Fine-scale thermal partitioning of ants under the shade of an the tropical rainforest canopy

Light may limit or constrain the activity of litter-dwelling arthropods in tropical forests. Canopies permit very little light to penetrate to the ground, and small sunflecks may be important to the denizens of leaf litter who may become active - or inactivated - by the penetration of light. We conducted a manipulative experiment by experimentally altering the light level under mature rainforest canopy to measure the occupancy rates and community composition of ants which occupied supplemental nesting structures. We found that the light environment predicted patch occupancy more robustly than other measures of habitat, including forest age and the properties of leaf litter. Even under conditions of nearly total canopy cover, the penetration of light through the canopy is a major environmental factor affecting distributions of ants at fine spatial scales.