Tuesday, October 26, 2010

They hatched! It's been 9 days since they were laid next to our front door. See my October 17, 2010 blog entry of their beautiful mother. Yesterday I noticed most of the grey eggs had turned a bright steel-blue color. I should have known some action was about to start, and yet I was a bit unprepared this morning as I was heading out the door.

I quickly got a container out. It's a simple plastic jar with cut pantyhose secured over the top with 2 rubber bands and tied in a loose knot. I've found rubber bands tend to deteriorate after a while, so using a backup is an easy solution. For insects that are tiny, like these 2mm Arachnis picta caterpillars, nylon keeps the critters from escaping and is stretchy enough to allow you to get into the container for feeding and cleaning.

I used a small soft paintbrush to collect the caterpillars onto a sheet of paper and then poured them into the container. In my haste, I neglected to add a damp paper towel to the bottom of the container. Some moisture is good, but when caterpillars are this small they can easily drown in a drop of water. Didn't you know? Caterpillars are not good swimmers.

I quickly threw in some organic carrot tops that I had on hand thinking primarily about accessibility to more of the same. Doh! I've inadvertently killed previous lepidopteran broods, because Btk is a commonly used organic pesticide. Later when I got back home, I went around outside and clipped various foliage with hopes they'd like one of them. I did a fairly extensive online search to see what the painted tiger moth larvae eat. There's no consistent information. Some say Lupinus, others say mustards or dandelion or bull thistle, and still others say radishes and Acanthus. I don't have easy access to any of those and am still kicking myself for pulling the dandelion shoots from my compost several weeks back.

ps 10/27/10 - I checked around noon and the caterpillars seem to like the carrot, dandelion, and fennel. They're already pooping tiny black specs, so that's a good sign. I'm still not sure if I'll keep these caterpillars, since it may take a whole year to properly rear them. Oh! I used the second pic of the container above, because the shiny plastic isn't very good with flashes indoors and I also wanted to show the unusually humongous waves we had yesterday.

pss 11/01/10 - Yesterday morning, several caterpillars had spun tiny little silk mats on the container. Today, I noticed several are bigger (3.5mm), lighter in color (must have molted over night), and hairier with bits of fluff next to them (cast exoskeletons). I'm still contemplating releasing them.

pss 11/06/10 - For the final post on these critters, click here.