Antistatic Foam as a Shocking Surface for Behavioral Studies with Honey Bees (Hymenoptera: Apidae) and American Cockroaches (Orthoptera: Blattelidae)

Abstract

The application of electric shock is useful in the study of the learning process in vertebrates and invertebrates. In most behavioral studies, electric current is delivered with a shock grid. When applying electric current to a terrestrial invertebrate the use of shock grids is problematic. An alternative used for many years is the “resistive-sheet,” an asphalt and graphite mixture painted on a nonconductive surface such as plastic. The resistive sheet has several limitations, including difficulty in applying the mixture uniformly and uneven distribution of current. This article advocates replacing the resistive sheet with antistatic foam. Antistatic foam is used to prevent damage to integrated circuits and circuit boards due to static electrical charge. The foam is easily manipulated, standardized, and with the addition of two wires delivers consistent current across its area. The efficacy of antistatic foam as a shocking surface was examined in two experiments. In the first, escape behavior in honey bees, Apis mellifera L., was examined by placing two groups of bees (n = 26) in a two compartment shuttle box. One group received 25 V AC shock that terminated when the bee crossed into the opposing compartment. A control group did not receive any shock. Results showed that bees in the shock group crossed into the opposing chamber significantly more often than the no-shock group (t= 6.796, df = 24, P < .001). In the second experiment, a contraction response was tested in a group (n = 10) of American cockroaches, Periplaneta americana L. Each roach was individually placed in the apparatus and received 1 min no shock (baseline), 1 min (1 s 50 V AC every 10 s) shock, and 1 min baseline. Roaches contracted significantly more often in the shock condition than in either of the baseline conditions (F= 10.049, df = 2,18, P = .001). These results demonstrate that antistatic foam can be used to create a shocking surface suitable for investigating behavior in insects.