Wilder Shawn M, Schneider Jutta M
School of Biological Sciences and Charles Perkins Centre, University of Sydney, Sydney, Australia; Department of Integrative Biology, Oklahoma State University, OK, USA.
Department of Biology, Zoological Institute and Museum, University of Hamburg, Germany.
J Insect Physiol. 2017 Jul;100:128-132. doi: 10.1016/j.jinsphys.2017.06.007. Epub 2017 Jun 11.
Sexual cannibalism has long been hypothesized to be a foraging decision in which females consume males for the nutrients in their bodies. While few studies have documented fecundity benefits of sexual cannibalism, several recent studies have documented benefits of cannibalism to egg hatching success or offspring survival. We tested if small supplements of dietary essential nutrients fed to female spiders, Argiope bruennichi, would result in increases in offspring survival similar to those seen following sexual cannibalism. All female spiders were prevented from cannibalizing their mates and subsequently fed either: a dead male spider, or a similarly-sized dead fly with one of four nutrient supplements (water control, dietary essential fatty acids, dietary essential amino acids, or nonessential amino and fatty acids). Females that consumed a small supplement of dietary essential amino acids produced offspring that survived simulated overwintering conditions significantly longer than offspring of other treatments. While a previous study found a significant effect of cannibalism on offspring survival using field-collected males as prey, the current study, which used lab-reared males as prey, found no effect of sexual cannibalism on offspring survival. Hence, our results suggest that dietary essential amino acids, which may be sequestered by males from their diet, could be valuable supplements that increase the success of the offspring of cannibalistic females. Further work is needed to determine the source and identity of these dietary essential amino acids and if other essential nutrients (e.g., trace elements, vitamins, etc.) may also be limiting in female diets and affect offspring success.
长期以来，人们一直假设性食同类现象是一种觅食决策，即雌性为获取雄性体内的营养而将其吃掉。虽然很少有研究记录性食同类现象对繁殖力的益处，但最近有几项研究记录了同类相食对卵孵化成功率或后代存活率的益处。我们测试了给雌性横纹金蛛喂食少量膳食必需营养素是否会导致后代存活率提高，类似于性食同类后所观察到的情况。所有雌性蜘蛛都被阻止吃掉它们的配偶，随后分别喂食：一只死雄蛛，或一只大小相似的死苍蝇，并添加四种营养补充剂之一（水对照、膳食必需脂肪酸、膳食必需氨基酸，或非必需氨基酸和脂肪酸）。食用少量膳食必需氨基酸的雌性所产生的后代在模拟越冬条件下存活的时间明显长于其他处理组的后代。虽然之前的一项研究发现以野外采集的雄性为猎物时，同类相食对后代存活率有显著影响，但本研究以实验室饲养的雄性为猎物，发现性食同类对后代存活率没有影响。因此，我们的结果表明，膳食必需氨基酸可能由雄性从其食物中获取，可能是有价值的补充剂，可提高食同类雌性后代的存活率。需要进一步的研究来确定这些膳食必需氨基酸的来源和特性，以及其他必需营养素（如微量元素、维生素等）是否也可能限制雌性的饮食并影响后代的存活率。
