I did a trek through the guatemaltecan jungle for 5 days to the biggest mayan pyramid in the world: El Dante (article is coming soon!) One of our group members showed us an incredible easy trick, how to detect spiders at night:

You have wear a headlamp and turn the angle of the light as low as possible. The eyes of the spiders will reflect the light and you’ll see a pair of diamonds for each spider. If you go closer, you’ll see them in total. It’s crazy how many spiders come out at night and with a normal torch or a straight set headlamp you won’t see any spiders. If you only have got a normal torch, hold it in an low angle on your head – it will work as well.