Effect of temperature on development time and life table parameters of Nephus hiekei Fursch, the important predator of Phenacoccus solenopsis Tinsley

The cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) has become a serious threat to agricultural and ornamental plants in Southwest Iran. Pest-control studies have found Nephus hiekei Fursch (Coleoptera: Coccinellidae), in large numbers on Phenacoccus solenopsis Tinsley, as a potential predator. However, there has been no investigation on this predator. In this research, the biology and age-stage, two-sex life table parameters of N. hiekei feeding on Ph. solenopsis were investigated at three constant temperatures (27, 32 and 37 +/- 1 degrees C, 65 +/- 5% RH and a photoperiod of 16:8 (L:D) h. The duration of total pre-adult stage was found to decrease raising temperature from 26.98 +/- 0.36 days at 27 degrees C to 14.24 +/- 0.27 days at 37 degrees C. The oviposition period lasted 63.95 +/- 3.14, 66.42 +/- 3.34 and 25.20 +/- 1.59 days at 27, 32, and 37 degrees C, respectively. Females laid an average of 365.68 +/- 22.36, 543.79 +/- 27.27 and 106.25 +/- 6.38 eggs, at these three temperatures, respectively. The intrinsic rate of increase (r(m) = 0.1333 +/- 0.0050 d(-1)), finite rate of increase (lambda = 1.1423 +/- 0.0057 d(-1)) and net reproductive rate (R-0 = 188.89 +/- 28.34 offspring) as well as gross reproductive rate (GRR = 308.31 +/- 39.54 offspring) were greatest at 32 degrees C. The shortest mean generation time (T = 26.74 +/- 0.65 days) was recorded at 37 degrees C and the longest at 27 degrees C (T = 56.48 +/- 1.0 days). These results indicate that N. hiekei can successfully survive and reproduce at temperatures of around 32 degrees C, and has good potential to be an effective biological control agent of Ph. solenopsis.

Automated summary

The study found that Nephus hiekei can thrive and reproduce most effectively at around 32 degrees Celsius, making it a potential efficient biological control agent for Phenacoccus solenopsis.