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Chinese Journal of Biological Control ›› 2024, Vol. 40 ›› Issue (5): 977-986.DOI: 10.16409/j.cnki.2095-039x.2023.11.020

• RESEARCH REPORTS • Previous Articles    

Effect of the Shield-shaped Structure of Cacopsylla chinensis Nymph on Predation Efficiency of Harmonia axyridis

XUE Fu1, JI Xinru1, GAO Xin1, ZHAO Longlong2, YANG Jinyv1, JI Jiayue2, MA Ruiyan1   

  1. 1. College of Plant Protection, Shanxi Agricultural University, Jinzhong 030801, China;
    2. Pomology Institute, Shanxi Agricultural University, Jinzhong 030815, China
  • Received:2023-08-01 Published:2024-10-11

Abstract: The morphological structure of prey may affect the predation efficiency of natural enemies. The aim of this study was to reveal the influence of the shield-shaped structure of Cacopsylla chinensis an important pest in pear orchard, on predation of the natural enemy Harmonia axyridis. In this study, we carried out two different mixed prey conditions, C. chinensis with Schizaphis piricola (CS) selection treatment and C. chinensis with Aphis citricola (CA) selection treatment. And the predation differences of H. axyridis on different types of preys were explored, such as C. chinensis nymphs (shield-shaped), S. piricola and A. citricola (ellipsoid-shaped). Furthermore, by setting different postures (dorsal facing upwards, abdomen facing upwards, and free movement) of C. chinensis nymphs to change protection effect of their shield-shaped structure, the predation differences of H. axyridis on the three postures of nymphs under different selection treatments were analyzed. The results showed that the 4th instar larvae of H. axyridis preyed on 37.00 C. chinensis and 42.20 S. piricola nymphs in CS treatment, and they preyed on 21.40 C. chinensis and 42.80 A. citricola nymphs in CA treatment. The female adults of H. axyridis preyed on 10.25 C. chinensis and 55.00 S. piricola nymphs in CS treatment, and they preyed on 21.80 C. chinensis and 48.20 A. citricola nymphs in CA treatment. The H. axyridis showed obvious predation preference on aphids. Under non-selective conditions, the predation number of the 2nd to 4th instar larva and female adult of H. axyridis on C. chinensis nymphs with abdomen facing upwards were 9.40, 27.40, 66.75 and 40.00, respectively, and the predation number on C. chinensis nymphs with dorsal facing upwards were 7.60, 15.60, 46.00 and 25.60, respectively. The predation number on H. axyridis of all ages on C. chinensis nymphs with abdomen facing upwards were larger than that on C. chinensis nymphs with dorsal facing upwards. Under selective conditions, the predation preferences of H. axyridis on different postures of nymphs were: C. chinensis nymphs with abdomen facing upwards>C. chinensis nymphs with free movement>C. chinensis nymphs with dorsal facing upwards. The average feeding time and instantaneous feeding duration of 4th instar larvae of H. axyridis on C. chinensis nymphs with dorsal facing upwards were both significantly longer than that of C.chinensis nymphs with abdomen facing upwards. The average feeding time of H. axyridis on C. chinensis nymphs with dorsal facing upwards and abdomen facing upwards were 31.71 min and 21.64 min, respectively. The instantaneous feeding duration of H. axyridis on C. chinensis nymphs with dorsal facing upwards and abdomen facing upwards were 37.38 min and 23.13 min, respectively. The results showed that the shield-shaped structure with dorsal facing upwards of C. chinensis nymphs increased the predation difficulty and decreased the predation efficiency of H. axyridis.

Key words: Harmonia axyridis, Cacopsylla chinensis, insect body structure, predatory preference, predatory efficiency

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