›› 2002, Vol. 45 ›› Issue (4): 482-486.

• RESEARCH PAPERS • Previous Articles     Next Articles

Bionomics and population dynamics of Microterys sinicus Jiang (Hymenoptera: Encyrtidae)

JIAO Yi1,2, ZHAO Ping1   

  • Online:2002-08-20 Published:2002-08-20

Abstract: The bionomics and population dynamics of Microterys sinicus Jiang, an important natural enemy of the white wax insect, Ericerus pela Chavannes, during the latter's oviposition period, were surveyed from 1995 to 1998 in Yunnan Province. It was found that the adults moved up and down host trees and fed on honeydew as supplementary nutrition. Copulation occurred on host trees. There were 34.39 ova in one female. The pre-oviposition period was 2-3 days. 81.72% of the total eggs laid were laid during the 4th-10th day of oviposition. The egg numbers, percentage of eggs laid and duration of oviposition were closed related to temperature. The highest oviposition numbers and oviposition percentages occurred at 27℃, and the shortest oviposition period at 30℃. Hatchability was above 80% from 21℃ to 27℃. The larvae underwent 5 instars. The 1st-4th instar larva consumed 14.6, 29.8, 69.4 and 126.9 eggs of the white wax insect respectively. The 5th instar larva stopped feeding, excreted and pupated in the host body. Generation time became shorter as the temperature increased with the shortest generation time occurring at 27℃. Excessively high or low temperatures were unfavorable to the development of the wasp. The thermal threshold and thermal sum for larval development were 11.84℃ and 574.32 daydegrees respectively. Supplementary nutrition could prolong adult lifespan, the duration of oviposition and increase female oviposition numbers remarkably. The first and middle tendays of April and the middle and last tendays of May were the peak periods of wasp abundance. The relationship between wasp quantities per ovisac and the percentage of health white wax insect eggs can be simulated with the index equation:Y=96.0829Exp(-0.1872x).

Key words: Microterys sinicus, behavior, generation time, population dynamics