What did spiders eat, for the most part, before insects evolved?
The earliest known fossil arachnid is dated to around 420 million years ago. The earliest known fossil “spider” dates to around 386 million years ago. Keep in mind, however, that neither of these examples would likely be extremely similar to what we call a “spider” today. The oldest known insect fossil also dates to similar periods as mentioned about, 396-407 million years ago. Based on this information, it is possible that insects did in fact arrive on the scene before spiders did. However, it is also possible that the early spiders would’ve eaten other arachnids. Most spiders are predators and eat insects, but there is one species that is vegetarian. There are also some spiders that are capable of taking down birds and lizards.
