Animals have evolved cognitive abilities whose impairment can incur dramatic fitness costs. While malnutrition is known to impact brain development and cognitive functions in vertebrates, little is known in insects, whose small brain appears particularly vulnerable to environmental stressors. Here, we investigated the influence of diet quality on learning and memory in the parasitoid wasp Venturia canescens. Newly emerged adults were exposed for 24h to either honey, sucrose solution 20%, sucrose solution 10%, or no food, before being conditioned in an olfactory associative learning task in which an odor (orange) was associated to a reward (host larvae). Wasps fed honey showed 3.5 times higher learning performances and 1.5 times longer memory retention times than wasps fed sucrose solutions and starved wasps. Poor diets also reduced longevity and fecundity. Our results demonstrate the importance of early adult nutrition for optimal cognitive function in these parasitoid wasps that must quickly develop olfactory memories for choosing high quality hosts for their progeny.

中文翻译：

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成人营养不良会影响寄生蜂的学习和记忆

动物已发展出认知能力，这种能力受损会招致巨大的健身成本。营养不良会影响脊椎动物的大脑发育和认知功能，而昆虫却知之甚少，昆虫的小大脑似乎特别容易受到环境压力的影响。在这里，我们调查了饮食质量对寄生类黄蜂Venturia canescens中学习和记忆的影响。将新生成年人暴露于蜂蜜，20％蔗糖溶液，10％蔗糖溶液或不食用的食物中24小时，然后将其置于嗅觉联想学习任务中，其中气味（橙色）与奖励（宿主幼虫）相关。饲喂蜂蜜的黄蜂的学习性能比饲喂蔗糖溶液和饥饿的黄蜂的学习性能高3.5倍，记忆保持时间长1.5倍。不良的饮食也降低了寿命和生殖能力。我们的研究结果表明，早期成人营养对于这些寄生蜂的最佳认知功能至关重要，这些寄生蜂必须迅速建立嗅觉记忆，以便为其后代选择高质量的宿主。