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Close-up of Leaf-cutter Ants Cutting


Movie 1. View from below of laboratory colony ants, Atta cephalotes, cutting leaves. In off-vein regions, the surface of the leaf opposite the ant tends to be cut by the proximal blade of the distal tooth (first tooth) as the tooth rides along the surface. In the first three clips, the ants are cutting Rubus armeniacus leaves (approximately 0.08 mm or 0.14 mm without and with the trichome [hair] mat), in the last 2 clips the ants are cutting approximately 0.25 mm thick Prunus lusitanica leaves. While the thicknesses of the leaves are sometimes greater than the distance between the two distal teeth for some of these foragers, these foragers tend to be smaller than wild colony foragers (see Figure 4 of the paper). The distance between the first and second tooth of an average sized wild colony cutter was about 0.15 mm, so the approximately 0.13 mm thick O. macrantha leaves would have been cut mainly by the V-blade between the first and second tooth. For veins, a sawing action is employed. Movies were made using a Nikon Coolpix 4500 mounted on a Zeiss dissection microscope. The frame rate has not been altered to speed up or slow down action in any of the three movies. Copyright Robert Schofield, rmss@conch.uoregon.edu


Movie 2. View from above of laboratory colony ants, Atta cephalotes, cutting leaves. The leading mandible is often used to partially cut through the leaf in advance of the lagging mandible, and is used as an anchor to pull the lagging mandible against in order to complete the partial cut. For increasingly larger veins, the mandibles are used with increasing symmetry in a sawing action. In the fifth clip, showing cutting of a large vein, the mouth parts of the ant are extended at one point, possibly to ingest sap. In the first 6 clips, the ants are cutting Rubus armeniacus leaves, in the last clip the ant was cutting a Prunus lusitanica leaf. Copyright Robert Schofield, rmss@conch.uoregon.edu


Movie 3. Two laboratory colony ants, Atta cephalotes, with highly worn mandibles appear to be having difficulties cutting Prunus lusitanica leaves. In the first clip an ant with a blunted distal tooth on the leading mandible appears to have difficulties using it as an anchor and to partially cut the leaf. The second clip shows a second ant cutting with blunted teeth in a view from below. Copyright Robert Schofield, rmss@conch.uoregon.edu

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