Temperature-dependent development and reproduction of rice leaffolder, Marasmia exigua (Lepidoptera: Pyralidae)

Abstract

Marasmia exigua (Butler) (Lepidoptera: Pyralidae) is one of the major rice leaffolders negatively affecting the rice production in the world. The growth and development of M. exigua was studied at seven constant temperatures (10, 15, 20, 25, 27, 30 and 35°C). The results showed that M. exigua eggs failed to hatch at 10°C and the larvae could not complete development at 15 and 35°C. The developmental times of each stage, survival rates of pre-adult, adult longevity, fecundities and oviposition days of M. exigua at 20, 25, 27 and 30°C were investigated using age-stage, two-sex life table. The total pre-adult development time decreased with the increase in temperature decreasing from 61.58 days at 20°C to 28.94 days at 30°C. The highest survival rate was observed at 25°C (73%). Male adult longevities were generally longer than that of females, except at 30°C. The highest mean fecundity, age-stage specific fecundity and age-specific fecundity peak values were all observed at 27°C. The maximum intrinsic rate of increase r and finite rate of increase λ were observed at 27°C, while the maximum net reproduction rate R0 was observed at 25°C. The longest mean generation time occurred at 20°C and the shortest at 27°C. These results provide better understanding on the development, reproduction and dynamic of M. exigua populations, their distribution, and might be utilized to forecast and manage M. exigua outbreaks in China.

Comparative Mitochondrial Analysis of Cnaphalocrocis exigua (Lepidoptera: Crambidae) and Its Close Relative C. medinalis

“…The overwintering C. exigua pupae were collected from rice stubble fields in Qianwei county (Leshan, Sichuan Province, China; E103° 93′, N29° 21′) in March 2016 and reared in an incubator (LAC-250HPY-2, Shanghai Longyue Instruments, Shanghai, China) under constant conditions (26 ± 1°C, 80 ± 5% RH, and a photoperiod of 14:10 (L:D) h) for two generations ( Liao et al 2017 ). The newly emerged adult were preserved in ethanol (100%) and stored at −80°C till the isolation of DNA.…”

“…The rice leaffolder C. medinalis had drawn much attention from researches worldwide for its ability to migrate and re-migrate over long distances ( Gao et al 2008 , Huang et al 2010 , Wang et al 2010 ). To date, only few studies were proceeded on C. exigua , and there was no evidence that support C. exigua can migrate yet ( Feng et al 2017 , Liao et al 2017 ). Though C. exigua is not as widely distributed as C. medinalis in China, but it has dominated paddy fields in many places of Sichuan Basin in southwest China which suggests it may become a principal rice pest ( Pan 1984 , Gao et al 2008 , Yang et al 2015 ).…”

Ambient temperature‐mediated enzymic activities and intestinal microflora in Lymantria dispar larvae

“…Especially for ectotherms, many cell-level physiological processes are sensitive to environmental temperature, such as the enzyme-mediated respiratory reaction (Matzelle et al, 2015;Parsons & Joern, 2014). In other words, inadaptable temperature would negatively impact on entomic development, reproduction, and even survival (Liao et al, 2017).…”

Chromosome‐level genome assembly of an agricultural pest, the rice leaffolder Cnaphalocrocis exigua (Crambidae, Lepidoptera)

“…Rice leaffolder leaffolder Cnaphalocrocis exigua was reared under laboratory conditions as previously described (Liao et al, 2017).…”