Temporal variation in reproductive investment, e.g. maternal egg provisioning, has a substantial effect on offspring fitness therefore has received great attention by evolutionary biologists. Maternal allocation into egg size and egg content directly influences performance of offspring in many taxa, but spiders have rarely been investigated in this regard. In this study, we investigate the temporal changes in maternal reproductive investment and offspring performance in an orb-web, Argiope radon. A group of male and female spiders were mated randomly in the laboratory. Female spiders were kept under standard condition until they laid egg sacs. For each egg sac, egg sac mass, egg size and egg protein content were measured across all egg sacs. Once the spiderlings emerged, emerging time and toleration to starvation of the spiderlings were recorded. Egg sacs laid early in life were heavier, have larger eggs and offspring emerge sooner than the egg sacs laid by the old females. The spiderlings from the early egg sacs were more likely to emerge, however, these offspring had less toleration to starvation than the egg sacs laid by old females. There was no significant correlation between egg size and egg protein content with offspring performance. The results showed how the female spiders strategically allocate resources to egg sacs and its consequences on the offspring emerging time and toleration to starvation. This study suggests an adaptive maternal reproductive investment strategy which allows the female spiders to gain maximum fitness in each reproductive bout.

中文翻译：

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蜘蛛网蛛（Argiope radon）中特定年龄段的生殖投资和后代表现

生殖投资的时间变化，例如母体卵的供应，对后代的适应性有很大影响，因此受到了进化生物学家的极大关注。产妇对卵大小和卵含量的分配直接影响许多类群的后代性能，但是很少有人在这方面研究蜘蛛。在这项研究中，我们调查了球网Argiope radon中母体生殖投资和后代表现的时间变化. A group of male and female spiders were mated randomly in the laboratory. Female spiders were kept under standard condition until they laid egg sacs. For each egg sac, egg sac mass, egg size and egg protein content were measured across all egg sacs. Once the spiderlings emerged, emerging time and toleration to starvation of the spiderlings were recorded. Egg sacs laid early in life were heavier, have larger eggs and offspring emerge sooner than the egg sacs laid by the old females. The spiderlings from the early egg sacs were more likely to emerge, however, these offspring had less toleration to starvation than the egg sacs laid by old females. There was no significant correlation between egg size and egg protein content with offspring performance. The results showed how the female spiders strategically allocate resources to egg sacs and its consequences on the offspring emerging time and toleration to starvation. This study suggests an adaptive maternal reproductive investment strategy which allows the female spiders to gain maximum fitness in each reproductive bout.