Caste Composition, Colony Size, And Baiting Of The Subterranean Termite Macrotermes Gilvus (Hagen) (Blattodea: Termitidae)
Loading...
Date
2015-06
Authors
Lee, Ching Chen
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The biological aspects and baiting of Macrotermes gilvus (Hagen) namely: (1) caste composition and colony size; (2) development of novel gas chromatography-mass spectrometry (GC-MS) assay for determination of bait toxicant; (3) efficacy of bait against different colony size, were focused in this study to provide an insight into the reasons behind lack of effectiveness of termites baits against this species. The optimum maintenance conditions of this species in laboratory were also studied to provide researchers with lab solutions in developing better management system against M. gilvus. The total number of termite individuals differed significantly among different-sized mounds. The population size of M. gilvus mounds ranged from 14,500 to 68,800 termite individuals. Larva caste (42.60%) was the most abundant in number in the termite colony followed by those of the workers (42.19%), soldiers (14.16%), and presoldiers (0.71%). Population parameters, mound parameters, and the queen weight were found to interrelate. The sex ratio of alates was significantly skewed toward females in most of the colonies. Of the 44 colonies surveyed, 13.6% were polygynous and 11.4% were polyandrous. A novel gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the screening of chlorfluazuron (CFZ) in termites. The assay was simple and rapid, with a short GC run time (10.0 min). The developed method was sensitive, as demonstrated by the detection and quantification limits of 0.003 μg/g and 0.1 μg/g, respectively. The linearity of the assay (r2 > 0.998), within- and between-assays accuracies and precisions (1.19–6.43%), and mean recovery (95.6%)
were within the acceptable range. All treated medium-sized colonies were moribund after 4 months baiting period; with termite cadavers inside, no larvae, queens appeared unhealthy, and a largely decreased population size (≥90%). On the contrary, the chlorfluazuron bait had limited detrimental effects on large-sized colonies. CFZ was only present in trace amounts in different termite castes and fungus combs, and the population size slightly decreased (≤40%). Since fungus combs are abundant in the large colonies, this might decrease the content of CFZ per unit fungus comb and hence slowing down the targeted larvae in accumulating the lethal dose. Larger groups (≥ 0.6 g) were more vigorous and had significantly higher survival rates than smaller groups (≤ 0.3 g). The population density for optimal survival of M. gilvus is 0.0025 g per container volume (mL) or 0.0169 g per matrix volume (cm3). In the termite groups of smaller size (i.e., 0.3 g) or groups maintained in smaller container (i.e., 100 mL), Xylaria spp. grew rapidly on fungus combs. Macrotermes gilvus showed satisfying survival rate when maintained in non-nutritious matrix (i.e., sand). There was no significant difference in the survival rate between different colonies.
Description
Keywords
The biological aspects and baiting , of Macrotermes gilvus.