The Life Cycle of a Woolly Bear

Close up of small white eggs – about 250

June 27. While gathering leaves for the cecropia larvae, (discussed in a separate post), I happened upon a huge clump of pearly white, round eggs, each about a millimeter big, on the underside of a leaf. My first estimate was that they numbered over 250. I believe they are Woolly Bears (Pyrrharctia isabella), but I am not entirely sure. They look freshly laid, might be a week before they open.

June 30. The eggs have faint black dots in their middles…a good sign.

July 2. Definite black spots, eggs will be opening soon. Can almost see the little larvae curled up inside. I am going to be really busy. At my dad’s house, I hope he has ash near by, I’m going to need a lot!

Feeding pattern of larvae – with left over of eggs

July 3. So the 250+ white eggs opened. I had an insane time trying to get them all sorted into their petri dishes and counted. I counted 260, plus or minus a few. They are barely 3 mm, grey, with a hint of fuzzy-ness. Very cute and hyper when “tickled” with my paint brush. Running around like crazy when prompted. Started them out with a mixture of oak, apple and maple leaves because I couldn’t find ash. The larvae ate all of their eggs shells, leaving just a fine layer where they had been attached, then started “moving out”. Started with dishes numbered 40:40:40:40 and 25:25:25:25. Took me two complete hours to do all this.

July 4. Too busy to spend the necessary time feeding, hope all is well.

July 5. The larvae are too small for my camera! My lens does not focus on that small, even through a magnifying glass, grrr.  I will get pictures of them as soon as they are big enough. They are very hyper and hungry. They eat by scraping off the bottom layer of the leaf instead of chewing from the edge inward.

July 6. They expanded overnight, and now the leaves look like the picture on the right, with only the veins left. Counted 254 larvae, they are blacker, and still eating like crazy.

July 7. Larvae appear even darker today, and numbers are down to 250. I am slowly getting faster at changing all these petri dishes, but it still takes me a good hour or more. Otherwise, nothing has changed.

July 8.  First molt has started, and the result are simply larger fuzzy grey/black larvae, who are once again ravenous. Started using tally marks to count them, got 249 today, in dishes of 18:22:24:24:40:40:40:41.  Still eating by scraping.

July 9. Same as yesterday.  I should note that before the molt, their hair was not very thick, and the body underneath was an almost shiny  grey-ish brown. Now they are fully covered in fuzz, can’t see the larva under the hair.

July 10. Too tired to spend all the necessary time, so just sliced up some leaves and added them to the dishes. Everyone looked fine.

July 11. All molting is complete. Larvae are now about 5 mm long. Counted 241.

July 12. Larvae are still growing, they are starting to eat holes in the leaves now, instead of just scraping. Average length is 6 mm.  counted 237, but might have miscounted.

July 13. Fed, but starting to get annoyed at this whole cleaning process.

July 15. Moved them to a two gallon container with large leaves spread across the floor in layers. This should give them more room, more food and I will have an easier time of feeding them. Counted 241 larvae, all of which fit nicely in this new “jar/home” of theirs. They are still about 6 mm, dark grey/black, and very hungry.

July 16. Everyone is eating and growing well, though some insist on climbing the walls, so I have to keep the lid on. Thank fully there is not enough moisture to fog the thing up…I will have to keep an eye on that though.

July 21. Took some days off writing notes, but have been feeding/adding leaves every day. They have grown considerably and filled out, might molt again soon. They are striping every leaf I put in with them, leaving just the veins. They have expanded to about one centimeter long. I can tell when they need to be fed because they start climbing the walls in search of food, which they are doing now, I shall feed them.

July 22. So, I opened up the container, and the first thing that crossed my mind was that they look like mini woolly bears. So, despite the fact that I named this post “Life Cycle of the Wooly bear”, I had no idea what they were until now. After having my mom and brother look at them, they confirmed my thought. I am raising 227 woolly bears! What am I going to DO with them all? If I let them all go as adults, I am going to have a population boom on my hands. If anyone wants any, or knows of any programs that could use about 200 larvae, I would be happy to know.

I will be adding pictures soon. 🙂

One thought on “The Life Cycle of a Woolly Bear

  1. avitamin says:

    I came here hunting something else, but this entertained me regardless. Inspiring stuff!

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