Wednesday, July 25, 2007

Life Cycle At A Glance

A female produces about 900 eggs in her short life of 5 to 8 days. Housefly adults, by contrast, live up to 30 days, and during this long period, they must eat, and in so doing, they are actively engaged in the spread of disease. Their naturally short life span is the reason why they are not vectors of human pathogens. BSF eggs are relatively slow in hatching: from 102 to 105 hours. The newly hatched larvae have a light cream color, and crawl onto the waste, where they begin to consume it with amazing speed. Under ideal conditions, it takes about two weeks for the larvae to reach maturity. If the temperature is not right, or if there is not enough food, this period of two weeks may extend to several months. The ability of the BSF larva to extend its life cycle under conditions of stress is a very important reason why it may be used for waste disposal processing. BSF larvae pass through five stages or instars. Upon reaching maturity, they are about 25 mm in length, 6 mm in diameter, and they weigh about 0.2 grams. The dormant puparium is dark brown to charcoal gray in color. These larvae and pupae are extremely tough and robust. They can survive under conditions of extreme oxygen deprivation.

14 comments:

Anonymous said...

does the bsf consume dead animals? if so could it find its way to a dead animal within 2 hours of the animal dying?

Greenie said...

Yes they do. If fact many organizations, such as zoos and municipalities have used BSF technologies to process road kill and deceased animals. Mammalian bones will not be eaten, but most of the rest of the carcass will. If poisons were used in the process, you may harm the grubs. Check with your extension office about compatibility issues.

JC said...

These BSF larvae fascinate me. They've become my pets. I can put almost anything in there and they eat it. They devour salad dressing, cheese, old meat and citrus on top of the standard fare. The only thing they can't seem to swallow is things with tough (high in cellulose) skins like the leaves of an artichoke or yard waste.

How well do they survive the winter?

Greenie said...

I have noticed they don't eat avocado skin either - I suppose the beneficial microbes will have to tackle those alone! They do not fancy yard clippings either. The pupae will overwinter in zones 7 and up, and can survive the colder areas with protection. Your can have year-round activity if you place your colony in a greenhouse.

dr h viswanatha prabhu said...

can the Bsf larvae used for vermiculture and do they produce manure like the earth worm/red wriglers

Anonymous said...

Wow your explanation of the BSF helped us so much to identify the mysterious living within our compost bin. They've been there for a good two months and we wondered why they hadn't turned into flies yet. :)

One thing we do not fully understand yet, is why some of the BSF larvae are different colours to others. Is it possible they are maturing at different stages?

From your fellow bsf friends :)

Anonymous said...

Hello what are the stages of development?
And what temp do they need to survive?

Anonymous said...

The soldier fly is amazing. I started an outdoor food waste bin more than a year ago using a standard blue plastic 55 gal drum with one end open and exposed to the atmosphere. I throw everything in there from egg shells, to waste fats, bones, vegetables, etc, and we're a household of 6 so I'm dumping food waste in almost every other evening. The larvae have voracious appetites to the point that our compost drum has handled all of our household food waste for more than a year without ever overflowing. The seem to really like paper products like nakpins and paper towels. The larvae process the food waste and shrink it down weekly. In the winter months, they tend to burrow deeper into the drum and activity slows to the point I thought they had all gone away, but the drum still stayed warm deep down so they must remain active. It rained pretty good in the spring and I noticed that thousands of dark brown/grey larvae magically emerged from the top of the drum. It seems that they like warmth and moisture too. We are completing our annual plum harvest now and the larvae are now back to the top of the drum because they enjoy the moisture from the waste plums we throw in there. I have come to appreciate and welcome the solider flies when I see them around.

Greenie said...

RE: Dr. H.V.P: Nope, they are not suitable for vermiculture and will actually out-compete redworms. They produce castings like other insects - very dry and pelletized. However, it is very difficult to separate this from the undigested residue which could harbor pathogens that came in on your food scraps. So, best to take this casting-residue mixture and feed it all to the redworms along with some wet shredded cardboard for final processing - the worms will devour all of this as microbes break it down. The pregnant BSF females won't tend to be interested in this worm bin food.

Greenie said...

RE: Different Colors: BSF larvae develop in instars - all of the juvenile stages are light colors except the final, prepupae stage with is dark brown to slate gray. The instar before that last tends to be light colored and very active - sometimes bigger than the dark color ones. But, they are actually younger.

Greenie said...

BSF have several stages: egg, larvae, pre-pupae, pupae and adult fly. The whole process is less than 30 days, but this species can over winter as a pre-pupae in a protected location. We don't find them too far north of PA, so there is a limitation to the cold they can endure. When temps start to reach up into the 60's you can set up your rearing systems.

Greenie said...

RE: 55 gallon drum. Even though the paper waste seems to be eaten by the grubs, they actually can't digest those, but the microbes associated with their colonies sure can, so the end result is those materials get broken down as well. Just not too much paper!

Anonymous said...

How long are they in pupae stage under ideal temps versus extreme conditions?

Greenie said...

We have witnessed everything from under 2 weeks in the warm summer months (or climate controlled conditions) to the entire winter, though there does seem to be a limit to the hardiness. They can survive ZONE 7 and higher, but only parts of ZONE 6.