Moth Night at Monte Bello OSP

Orange-yellow geometrid

Orange-yellow moth (a geometer)

The third annual National Moth Week is on as I write this, from July 19-27, 2014. We’ve tested out the evening insect activity a few times at two locations, and I was anxious to try a public event.

On our night hikes, sometimes we have a few moths as we walk through the woods. Usually it’s later in the year, and we get Edwards’ glassy-wing and a shaggy moth in the genus Tolype. The only sphinx moth that we’ve seen was a large green caterpillar, once, at the side of the trail before dark.

We (JO, JH and TS and I) checked out the location on the Wednesday before the event. It was windy and relatively cold. I had to put on a couple more layers. We put up a frame with a sheet and blacklight, tested a small light with a white umbrella, and set up a rope and sheet to see how it would fare in breeze. The wind seemed to blow from the southwest, and blew through the lot. JH said that one moth and a bug landed on the sheet, but that was it. We picked some likely spots to set up on Saturday, hoping that the weather would improve.

The evenings prior to the event weren’t terribly warm. We watched the local forecast with bated breath, hoping that the predicted warm temperatures would hold.

We headed up early to have a group dinner. There was only a small breeze, and at 7:30, the local station recorded 66F. Sunset came around 8:30, but at 7:45, thick clouds to the northwest with a few pockets of rainy-looking wisps (virga) made us wonder if it would shed some drops. By 8:20, the clouds were purple and pink. This was one of the most spectacular sunsets we’ve had, and participants who had arrived early were as captivated at the sight as we were. As dusk came, juvenile owls screeched and coyotes yipped.

9:15, courtesy Jack Owicki

9:15, courtesy Jack Owicki

With the much-appreciated help of two unofficial nature enthusiasts who brought extra equipment, we set up four stations to accommodate the 22 people who had reserved spots, and the 7 of us (JO, JH, KG, and CR, KU and KH). The frame and TS’ long blacklight powered by the car battery went in about the same place as on Wednesday, facing southwest in the firebreak, hoping for insects from the canyon and woods across the way. We set up a rope and sheet with a bulb in a reflector at the northeast site, for insects in the close trees and coming up from Los Trancos. Two other sheets and tube blacklights went in the lot proper, across the kiosk on the south side, and against the fenced-in vegetation on the north side.

The official start time was 8:30, and everyone who was going to arrive were there and ready by 8:45. We gathered and took care of the usual business, adding that since we were at the lot, participants were free to leave after signing out. We had special permission to stay at the lot until midnight.

The first insect, not a moth but a native agile ground mantis (a first for me), arrived at the NE sheet around 9:15. A black burying beetle with hitchhikers (phoretic mites), also appeared. These carrion beetles are one of the undertakers of the animal world, preparing and burying small vertebrate carcasses with which they feed their young.

Many of the participants went on the optional short hike to the sag pond. Some of the creatures that we’ve recently seen in that area were not apparent, but the group heard a great horned owl, and wood roaches in apparent association with harvester ants, which we’ve observed before.

Psssst…a raindrop hit the bulb. There were a few more scattered drops, enough so that I angled the light down a little, then it stopped.

Tolype detail

Tolype wing detail

At 9:40, a shaggy Tolype flew in, settled on the NE sheet, and stayed there all night. Around 9:50, shrieks came from the SW sheet. Another first, and by far the largest insect we’ve seen up there (anywhere in CA, in body size) at around 60mm, a giant water bug! That too stayed for a long time. At one point, it flew onto my pant leg as I sat on the bottom part of the sheet taking photos. Then, for some reason which I haven’t figured out yet, it proceeded to pump its thorax lengthwise. Perhaps that was an example of augmented respiration. I wondered whether this was a male or female. These bugs display parental care, as do the burying beetles (but in a different way). Dad cares for the eggs, and how depends on the subfamily.

Another large insect showed up on the north sheet after 10:00, a long-horned Prionus. We’ve only seen one, at Long Ridge OSP, in 2010. In contrast to that, on the back side of the same sheet someone spotted a very small fan-shaped moth. I had seen pictures of these many-plumed moths, but didn’t realize they were so small. Speaking of small, a tiny solifugid (“camel spider”/”wind scorpion”/”sun spider”), a fast arachnid in an order separate from spiders, ran around the bottom of one of the sheets. That is probably the smallest one we’ve seen.

At around 10:40, a ten-lined June beetle flew in to the south sheet. That was the number three spot of the trio of big “bugs”, also a first for us there.

Several nocturnal male velvet ants showed up during the night. Wasps, not ants; female velvet ants have no wings.

Of the other more interesting moths, some were mottled with green and brown, perfect for camouflage against lichen- or moss-covered tree bark flew in to more than one sheet. The most unusual for me besides the many-plumed moth in this area was a yellow-orange moth, wings bordered with brown fringe.

Two tree crickets, a grasshopper, katydid, various lacewings, caddisflies, tiny water boatmen, other beetles, and finally, an adult antlion also showed up to top off the evening.

A few people stayed until close to the end. The three big bugs also stuck around.

The big three

The big three

More photos here, and here.


8/3/14: On 7/25, we went to Alpine Pond at Skyline Ridge to compare. The temperature at 9:00 was 72F. Two juvenile great horned owls screeched.

Field crickets chirped visibly on the dam. A 32mm giant water scavenger beetle buzzed in loudly. Last year was the year of trapdoor spiders; this year must be the year of big bugs.

Photos from that night are here.


You can also see my iNaturalist observations for MROSD here.