Demonstration of an adaptive response to preconditioning Frankliniella occidentalis (Pergande) to sublethal doses of spinosad: a hormetic-dose response

Abstract

Sublethal doses of some insecticides have been reported to either stimulate or reduce the survival and fecundity of insects. Many sublethal-effect studies have been conducted after exposure of only one generation to sublethal insecticides, and there is little information about the sublethal effects on insects after long-term exposure to sublethal insecticides. In this study, changes in biological characteristics were investigated in spinosad-susceptible (Spin-S) and sublethal-spinosad-treated (Spin-Sub) strains of Frankliniella occidentalis (Pergande) after exposure to their corresponding sublethal concentrations of spinosad. The results showed that for the Spin-S strain, the LC10 concentration of spinosad slightly affected the biotic fitness both in parents and offspring of F. occidentalis. The LC25 concentration of spinosad prolonged the development time, reduced the fecundity, and significantly reduced the intrinsic rate of increase, the net reproductive rate and the finite rate of increase in the Spin-S strain. However, the negative effects were not as pronounced in the offspring (F1 generation) as in the parent generation. For the Spin-Sub strain, the LC10 and LC25 concentrations of spinosad had little negative effect on the development and fecundity, and no significant difference was found between the effects of the LC10 and LC25 treatments on the Spin-Sub strain. The Spin-Sub strain exhibited a shorter developmental time, and larger intrinsic rates of increase and net reproductive rates, compared with the corresponding treatments of the Spin-S strain. These findings combined with our previous studies suggest that the biotic fitness increased in the Spin-Sub strain and the strain became more adaptable to sublethal doses of spinosad, compared with the Spin-S strain. Physiological and biochemical adaptation may contribute to these changes after long treatment times at sublethal doses.

Lethal and sublethal effects of fluralaner on the two‐spotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae)

“…Numerous studies have been conducted to analyze the sublethal effects of various acaricides, including pyridine, azomethine, pyrethroid, neonicotinoids, tetrazine and organophosphates derivatives towards TSSM . It is surprising that sublethal concentrations of certain acaricides possibly lead to an increase in TSSM populations rather than a reduction due to physiological and biochemical adaptation . For example, the LC 20 of spinetoram could increase the number of eggs per female adult to 117.13%, which indicates that spinetoram is likely to cause outbreaks of TSSM in the field .…”

“…41,42 It is surprising that sublethal concentrations of certain acaricides possibly lead to an increase in TSSM populations rather than a reduction due to physiological and biochemical adaptation. 4,43,44 For example, the LC 20 of spinetoram could increase the number of eggs per female adult to 117.13%, which indicates that spinetoram is likely to cause outbreaks of TSSM in the field. 4 Therefore, sublethal effects of a novel acaricide should be examined before its use in the field.…”

The Role of Heavy Metals in Plant Response to Biotic Stress

“…Hormesis effects of metals on insects are presented in Table 2 . It should also be mentioned that the hormesis effect on insects is mostly observed in response to different insecticides [ 87 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 ].…”

Sublethal effects of four insecticides on folding and spinning behavior in the rice leaffolder, Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae)

“…Examples of physiological responses are changes in glutathione S‐transferases and other metabolic enzymes , . Behavioral responses such as avoidance are less well characterized and are now considered important by some researchers . Behavior is a sensitive signal and marker reflecting the insect's body status and response to the environment, including exposure to insecticides, especially sublethal doses of insecticides, and can provide useful information that can contribute to management , , …”

“…9,10 Behavioral responses such as avoidance are less well characterized and are now considered important by some researchers. [11][12][13][14][15] Behavior is a sensitive signal and marker reflecting the insect's body status and response to the environment, including exposure to insecticides, especially sublethal doses of insecticides, Means in the same column of the particular instar period followed by different letters are significantly different (P < 0.05).…”