Effect of Temperature on Demography and Predation Rate of Menochilus sexmaculatus (Coleoptera: Coccinellidae) Reared on Phenacoccus solenopsis (Hemiptera: Pseudococcidae)
Effect of Temperature on Demography and Predation Rate of Menochilus sexmaculatus (Coleoptera: Coccinellidae) Reared on Phenacoccus solenopsis (Hemiptera: Pseudococcidae)
Ayesha Iftikhar1,*, Muhammad Asif Aziz1, Muhammad Naeem1, Munir Ahmad1 and Tariq Mukhtar2
ABSTRACT
Zigzag beetle, Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae) is an important predator of cotton mealy bug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae). Understanding the effect of temperature variations on its demography and predation rate is necessary to predict the population dynamics of this beetle against cotton mealy bug. Age-stage, two sex life tables of zigzag beetle were constructed at three different temperature regimes: 24 ± 0.5 °C and 27 ± 0.5 °C with 60-70% R.H. and ambient condition (32 ± 4 °C; 16-50% R.H.) with 14:10 h (L:D) photoperiod using cotton mealy bug as a host. According to the results, the immature duration and adult longevity were comparatively longer at lower temperature (24 ± 0.5 °C) and shorter at higher temperatures. Among population dynamic parameters, net reproductive rate (R0) was 216.52, 105.99 and 27.07 off-springs per individual, intrinsic rate of increase (r) was 0.1543, 0.1600 and 0.1518 off-springs per female per day at 27 ± 0.5, 24 ± 0.5, and 32 ± 4.0 °C, respectively. Survival rate (sxj) and age-stage specific fecundity (fx7) were greater at 24 ± 0.5 °C. Among immature stages, 4th instar was the most voracious with highest predation rate. Adult females consumed more cotton mealy bug nymphs at 24 ± 0.5 °C. Net predation rate (C0) of the beetle was 5548, 4463.2 and 2016.90 at 24 ± 0.5 °C, 27 ± 0.5 °C and 32 ± 4 °C, respectively. The values of transformational rate (Qp) exhibited that 25.62, 42.11 and 74.50 nymphs of P. solenopsis were required per female beetle to lay one egg at 24 ± 0.5 °C, 27 ± 0.5 °C and 32±4°C, respectively. Finite predation rate (ω) was more (7.64) at 24±0.5°C followed by 27±0.5°C (6.56) and the lowest at 32 ± 4 °C (0.66). Adult beetles proved strong natural enemies of P. solenopsis. Our study provides detailed basic information for successful rearing of M. sexmaculatus in the laboratory and use as a bio-control agent against cotton mealy bug in the field at different temperature conditions.
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October 2018
Vol. 50, Iss. 5, Pages 1601-1998
