Tunnelling behaviour and barrier penetration of subterranean termites with special reference to Coptotermes gestroi (Wasmann) (Isoptera: Rhinotermitidae)
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Date
2007
Authors
Yeoh, Boon Hoi
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Abstract
This study focuses on tunneling behaviour and barrier penetration of
subterranean termites especially to Coptotermes gestroi (Wasmann). In addition,
horizontal transmission of several toxicants among the C. gestroi was also
studied.
Comparative tunneling behaviour of three species of Coptotermes, namely
C. gestroi, Coptotermes curvignathus Holmgren and Coptotermes kalshoveni
Kemner in different tunneling mediums (agar and sand) revealed that C.
curvignathus was the most aggressive species with extensive tunnel formation,
followed by C. gestroi. Coptotermes kalshoveni has the least tunneling activity;
however, it showed the highest wood consumption rate in the 28 d evaluation
period, suggesting higher resource fidelity. Both C. gestroi and C. kalshoveni
were found to prefer rubber over pine wood, while C. curvignathus showed no
preference between rubber and pine wood.
Contact toxicities of six technical grade insecticides (bifenthrin,
chlorfenapyr, chlorantraniliprole, fipronil, imidacloprid and indoxacarb) in C.
gestroi were determined by topical application. Results indicated that bifenthrin
was the most toxic contact insecticide against C. gestroi. Further experiments
were carried out to evaluate the barrier penetration and tunneling activities of the
termites by using seven formulated termiticides, Biflex® (bifenthrin) 24 % EC
[FMC], Terminator® (chlorfenapyr) 24 % SC [WellTech Healthcare Co. Ltd,
Thailand], DPX-E2Y45 (chlorantraniliprole) 18.5 % SC [DuPont Professional
Products], Termidor® (fipronil) 2.5 % EC [Bayer Environmental Science], DPX
HGW86-198 10 % SC [DuPont Professional Products], Premise® (imidacloprid)
20 % SC [Bayer Environmental Science] and indoxacarb 14.5 % SC [DuPont
Professional Products]. It was found that all the termiticides tested were able to
stop or suppress termites foraging activities, regardless of their repellent or non
repellent properties. Response of subterranean termites in termiticide-treated
sand suggested that termiticide properties (repellent or non-repellent) may be
depended on the concentrations used.
The formulated termiticides were further tested for horizontal transmission
activities among the nestmates (exposed to unexposed termites) by using
recommended concentration by the manufacturers. Mortalities of unexposed
termites varied with different active ingredients, donor exposure duration and
donor : recipient ratio. Increased exposure duration and mixing ratio significantly
caused a greater effect to the test insects.
Description
Master
Keywords
Biological science , Tunnelling behaviour , Subterranean termites , Coptotermes gestroi