異角釉小蜂 (Hemiptarsenus varicornis) (膜翅目：釉小蜂科) 之貯存與產卵調節能力

Abstract

本文探討異角釉小蜂 (Hemiptarsenus varicornis (Girault)) 貯存之蟲期與條件及雌蜂經貯存後之產卵調節能力。結果得知第一日齡蛹在 8℃ 下經貯存1～2 週後在 25℃ 下之羽化率即下降為 71.2～73.4%，與對照組之 96.0% 呈顯著差異。而第一日齡蛹在 10℃ 下經貯存 1～5 週後在 25℃ 下之羽化率卻高達 91.7～99.0%，與對照組無顯著差異，且彼等初羽化成蜂移入 25℃ 定溫並每日供應寄主非洲菊斑潛蠅 (Liriomyza trifolii (Burgess)) 與純蜂蜜時，其雌、雄蜂壽命與子代雌性比雖不受蜂蛹低溫貯存1～4 週之影響，但其致死寄主總數與子蜂數卻受彼等蜂蛹低溫貯存之影響，較對照組各減少 44.3～54.7% 與 55.9～67.2%。成蜂在 15～30℃ 下僅以純蜂蜜餵食時，以 15℃ 時雌、雄蜂壽命最長，其實測值各為 44.7與 42.3日，且雌、雄蜂各貯存至 38 與 37 日時，其存活率仍高達 80%。同時發現雌蜂在15 或 25℃ 下餵食純蜂蜜待貯存期滿移入 25℃ 定溫且每日供應寄主與純蜂蜜後，僅雌蜂在 15℃ 下貯存 10 日者，其生育力（fertility）與致死寄主能力與對照組無顯著差異；而雌蜂在 15 或 25℃ 下各貯存 20～30 或 10～15 日者，其壽命、致死寄主總數及子代雌性比等雖與對照組無顯著差異，但其子蜂數卻顯著較對照組各減少 39.2～43.6% 與 31.4～33.3%。總之，室內繁殖異角釉小蜂時之貯存條件較嚴，其中以雌蜂在 15℃ 下餵食純蜂蜜貯存 10 日者為最適，其次為雌蜂在15 或 25℃ 下餵食純蜂蜜各貯存 20～30 或 10～15 日，再次為第一日齡蛹在10℃ 下貯存 1～4 週。但田間以生物藥劑方式釋放異角釉小蜂時，其貯存之條件可較繁殖時為寬，其中以雌蜂在 15 或 25℃ 下餵食純蜂蜜各貯存 10～30 或 10～15 日為最適，其次為雌蜂在 15℃ 下餵食純蜂蜜貯存 40 日或第一日齡蛹在 10℃ 下貯存 1～4 週。另雌蜂經貯存後再遇寄主時確具產卵調節能力，其中以 15℃ 下隔離寄主 10 日者之日寄生型式與對照組最為近似，其他各處理組之開始產卵日期、產卵高峰期之發生與持續期雖與對照組略同，但彼等產卵高峰期間之日產卵寄生數卻較照組降低。 In this study, we investigated the suitable life stages and conditions for storage of the wasp, Hemiptarsenus varicornis (Girault). The wasp’s oviposition- regulating capability after storage was also determined. Results showed that there was a significant difference in the percent emergence between 1-day-old pupae stored at 8℃ for 1-2 weeks (% emergence = 71.2-73.4%) and the control (% emergence = 96%). However, the percent emergence did not decrease if the 1-day-old pupae were stored at 10℃ for 1-5 weeks. Emerged from the pupae previously stored at 10℃ for 1-4 weeks, and followed by rearing at 25℃ with honey and host (Liriomyza trifolii (Burgess)), the wasps were not affected by the storage conditions in their adult longevity in both sexes and offspring sex ratio. However, the wasp’s host-killing capability and offspring production decreased by 44.3-54.7% and 55.9-69.2%, respectively, compared to those of the control. Adults were fed only with honey at between 15 and 30℃ for various time periods for the study of storage conditions. It was found that mean adult longevity was the highest under the 15℃ storage conditions with the female and male longevity of 44.7 and 42.3 days, respectively. In addition, the survival rate still reached 80% after the female and male had been stored for 38 and 37 days, respectively. After the end of the storage periods, wasps were kept at 25℃ with both honey and hosts to evaluate their capability of host-killing and offspring production. The results revealed that the host-killing capability and fertility of the wasps were not influenced after the adults had been stored at 15℃ for 10 days. Although adult longevity, host-killing capability, and female progeny proportion were not affected, the total offspring production decreased significantly after adult wasps had been stored at 15℃ for 20-30 days or 25℃ for 10-15 days. Maintaining a high fertility of the wasp is essential to rearing H. varicornis for mass production. For this purpose, suitable conditions to store the colony according to priority are (1) female wasps at 15℃ for 10 days, (2) female wasps at 15℃ for 20-30 days or 25℃ for 10-15 days and (3) 1-day-old pupae at 10℃ for 1-4 weeks. With the field release of H. varicornis as a bioinsecticide, the primary concern is the host-killing capability of the wasp. As such, the storage conditions can be less restrictive as (1) female wasps at 15℃ for 10-30 days or 25℃ for 10-15 days, and (2) female wasps at 15℃ for 40 days or 1-day-old pupae at 10℃ for 1-4 weeks. Female wasp has an ability to self-regulate oviposition in response to different storage conditions. Under the storage conditions at 15℃ for 10 days, female H. varicornis shows a comparable daily oviposition pattern to that of the control. Although the oviposition schedules and the occurrence and persistence of the peak oviposition period were similar to the control under other storage conditions, the number of daily eggs laid by the wasp at its peak oviposition period was lower than that of the control.