Data from: Phytophagous insect oviposition shifts in response to probability of flower abortion owing to the presence of basal fruits

Phytophagous insects use a wide-range of indicators or associated cues to avoid laying eggs in sites where offspring survival is low. For insects that lay eggs in flowers, these unsuitable sites may be created by the host plant's resource allocation to flowers. In the sequentially flowering host plant, Yucca glauca, late-opening distal flowers are more likely to be aborted in the presence of already-initiated basal fruits because they are strong resource sinks. If flowers are aborted, all eggs of the phytophagous insect, Tegeticula yuccasella, within the flower die. We used the phytophagous insect T. yuccasella that lays eggs in and pollinates host plant Y. glauca flowers to test the hypothesis that phytophagous insect females are less likely to invest eggs in host plant flowers if basal fruits are present because they are more likely to be aborted. We also investigated potential predictors of arrival of T. yuccasella at inflorescences at the onset of flowering. These factors may influence a phytophagous insect's decisions to select oviposition sites. We carried out a behavioral experiment using wild-caught T. yuccasella females on manipulated inflorescences with distal flowers with basal fruits and without fruits. As potential predictors of T. yuccasella arriving at inflorescences we used floral display size and day of onset of flowering. In support of our hypothesis, our experimental results showed that T. yuccasella was significantly less likely to oviposit in distal flowers on inflorescences with basal fruits. We also found that T. yuccasella arrival was higher at inflorescences with larger floral display size and earlier in the flowering season. These findings uncover a novel indicator of unsuitable oviposition sites – presence of basal fruits, that phytophagous insects use to make oviposition decisions. Further, our study contributes to the growing body of evidence that shows that females prefer sites that increase the probability of survival of their offspring.植食性昆虫（phytophagous insects）会借助多样的指示信号或关联线索，规避在子代存活率较低的位点产卵。对于在花部产卵的昆虫而言，这类不适宜产卵的位点往往由宿主植物对花部的资源分配所塑造。在依次开花的宿主植物狭叶丝兰（Yucca glauca）中，若已形成基生果序，后期开放的远端花更易发生败育——因远端花是较强的资源库。若花部败育，栖息于其中的植食性昆虫丝兰蛾（Tegeticula yuccasella）的所有卵均会死亡。本研究以在狭叶丝兰（Yucca glauca）花部产卵并为其传粉的丝兰蛾（Tegeticula yuccasella）为研究对象，旨在验证如下假说：当基生果序存在时，植食性昆虫雌虫更倾向于不在宿主花部投入卵粒，因这类远端花更易发生败育。我们同时探究了始花期时丝兰蛾（Tegeticula yuccasella）抵达花序的潜在预测因子，上述因素均可能影响植食性昆虫的产卵位点选择决策。本研究通过对花序进行操控，设置了带有基生果序的远端花与无果序两种处理组，对野外捕获的丝兰蛾（Tegeticula yuccasella）雌虫开展行为学实验，并以花展示大小与始花日期作为丝兰蛾抵达花序的潜在预测因子。实验结果验证了我们的假说：相较于无果序的花序，丝兰蛾在带有基生果序的花序远端花中的产卵概率显著更低。我们还发现，花展示规模更大、始花期更早的花序，其丝兰蛾的抵达率更高。本研究揭示了植食性昆虫用于产卵位点决策的一类全新不适宜产卵位点指示信号——基生果序的存在，此外，本研究为日益增多的相关证据链补充了新案例，证明雌虫会偏好能提升子代存活概率的产卵位点。