–plant species (Sendoya et al 2009, Lange et al 2013, Moura et al 2022). The other top-studied plants such as Qualea , Banisteriopsis and Ouratea also occur in a community with several other EFN–plants.…”

“…Fabaceae shared six species with other biomes, while Bignoniaceae and Euphorbiaceae shared one (Figure 9). species (Sendoya et al 2009, Lange et al 2013, Moura et al 2022. The other top-studied plants such as Qualea, Banisteriopsis and Ouratea also occur in a community with several other EFN-plants.…”