Department of Biology, Washington and Lee University, Lexington, VA, United States of America.
PLoS One. 2020 Dec 9;15(12):e0237286. doi: 10.1371/journal.pone.0237286. eCollection 2020.
Cobweb weaving spiders and their relatives spin multiple task-specific fiber types. The unique material properties of each silk type result from differences in amino acid sequence and structure of their component proteins, primarily spidroins (spider fibrous proteins). Amino acid content and gene expression measurements of spider silks suggest some spiders change expression patterns of individual protein components in response to environmental cues. We quantified mRNA abundance of three spidroin encoding genes involved in prey capture in the common house spider, Parasteatoda tepidariorum (Theridiidae), fed different diets. After 10 days of acclimation to the lab on a diet of mealworms, spiders were split into three groups: (1) individuals were immediately dissected, (2) spiders were fed high-energy crickets, or (3) spiders were fed low-energy flies, for 1 month. All spiders gained mass during the acclimation period and cricket-fed spiders continued to gain mass, while fly-fed spiders either maintained or lost mass. Using quantitative PCR, we found no significant differences in the absolute or relative abundance of dragline gene transcripts, major ampullate spidroin 1 (MaSp1) and major ampullate spidroin 2 (MaSp2), among groups. In contrast, prey-wrapping minor ampullate spidroin (MiSp) gene transcripts were significantly less abundant in fly-fed than lab-acclimated spiders. However, when measured relative to Actin, cricket-fed spiders showed the lowest expression of MiSp. Our results suggest that house spiders are able to maintain silk production, even in the face of a low-quality diet.
蛛网编织蜘蛛及其近亲会纺出多种特定任务的纤维类型。每种丝的独特材料特性是由其组成蛋白（主要是蛛丝蛋白）的氨基酸序列和结构的差异造成的。蜘蛛丝的氨基酸含量和基因表达测量表明，一些蜘蛛会根据环境线索改变单个蛋白成分的表达模式。我们量化了参与捕食的三种蛛丝蛋白编码基因在普通家蜘蛛（Theridiidae 科）中的 mRNA 丰度，这些蜘蛛喂食不同的食物。在实验室中以黄粉虫为食适应 10 天后，将蜘蛛分为三组：（1）立即解剖个体，（2）喂食高能量蟋蟀，或（3）喂食低能量苍蝇，持续 1 个月。所有蜘蛛在适应期都增加了体重，而喂食蟋蟀的蜘蛛继续增加体重，而喂食苍蝇的蜘蛛则保持或减少了体重。通过定量 PCR，我们发现各组间拖丝基因转录物、大囊蛛丝蛋白 1（MaSp1）和大囊蛛丝蛋白 2（MaSp2）的绝对和相对丰度没有显著差异。相比之下，在喂食苍蝇的蜘蛛中，猎物缠绕的小囊蛛丝蛋白（MiSp）基因转录物的丰度明显低于实验室适应的蜘蛛。然而，当与肌动蛋白相比时，喂食蟋蟀的蜘蛛表现出最低的 MiSp 表达。我们的结果表明，家蜘蛛能够维持丝的产生，即使面对低质量的饮食。
