Floral resource partitioning by ants and bees in a jambolan Syzygium jambolanum (Myrtaceae) agroforestry system in Brazilian Meridional Amazon

Dyer

2014

Biotropica

Self Cite

In closed‐canopy tropical forest understory, light availability is a significant determinant of habitat diversity because canopy structure is highly variable in most tropical forests. Consequently, variation in canopy cover affects the composition and distribution of plant species via creating variable light environments. Nevertheless, little is known about how variation in canopy openness structures patterns of plant–animal interactions. Because of the great diversity and dominance of ants in tropical environments, we used ant–plant interactions as a focal network to evaluate how variation in canopy cover influences patterns of plant–insect interactions in the Brazilian Amazon rain forest. We observed that small increases in canopy openness are associated with increased diversity of ant–plant interactions in our study area, and this change is independent of plant or ant species richness. Additionally, we found smaller niche overlap for both ants and plants associated with greater canopy openness. We hypothesize that enhanced light availability increases the breadth of ant foraging sources because variation in light availability gives rise to plant resources of different quality and amounts. Moreover, greater light availability promotes vegetative growth in plants, creating ant foraging ‘bridges’ between plants. In sum, our results highlight the importance of environmental heterogeneity as a determinant of ant–plant interaction diversity in tropical environments.

“…This Amazonian region presents two well‐characterized seasons: a dry season (May to October) and a rainy season (November–April; Dáttilo et al . ).…”

Section: Methodsmentioning

confidence: 97%

Canopy Openness Enhances Diversity of Ant–Plant Interactions in the Brazilian Amazon Rain Forest

Dyer

2014

Biotropica

Self Cite

“…According to the Köppen classification, the climate is tropical humid (Am). Mean annual temperature is 24°C, mean annual relative humidity is 85%, and mean annual rainfall ranges from 2000–2300 mm (Dáttilo et al 2012). Moreover, in this region there are two well‐defined seasons, a rainy season from November to April, and a dry season from May to October.…”

Section: Methodsmentioning

confidence: 99%

Spatial structure of ant–plant mutualistic networks

Guimarães

Izzo

2013

Oikos

Self Cite

146

143

The structure of mutualistic networks provides insights into ecological and coevolutionary dynamics of interacting species. However, the spatial effect has only recently been incorporated as a factor structuring mutualistic networks. In this study, we evaluated how the topological structure and species turnover of ant–plant mutualistic networks vary over a spatial gradient. We showed that although the ant and plant composition of networks changed over space, the central core of generalist species and the structure of networks remained unaltered on a geographic distance of up to 5099 m in the southern Brazilian Amazon. This finding indicates that independently of variation in local and landscape environmental factors, the nonrandom pattern organization of these interacting assemblages do not change. Finally, we suggest that a stable core can increase the potential for coevolutionary convergence of traits among species from both sides of the interaction within the community. These findings contribute to our understanding of the maintenance of biodiversity and coevolutionary processes.

“…Fruits were isolated from their visitors for 24 hours, and we measured the volume of nectar (by graduates microcapillary) every 4 hours (n07 measurements). We quantified the nectar volume using 1-mL microcapillaries (graduated by 0.1 mL divisions) (Heil et al 2000;Da´ttilo et al 2012). To evaluate the variation in nectar secretion during fruit ontogeny, we collected the fruits used previously and measured the diameter of each fruit.…”

Section: Data Collectionmentioning

confidence: 99%

Temporal variation in extrafloral nectar secretion in different ontogenic stages of the fruits ofAlibertia verrucosaS. Moore (Rubiaceae) in a Neotropical savanna

Falcão

Journal of Plant Interactions

Izzo

2013

In this study, we evaluate the temporal variation in extrafloral nectaries (EFNs) secretion in different ontogenic stages of Alibertia verrucosa (Rubiaceae) fruits in a Neotropical savanna. We observe greater nectar secretion rate in fruits of intermediate size compared with young or ripe fruit, indicating that they are possibly more protected by ants. In addition, the nectar secretion was higher at night, a pattern that could be associated with an increase of herbivore pressure and water stress during the daylight hours. In fact, due to the high temperature and low humidity during the day in savannas, most herbivores display strong nocturnal activity, and plants can avoid nectar secretion in this period. Our results indicate that A. verrucosa can change the ants' attraction according to EFN secretion during the ontogenic stages of the fruits, probably secreting more nectar when the biotic defense are more necessary for the protection of the fruits and the plant as a whole.