I had my bearded dragon outdoors the other afternoon to get his 20 minutes of sunshine (me too!) when I spied something unusual moving in the grass. The object of my attention was a fairly large caterpillar lying in the middle of 25-30 voracious Thatching Ants (Formica obscuripes), intent on relocating the caterpillar (their dinner), even if they had to do it one bite at a time.
Observing them at work, I thought of how the Egyptian pyramids were built. Humans. Lots of them. Carrying those giant blocks and stacking them required formidable effort. Perhaps these ants in their orchestrated labor efforts would successfully lug this lepidopteran larvae back to their nest.
I did not stay and watch to the end. I watched just long enough and filmed this clip. I felt a bit sad for the caterpillar, wondered about the butterfly or moth it might have become, and I marveled a little about these industrious ants that cooperate for the collective benefit of the colony.
I found this specimen at the Friday Harbor Post Office yesterday and picked it up to save in my collection. It’s a bit bird-pecked, but worth keeping for passing around at my upcoming insect talk at the library in October.
Lots of folks emailed me earlier in the year with photos of caterpillars they were finding. The larval form of this moth looks like the two photos below, depending on the developmental instar.
These moths are fairly common throughout the San Juan Islands. The larvae feed on Douglas Fir (Pseudotsuga menziesi) and other conifers. The name, argentum comes from Latin referring to the silver spots on the wings of adults.
While larvae are defoliators, they are not usually present in high enough numbers to cause economic damage or require any chemical control. Also, while very pretty to look at, the caterpillars do have urticating hairs which can cause stinging, burning, or rash in sensitive people. Take a photo or observe them, but resist the temptation to pick them up!
I’m always excited when someone asks me to ID a bug for them! This came from the women over at Browne’s Garden Center – https://www.browneshomecenter.com/garden-center/, San Juan Island, WA. It’s the “black form” of the White-Lined Sphinx Moth (Hyles lineata). The larva are sometimes called Purslane caterpillars. They will eat Fireweed (Epilobium angustifolium), other fireweeds, and other various plants in the evening primrose family.
I spent a good part of the day combing through my insect photos from the past 9 years. There are thousands. Finally, I found the ones I was searching for. I credit Victoria Compton on San Juan Island, WA for helping me out on this one. She sent a photo the other day to my email with a caterpillar and had suggested an ID. Not only was she correct, but in ID’ing the caterpillar, it enabled me to match up one of my adult moth photos that had been sitting around nameless since 2016. The photos I found today were of the same caterpillar that had been a mystery to me since 2013. It’s a nice “aha” moment when you connect the dots! Below are the pics for you to see.
Lophocampa roseata Photographed July 10, 2016 San Juan Island, WA
Lophocampa roseata larva Photographed October 6, 2013 San Juan Island, WA
This is a Tiger moth in the family Erebidae, subfamily Arctiinae. The scientific name is Lophocampa roseata (also known as the Rosy aemilia). It was first described by Francis Walker in 1868. They are found in Western Oregon and Washington as well as in Southwestern B.C. and are associated with habitats of conifer forests and maple trees. The sources I checked list them as somewhat rare and Natureserve lists them as “critically imperiled.” So, I guess we have another beautiful Lepidoptera on San Juan Island to care for along with the Marble Butterfly!
***Critically imperiled Tiger Moth. Please post/email photos if you live in San Juan County, WA and come across one in the adult or larval stage. Thanks!
Lophocampa roseata larva Photographed October 6, 2013 by Cynthia Brast San Juan Island, WA
Lophocampa roseata larva Photographed September 26, 2018by Victoria Compton San Juan Island, WA