ABSTRACT
Objective:To evaluate the efficacy of symbiotic bacteria,Xenorhabdus indica,Xenorhabdus stockiae,Photorhabdus luminescens subsp,akhurstii and Photorhabdus luminescens subsp.hainanensis as a larvicide against Aedes aegypti and Aedes albopictus.Methods:Larvae (L3-L4) of Aedes aegyptiand Aedes albopictus were given 2 mL of a suspension 107-108 CFU/mL of each symbiotic bacterium.Distilled water and Escherichia coli ATCC· 25922 were used as the control.The morality rate of the larval mosquitoes was observed at 24,48,72 and 96 h.The experiment was performed in triplicates.Results:The larvae of both Aedes species started to die at 24 h exposure.Aedes aegypti showed the highest mortality rate (87％-99％),96 h after exposure to Xenorhabdus stockiae (bNBP22.2_TH).The mortality rate of Aedes albopictus was between 82％ and 96％ at 96 h after exposure to Xenorhabdus indica (bKK26.2_TH).Low effectiveness of distilled water and Escherichia coliATCC· 25922 were observed in both Aedes larvae,with a mortality rate of 2％ to 12％.Conclusions:The study confirms the oral toxicity of Xenorhabdus and Photorhabdus bacteria against Aedes spp.Xenorhabdus stockiae and Xenorhabdusindica may be an alternative agent for control Aedes spp.This is basic information for further study on the mechanism of action on Aedes larvae or application to control mosquito larvae in the community.
ABSTRACT
preliminary study on insects associated with pig carcasses was conducted in Phitsanulok, northern Thailand. Five decomposition stages of pig carcasses were categorized: fresh (0-1 day after death), bloated (2 days after death), active (3 days after death), advanced (4- 6 days after death) and dry (7-30 days after death). The arthropod species collected from the corpses in the field sites were mainly classified belonging to two orders and nine families, namely order Diptera (family Calliphoridae: Chrysomya rufifacies and Chrysomya megacephala, family Muscidae: Musca domestica, family Faniidae: Fannia canicularis, family Sarcophagidae: Parasarcophaga ruficornis and family Piophilidae: Piophila casei,) and order Coleoptera (family Dermestidae: Dermestes maculatus, family Histeridae: Hister sp., family Cleridae: Necrobia rufipes and family Trogidae: Trox sp). The forensically dominant fly was C. rufifacies, while the beetle was D. maculatus. The beetles associated with pig carcasses found in this study are first reported in Phitsanulok, Thailand. In addition, ants, bees, spiders and millipedes were also associated with the carcasses. These findings may provide data for further use in legal investigations in Thailand.