Heat-Dependent Fecundity Enhancement Observed inNilaparvata lugens(Hemiptera: Delphacidae) After Treatment With Triazophos

Abstract

The brown planthopper Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) is a serious pest of rice crops in the temperate and tropical regions of Asia and Australia, and it is also a classic example of an insecticide-induced resurgent pest. Brown planthopper outbreaks have been reported to be closely associated with pesticide application. Previous studies have shown that the insecticide triazophos enhances thermal tolerance and fecundity in brown planthopper. However, the effects of triazophos and high temperature on reproductive capacity have not been studied in high temperature-conditioned reciprocal pairs of adult males and females. The present experiments showed that triazophos enhanced the reproductive capacity of brown planthopper under high temperature (34°C). The number of eggs laid by females treated with 40 ppm triazophos at 34°C approximately doubled compared with untreated insects. Furthermore, the triazophos-induced fecundity enhancement at 34°C was significantly greater than that at 26°C, and the number of eggs laid for mating pair of adult males at 34°C with adult females under 34°C (♂(34) × ♀(34)) were significantly greater than that of adult males at 26°C (♂(26) × ♀3(4)), suggesting that this insecticide enhances the resistance of brown planthopper to high-temperature stress. Insecticide-induced enhancement of reproductive capacity in brown planthopper under high temperatures should be of great concern, and it has important implications for forecasting future brown planthopper outbreaks as well as the pesticide-selection process.

Pesticide-induced resurgence in brown planthopper is mediated by action on a suite of genes that promote juvenile hormone biosynthesis and female fecundity

“…Thus, insecticide-enhanced reproduction is likely a key factor in the BPH resurgence observed when farmers use EB and abamectin to control leaffolders in rice crops in China [26]. Although this is the first report of sublethal doses of avermectins enhancing insect fecundity, our findings are consistent with previous studies which have shown that certain insecticides, herbicides and fungicides stimulate BPH reproduction [3,7,14,[60][61][62][63][64][65]. Intriguingly, we show that EB only induces fecundity in female adults and is specific to BPH, with EB exposure failing to enhance reproduction in two related species, the small brown planthopper, L. striatellus and the white backed planthopper, S. furcifera, or the model insect D. melanogaster.…”

Temperature-dependent oviposition and nymph performance reveal distinct thermal niches of coexisting planthoppers with similar thresholds for development

“…Some regions include multiple published studies. 1 = South Korea [35,36]; 2 = Kafr-el-Sheikh, Egypt [37]; 3 = Hangzhou, China [33,[38][39][40]; 4 = Niigata, Japan [41]; 5 = Guangzhou, China [42]; 6 = Laguna, Philippines [43,44]; 7 = Kagawa, Japan; 8 = Jiangsu, China; 9 = Jiangxi, China; 10 = central Japan [34]; 11 = Hiroshima, Japan; 12 = Guangxi, China [45]; 13 = Godavari, India [46,47]; 14 = Shanghai, China; 15 = Yunnan, China; 16 = Pulau Pinang, Malaysia [10,11]; 17 = Odisha, India [48]; 18 = New Delhi and Haryana, India [19,49]; 19 = Tamil Nadu, India [50]; 20 = Khin Kaen, Thailand [51]; 21 = Rajendranagar, India [52,53]; 22 = Punjab, India [47,54]; 23 = Varanasi, India [55]. Sites are listed in chronological order of published studies; 'b' indicates studies with BPH, 'w' indicates studies with WBPH.…”

Response of wheat aphid to insecticides is influenced by the interaction between temperature amplitudes and insecticide characteristics

“…For example, these interactions have been shown to increase the mortality of subsequent life stages ( Janssens et al, 2018 ), decrease anti-predation behavior ( Tran et al, 2019 ), and decrease longevity and fecundity ( Zuo et al, 2015 ). However, some studies also found that the interaction between temperature and insecticides may increase adult reproduction ( Cheng et al, 2014 ), alleviate oxidative damage ( Janssens et al, 2018 ), and improve the viral diffusion of disease-carrying insects ( Muturi and Alto, 2011 ). The delayed effect of this interaction effect can even be transmitted across generations, impacting the survival ( Tran et al, 2018 ), development, reproduction ( Zuo et al, 2015 ), and the anti-predation ability of offspring ( Tran et al, 2019 ).…”