Anyone have any cogent thoughts on how spiders ever 'learned' to spin webs?

Question

This has always puzzled me a bit. I just can't see how such a complex behavior could have evolved. Please don't think that I doubt evolution, I'm sure there's a logical answer.

Answer 1

I have wondered about that too. It is such an amazing feat of construction. The bottom line is though that web spinning is encoded in the spider's DNA, and anything encoded in DNA will be subject to evolutionary forces.

If silk was unique to orb-spinning spiders then it would be difficult to explain how it evolved, but I think the clue to its origin is the fact that many other arthropods use silk to protect themselves or their eggs. Spiders make silk egg-nests of course, and baby spiders use silk for flying. Perhaps an ancester of the spider happened to make silk for some other purpose that happened to be sticky enough to catch prey. That would give it an advantage because its silk would sometimes accidentally catch a passing insect. It is a small step from there to deliberately laying silk threads to catch prey, and then the design would be gradually refined through evolutionary trial and error to arrive at the best shape.

Answer 2

It all goes back to Arachne and her vain little boast to Athena...

Answer 3

Yes I always think the same thing too but about how birds make nests rather than spiders- somehow they have progressed from squatting down and having an egg pushed out of their vent to collecting materials and constructing a variety of amazing nests.

I think the answer is that these things evolved over millions of years so there was time for the progression and development of the most minute changes which add up to what we see today.