Sublethal and Transgenerational Toxicities of Chlorfenapyr on Biological Traits and Enzyme Activities of Paracoccus marginatus (Hemiptera: Pseudococcidae)

Abstract

Papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), is an economically important, invasive insect that is now distributed worldwide. Chlorfenapyr has been demonstrated to have a significant control effect on P. marginatus. In order to evaluate the sublethal and transgenerational effects of chlorfenapyr on P. marginatus, the life table data of three consecutive generations were collected and analyzed by the age stage, two-sex life table method, and the enzyme activities were assayed using a spectrophotometer. The results showed that exposure to the insecticide had significant effects on the biological traits of subsequent generations of P. marginatus, and a higher intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and a shorter mean generation time (T) were observed in the chlorfenapyr-treated F1 mealybugs. Enzyme activity assays showed that chlorfenapyr significantly inhibited the activities of catalase (CAT) and peroxidase (POD) while activating the activities of superoxide dismutase (SOD), which suggested that SOD, CAT, and POD may play an important role in the self-defense of P. marginatus against chlorfenapyr. These results conclusively demonstrated that exposure of P. marginatus to sublethal concentrations of chlorfenapyr induced hormetic effects on the F1 generation while having negative effects on the F0 and F3 generations.

TestingAnopheleslarvae and adults using standard bioassays reveals susceptibility to chlorfenapyr (pyrrole) while highlighting variability between species

“…The toxicity of chlorfenapyr has been tested on immature stages of various insect pests using diverse routes of exposure (41)(42)(43)(44). Regarding mosquitoes, Yuan et al, 2015 (45) measured a median lethal concentration (LC50) of 35 ng/ml after 24 h by dipping early fourth instar larvae of Culex pipiens pallens in 200 ml water containing a concentration of chlorfenapyr.…”

Impact of Insecticides at Sublethal Concentrations on the Enzyme Activities in Adult Musca domestica L.

“…Dewer et al (2016) emphasized that there was no impact of chlorpyriphos and methomyl on the AChE activity in the maggots of Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae) when these insecticides were applied at sublethal doses [ 55 ]. The results of the study by Li et al (2022) showed that the activities of AChE and CarE were not affected by the chlorfenapyr at the sublethal concentration applied on the nymphs of the papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera:Pseudococcidae) [ 9 ]. In a study by Carvalho et al (2013), fipronil did not modulate the AChE and one of the CarE isoforms (CarE-2) and, at the same time, increased the CarE-2 activity and decreased the CarE-3 activity in the honeybee Apis mellifera L. (Apidae:Hymenoptera) [ 44 ].…”

“…Field insect populations are under the acute and chronic influence of lethal and sublethal pesticide concentrations. It can lead to various consequences: insect death, changes in their life cycle, fertility, behavior, physiological, biochemical, molecular, and genetic parameters of both the parent generation and their offspring [ 7 , 8 , 9 ]. The study of the chronic and sublethal effects of an insecticidal exposure and their species-specific characteristics is important for a deeper understanding of the environmental and evolutionary patterns of pesticidal resistance.…”

Effects of thiamethoxam on physiological and molecular responses to potato plant (Solanum tuberosum), green peach aphid (Myzus persicae), and parasitoid (Aphidius gifuensis)

“…It may have several negative effects on insects, including mortality, longevity, changes in fecundity, behavior, and physiological, biochemical, molecular, and genetic characteristics of both the parent generation and their progeny. 14,15 The second generation of neonicotinoid compounds, thiamethoxam is regarded as the second-largest neonicotinoid in terms of sales, being registered in at least 65 countries for 115 crops. 16 It works in the same way as nicotine, interfering with the nicotinic acetylcholine receptors in the neurological system of the insects.…”

“…Pesticide doses that are lethal and sublethal have an immediate and long‐term impact on field insect populations. It may have several negative effects on insects, including mortality, longevity, changes in fecundity, behavior, and physiological, biochemical, molecular, and genetic characteristics of both the parent generation and their progeny 14,15 . The second generation of neonicotinoid compounds, thiamethoxam is regarded as the second‐largest neonicotinoid in terms of sales, being registered in at least 65 countries for 115 crops 16 .…”