I would love to document moth diversity while travelling abroad, by occasionally setting up a light trap at night. So far I did this in my own garden only (but quite successfully so). Anything I should keep in mind? I am especially worried about attracting humans rather than moths, or annoying the former. Maybe a smaller light source is best, something like a torch that can be directed at a sheet and will not radiate in all directions? What is your experience? What about moth trapping in protected areas, is this usually allowed?
I only know that in Spain you need a special permit to set up a light-trap, and it is usually not allowed in National Parks. I have started to walk around town at night and look at lit facades or shop windows, where I usually see moths without having to have a permit.
I’m not sure about permits and such, but I hung up a sheet and used 2 LED UV lights attached to a powerbank this past weekend. It worked great! I only had the sheet out for a few hours and was sure to “evict” everyone when I was done so the sheet wouldn’t become a buffet for the birds in the morning. The LED lights were under $10 on Amazon, though I’m sure you could also pick them up at your local hardware store. They were very lightweight and packable.
You could also use white lights, which might attract less attention. Just make sure they’re pretty bright.
I just bring a white t-shirt and hang it on a coat hanger. Or you can spread a sheet on the ground and put a light on it. My brain does not do well with strings and knots so those are easy alternatives.
There are issues with permits for many countries, especially if one wants to record moths in a protected area (e.g. nature reserves, national parks, country parks). Whichever country you are going to, try contacting active moth-ers there first to get an idea of permit requirements.
As to what lights to use - anything that emits ultraviolet light between 360 nm and 400 nm (so-called UV-a) will do. LEDs certainly work well in areas with low or no background light pollution, but anywhere there is significant background light pollution (in or near cities, for example), an LED gives less “pulling power”