best times to run a MV light and sheet?

[Jon D]

Brand new to "mothing" this summer using a 250 watt mercury vapor light and sheet in my backyard.  I am about a mile or so from the closest woods, so my desired moths -Saturniidae- have been spotty at best.  I have to keep an eye on the electricity usage also.  So, what are the best times I should be running the set up?  My understanding is that warm, humid and preferably cloudy, moonless nights are best.  So, with an ever waxing moon present right now after sunset and basically clear skies, should I save the light (and electricity) for more suitable nights in a week or so when the moon is out of the picture? 

Any thoughts/ experiences/ ideas would be welcome.  I am in Northern VA not far from Washington, DC.     

[kevinkk]

For me, here in the Pacific Northwest, as well as a couple other states, along with a trip a long time ago to the D.R.,
the best times seem to be about a half hour to an hour after dusk, until about 2 am, when possible I let my uv light
run all night, but power really isn't an issue, except using up battery power.
It always seemed after I went to sleep after 1 or 2 am, there would be more moths on the sheet in the morning.
If you want to hit the sweet spot- it's probably 11pm to about 2am.
Moths will fly some distance, the higher you can set up the light, the better, I try for an open area, but it's not
always possible.

[Jon D]

Jun 30, 2020 9:48:17 GMT -8 kevinkk said:

For me, here in the Pacific Northwest, as well as a couple other states, along with a trip a long time ago to the D.R.,
the best times seem to be about a half hour to an hour after dusk, until about 2 am, when possible I let my uv light
run all night, but power really isn't an issue, except using up battery power.
It always seemed after I went to sleep after 1 or 2 am, there would be more moths on the sheet in the morning.
If you want to hit the sweet spot- it's probably 11pm to about 2am.
Moths will fly some distance, the higher you can set up the light, the better, I try for an open area, but it's not
always possible.

Thanks for your input.  When you say "uv light" are you referring to mercury vapor, or something like a blacklight?  What about the moon, is there any point running the setup until it's out of the way again in a week or so?

I actually could set up my MV light in a tree if I wanted to and that would put it above most of the roofs in the area, but placement of the sheet would be an issue I would think. 

[mothman27]

I find that very successful nights can be had even with a large moon. Overall, it is better if the moon is not as visible but it's not necessary. 
As you mentioned in the initial post hot, humid and moonless nights would be ideal. I don't usually consider cloudy nights to be preferable. 

Also, as you mentioned saturniids are not plentiful, even with the best of nights and lots of forest, sometimes they just don't seem to come.

This year I invested in some new bulbs. I use two 250w Mercury vapors as well as a 160w MV and a couple blacklight 40w tubes by a sheet. 

This summer I have had my lights on from about 10pm to 5:30am when I check them. I have had much more success with this than previous years. All the bugs which have come throughout the night seem to stay until about 6am(dawn). If you wait until it's getting pretty light they start flying away pretty quick and you don't know what you may have missed. 

Here are some photos from two nights ago (with almost half moon) with quite a few worth keeping.

[exoticimports]

Different species fly at different times.

All th S abbotti and lucanids I got this year were just after dusk. A Luna tends to fly after midnight.

Some catocala will come at dusk as well.

[kevinkk]

Mothman27 is correct, the moon, while a night with no moon is best, isn't a washout.
When I referred to "uv", I mean ultraviolet florescent bulbs, not a classic "black light"
that people use for posters and the like.
Light bulbs do wear out, emitting less of the useful spectrum over time, it all depends on
how long it is used, I'm sure there are different opinions about that issue.But it is
something that happens, and new bulbs will always work best, although with normal use,
I'd take a guess that a bulb should be useful for several seasons.
Having your light close to the sheet so it reflects light and allows insects to land is
the whole point of deciding how to use the light.
A lot of people take advantage of lighting on streets, and other places, but that can
present some security issues, along with the many street lights going to a sodium based
yellow light, which still attracts insects, but not as many.
Animals are a problem sometimes, I spent one summer in Indiana and had a terrible time
with a cat...along with the skunks, but that cat was the worst.

[Jon D]

Wow, that's quite a set up you have there.  Now tell me what is responsible for more success, the different lighting set up? 

Jun 30, 2020 11:05:43 GMT -8 mothman27 said:

I find that very successful nights can be had even with a large moon. Overall, it is better if the moon is not as visible but it's not necessary. 
As you mentioned in the initial post hot, humid and moonless nights would be ideal. I don't usually consider cloudy nights to be preferable. 

Also, as you mentioned saturniids are not plentiful, even with the best of nights and lots of forest, sometimes they just don't seem to come.

This year I invested in some new bulbs. I use two 250w Mercury vapors as well as a 160w MV and a couple blacklight 40w tubes by a sheet. 

