Hi everyone. Yesterday I used a blacklight in my backyard for the first time. It worked decently well; we had a tussock moth and two geometer moths, and some other ones I can’t ID. Anyway, I left the blacklight up all night and took it down just before dawn. When I tried to get the moths off an hour later, they really did not want to fly away. One of the geometer moths crawled up on my finger and I left it on the underside of a leaf. I looked again now, 10 hours later, and it’s still there. Some of the rest are just kinda in my lawn. I’m kinda concerned that I’ve done lasting damage to these moths. Should I not have left the light on all night?
I think you’re supposed to turn it off when you’re done, then gently shake the moths off the sheet, so they can go about their business for the rest of the night and find a hiding/resting spot before morning.
I doubt you did lasting damage, though. If they survive the day without getting eaten by birds, they will probably fly away once it gets dark.
I’m not a moth expert by any means - I’m just reporting what I’ve seen others do.
That is totally normal! A lot of moths will stay at the sheet all night and be very sluggish in the morning. This is particularly true when morning temperatures are cooler, but some moths will remain at the sheet all night even with warm temps. And then once the sun comes up, they are naturally inactive in daytime.
The key is to 1.) get up before first light to check the sheet and 2.) hide the moths in vegetation when you are done photographing them. If you just leave them on the sheet or sitting in the open, birds will eat them. You need to hide them in a bush or dense vegetation if you don’t want that to happen.
Most moth species are active for a very specific portion of the night, and they won’t fly any more after they settle in. So if it was active at say 10:00 PM, chances are it’s done moving for the night by midnight or so. Some species don’t even become active until much later (one of the highlights of this time of year where I live is Psectraglaea carnosa, which doesn’t really start moving until 3-4 AM). Also if the temperature is too cold, moths will sometimes sit in the same place for days at a time waiting for appropriate conditions. Depending on the species, some even lack mouthparts as adults and can’t feed, so they’ll stay still as long as possible to avoid burning calories that they can never recover. In short, there are plenty of reasons why a moth might sit in one place for a long time (days even) without there being anything wrong with it. They spend an inordinate amount of their time sitting still and avoiding movement. The only real harm that attracting them to a blacklight can have is that it leaves them out in the open to be easy pickings for predators like birds in the morning.
Ah okay I see! Thanks everyone. I did know to turn off the light before first light, but I thought I could just leave them there and they’d fly away. Actually I was kinda hoping that they would stay so I could see them in the daylight and then push them away. I didn’t realize that when moths are inactive, they are really inactive. I mean humans are typically inactive at 3:00AM but if you wake me up at that time I’m still fully capable of waking up. I guess insects are different.
I see. I considered doing that, and I did when the moths just crawled on me, but I figured that vegetation has predators too, and I would’ve preferred it if the moths woke up and got to a place they considered safe.
Are you suggesting I should pick up the moths with my fingers? I don’t like doing that because I’m afraid I’ll hurt them
Yeah, I noticed that I only got my pretty green geometer moths very early in the morning! But yes, I am concerned about them being birdfood. I mean, they weren’t out in the open naturally, I kind of forced them to be with my trickery. I got my tussock moth at like 10 PM and it stayed all night. Maybe I should’ve shooed it off immediately after seeing it and photographing it?
I turn my lights off around 3:00 am. I think if you turn them off a little before dawn, many species are already settled for the day to avoid early predators and they will not fly anywhere until the next evening. The shake is a good idea too.
You can pick up moths, but gently. Don’t grab and pull when they are clinging to a sheet, or their legs might detach from their body. Instead, put your forefinger in front of the moth’s head and gently slide it under the moth’s body. The moth will instinctively want to crawl onto your finger and cling to your fingertip.
My routine is to check the sheet about half an hour before first light. I put any moths I want to photograph in a large soft mesh enclosure (the kind used for rearing caterpillars) where they will be safe from birds. Then I turn off the black lights (otherwise the moths will come right back to the sheet when you shoo them off). I then move the moths I don’t want to photograph (because they are common species or duplicates) to safe hiding spots. And then I wait about an hour until the sun comes up, and I go back outside to photograph the ones in the enclosure. I hide them when I’m done. It is a multi-step process, but I much prefer photographing in natural light, and also the moths are often sluggish and cooperative first thing in the morning.
Awesome advice, thank you so much! I also would love to photograph in natural light. And thanks for reassuring me about letting the moth onto my finger
You should preferably switch off it before dawn, before they enter an inactive state similar to sleep.
I find the best way to pick up sluggish moths in the morning is to place my finger in front of their head and gently push towards them, then they usually clamber clumsily onto my finger. On a vertical sheet you might just knock them off though, so either make the moth horizontal first, or put your other hand beneath to catch it.
Hopefully, one night you will set up in the tropics on a perfect night with no moon, clouds, and maybe some fog and realize the best you can do sometimes is shake it and run.
Please explain the ‘’run’’ part
Ideally have the lights turn off a few hours before sunrise. I have my lights set to turn off by 3. Likelihood of me being up past that are extremely low. It definitely minimizes what is left on the sheets when the light, and birds, show up.
Bugs in eyes
Bugs in clothes
Bugs in ears
Bugs up nose