Estimation of population growth for two species of lady beetles (Coleoptera: Coccinellidae) under different temperatures

Abstract

ABSTRACT The ladybird beetles Tenuisvalvae notata (Mulsant), and Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) are important biological control agents of mealybugs (Hemiptera: Pseudococcidae). One of the factors affecting the establishment and success of these predators is temperature, which imposes limits on their development and distribution. In this study, the developmental times and reproduction of these ladybirds at 25°C and 28°C were estimated. We also estimated fertility life-table parameters and the number of generations that could potentially be produced annually in 6 localities of interest. For both species, the developmental period (egg to adult) declined 6–10 days with an increase in temperature from 25°C to 28°C. However, this increase in temperature did not significantly affect female longevity or egg production. The mean generation time (T), and intrinsic rate of increase (r m) were statistically higher at 28°C for T. notata. The r m varied from 0.052 to 0.063 for T. notata and from 0.048 to 0.051 for C. montrouzieri reared at 25°C and 28°C, respectively. We estimated that T. notata and C. montrouzieri can complete 9 and 12 generations annually, respectively, especially in Surubim and Bom Jardim, in Pernambuco, and Cruz das Almas, in Bahia, with the highest estimated number of generations due to temperatures higher. Results confirm the direct influence of temperature on the development and distribution of these ladybird beetle species, which is important to the biological control of mealybugs in infested areas.