Population Regulation Of Apolygus Lucorum (Meyer-Dur)by Host Plant Flowers

Apolygus lucorum (Heteroptera:Miridae) has a wide host plant range, and is the dominant species of pestiferous mirid bugs affecting cotton, many fruit trees and other crops commonly planted in the Chinese Yangtze River and Yellow River Cotton-growing Regions. A. lucorum adults have a strong preference to the flowering plants, and usually seriously damage the plants at the flowering period. This paper studies the preference behavior of A. lucorum to flowering plants and the associated mechanisms of chemical communication, in order to understand the interactions between A. lucorum and host plants. The main results of this study are listed as follows:Field trials in2010and2011showed that adults and nymphs were significantly more abundant on flowering plants (inc. cotton, balsamine and castor-oil plant) than on non-flowering plants. Oviposition choice trials in field cages revealed that female adults preferred to lay eggs on flowering plants. Laboratory performance trials demonstrated that adult longevity and fecundity, and nymphal development rate and survival were significantly higher on flowering plants, compared with non-flowering plants.In contrast, no significant differences were observed for the sex ratio. Lastly, simple linear regression analysis showed that adult and nymph abundances in the field was correlated, nymphal development rate and survival in the laboratory were correlated with adult fecundity, and that adult longevity and fecundity were correlated in the laboratory. In conclusion, since a positive preference-performance correlation was determined for A. lucorum, no evident behavioral trade-offs were found for host plant selection by this polyphagous mirid bug. Olfactometer trials showed that more male and female adults selected flowering plants, comparing with non-flowering plants. By the GC-EAD and GC-MS detection, we identified the active substances of volatile compositions of cotton, balsamine and castor-oil plant. Six to seven active substances were found in the three plant species, mainly including Ethylbenzene、1,3-dimethylbenzene、2-Propenoic acid, butyl ester、Propanoic acid, butyl este、Butanoic acid, butyl ester、(E)-3-Hexenyl acetate、1-ethyl-4-(2-methylpropyl)-(or Linalool). The content of2-Propenoic acid and butyl ester was significantly higher in flowering plants than in non-flowering plants. We inferred that A. lucorum adults select these host plants at flowering stage by using these two volatile as important cues.