Effects Of Landscape Diversity On Population Dynamics Of Plutella Xylostella And Cotesia Plutellae

Several studies have shown that agricultural landscape diversity affects the abundance and dynamics of pest and natural enemy system. In this study, we analyzed the effects of landscape diversity on Plutella xylostella (diamondback moth (DBM)) and Cotesia plutellae populations taking into consideration their population characteristics. We also measured the key factors that influenced population density and parasitism rate. Results showed that:1. Landscape diversity did not significantly influence the migration time of DBM, but influenced the migration time of Cotesia plutellae in complex landscape. Landscape diversity did not influence the migration numbers of DBM and Cotesia plutellae, and seasonality only influence the migration number of Cotesia plutellae in moderate complex landscape.2. The Population growth rate of DBM was affected by seasonality and landscape diversity. Neither the landscape diversity nor seasonality significantly affected the population growth rate of Cotesia plutellae.3. The population trend of DBM and Cotesia plutellae differed between sampling date but not among agriculture landscapes. Human disturbance may affect the differences of DBM abundance in different seasons. Both human disturbance and variation in wasp species dominance might have influenced Cotesia plutellae abundance.4. Landscape diversity, seasonality and edge effect were the key factors that influence the density of DBM. Landscape diversity was the key landscape factor, and seasonality was the key non-landscape factor. The factors that influence Cotesia plutellae were landscape diversity, seasonality, edge effect and DBM density. Landscape diversity and DBM density were the key factors that influenced Cotesia plutellae density Parasitism rate greatly varied among seasons.