I have been inundated with hatchling caterpillars… ahh, this is how life should be. My favorite part of entomology is catching and caring for the insects themselves. For the past week I have been rearing a few species in the lab, but some of the clutches were so large I had to transfer them to sleeved branches outside. If you keep too many caterpillars together, they are more prone to disease. Last year I lost many caterpillars to something I called the “butt sickness”… we do not know if it was a bacteria or virus, but it caused intestinal issues until they perished. The butt sickness spread through a few dozen of my caterpillars. Poor little guys. I don’t want that to happen again!
Also, feeding caterpillars picked leaves (as opposed to rearing them on living plants) stunts their growth. This has been documented in books and passed along through anecdotes, but I am not sure if it has been systematically studied. I do know that many of my adults emerging now, which I reared last summer in the lab, are much smaller than wild caught specimens. We would prefer to get healthy, normal sized adults for our collection.
Of the caterpillars I am putting outside in netting, some will stay there until they are ready to pupate and I will simply observe them through the netting. I am interested in whether they rest on the upper or under side of the leaf, if they change their habits depending on the time of day, and whether their behaviors change when they change colors.
Others will be removed once they are larger to use in bird predation experiments. I have a meeting with a collaborator from another university tomorrow to get equipment for that.
Here are some of my little darlings. This species is Acronict lobeliae. It goes through several color/pattern changes throughout its life as a caterpillar. This is the second instar.
Here I am moving some caterpillars to their new enclosure outside. I call these my “poodles” because of their fluffy end segments. They are actually Acronicta impleta. You can sort of see them… the black fuzzy specks that are about 4mm long…
Some of the sleeves all set up.
This is my first time rearing caterpillars outside, so I am hoping everything goes smoothly. I have more eggs waiting to hatch, and more eggs are on their way from a collaborator. I am going to be doing much more serious blacklighting this week and next week, hoping to get some more females.