Physiological Responses of the Firefly Pyrocoelia analis (Coleoptera: Lampyridae) to an Environmental Residue From Chemical Pesticide Imidacloprid

Abstract

Imidacloprid, a neonicotinoid insecticide, is widely applied to control insect pests across a broad spectrum. Though the impact of residues from this chemical pesticide on non-target organisms in the field has been reported, it was not well characterized across a wide range of ecosystems, especially for some species considered as environmental indicators that live in forests. The effects of sublethal dose of imidacloprid on firefly, Pyrocoelia analis, were analyzed physiologically and biochemically in this study to better understand the impact of chemical pesticide application on environmental indicators such as fireflies. After imidacloprid treatment, the midgut tissues of the larva presented an abnormal morphology featured as atrophy of fat body cells, shrinking cells, and the destruction of a midgut structure. The activities of antioxidant enzymes, superoxide dismutase, catalase, and peroxidase were noticeably increased during early exposure to sublethal imidacloprid and then decreased at later stages. The malondialdehyde content significantly increased after 12 h of exposure to imidacloprid compared with the control. Similarly, the enzyme activities of polyphenol oxidase and acetylcholinesterase were increased after the imidacloprid treatment and then decreased at the later stage. In summary, a sublethal dose of imidacloprid caused destructive change in the tissue structure, and this damage was followed by an excessive reactive oxygen species that could not be eliminated by antioxidant enzymes. Our results indicated that the residues of imidacloprid might cause severe toxicity to non-target insects in the environment even far away from the agro-ecosystem where the chemicals were applied.

Insects as bioindicator: A hidden gem for environmental monitoring

“…Utilizing abundant species (or groups of species) with constricted elevation ranges as bioindicators can help to monitor the effects of climate change on the biota and determine how species are adapting through time. According to their findings, imidacloprid residues may be extremely hazardous to non-target insects in the environment, even in areas far from the agro ecosystem where the herbicides were used (Wang et al, 2022). Their findings showed that the Scarabaeinae fauna of Itatiaia is incredibly diverse, with wide fluctuations in richness and abundance along the elevation gradient and notable phonological shifts at the community level related to seasonal climate variations (Araújo et al, 2022).…”

Illuminating Firefly Diversity: Trends, Threats and Conservation Strategies

“…In addition, larvae of both species exhibited marked sublethal responses when exposed to lower soil concentrations, including significantly reduced feeding behavior and impaired movement. Another study [61] tested the neonicotinoid imidacloprid at field-relevant concentrations and found that while it caused low mortality in soil-dwelling larvae of the Asian firefly Pyrocoelia analis, its sublethal effects included changes in midgut tissue morphology, convulsive body movements, persistent luminescence and other physiological changes.…”

Multifunctional Mesoporous Silica Nanosheets for Smart Pesticide Delivery and Enhancing Pesticide Deposition

“…Among them, imidacloprid is a representative neonicotinoid insecticide. As a competitive inhibitor, it can selectively block nicotinic acetylcholine receptors in insects’ central nervous systems, interrupting normal nervous system signal transmission and killing the insects . However, it also has some drawbacks of easy photooxidation and degradation.…”

“…As a competitive inhibitor, it can selectively block nicotinic acetylcholine receptors in insects' central nervous systems, interrupting normal nervous system signal transmission and killing the insects. 26 However, it also has some drawbacks of easy photooxidation and degradation. The overdosage for better insecticidal efficacy would cause adverse ecological and health problems.…”