What's That Bug? does not endorse extermination

devoted mom
Location:  Los Angeles, CA
October 19, 2010 12:34 am
This little lady (or man) has been stationary for several days now on the outside of our house. I would normally think a bug that hasn’t moved for 4 days with such death grip is well, dead, but there are babies to protect, so I’m not quite sure. She’s a beauty! Any idea what she is?
Signature:  Julie

Painted Tiger Moth laying eggs

Hi Julie,
It is the right time of year with the correct weather conditions for the Painted Tiger Moths,
Arachnis picta, to be flying, mating and laying eggs.  One was perched for several days on the door jamb of our Mt. Washington, Los Angeles offices for several days and she finally dropped dead without laying eggs.  A pair was spotted this morning on the fence post near the chicken coop and they were in the act of mating, and this evening, there was a female depositing eggs on the front porch beneath the porch light.  Nearly every year a female lays eggs under the porch light.  After a week or so, depending upon the temperature, the eggs will hatch into tiny fuzzy caterpillars that will disperse and begin feeding on many weedy type plants that sprout after the first rains.  The caterpillars are a typical Woolly Bear.  Adult Painted Tiger Moths do not feed as adults.  According to Charles Hogue in Insects of the Los Angeles Basin: “The mature larva is about 1 1/2 inches (40 mm) long and is densely covered with stiff black hairs; The head is black. The caterpillar feeds nocturnally on a great variety of weedy plants, including wild radish, Wandering Jew, and Acanthus. It hides during the day, sometimes retreating into the soil, and it rolls into a ball when disturbed, It develops during the winter and then is somewhat dormant (although active, it does little feeding) until late the following summer, when it pupates; on a warm fall evening, the adult emerges. Individual caterpillars occasionally pupate immediately after maturing and pass the summer in the pupal stage.”

What's That Bug? does not endorse extermination

10 Responses to Painted Tiger Moth laying eggs

  1. ZTWP says:

    Hey! This was an informative post. I captured one of these little ladies because she was striking. She proceeded to lay about 300 eggs over a period of days. In fact she managed to escape from my container on the second night and laid some eggs high on a wall. I found her, thinking it was a different one, on the floor so I brought her back. Anyway it has been long enough, about a week and the little ones are coming out. I don’t know what they eat. And I don’t know their life cycle. I tossed in some mint leaves and blades of grass and the first batch of tiny caterpillars fell off the napkin where they had been laid onto the bottom of the container. What do your do? The ones which were laid on the wall near the porch light? Do they eventually drop/crawl to the ground to begin feasting on plants? Do these critters overwinter and where do the pupate?

    • bugman says:

      According to Charles Hogue in Insects of the Los Angeles Basin: “The mature larva is about 1 1/2 inches (40 mm) long and is densely covered with stiff black hairs; The head is black. The caterpillar feeds nocturnally on a great variety of weedy plants, including wild radish, Wandering Jew, and Acanthus. It hides during the day, sometimes retreating into the soil, and it rolls into a ball when disturbed, It develops during the winter and then is somewhat dormant (although active, it does little feeding) until late the following summer, when it pupates; on a warm fall evening, the adult emerges. Individual caterpillars occasionally pupate immediately after maturing and pass the summer in the pupal stage.”

  2. ZTWP says:

    Have you any experience with them? The little caterpillars emerged at the same time and remained within their cluster till I threw in some food in which they were knocked off the paper towel where they were laid. I have a second group that emerged late last night and are still in their cluster, about 20 hours post hatching. The first group remained in their cluster for at least 48 hours before they fell off. Many are feeding on the plants I threw in, some have climed up the eclosure.

  3. ZTWP says:

    Okay then, we’ll see what happens!

  4. jayflo says:

    Last year 1 Painted Tiger moth came and laid eggs on our front door. Now we have 3 but only 1 (could be same as last year) is laying eggs, for now. Once the caterpillars hatch they will fall onto concrete and have a long way to go to dirt . Can we carefully pick the eggs off the door (once mother is gone) into a small container then drop in the surrounding flower beds once hatched? Please advise.

    • bugman says:

      The egg laying moth from this year is not the same individual as the one you had last year. The first meal of the caterpillar is part of its egg shell. Though it has some distance to wander, the newly hatched caterpillars are quite capable of finding food. You should not attempt to dislodge the eggs. They may get damaged. If you want to try to locate caterpillars that have hatched, handle them with care.

      • Barbara McFarland says:

        One laid hers in my kitchen sink. I waited until they were all hatched and after they ate their shells I either carefully lifted them from the side with my finger, if they rolled into a ball I gently plucked them up by the long hairs on their back (almost invisible to the naked eye but you know they’re there because the caterpillar is now apparently floating above the surface) or best yet use the leaves of your local weeds to lift them and move them. I think I got all of mine. They really seem to like hibiscus and a local tall, yellow flowering weed.

  5. Karen Tate says:

    I had a moth lay eggs on the back passenger side fender of my jeep, they were bluish grey in color pictures attached dont show correct color, is it unusual for them to lay eggs on a vehicle that is driven everyday??

    • bugman says:

      Certain species of Tiger Moths are opportunistic, and they will lay eggs in many unusual places. The caterpillars hatch and begin feeding on the egg shells before dispersing in search of appropriate feeding locations, and since many Tiger Moths are general feeders rather than being limited to a specific plant, the female is not compelled to locate suitable food plants when laying her eggs.

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