Discovering the Giant Nest Architecture of Grass-Cutting Ants, Atta capiguara (Hymenoptera, Formicidae)

Abstract

Atta capiguara is a grass-cutting ant species frequently found in Cerrado biome. However, little is known about the giant nest architecture of this ant. In this study, we investigated the architecture of three A. capiguara nests from a fragment of Cerrado in Botucatu, São Paulo, Brazil. Casts were made of the nests by filling them with cement to permit better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. The results showed the shape of Atta capiguara nests consisting of mounds of loose soil with unique features resembling a conic section. The fungus chambers were found distant from the mound of loose soil and were spaced apart and distributed laterally at the soil profile. The waste chambers were located beneath the largest mound of loose soil. Both the fungus and waste chambers were separated and distant. Our study contributes to a better understanding of the so far unknown nest architecture of the grass-cutting ant A. capiguara.

The complex nest architecture of the Ponerinae ant Odontomachus chelifer

“…So far, there is no record of Ponerinae species building similar structures to the one described in this study. This system of multiple entrances, chambers and connections, and various sectors of the nest can be related to airflow to maintain its internal conditions, in a pattern similar to that of nests of Atta [ 23 , 25 , 37 , 38 , 39 ], in a much smaller scale.…”

Interspecific Eavesdropping on Ant Chemical Communication

“…Ant nests are compartmentalized into different chambers containing the queen, brood, workers, food, and detritus. For example, leaf-cutter ants have four kinds of nest chambers (empty, garden filled, dirt/sand filled, and detritus filled chambers) (Moser, 2006;Forti et al, 2017) whereas other species may have 3-4 (entrance, queen, worker with brood, worker without brood) (Heyman et al, 2017), providing vastly different microhabitats. Ants often maintain unique chemical signatures in different chambers, providing spatiotemporal guidance for workers (Heyman et al, 2017).…”

Nest Architecture Development of Grass-Cutting Ants, Atta capiguara (Hymenoptera: Formicidae)

“…Among the 17 known species of Atta (F.), A. sexdens, A. laevigata, A. bisphaerica, A. capiguara and A. cephalotes are described and cause economic damages to crops in Brazil (Bolton et al, 2006). Atta capiguara (G.), commonly found in the Cerrado biome, is a grass-cutting ant that causes damages to pastures, as well as to rice, maize and sugarcane crops (Mariconi et al, 1961;Forti et al, 2017). Although leaf-cutting ants are distributed in the Neotropical region, A. capiguara is present only in South America (Mariconi et al, 1961;Forti et al, 2017).…”

“…Atta capiguara (G.), commonly found in the Cerrado biome, is a grass-cutting ant that causes damages to pastures, as well as to rice, maize and sugarcane crops (Mariconi et al, 1961;Forti et al, 2017). Although leaf-cutting ants are distributed in the Neotropical region, A. capiguara is present only in South America (Mariconi et al, 1961;Forti et al, 2017).…”

“…Few studies about the nest architecture development of Atta are available (Autuori, 1941;Forti et al, 2018). In the case of A. capiguara, research on architecture has been conducted only in nests of colonies considered mature (> 5 years of age) (Mariconi et al, 1961;Forti et al, 2017). In the A. capiguara nest excavated by Forti et al (2017), aged around 8 years, 72 fungus chambers and 10 waste chambers were found, most of them connected to the main tunnel, at an average depth of 1.2 meter.…”