Drinking behaviour in the cockroach Periplaneta americana: An automated method for the measurement of periodicity and uptake

A low-cost fluid delivery system is described that permits individual insects to drink ad libitum from a contact-sensitive capillary tube. Uptake is determined by periodic visual observation or by automatic infra-red detection of a travelling marker, in conjunction with an identical tube serving as an evaporation control. In adult males maintained on a balanced diet and subject to a 12 h light-12 h dark photoperiod for 10 days, the daily consumption of tapwater varied between 52 and 140 μl.