NMDS results obtained for the composition of ant species on Cerrado plants with and without EFNs (N = 10 transects) for both seasons.

<p>The composition of ant fauna did not differ (P > 0.05) between the groups according with ANOSIM tests.</p

Seasonal ant visitation patterns on Cerrado plants with and without EFNs.

<p>Number of ant species (A) and ant workers (B) per plant. Black horizontal lines represent the median, boxes designate the second and third quartiles, and vertical bars indicate the range of data without outliers. Asterisks indicate significant differences (P < 0.5) between adjacent pairs of categories following contrast procedure.</p

Temporal Variation in the Abundance and Richness of Foliage-Dwelling Ants Mediated by Extrafloral Nectar

<div><p>Plants bearing extrafloral nectaries (EFNs) are common in the Brazilian cerrado savanna, where climatic conditions having marked seasonality influence arboreal ant fauna organization. These ant-plant interactions have rarely been studied at community level. Here, we tested whether: 1) EFN-bearing plants are more visited by ants than EFN-lacking plants; 2) ant visitation is higher in the rainy season than in dry season; 3) plants producing young leaves are more visited than those lacking young leaves in the rainy season; 4) during the dry season, plants with old leaves and flowers are more visited than plants with young leaves and bare of leaves or flowers; 5) the composition of visiting ant fauna differs between plants with and without EFNs. Field work was done in a cerrado reserve near Uberlândia, MG State, Brazil, along ten transects (total area 3,000 m²), in the rainy (October-January) and dry seasons (April-July) of 2010–2011. Plants (72 species; 762 individuals) were checked three times per season for ant presence. Results showed that 21 species (29%) and 266 individuals (35%) possessed EFNs. These plants attracted 38 ant species (36 in rainy, 26 in dry season). In the rainy season, plants with EFNs had higher ant abundance/richness than plants without EFNs, but in the dry season, EFN presence did not influence ant visitation. Plant phenology affected ant richness and abundance in different ways: plants with young leaves possessed higher ant richness in the rainy season, but in the dry season ant abundance was higher on plants possessing old leaves or flowers. The species composition of plant-associated ant communities, however, did not differ between plants with and without EFNs in either season. These findings suggest that the effect of EFN presence on a community of plant-visiting ants is context dependent, being conditioned to seasonal variation.</p></div

Number of plants according to phenological state across seasons.

<p>Number of plants according to phenological state across seasons.</p

Percentage of Cerrado plants on which each ant species was found in each season.

<p>Plants were divided according with the presence (N = 266) or absence (N = 496) of EFNs for each season. Figure shows only ant species with ten occurrences or more.</p

Ant visitation patterns on Cerrado plants according to phenological factors.

<p>Plants with and without old leaves according to the seasons (A), plants with and without flowers or floral buds according to the seasons (B). Black horizontal lines represent the median, boxes designate the second and third quartiles, and vertical bars indicate the range of data without outliers. Asterisks indicate significant differences (P < 0.5) between adjacent pairs of categories following contrast procedure.</p