Effect of temperature on population growth and life table parameters of Nephus arcuatus (Coleoptera: Coccinellidae)

Abstract

The development, reproduction and life table parameters of the predator Nephus arcuatus Kapur (Coleoptera: Coccinellidae), the most important predator of the spherical mealybug, Nipaecoccus viridis (Newstead) (Homoptera: Pseudococcidae) were studied at five constant temperatures (15, 20, 25, 30 and 35 ± 1°C, 65 ± 5% RH and a photoperiod of 14L : 10D). The duration of total pre-adult stage was found to decrease with increase in temperature from 60.0 days at 20°C to 15.3 days at 35°C. The oviposition period lasted 58.5, 44.7, 53.2 and 24.5 days at 20, 25, 30 and 35°C, respectively, with females laying an average of 164.8, 415.2, 660.4 and 136.6 eggs, respectively, at these four temperatures. Life table data were analyzed using an age-stage, two-sex life table. The intrinsic rate of increase (rm = 0.1540 d-1), finite rate of increase (λ = 1.1666 d-1) and net reproductive rate (R0 = 197.9 offspring) were greatest at 30°C. The shortest mean generation time (T = 30.6 days) was recorded at 35°C. These results indicate that N. arcuatus can successfully survive and reproduce at temperatures of around 30°C and has the potential to be an effective biological control agent of N. viridis and other mealybugs in warm regions.

Keywords

• coleoptera
• coccinellidae
• nephus arcuatus
• homoptera
• pseudococcidae
• nipaecoccus viridis
• temperature
• life table
• biological control