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Comment by zabzonk | Hacker News Reader

i worked in geneva, switzerland for about 6 months, and in the summer literally every streetlight was surrounded by masses of spider webs - they had worked out that this was where small flying creatures were to be found. strangely, i've never seen this anywhere else, at least not in such profusion.

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This is extremely common worldwide. I've observed it in rural Nova Scotia, the Netherlands, and the Peruvian rainforest. I'm sure it happens elsewhere, but those are the places I have made note of it.

I think the spiders have not so much figured it out as there is a selection bias. Spiders randomly make their nests. The spiders that randomly make a nest near a light source end up with a larger supply of food and grow large. In my current garden, the spiders that end up near a particular fern always grow the largest. My brother used to feed spiders that made their webs in a particular corner of a cabin as a reward for the entertainment they provided when they were building their webs. I have also walked into countless webs from large spiders in the forest over my life.

Everything points to just randomized locations but being near lights generally being good for the lucky spiders that end up there. You will often see spider fights in such locations after a larger moth or other insect breaks the web of one spider and drops it into another spiders web.

> I've observed it in rural Nova Scotia, the Netherlands, and the Peruvian rainforest

You found streetlights in the Peruvian rainforest?

Iquitos? there are a few cities out there.

The lodge I was staying at had lighting, fed from a generator. Electricity in remote areas is ubiquitous in the 21st century.

I was in Borneo last month and saw round lamps in a rainforest covered in swarms of ants at night, all standing equidistant and with their jaws wide open and raised. I picked up a leaf and poked one in the mouth and it immediately clamped shut and other nearby ants rushed over to assist the ant in pulling in the leaf.

It seems like the ants stand on the lamps and wait to catch other insects that fly by then strike in unison. It was an incredible strategy.

In Australia, the windows of my home which have light shining through them every evening, are surrounded by insect eating lizards and spiders. Definitely a thing everywhere in the world. The number of actual insects varies (from none to plague proportions) depending on the weather, but the predators which have longer lives are always there, waiting.

Which is great, because I'd rather have spiders guarding my windows than insects leaking inside.

I once let a small moth-like flying insect live free in my house and later discovered the damned thing had laid eggs in every package of dried plant food in my cupboard, including a few glass jars I thought were airtight, and were crawling with maggots.

As I tossed most of my stored food, I swore to never let another insect in the house again. Praise spiders.

In Costa Rica I would find toads culstered at the bottom of street lamps, waiting to eat insects that would come crashing down.

ooh, that sounds nice - i like toads. on my street in london uk i would often find one on the pavement in breeding season, trying to get across the main road on its way to the local big park, which had a pond. i would grab them and carry them across, so they didn't get runover.

HA! Indeed!

I have small frogs that climb on the windows in the summer to feast on the bugs attracted to the inside lights. It is wonderous and hilarious to see

Growing up I had a cat--she was semi-feral (when we took her in to be spayed the doc found it had already been done, this was before trap-and-release) and had discovered that my father watched TV in the evenings and this made the window good hunting grounds for larger insects. In time I was able to get her trust and turn her into a pet although she was always far more self-reliant than a typical pet. (The idea of going to a human for help didn't seem to be within her thoughts. Empty food dish, she would try to slip into the closet where the bag of food was stored. Trapped in the closet she would simply wait for someone to open it.)

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