Impact of variable temperature combinations on the stage-specific development, survival and life table parameters of Nilaparvata lugens (Stål) (Hemiptera: Delphacidae)

Abstract

Abstract Temperature is an only critical factor which influences insect population dynamics, development and reproduction. Nilaparvata lugens (Stål) is one of the major insect pests of paddy crop in East and Southeast Asia, which significantly reduces the quality and quantity of yield. The effect of five set of variable temperature combinations of 23:9, 27:12, 33:19, 36:23 and 39:27°C at 75 ± 5 per cent humidity and 14 h photoperiod under laboratory conditions were studied on the stage-specific development, survival and life table parameters of N. lugens. The optimum temperature range lies between 27:12°C and 33:19°C as fecundity (102 ± 8.50–112 ± 3.75), per cent egg hatchability (86.86 ± 1.21–87.14 ± 1.99) and per cent viability of fifth nymphal instar was maximum at these combinations. Similarly, the net reproductive rate (R0) (163.49) and intrinsic rate of increase (rm) (0.1993 females female− 1 day− 1) were maximum at 33:19°C. Generation time (T) decreases significantly with increase in temperature. The finite rate of increase (λ) varied from 1.1522 to 1.1300 females female-1 day-1 with multiplication rate (erm)7 of 2.3821 to 4.2501, respectively, at temperature combinations of 23:9 to 39:27°C. The relatively high values of life table parameters at 33:19°C followed by 27:12°C temperature combinations suggests that N. lugens thrive well at these temperatures. The present studies can be helpful in understanding the adoption of N. lugens to higher range of temperature combinations under changing climatic conditions. The implications of this study also aids in predicting the population dynamics of N. lugens under field conditions and devising eco-friendly management strategies.