Effect of non-repellent insecticides on tunneling and walking abilities of R. flavipes workers (Isoptera: Rhinotermitidae)

The effects of Indoxacarb and Fipronil on the tunneling and walking abilities of eastern subterranean termites (ESTs) were studied to improve understanding of the potential for horizontal transfer and general effectiveness.ESTs were exposed to 200ppm Indoxacarb-treated filter paper for various periods; their tunneling ability was subsequently tested in arenas containing soil (18% moisture w/w). Tunneling behavior was recorded at 8hour intervals until cessation of tunneling. Tunneling characteristics studied included: number of tunnels, total tunnel length, and mean tunnel length. A second study tested relative effects of different concentrations of Indoxacarb and Fipronil on tunneling behavior. Walking ability/mobility of termites exposed to these non-repellent insecticides was tested in arenas consisting of Petri dishes (13.6cm internal diameter) provided with Whattman no.1 filter paper of the same diameter. A circular ink trail (8.8-cm diameter) made on the filter paper with a pen (Paper mate Write Bros. Med. PT.) provided a trail for the termites to follow. Total distance moved by termites in sixty seconds was measured with the aid of a thread and measuring scale. Measurements were repeated at 2-hour intervals until cessation of walking. The tunneling test revealed interesting behaviors including conditions that encourage branching of tunnels. Intoxicated termites spent considerable lengths of time at the tunnel head, eliciting a range of behaviors from termites waiting to get to this area. Walking ability generally decreased with time but reduced drastically when termites became uncoordinated.