Effects of Dolichodial Extracted from Dolichoderus thoracicus, (Hymenoptera: Formicidae) on Selected Species of Ants, Termites, Mosquito Larvae and Brine Shrimp Larvae

Shabanun Salwa, Mohd Yusof and Zaini, Assim and Fasihuddin Badruddin, Ahmad (2023) Effects of Dolichodial Extracted from Dolichoderus thoracicus, (Hymenoptera: Formicidae) on Selected Species of Ants, Termites, Mosquito Larvae and Brine Shrimp Larvae. PhD thesis, Universiti Malaysia Sarawak.

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Abstract

Dolichodial is a monoterpene with two aldehyde groups and a methyl group attached. It was detected in defensive secretes, semiochemical from Dolichoderus thoracicus as cyclopentaneacetaldehyde, 2 formyl-3 methyl- alpha- methylene. Result of preliminary test upon efficacy of different solvent to extract dolichodial from D. thoracicus indicates that ethyl acetate solvent was more effective than n-hexane, dichloromethane and methanol. Fractionation procedure using column chromatography and TLC revealed that chemical composition of D. thoracicus extracts was dominated by hydrocarbon with 36 compounds successfully identified other than 19 lipids, 4 terpene/terpenoids and 9 miscellaneous compounds, ranging from 0.01% to 96.36% mean of composition. Five bioassays of 7 different species of organisms were carried out to investigate toxin and repellent effects of constituted compounds. The results from termite assay revealed that the dolichodial fraction extracted from D. thoracicus had the highest number of termites activities (8.00-63.67) and possessed the longest duration of repellent (64.00-70.00 min) in 1000 ppm concentration compared to 100 ppm (28.33-33.33 min) in both species of termites Nasutitermes longinasus and Macrotermes gilvus. Isolated dolichodial successfully recorded complete mortality upon mosquito larvae. Aedes albopictus and Aedes aegyptishowed LC90 of 1031.51 ppm and 1869.84 ppm, respectively. Meanwhile, Paratrechina longicornis and Anoplelopis gracilipes recorded LC90 of 747.65 ppm and 857.51 ppm, respectively. Isolated dolichodial was less sensitive and less efficient toward termites colony compared to another tested insect with LC50 of 126.63 ppm for N. longinasus and 149.14 ppm for Coptotermes gestroi. In contrast, LC50 of dolichodial fraction was recorded the lowest in ant colony, P. longicornis and A. gracilipes with 61.17 ppm and 54.62 ppm, respectively. This indicates that dolichodial is possibly highly toxic towards ant colony. Artemia salina larvae showed LC50 at 80.73 ppm in the cytotoxicity test. Probit analysis of LC50 also indicates that there was a correlation between toxicity of dolichodial fractions and mortality of tested species. The toxic activity was, therefore, positively influenced by increase concentration. From the findings, this present study suggests that dolichodial was dominant in D. thoracicus from ethyl acetate extracts and showed highest bioactivity against the tested species. Terpene and aldehyde groups of dolichodial may contribute to its toxicity and repellent effects. Hence, it could be developed to a new type of eco-friendly natural insecticide or repellent for the biological control of pest including ants, termites and mosquitoes.

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