Abstract:

【Objective】 The characteristics of intraspecific predation between Stratiolaelaps scimitus and Hyposipis chianensis were investigated to provide knowledge of combined release of the two predatory mites. 【Method】 The intraspecific predation of S. scimitus and H. chianensis at different stages was tested with or without natural prey, Tyrophagus putrescentiae. The development of nymphs and fecundity of adult females of both predators was also studied. 【Result】 In the presence of natural prey, the intraspecific predation was rare at all stages of both predators. While in the absence of natural prey, the intraspecific predation occurred frequently. The predation level was correlated with the stages of both predators and prey. Nymphs of H. chianensis never preyed on larvae of S. scimitus. Preying on eggs and larvae of H. chianensis, 80% and 100% nymphs of S. scimitus could develop into adults and the developmental periods of nymphal mites were 7.88 d and 7.30 d, respectively. Fed on eggs of S. scimitus, only 30% of nymphs of H. chianensis could develop into adults. Adult females of both predators preying on each other laid significantly fewer eggs than those preying on T. putrescentiae, which showed the population of both predators couldn’t increase normally. 【Conclusion】 S. scimitus and H. chianensis were not suitable for each other as a prey, and they would avoid to prey on each other when suitable preys were available. Therefore, the two predator mites could be combinable released at the high population density of pests.

Key words: Stratiolaelaps scimitus, Hyposipis chianensis, interspecific predation, development, fecundity