Ants, Cataglyphis cursor, Use Precisely Directed Rescue Behavior to Free Entrapped Relatives

Although helping behavior is ubiquitous throughout the animal kingdom, actual rescue activity is particularly rare. Nonetheless, here we report the first experimental evidence that ants, Cataglyphis cursor, use precisely directed rescue behavior to free entrapped victims; equally important, they carefully discriminate between individuals in distress, offering aid only to nestmates. Our experiments simulate a natural situation, which we often observed in the field when collecting Catagyphis ants, causing sand to collapse in the process. Using a novel experimental technique that binds victims experimentally, we observed the behavior of separate, randomly chosen groups of 5 C. cursor nestmates under one of six conditions. In five of these conditions, a test stimulus (the “victim”) was ensnared with nylon thread and held partially beneath the sand. The test stimulus was either (1) an individual from the same colony; (2) an individual from a different colony of C cursor; (3) an ant from a different ant species; (4) a common prey item; or, (5) a motionless (chilled) nestmate. In the final condition, the test stimulus (6) consisted of the empty snare apparatus. Our results demonstrate that ants are able to recognize what, exactly, holds their relative in place and direct their behavior to that object, the snare, in particular. They begin by excavating sand, which exposes the nylon snare, transporting sand away from it, and then biting at the snare itself. Snare biting, a behavior never before reported in the literature, demonstrates that rescue behavior is far more sophisticated, exact and complexly organized than the simple forms of helping behavior already known, namely limb pulling and sand digging. That is, limb pulling and sand digging could be released directly by a chemical call for help and thus result from a very simple mechanism. However, it's difficult to see how this same releasing mechanism could guide rescuers to the precise location of the nylon thread, and enable them to target their bites to the thread itself

The drawer system concept for the ATLAS Tilecal readout

One strong constraint in ATLAS is the easy and fast access to the Tile calorimeter readout without any destructive interference with the rest of the detector. Therefore the drawer system has been designed to place all PMTs and associated electronics on a movable system inside the TILECAL girders which provide both, the structural support to the individual modules and the solenoid return flux. In case of faulty readout elements, these elements can be replaced because of the motion of the endcaps. In this note, the complete system from the manufacturing technique up to the readout components, is described. Each drawer is considered as an autonomous subsystem which requires a dedicated test bench. 1 Design specifications One of the major interest of the Tile calorimeter cell configuration is to have all readout components outside the active part of the calorimeter. However, at this place there is no space for access available without removing the muon chambers. The drawer concept descr..