Species diversity of fireflies in the carbamate contaminated areas in the lower Northern region, Thailand

Abstract

Carbamate is one of the most commonly used insecticides in Thailand, which has raised public concern about their toxicity and effect on the environment. The use of carbamate insecticides could potentially cause a decline in beneficial arthropod biodiversity. Fireflies have been recognized as environmentally sensitive arthropods and labeled as a biological indicator. However, recent discoveries show that they may change their preferred habitat. Therefore, this research examined whether firefly species might adapt to living in insecticide-affected habitats, particularly those polluted with carbamate insecticides. Six spots in the lower part Thailand's northern region were studied to determine their firefly population and insecticide levels. Soil samples for each study area were collected to quantify the carbamate insecticides levels. Taxonomy of both adult and larval stages of fireflies were performed at each study area and the individual species were identified. Four species of fireflies (Lamprigera tenebrosa, Pyrocoelia praetexta, Asymmetricata circumdata, and Mediopteryx sp.) were identified in areas contaminated with two carbamate insecticides; oxamyl (detected in 5 sample sites), was found as the most common carbamate insecticides followed by methomyl (detected in 1 sample site). The level of oxamyl in soil samples ranged from 0.08 - 0.11 mg/kg, and the level of methomyl was 0.01 mg/kg. A low amount of carbamate pesticides discovered in this study, together with the presence of fireflies, suggested that certain firefly species can survive in such contaminated habitats.