Variations in the Life-History Parameters among Populations of Amblyseius womersleyi Schicha with Different Diapause Characteristics (Acari: Phytoseiidae)

Abstract

Several life-history parameters were compared among 3 populations of the phytoseiid mite, Amblyseius womersleyi Schicha, with different capacities for diapause. The parameters were monitored at 18, 20 and 25°C: 16L8D, at which diapause was not induced. Large variations were demonstrated among populations in the temperature effect on total oviposition and age-specific oviposition pattern. In the Aomori and Kyoto populations, which had high and intermediate diapause capacity, respectively, temperature affected total oviposition, and females laid significantly fewer eggs at 18 and 20°C than at 25°C in the Aomori population, and fewer at 18°C than at 20 and 25°C in the Kyoto population. On the other hand, in the Naha population which had a very weak diapause capacity, temperature did not affect the total oviposition. These results showed that the lower the capacity for diapause, the wider is the temperature range at which full reproduction is achieved.