Genetic Variation and Cluster Formation of the Ant Azteca in Coffee Agroecosystems

Ant Azteca;Coffee Agroecosystems;Natural Resources and Environment

Remfert, JaneCortes-Ortiz, Liliana ;

University of Michigan

关键词: Ant Azteca;    Coffee Agroecosystems;    Natural Resources and Environment;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/94542/JaneRemfert.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The spatial distribution of organisms is an important concept in ecology and it hasbeen recently recognized that large-scale spatial patterns may depend only on local-levelinteractions. The ant Azteca instabilis has been shown to have a spatially aggregateddistribution despite a homogeneous environment in a coffee agroecosystems with evenlyplanted shade trees,. It has been argued that this self-organized pattern is the result ofendogenous local forces that include a process of local expansion and density dependentcontrol. In this study we sample ants from a 45-hectar plot within a coffee plantation andused behavioral assays of aggression, mitochondrial sequence data, and fivemicrosatellites to elucidate processes contributing to this self-organized pattern.High levels of aggression between groups and strong genetic divergence providestrong evidence for the presence of two evolutionary distinct units in this system. Lowlevels of aggression among nests within a cluster, lack of genetic differentiation, andsignificant isolation by distance all support a local nest expansion process throughbudding. Significant genetic differentiation between most clusters and lack of isolationby distance at the cluster level indicates that new cluster establishment could behappening via flying queens from other areas. Lack of differentiation between someclusters, however, suggest that large scale budding or short distance dispersal could alsobe responsible for the establishment of new clusters. This study confirms the existence oftwo evolutionary units co-inhabiting the 45-hectare plot. Furthermore, it confirms theformation of clusters through a colony budding process. However, the establishment ofnew colonies from which the cluster eventually emerge could be either through newflying queens from a regional pool, queens flying short distances or from long distancebubbing.