Borate-treated food affects survival, vitamin B12 content, and digestive processes of subterranean termites

IRG/WP 1448

L H Williams, S I Sallay, J A Breznak

Toxicity of boron compounds was studied by analyzing survival rates and vitamin B12 contents in Formosan subterranean termites, Coptotermes formosanus Shiraki, that were exposed to dietary treatments for 10 days. The dietary treatments applied in moistened cellulose were (a) 0.05% boric acid equivalent (BAE) of disodium octaborate tetrahydrate, (b) 0.05% BAE of anmonium pentaborate plus sodium sulfate, (c) antibacterial control 0.09% streptomycin D, (d) untreated control-moistened cellulose, and (e) starvation control-no food. The main effects - colony and treatment -, and their interaction were shown to be significant by analysis of variance (ANOVA) tests. Survival of termites on diets (c) and (d) was not significantly different (P <0.05). Survival of termites on diet (d) was significantly higher than survival of termites exposed to diets (a), (b), and (e). Vitamin B12 content of termites exposed to diets (a), (b), (c), and (e) was significantly less than that of termites exposed to diet (d). Ingestion of borate-treated (and molybdate-treated) food by Reticulitermes flavipes (Kollar) suppressed the rates of methane production and H2-dependent reduction of CO2 to acetate by hindgut microbiota, apparently by indirect means. The mechanisms of how borate-treated food affects digestive processes or vitamin B12 contents of termites remains undefined. Results are discussed in relation to termite gut microecology and borate use for wood protection.


Keywords: INSECTS; TERMITES; COPTOTERMES FORMOSANUS; RETICULITERMES FLAVIPES; LYCTUS BRUNNEUS; DISODIUM OCTABORATE TETRAHYDRATE; AMMONIUM PENTABORATE; BORON; BACTERIA; ACETOGENESIS; METHANOGENESIS; VITAMIN B 12

Conference: 90-05-13/18 Rotorua, New Zealand


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