ABSTRACT An augmentative biological control strategy against Ceratitis capitata (= medfly) in fruit-producing irrigated-valleys of San Juan, central-western Argentina, has been recently implemented by the San Juan Fruit Fly Control and Eradication Program. The Asian-native parasitoid Diachasmimorpha longicaudata is currently reared at the San Juan Medfly and Parasitoids Mass Rearing Facility for this purpose. In this regard, the objective of this study was to evaluate adult emergence and offspring sex ratio to improve parasitoid production. Three medfly strains at different host larvae densities and exposure times to female parasitoids were assessed. Prevalence of superparasitism was also considered. Three parasitoid population lines were used in the trials: one reared on medfly larvae of the Vienna-8 temperature-sensitive lethal (tsl) genetic sexing strain without inversion, and the other two on larvae of biparental medfly strains native to San Juan (central-western Argentina) and Tucumán (northwestern Argentina). Gamma-irradiated 6 d-old larvae (early third-instars) of each medfly strain were exposed to parasitoids for 30, 60, 90, and 120 min at 3:1, 6:1, and 9:1 host/parasitoid ratios. The Vienna-8 C. capitata strain was as efficient in producing parasitoids as both biparental native strains. Medfly larvae exposed to 10 female parasitoids for a relatively long time (1.30 hrs) at a high ratio (6–9:1) of host to parasitoid were enough to achieve the highest mean adult emergence (50–60%) and a female-biased offspring sex ratio. Superparasitism positively influenced female parasitoid production. These findings may be used to develop a more cost-effective mass rearing method for D. longicaudata.

中文翻译：

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三种地中海果蝇品系辐照幼虫的暴露时间和比例对长尾螟（膜翅目：茧蜂科）大规模饲养后代产量的影响

摘要 最近，圣胡安果蝇控制和根除计划在阿根廷中西部圣胡安的水果生产灌溉谷实施了一种针对头蠹虫（=地中海果蝇）的增强生物控制策略。为此，亚洲本土寄生蜂 Diachasmimorpha longicaudata 目前在圣胡安地中海果蝇和寄生蜂大规模饲养设施饲养。在这方面，本研究的目的是评估成虫羽化和后代性别比以提高寄生蜂产量。评估了不同寄主幼虫密度和雌性寄生蜂暴露时间的三种地中海果蝇品系。还考虑了超寄生的流行。试验中使用了三种寄生蜂群系：一个饲养在无倒位的 Vienna-8 温度敏感致死 (tsl) 遗传性别分性别株的地中海果蝇幼虫上，另外两个饲养在原产于圣胡安（阿根廷中西部）和 Tucumán（阿根廷西北部）的双亲地中海果蝇株的幼虫上。将每个地中海果蝇菌株的 6 d 龄幼虫（早期三龄）以 3:1、6:1 和 9:1 寄主/寄生物比暴露于寄生物 30、60、90 和 120 分钟。Vienna-8 C. capata 菌株在生产寄生蜂方面与双亲原生菌株一样有效。地中海果蝇幼虫在相对较长的时间（1.30 小时）以宿主与寄生物的高比例（6-9:1）暴露于 10 只雌性寄生物，足以达到最高的平均成虫出现（50-60%）和雌性-有偏差的后代性别比。超寄生对雌性寄生蜂产生积极影响。