Supplementary material

Multiple feeder array

Feeders are connected to a pump via a tubing system: transparent PVC-tube (Nalgene 380, Neolab, Heidelberg, Germany, inner diameter 1.6·mm, outer diameter 3.2·mm) joined by polypropylene connectors (Neolab, Heidelberg, Germany,pressure resistant) and at the feeder connected to an injection cannula (20G 3 1.5·inch needle) fixed via a LuerLock connection to the back of the feeder head. An alternative connection is a flanged Teflon tube (diameter 1.0·mm/1.6·mm) screwed into the back of the feeder with a hollow screw. Feeders can be cleaned automatically by means of this communal tubing system. Supply valves control the type of liquid pumped into the system (nectar, or hot water or alcohol for cleaning) or permit emptying all liquid into a waste holder (Fig.·1). Sugar water is cooled at 7°C in 500·ml polypropylene bottles in a regulated Peltier element refrigerator (4l contents) with electronic temperature control. Cleaning water is heated to 60°C in a water bath.

As the silicon tubes required for the pinch valves are not airtight, small air bubbles occur in the tube system after more than 14·h of operation. Therefore, the system has to be emptied and refilled once every 24·h, to prevent irregular amounts of liquid being supplied.

Cleaning the tubing system with hot water and alcohol every 3–4·days prevents fungal growth in the sugar solution. For this, the sugar solution is sucked out and the tubing system flushed with hot water (six times the tube volume) and then filled with 70% alcohol, all by automatic pump and valve operation. The alcohol is drained away after 60·min and the system flushed once more with hot water (6 times the tube volume). This cleaning procedure runs automatically at a predetermined time during the daily resting phase of the animals. Before the equipment is set in operation, the system is flushed once again with water (1–2 times the tubing volume). Manual filling occurs via a mobile hand control with seven signal lines. Signals open or close nectar valves, set the direction of flow and the speed of the pump, and select the pump procedure to be switched on.

Files in this Data Supplement:

• Supplemental Figure 1 (PDF version) -

  Fig.·1 Pump and tubing system for the 64-feeder array. Feeders are numbered 1–64. r1–r8: valves for horizontal feeder rows 1–8; o1–o8: overflow valves for pressure regulation. Liquid reservoirs are alcohol (a), hot water (h), waste (w), sugar water / nectar (n); s1–s4: reservoir valves; p=stepping-motor syringe pump. Black rectangles are electromagnetic pinch valves (AscoJoucomatic, Rueil Malmaison Cedex, France, W295A112-12VDC, with 55 shore silicon tube).

• Supplemental Figure 1 (JPEG version)