The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a major pest of wheat grown on the Northern Great Plains and Canadian Prairies of North America, causing economic losses of as much as $350 million annually. Two species that parasitize wheat stem sawfly larvae in wheat stems are Bracon cephi (Gahan) and B. lissogaster Muesebeck (Hymenoptera: Braconidae). Carbohydrate-rich diets increase adult parasitoid longevity and reproductive parameters, enhancing their success as natural enemies. In previous studies, these species had increased longevity, egg load, and volume when fed sucrose solutions, encouraging further research on their nutritional needs. Therefore, we conducted experiments with artificial diets using adult females fed sucrose, glucose, and fructose solutions. Females were also fed these sugars in combination with a mixture of amino acids. We assessed individuals daily for longevity. Both species benefited from diets containing carbohydrates, with an increase in longevity from an average of 9 to 51 days for B. cephi, and from 6 to 34 days for B. lissogaster. Additional experiments assessed egg load and volume after 2, 5, and 10 days of cumulative feeding in B. cephi. These females produced 1.4-fold more eggs when fed amino acids, 2.5-fold more with sugar, and 2.7-fold more when fed sugar with amino acids. They had a 1.3-fold increase in egg volume when fed amino acids, 1.9-fold with sugar, and 2.1-fold when fed sugar with amino acids. Our study reveals the nutritional requirements of these braconid parasitoids and the benefits of nutritional sources when implementing conservation biological control strategies.

中文翻译：

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膳食糖和氨基酸可延长 Bracon cephi 和 B. lissogaster 的寿命并提高繁殖参数，这两种寄生蜂专门捕食小麦茎叶蜂

小麦茎叶蜂Cephus cinctus Norton（膜翅目：叶蜂科）是生长在北美大平原北部和加拿大大草原上的小麦的主要害虫，每年造成的经济损失高达 3.5 亿美元。在小麦茎中寄生小麦茎叶蜂幼虫的两个物种是Bracon cephi (Gahan) 和B. lissogasterMuesebeck（膜翅目：茧蜂科）。富含碳水化合物的饮食可延长成虫寄生蜂的寿命和生殖参数，从而提高它们作为天敌的成功率。在之前的研究中，这些物种在喂食蔗糖溶液后寿命延长、产卵量和体积增加，这鼓励了对其营养需求的进一步研究。因此，我们使用喂食蔗糖、葡萄糖和果糖溶液的成年雌性进行了人工饮食实验。雌性也被喂食这些糖和氨基酸混合物。我们每天评估个人的寿命。这两个物种都受益于含有碳水化合物的饮食，B. cephi 的平均寿命从 9 天增加到 51 天，B. lissogaster的平均寿命从 6 天增加到 34 天. 额外的实验评估了在B. cephi中累积喂养 2、5 和 10 天后的卵负荷和体积。这些雌性在喂食氨基酸时产卵多 1.4 倍，喂食糖时产卵多 2.5 倍，喂食糖和氨基酸时产卵多 2.7 倍。当喂食氨基酸时，它们的卵体积增加了 1.3 倍，喂食糖时增加了 1.9 倍，喂食糖和氨基酸时增加了 2.1 倍。我们的研究揭示了这些茧形寄生蜂的营养需求以及实施保护性生物控制策略时营养来源的益处。