MAY 30
Today I harvested the first of the prepupal black soldier fly larvae from this year’s colony. At this stage their instinct is to leave the food source and find a suitable place to pupate. I don’t know much about this part of the BSF life cycle so I want to find out first hand. I put the harvested larvae into a closed container and I’ll be observing their behavior and changes, hopefully until the point where they emerge as adults.
When BSFL enter into their 5th and final stage as larvae they undergo some interesting changes. They go from a pale “grub” color to a dark coffee brown, and their mouth is replaced by a hook-like appendage to help them crawl in search of a good pupation site. They also empty their gut and excrete an antibiotic, a behavior which I find fascinating. A veterinarian friend of mine wonders if animals that eat the 5th stage larvae might benefit from ingesting the antibiotic.
Update MAY 31
Yesterday I placed about 15 prepupal BSF larvae into a one gallon container with some leaves and grass. If you click the photo above to enlarge it you can see a few of them. I added a handful of sand to one corner of the container and the larvae quickly buried themselves in it. One entered the sand but came back out and settled under a leaf.
I found a great poster by the Swiss Federal Institute of Aquatic Science and Technology (eawag), which outlines the BSF life cycle. BSF LIFE CYCLE
JUNE 2
They’re just laying there…
JUNE 6
*tap tap tap*
JUNE 9
I spoke with Dr. Olivier and he said that sand isn’t the best material for a pupation site. He recommended using sawdust to house pupae. He also puts some in the BioPod collection bucket to help keep it dry. He told me about a hamster bedding that works well, I think it was Aspen Bedding.
My pupae are still pupating…..
JUNE 19
Still waiting!
JUNE 26
Today I noticed adult BSF emerging from the pupae for the first time. It’s very possible that they started coming out before that but what can I say, I’ve been busy. 
I tried to photograph the process of the adults emerging but it happens very quickly. I checked on the pupae at one point and I noticed that an adult had it’s head out of the casing. I ran for my nearby camera and in the 20-30 seconds it took me to return the fly was already out and expanding it’s wings.
Comments 4
Hey Jerry, the BSF larvae you sent to me have started emerging as adults, also. I think the first one emerged about June 26th, and at least 2-3 others have become adults now. I’m keeping them in an inexpensive 10′ square screened gazebo to try to keep the adults close to the food source (and to each other).
Posted 02 Jul 2008 at 12:23 pm ¶Glad to hear it Jase, I hope they mate for you.
Do you have any Barry White?
Posted 02 Jul 2008 at 2:07 pm ¶Hey Jerry, update? How long did it take for them all to emerge?
What was the temperature while you were doing this? As I’m sure you know, temp makes a huge difference in how fast many insect species go through their cycles.
Posted 17 Jul 2008 at 2:53 pm ¶I have to admit that I didn’t keep close records on these pupae. The average daytime temperature was in the mid 80;s and the lows were in the low 70’s. I would estimate that there was a week long spread in the emergence of these adults, but I can’t be sure exactly when each one pupated. Some probably pupated before others. In the future I’ll run some more controlled tests.
Posted 17 Jul 2008 at 3:08 pm ¶Post a Comment