Photos from the Field: Leal et al. Leaf-cutter ants in human-modified landscapes

Leal, I. R., Wirth, R. and Tabarelli, M. (2014), The Multiple Impacts of Leaf-Cutting Ants and Their Novel Ecological Role in Human-Modified Neotropical Forests. Biotropica, 46: 516–528. doi: 10.1111/btp.12126

Herbivory has been identified as a potent evolutionary force, but its ecological impacts have been frequently underestimated. Leaf-cutting ants represent one of the most important herbivores of the Neotropics and offer an interesting opportunity to address the role played by herbivorous insects through a perspective that embraces population- to ecosystem-level effects. Here we: (1) qualitatively summarize the multiple ways leaf-cutting ants interact with food plants and their habitats and elucidate the ultimate outcome of such interactions at multiple organization levels; (2) update our understanding of leaf-cutting ant-promoted disturbance regimes; and (3) examine potential ecological roles by leaf-cutting ants within the context of human-modified landscapes to guide future research agendas. First, we find that leaf-cutting ants show that some herbivorous insects are able to generate ecologically important disturbance regimes via non-trophic activities. Second, impacts of leaf-cutting ants can be observed at multiple spatio-temporal scales and levels of biological organization. Third, ecosystem-level effects from leaf-cutting ants are ecosystem engineering capable not only of altering the abundance of other organisms, but also the successional trajectory of vegetation. Finally, effects of leaf-cutting ants are context-dependent, species-specific, and synergistically modulated by anthropogenic interferences. Future research should examine how leaf-cutting ants respond to deforestation and influence remaining vegetation in human-modified landscapes. By promoting either heterogeneity or homogeneity, leaf-cutting ants operate not only as agricultural pests but also as ecological key players.

 

Rainer Wirth and Sebastian Meyer (former PhD student) on the mound of an Atta cephalotes nest. Such nests have been shown to operate as ecological filters by creating a specific disturbance regime that differs from other disturbances in tropical forests. Original results published in Correa et al. 2010, Meyer et al. 2011a and 2011b.

Rainer Wirth and Sebastian Meyer (former PhD student) on the mound of an Atta cephalotes nest. Such nests have been shown to operate as ecological filters by creating a specific disturbance regime that differs from other disturbances in tropical forests. Original results published in Correa et al. 2010, Meyer et al. 2011a and 2011b.

Fragmented landscape of Serra Grande (Alagoas, NE-Brazil) with Atlantic forest fragments surrounded by sugar cane fields. Photos: Adriano Gambarini.

Fragmented landscape of Serra Grande (Alagoas, NE-Brazil) with Atlantic forest fragments surrounded by sugar cane fields. Photos: Adriano Gambarini.

“Forest greenhouse” with seedlings of Atlantic Forest trees, pregrown for a transplantation experiment to assess nest effects on seedling performance and fate. Right: Sebastian Meyer measuring seedling growth. Original results published in Meyer et al. 2011b.

“Forest greenhouse” with seedlings of Atlantic Forest trees, pregrown for a transplantation experiment to assess nest effects on seedling performance and fate. Right: Sebastian Meyer measuring seedling growth. Original results published in Meyer et al. 2011b.

Inara Leal with Eleno José de Araújo († June 2006). In memoriam to ‘Senhor Heleno’ - the region’s foremost native naturalist, herbalist, wise man and ardent supporter of our research.

Inara Leal with Eleno José de Araújo († June 2006). In memoriam to ‘Senhor Heleno’ – the region’s foremost native naturalist, herbalist, wise man and ardent supporter of our research.

Researchers of the early project days during a survey on leaf-cutting ant colony density (from front to back: Rainer Wirth, Manoel Araujo Junior, Inara R. Leal, Walkiria R. Almeida, Ursula Andres Silveira da Costa). Original results published in Wirth et al. 2007, Meyer et al. 2009, and Dohm et al. 2011.

Researchers of the early project days during a survey on leaf-cutting ant colony density (from front to back: Rainer Wirth, Manoel Araujo Junior, Inara R. Leal, Walkiria R. Almeida, Ursula Andres Silveira da Costa). Original results published in Wirth et al. 2007, Meyer et al. 2009, and Dohm et al. 2011.

Leaf-cutting ant (Atta cephalotes) carrying leaf fragments. Photo: Rainer Wirth

Leaf-cutting ant (Atta cephalotes) carrying leaf fragments. Photo: Rainer Wirth