Is it ethical to attract moths using ultraviolet light?

I enjoy finding and photographing moths and other insects that I find. I know that I might attract more bugs, and at the same time maybe a larger variety of them too, using UV lights. I’m worried about if UV lighting for moths can end up hurting them. Could the UV lighting disrupt mating patterns or even halt mating for some bugs all together? Would attracting and concentrating lots of bugs into one place will make them easy targets for predators? Will the bugs exhaust too much valuable energy from flying around the UV light, leaving them more vulnerable to predators, hurting themselves by repeatedly flying into walls, or even dying of exhaustion? I’ve read the replies of people who have responded to others with this question. The responses vary widely from some people encouraging the use of UV lights to attract insects for the sake of research, to claiming that the negative side effects are negligible, to going in depth about light pollution and how artificial lighting is directly and indirectly harming countless species.
Maybe I’m doing this all wrong in the first place. Maybe my problem is that I’m asking an internet forum where anyone can state their opinions rather than reading scholarly articles or scientific research on the subject. I’m prone to forming strong opinions on things, and I don’t want to cause potential harm to bugs by believing that UV lights will do them no real harm, but I also don’t want to bring myself down by feeling that everyday objects like streetlamps are harmful and their presence is distasteful.

3 Likes

I know this is a problem in tropical areas of the USA with invasive geckos

1 Like

In my case I don’t live in a tropical area. But there’s still a threat posed by birds and bats, as well as by some other insects and arachnids.

Related topic: Ethics of Attracting Moths to Light

5 Likes

I actually have already read that post.

1 Like

Issues like this are often a matter of scale.

Are you setting up a gigantic UV light panel that is on at all times every night, all night, or are you occasionally shining a UV light onto a small piece of white fabric for an hour or two a few times a month?

The answer as to the impact and ethics of those two scenarios is wildly different.

Discussion of light pollution and the impacts it has are important, but they’re not really relevant to the scenario most iNat users would be applying in setting up their own small scale UV system to monitor the local insects.

20 Likes

My take on this is that such lights should probably be used:

  • sparingly, like don’t turn your property into a black light rave party all night, but just set up a small station
  • with supervision, so don’t just leave it up indefinitely
  • inconsistently, or only barely consistently enough as needed for scientific purposes, so that predators don’t get used to it and creatures attracted to it aren’t stressed out from repeated stimulation
  • not near dusk or dawn, as that might also attract more predators
  • without killing anything (with maybe some exceptions)
  • preferably in such a way that doesn’t contribute to light pollution (e.g. hood your lights)
  • in a place that’s convenient for observation and cleanup
8 Likes

Thats more like what I would do.

1 Like

I was going to give my thoughts, but they have been pretty well covered here and in the older post – not sure what you’re asking that wasn’t already covered in the older post?

3 Likes

Personally I only use the trap once a week and I make sure to turn the light off around 1-2am to allow the moths to disperse and still have some time to do moth stuff. Running it over night and checking it in the morning can reveal some moths that I’d have missed otherwise though. I’ve noticed that even with my weekly schedule a number of spiders have started hanging around near where I trap and I have to make sure to remove them before they get an easy meal. There’s one massive spider that I didn’t notice though and it must have been doing very well on a diet of fat moths delivered to its door.
I’m also currently raising some Oak Eggar caterpillars because the moth left eggs in the pot I stuck it in. Once they’re big enough I’ll release them somewhere suitable.

I’m in Australia and I live in the bush, but not all that far from a few towns. I light trap regularly and sometimes I will do successive nights. However, I may then go weeks without doing another session. I have turned up new species, species that have not been seen in over 100 years, etc. I think this is invaluable information.

However, I do not leave the light on all night, I usually do 3 hours of an evening or the same in the early hours of the morning but I make sure the light is off well before daylight starts. I do get the odd Boobook or Tawny Frogmouth coming in to take a few moths but that’s not every session. But, I did find if I leave it too late of a morning to turn the light off, birds will come in and take a lot of moths. So this is just something I need to make sure doesn’t happen.

By trapping, I mean I hang up a white sheet and use a 250W mercury vapour lamp. The insects come in and I photograph them. I do not collect or kill anything. Then when I am done I gently shake the sheet until everything has left.

I’ve often wondered if to many sessions can or will have an effect but then I drive down towards town and see how many lights are on and I just can’t help but feel that the odd trapping session at home in the bush is nothing compared to the light pollution in human areas.

4 Likes

If you’re looking for scholarly articles about bugs and UV light, here’s a good one, and here’s an article that goes over it (briefly, with less jargon).

1 Like