A Pest or Otherwise? Encounter of Oryctes rhinoceros (Coleoptera: Scarabaeidae) with Persistent Organic Pollutants

Abstract

The potential use of invertebrates as bioreactors to treat environmental pollutants is promising and of great interest. Three types of the persistent organic pollutants (POPs), namely pentachlorophenol (PCP), PAHs (naphthalene and phenanthrene) and dieldrin (DLN), were spiked in soil and treated by using Oryctes rhinoceros larvae, a known pest of coconut trees in southeast Asia, and also the indicators of POP toxicity and the fate and degradability of the ingested POPs were assessed. The larvae were tested at various levels of the POPs and went through an acclimation process. Without acclimation, the tolerance limits of the larvae toward PCP, PAHs and DLN were 200, 100 and 0.1 mg/kg-soil, respectively, yet with acclimation, the tolerance levels increased to 800, 400 and 0.5 mg/kg-soil, respectively. Biodegradation rates of all the tested POPs were >90% by week 2, with <5% and nearly 0% remaining in the feces and body of the larvae, respectively. The results suggest that the use of the beetle larvae in soil POP decontamination is doable.