"It's kind of obvious in retrospect," Xu said, "but sticky spider webs may be a 'natural' DNA sampling device for DNA from the spider, and from what it's been eating."

徐说，“现在回想起来好像也很显而易见，粘粘的蜘蛛网是收集蜘蛛及其食物dna的“自然”采样设备。”

youdao

"(Air-sampling devices) collect particles from the air onto a transparent, sticky surface, " the website's FAQ page says.

CNN: What's in a pollen count, anyway?