关键词: 六斑异瓢虫, 核桃扁叶甲, 形态特征, 生物学特性, 捕食能力

Abstract: 【Aim】 To explore the biological characteristics of Aiolocaria hexaspilota fed on Gastrolina depressa larvae, so as to provide a theoretical basis for the control of G. depressa using A. hexaspilota. 【Methods】 The life history, morphological characteristics, life habits, duration and survival rates of different developmental stages of A. hexaspilota were observed and recorded in the field and laboratory, and the predatory capacities of the 2nd-4th instar larvae and adults of A. hexaspilota on the 2nd instar larvae of G. depressa at different densities were assayed. The Holling type Ⅱ model was used to fit the functional response and searching efficiency of A. hexaspilota on the 2nd instar larvae of G. depressa. 【Results】 One generation of A. hexaspilota occurred in a year in Tai′an City, Shandong Province, East China. It overwintered as adults. The peak period of female adult oviposition was during late April-middle May, that of incubation was during early May-early June, that of pupation was during late May-late June, and that of adult eclosion was during early June-middle July. Under the condition of (25±0.5) ℃, RH 80%±3% and photoperiod of 14L∶10D, the egg, 1st-4th instar larval and pupal duration of A. hexaspilota was (3.84±0.13), (2.24±0.25), (1.90±0.21), (2.85±0.46), (4.42±0.42) and (5.68±0.30) d, respectively, the egg, 1st-4th instar larval and pupal survival rates were 93.18%, 93.33%, 96.43%, 96.67%, 94.00% and 96.00%, respectively, the average fecundity in its whole life was 800 eggs laid per female and the oviposition period was 40-60 d. The predation of the 2nd-4th instar larvae and adults of A. hexaspilota on the 2nd instar larvae of G. depressa followed a Holling type Ⅱ functional response. The 4th instar larvae of A. hexaspilota preying on the 2nd instar larvae of G. depressa had the strongest predation capacity, with the a′/T_h value of 78.67, the largest daily maximal theoretical predation amount, with the 1/T_h value of 53.76 individuals, and the shortest handling time (0.0186 d). The 2nd instar larvae of A. hexaspilota preying on the 2nd instar larvae of G. depressa had the lowest predation capacity, with the a′/T_h value of 31.20. The predation amount of A. hexaspilota on the 2nd instar larvae of G. depressa was positively correlated with the prey density, while its searching efficiency was negatively correlated with the prey density. χ2 test showed that the theoretically expected χ2 values fit the observed values. 【Conclusion】 These results indicate that A. hexaspilota has a good control potential on G. depressa larvae. This study provides a theoretical basis for more efficient utilization of A. hexaspilota resources and evaluating the potential of A. hexaspilota as a biological control for G. depressa.

Key words:  Aiolocaria hexaspilota, Gastrolina depressa; morphological characteristics, biological characteristics, predatory capacity