Biomarkers of the influence of pyrethroids and neonicotinoids on amphibian larvae

Abstract

Currently, most amphibian populations in the world exist under the influence of numerous stress factors. Among them, the main factors that affect almost all terrestrial animals, namely, the fragmentation of habitats, environmental pollution and anthropic transformation of landscapes. Moreover, those factors are joined by negative causes that affect only amphibians – specific viral and fungal infections: ranaviruses (Ambystoma tigrinum virus (ATV), Bohle iridovirus (BIV), and frog virus 3) (also dangerous for some reptiles) and chytrid fungi (Batrachochytrium dendrobatidis and B. salamandrivorans). All these factors are one of the main reasons for the current global decline of amphibian populations in the world. In today's world, agricultural chemicals are one of the most important in terms of toxicity, environmental emissions and total area of impact. Among them, a significant proportion are formed by synthetic insecticides, which include pyrethroids and neonicotinoids. Pollution by these substances has a negative impact on amphibian populations, despite the relatively short period of their life in the environment. The vast majority of studies on the effects of pyrethroid and neonicotinoid insecticides were made in laboratory experiments with the larval stages of tailless amphibians. Tadpoles are easy to get in sufficient quantities and kept in the laboratory. Cypermethrin reduces the viability of tadpoles and causes precocious metamorphosis of survived larvae. However, in a combination with other pesticides, it delays metamorphosis. In addition, embryos were more resistant to pyrethroids than tadpoles. Pyrethroid pesticides cause spasms indicating adverse neurological effects. Formation of oral apparatus abnormalities in tadpoles, anisochromasia and increasing number of immature erythrocytes are also caused by pyrethroids. Neonicotinoids show similar effects. Under the action of imidacloprid the erythrocytes are also disturbed that is showed up in the DNA damage and micronuclei formation. Neurological disorders are manifested in the ability to perceive or respond to a predator, disorientation, erratic movement and loss of balance. Pyrethroids and neonicotinoids have been shown cause a variety of disorders: increase mortality and reduce survival of tadpoles; have a teratogenic effect and affect the metamorphosis and morphological parameters of amphibians; change many biochemical parameters that characterize the protein metabolism and oxidative stress; have genotoxic effects and affect the state of the nervous system and animal behaviour. Most of these parameters are proposed for use as biomarkers of pesticide intoxication.

Low doses of imidacloprid induce disruption of intercellular adhesion and initiate proinflammatory changes in Caco-2 cells

“…The toxicity of imidacloprid was suggested for crabs and piglets (Hernandez et al, 2018;Hong et al, 2020). Many different effects of neonicotinoids were found in amphibian larvae (Gasso et al, 2020b). Since neonicotinoids exert affinity for nAChR, the most important targets of its toxicity are the cells that are highly expressing nAChR.…”

Influence of pyrethroid and neonicotinoid insecticides on post-metamorphic amphibians (literature review)

“…Вони є поколінням інсектицидів, які прийшли на зміну більш стійким у навколишньому середовищі фосфорорганічним і хлорорганічним сполукам (Zalom et al, 2005;Giesy et al, 2014). Однак ці речовини можуть викликати негативні реакції також у нецільових видів тварин (Smith & Stratton, 1986;Nedzvetsky et al, 2020;, у тому числі в амфібій (Gasso et al, 2020;Agostini et al, 2022;Fonseca Peña et al, 2022). За даними Glaberman et al (2021), земноводні можуть проявляти навіть більшу чутливість, ніж риби, до деяких видів піретроїдів.…”

Toxicity of neonicotinoid and pyrethroid insecticides on early development of common carp (Cyprinus carpio L.) (Overview)

“…Pyrethroid and neonicotinoid insecticides are widely used worldwide as plant protection agents (Banaei et al, 2017). These substances have low toxicity to birds and mammals, but are highly toxic to aquatic organisms (Xu et al, 2018;Gasso et al, 2020;Nedzvetsky et al, 2020;Yermolenko et al, 2022). Due to the penetration of pyrethroids and neonicotinoids into the organism of fish embryos, larvae, and fry, biological changes may occur, which subsequently cause death and developmental abnormalities.…”