This summer I have had my lights on from about 10pm to 5:30am when I check them. I have had much more success with this than previous years. All the bugs which have come throughout the night seem to stay until about 6am(dawn). If you wait until it's getting pretty light they start flying away pretty quick and you don't know what you may have missed. 

Here are some

[Jon D]

Jun 30, 2020 16:24:56 GMT -8 kevinkk said:

Mothman27 is correct, the moon, while a night with no moon is best, isn't a washout.
When I referred to "uv", I mean ultraviolet florescent bulbs, not a classic "black light"
that people use for posters and the like.
Light bulbs do wear out, emitting less of the useful spectrum over time, it all depends on
how long it is used, I'm sure there are different opinions about that issue.But it is
something that happens, and new bulbs will always work best, although with normal use,
I'd take a guess that a bulb should be useful for several seasons.
Having your light close to the sheet so it reflects light and allows insects to land is
the whole point of deciding how to use the light.
A lot of people take advantage of lighting on streets, and other places, but that can
present some security issues, along with the many street lights going to a sodium based
yellow light, which still attracts insects, but not as many.
Animals are a problem sometimes, I spent one summer in Indiana and had a terrible time
with a cat...along with the skunks, but that cat was the worst.

Hmmm, I may not be familiar with the UV you speak of.  To combat the Covid-19 where I work, a type of UV light called UVC is being used on rooms and equipment.  A human cannot be exposed to it or suffer burns or eye damage.  And, if it's not a "black light", it must be a special UV spectrum?

I do have stray cats where I live, so I'm going to have to keep watch.  People keep feeding them and they in turn keep having more and more kittens that run around as ferals.   

[58chevy]

Jon D, Leptraps.com sells the UV fluorescent bulbs that mothman27 is talking about.

[kevinkk]

Jon D,
I buy all my lighting supplies from Bioquip, they sell spare bulbs, ac/dc setups, dc only as well. The uv I'm talking about s the same light used
in bug zappers, I am not familiar with the type of uv used for sterilization.

[mothman27]

I have purchased most of mine from ebay. 

[Jon D]

I don't consider I've had the greatest experience myself with the light and sheet set up, but last night it was 75 F and 96% humidity. Within 5 minutes after the lamp was turned on, it was surrounded by bugs. Within an hour, a large silkworm moth flew close but turned and flew away before I could net it. However, between 11 PM- 1 AM, two Imperial moths visited and managed to grab those. I also had an Imperial the night before even though it was much cooler and less humid.

To be honest, I would have missed most of the larger moths this summer had I not been watching. Many will fly near the bulb, but not always to the sheet. Of the fourteen silkworm moths that have shown up since the last week of April, only two Lunas were actually on the curtain. The remainder were either on the ground or flying around randomly while I was trying to net them. I've tried adding other nights nearer the curtain and even a de-electrified black light to the other side of the curtain, but it hasn't made any difference in moths actually clinging to the curtain. My best bet has been to watch. This is no doubt why, when I started with the light this time last summer, that I had no large moths because I was only checking once every couple of hours. Constant watching, in my experience, seems to be the deal. Over the next year, I'm going to try and find a video camera that will do the job. The security camera I tried doesn't have very good AGC and the MV light overwhelms it.

[joniverson]

Another Imperial last night. That makes four since Jul 17 and the most Saturniidae I've had within such a time period. There must be an Imperial hot spot nearby!  Perhaps the three pine trees, sugar maple, and ash were the hosts.  However, in the 40+ years I've lived here, I've never seen a caterpillar. 

[kevinkk]

Not seeing larva isn't a surprise, larva are hard to see, and it's usually lucky chance finding a caterpillar.
A lot of moths fly in to the light and land nearby, I always check the nearby grass or weeds with a headlamp or
flashlight.
Sometimes they fly in and buzz around and leave, or come back later.

Whenever I run a light, I'm out camping, and there to watch to begin with, but there are nearly always more moths
in the morning, even after going to sleep at 2 or so.

[joniverson]

Tonight was probably the best night, Saturniidae wise, since I started running the light in late April. I actually acquired three and one flew away before I could get to it. I was surprised with the quarter moon present as it hadn't set yet and these moths were caught between 10-11 PM. There was activity all around the light and I just turned it off a little while ago. I kept track of the temps, humidity, and wind. It averaged 76.5 F with 88.5% humidity and very little or no wind. Now I think I know the best type of night to seek.

After pinning others from the last ten days or so, I'm all out of boards so these will have to wait.

I'm beginning to think that the reason I didn't have any success last summer with the light was because 1) I wasn't watching it close enough and 2) I wasn't using a block like this year so in the observing direction, the lamp brightness is nullified. I run a small copper rod in parallel just beyond the bulb and I can move it in a circle around the lamp. This makes a huge difference while I am observing and the shadow only affects a very small area (just me in the observing chair).