The Fitness of Metaseiulus occidentalis (Acari: Phytoseiidae) Adult Females after Different Intervals of Storage at Low Temperatures

Yanar, Durdane; Hoy, Marjorie A.

The Fitness of Metaseiulus occidentalis (Acari: Phytoseiidae) Adult Females after Different Intervals of Storage at Low Temperatures

2015

Yanar, Durdane | Hoy, Marjorie A.

This study was carried out to determine the effects of temperature, relative humidity (RH), and an additional food source (honey) on the survival of Metaseiulus occidentalis (Nesbitt) (Acari: Phytoseiidae) females under cold-storage conditions. Survival was evaluated after 2, 4, and 8 wk at 7 or 10 °C under 75 or 95% RH. At the end of each cold-storage interval, surviving females were transferred to bean leaf discs with Tetranychus urticae Koch (Prostigmata: Tetranychidae) as prey, and their longevity, total number of eggs, and number of eggs each female produced per day were recorded. The highest survival rate (78.3%) was observed after 2 wk at 10 °C and 95% RH without honey in the tube. Survival was next highest (75%) after 2 wk at 7 °C and 95% RH without honey in tube. Survival was 76.7% at 7 °C with 95% RH without honey after 4 wk. Survival was low after 8 wk at both 7 or 10 °C, with 0 and 13.3% survival, respectively, at 95% RH. Adult longevity, the total number of eggs deposited, and the average number of eggs per female per day were not significantly different between females held for 2 or 4 wk at 7 or 10 °C at 95% RH with or without honey. Based on these results, M. occidentalis can be cold stored at 7 and 10 °C at 95% RH for up to 4 wk, but adding honey provided no benefit to the females.

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