Microgeographic and vertical distribution of Acromyrmex landolti (Hymenoptera: Formicidae) nests in a neotropical savanna

• Published in: Environmental entomology Vol. 27; no. 3; pp. 636 - 641
• Main Authors: Lapointe, S.L. (U.S. Horticultural Research Laboratory, USDA-ARS, Apopka, FL.), Serrano, M.S, Jones, P.G
• Format: Journal Article
• Language: English
• Published: Lanham, MD Entomological Society of America 01-06-1998
• Subjects: ACROMYRMEX; Animal and plant ecology; Animal, plant and microbial ecology; Animals; ANT FUNGUS GARDENS; Biological and medical sciences; CARACTERISTICAS MORFOLOGICAS SUELO; COLOMBIA; COLOMBIE; CONTENIDO DE AGUA EN EL SUELO; Demecology; DEPTH; DISTRIBUCION ESPACIAL; DISTRIBUCION GEOGRAFICA; DISTRIBUTION GEOGRAPHIQUE; DISTRIBUTION SPATIALE; DRY SEASON; ESTACION HUMEDA; ESTACION SECA; Fundamental and applied biological sciences. Psychology; GEOGRAPHICAL DISTRIBUTION; MICRORELIEF; NESTING; NIDIFICACION; NIDIFICATION; PROFONDEUR; PROFUNDIDAD; Protozoa. Invertebrata; SABANAS; SAISON HUMIDE; SAISON SECHE; SAVANE; SAVANNAS; SEASONAL VARIATION; SOIL MORPHOLOGICAL FEATURES; SOIL WATER CONTENT; SPATIAL DISTRIBUTION; TENEUR EN EAU DU SOL; TRAIT MORPHOLOGIQUE DU SOL; VARIACION ESTACIONAL; VARIATION SAISONNIERE; WET SEASON; South America; Colombia; America; Formicidae; Savannah; Insecta; Vertical distribution; Tropical zone; Social insect; Formicoidea; Pest; Spatial distribution; Seasonal variation; Arthropoda; Colony; Population dynamics; Hymenoptera; Invertebrata; Population density; Aculeata
• ISSN: 0046-225X; 1938-2936
• DOI: 10.1093/ee/27.3.636

Nests of the grass-cutting attine ant Acromyrmex landolti (Forel) were excavated in a lowland tropical savanna in eastern Colombia over a period of 27 mo. Of 135 colonies, nests excavated during the dry season were deeper, had more chambers, and were approximately 2.5 times larger than those excavated in the same area of native savanna during the wet season. Chambers containing fungus gardens were found to a depth exceeding 2 m during the dry season. During the rainy season, all chambers containing fungus gardens were located within 30 cm of the soil surface. Individual chamber size did not vary seasonally. During the rainy season, colonies relocated to superficial chambers and were smallest in terms of total colony volume and number of chambers per colony. During the dry season, colonies excavated new chambers to depths where soil moisture asymptotically approached a maximum level. Maps of colony location and microtopography of the savanna revealed an aggregated distribution associated with microrelief. Colonies were aggregated on slightly raised ridges that were most likely caused by surface water runoff. Implications for sampling and control are discussed