Attracting moths at night using lights has yielded an amazing number of species that I never even dreamed existed. My last count was at 865 moth species with 34 new species added to the checklist this year alone.

Many other insects, besides moths, come out at night to my lights. These include beetles, flies, Hymenoptera, and typical bugs. There are also leafhoppers, mayflies, caddisflies, Neuroptera, arachnids, myriapods, and Collembola. During the warmer, humid months of summer, there can be a lot of insect activity at the moth light.

People who put out bird feeders are often horrified when a shrike or hawk comes swooping in and takes away a chickadee. Those birds must eat, but that is not why we put out feeders. At night, attracting moths can pose similar problems with spiders, ants, and frogs drawn in by all the insect activity. Snakes then follow, hunting the frogs.

Here I present some photos of various predators that have come to my moth light. They include harvestmen, spiders, lacewings, ants, and frogs observed preying upon moths and other insects attracted to my moth light. The worst instance of predation, from my perspective, involved a fishing spider (Dolomedes tenebrosus). It captured and ate a twin-spotted sphinx (Smerinthus jamaicensis). I was upset, but it was too late for the moth. The spider’s venom acts quickly, and there was no saving it.

Arachnids: spiders and harvestmen

In the top photo is a harvestman (Leiobunum sp.), an arachnid, that has captured and killed a horned spanworm moth (Nematocampa resistaria). I have no idea how it accomplished this. They have no venom glands. They also lack sticky silk threads to snare prey like their spider relatives. Harvestmen are ambush hunters, but this is a large moth compared to the harvestman. Did it poison the moth using secretions from its scent glands (ozopores)? Does it use those secretions to secure prey, not just to deter enemies? All sources I have checked say no, but maybe this is something waiting to be discovered.

I should add that not all the harvestmen who come to the mothing light eat insects. One evening, I left out peels from very ripe bananas. I hoped the aldehydes and other volatiles would attract certain kinds of moths. That didn’t work, but I did see a harvestman consuming some of the pulp left on the skin. I wonder if it got its five servings a day of fruit?

Above is a fishing spider (Dolomedes tenebrosus) that has captured and is eating a northern gluphisia moth (Gluphisia septentrionis). The same spider appeared the next evening and captured another northern gluphisia.

Some spiders, like this lichen orbweaver (Araneus bicentenarius) above, build webs near the moth light. They do this probably because the corner of the porch wall offers a convenient trapping location. My moth light unintentionally lures moths and other insects near the orb web, where they can be trapped.

This spider didn’t stay long for some reason, and no insects were trapped. It may have been because a pair of eastern phoebes (Sayornis phoebe) were nesting in a little nook overhead. They may have created too much disturbance, or even eaten the spider. In any event, the spider was gone after one day. Phoebes do eat moths and I have seen them capturing moths that remained on the porch wall after sunrise.

Hymenoptera: ants

Ants are active during the day and also at night. This is not surprising as they spend a good part of their lives in dark tunnels, finding their way using scent trails laid down by other ants. Above, a swarm of Crematogaster sp. (acrobat ants) has captured and is dismantling a tiny caddisfly that got tangled in spider web fragments.

Neuroptera: lacewings

Lacewings eat aphids and other small soft-bodied arthropod prey, including insect eggs. This lacewing (Chrysoperla sp.) was searching in spider web fragments where small leaf hoppers, like Chlorotettix spp. and psyllids, became entangled. When the lacewing found one, it ate it.

Amphibians: frogs

Finally, a gray (okay, this one is green) tree frog (Hyla versicolor) on the hunt, searching for minute insects like this psyllid drawn to the moth light. Gray tree frogs are frequent visitors to the moth light, searching for food. With their sticky foot pads, they can climb up the walls to hunt for prey. Most of the gray tree frogs are small young-of-the-year individuals, but sometimes larger adults show up.

Spring peepers (Pseudacris crucifer) are common visitors. Like the gray tree frogs, many are young-of-the-year.

Down below on the ground, American toads (Anaxyrus americanus) search for fallen insects. Green frogs (Lithobates clamitans), mink frogs (Lithobates septentrionalis), and wood frogs (Lithobates sylvaticus) also look for insects that may be on the ground or under the porch. Some green frogs and mink frogs took up residence on the porch, living in pans where I was growing duckweed and other floating aquatics. Garter snakes (Thamnophis sirtalis) occasionally come by, too, and prey upon the terrestrial amphibians.

Some final thoughts

So, do you do mothing? And if you do, have you seen spiders or other predators coming by in search of food? What did you think about that? Should these predators be chased away?