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  • The Science of Black Soldier Fly

    You will find incredible detailed explanation of black soldier fly at evoconsys.com/blog
  • Bearded Dragon Hatchlings Grow Faster When Fed BSFL As Staple Diet

    Black soldier fly larvae (BSFL) has long been admired among the reptile community for their superior nutrition benefits, however, there was no study demonstrated how could the dietary intake of BSFL benefit the reptile. Our study first shown that bearded dragon hatchlings grew faster on a BSFL staple diet than those on supplemented dubia staple diet; at the end of the 8th week, the BSFL group dragons weighted 35.29% more than the others. In addition, the molting time for the dragons on BSFL diet averaging 2 days earlier than the dragons on supplemented dubia diet.

    The study demonstrated that our BSFL could provide sufficient protein and calcium for faster growth of bearded dragons, without any additional supplement.

    Black soldier fly larvae (BSFL) have recently been accepted as the best staple feeder insect for many reptiles, because of their naturally high calcium content. However, studies indicate that the nutritional value of BSFL is greatly influenced by rearing practices and diet, and there are no data to demonstrate how or why BSFL are the best feeder insects. Currently, dubia roaches have been catching a lot of attention for the higher nutritional values than crickets, superworms and mealworms, and are the most popular feeder insects used among reptile breeders in the US. We designed a feeding trail to compare our BSFL to dubia roaches, in order to provide this information to reptile breeders and hobbyists.

    We were grateful to have the Dragon Den (Josh/Glenn) to perform this experiment. This controlled study included 6 bearded dragon (hypo trans/double het hypo trans, reds) hatchlings from the same clutch of eggs. Three of them were provided dubia roaches with calcium and vitamin D3 supplement (AKA dusted dubia roaches), and the other three were provided unsupplemented Symton feeding grade BSFL. The insect mass was provided equal amount, however, there could be bias due to palatability. The calcium content indeed is not equal, nor for the Ca:P ratio, because this is a major point we tried to hit--to compare the most common practice with feeding BSFL. In one study done by Saint Louis Zoo, they found that the Ca content in supplemented cricket is much higher than in the BSFL, causing an imbalance of Ca:P (5.3:1), versus in the BSFL is 2.5:1. The off-chart Ca content could block the P absorption, and this is why the dragons in our study can absorb better nutrient from the BSFL, resulting in greater weight gain per insect mass, and molt two days faster. Along with the insects, the dragons were provided adequate vegetables to make the diet balanced, such as kale, collards, mustard, butternut squash, and zucchini. Also, floor heat lights and ZOOMED 10.0 UVB lamps were installed in the enclosures. Temperature was kept between 80-85F. A weight measurement of each dragon was taken every week, until all dragons in both treatments successfully molted twice. The study lasted 8 weeks, and all dragons showed healthy signs of development throughout the study.

    The results show that dragons fed on unsupplemented Symton feeding grade black soldier gain weight faster than those fed on dusted dubia roaches. The individual variation is small as in the end of the 8th week, the standard deviations of weights were only 0.58g in the dubia group and 1.53g in the BSFL group, when the difference of mean was 4.00g. Statistically (ONE-Way ANOVA, p=0.0132) their weights were different between groups, and the effect should be accounted to the feeder insects, not genetic variations of the dragons. Although we only used 3 replicates in this study, which is the minimal number for experiment replicate in scientific manner, because this study had only one variable, it generates enough statistic power to make an inference. At the end of the 8th week, dragons fed our BSFL weighed 35.29% more than those fed on ​dusted dubia roaches. For this particular study, because there were extremely small variations between individuals, we are 95% confident about the result, statistically.

    The study demonstrated that our BSFL could provide sufficient protein and calcium for faster growth of bearded dragons, without any additional supplement. However, it should be noted that these data only apply to our feeding grade black soldier fly larvae, that were reared on a proprietary diet formula and rearing conditions, and result does not apply to compost grade product. 

  • Intensive Black Soldier Fly Farming

    Black soldier fly is native to most area in the United States, but the density of the population might vary across states. If you don't see them frequently in your area, it means you don't have millions of them around, and you will find it hard to attract fertilized females to lay eggs in your nursery. In this situation, a fly cage is highly recommended. In the picture below, there are two types of cages. One is made from PVC pipes (48*25*20 inch), and covered with baby insect proof net. The size of this type is limited by the size of available netting. In the middle is a wood framed cage (48*48*48 inch), and it's covered by common screen mesh. Either one works pretty well.

    Allowing maximum amount of direct sunlight available to the setup is the key for the successful mating. If you are breeding indoor, make sure your colony get the window that is facing south to maximize the photoperiod. Besides, temperature should be kept above 23 degree Celsius all the time for successful mating, and above 13 degree Celsius to keep flies alive. Humidity should be around 50%. In the cage, all you need is to provide a clean water source and a attractant for oviposition (egg laying). To make clean water available to the flies, you can place a small fountain, but make sure to avoid deep water standing, because black soldier fly are easy to drawn. For the oviposition site, a plastic box with rotting organic matter (such as bananas, corn meal, wheat bran) is necessary. For the best result, place a couple thousand young larvae in in the organic matter. The adult black soldier flies do not eat, the food is just for them to know where to lay eggs. Directly above the rotting material, using rubber band to hold together 4-5 pieces of cardboard, and the fertile females would lay eggs in the cardboard flutes. The food should be kept moisture all the time, otherwise the female will lay directly on the food source, which will cause inconvenience for management. Usually, if you do not use antibiotics in the food for attractant, the material will mold up after 2 or 3 day, and you have to replace the material frequently to avoid stinks. One way we found to be effective to prevent molds is introducing one or two thousand small black soldier fly larvae in the food source, because the larvae can consume the fungi that cause the mold, and they can produce chemicals that inhibits fungi and bacterias growth. In this way you can change the food source less frequently.

    Farmers should harvest the eggs (replace the cardboard) every day or every two days to make the empty flute space available for the oviposition. The eggs can be directly introduced to the working grub compost for hatching. The black soldier fly larvae will not consume your eggs, unless the eggs are already dead and rotting. This is a good thing because when the larvae consume those rotting eggs, others eggs that haven't been infected will be fine till hatching.

    Setting up a nursery can help you have a better idea of how many small larvae you are dealing with, and can help you to detect some other problems that you might otherwise not be aware of, such as hatching failure. At the right side is the video we made to explain how we set up nursery for black soldier fly hatching. Most importantly, this set up can allow you leave it unattended for ten days, and it can still do its work. It might not be the most effective way, but is the most effective one we found after numerous experiments. 

    Im most cases, the eggs failure is result of extremely low humidity plus high temperature. These environments are often found in small rooms with heater turned on. In some other cases it is due to unfertilized eggs. Although black soldier fly does not lay eggs if they never mated before, females do have eggs developed in the ovaries regardless of the mating. If the female ever formed a pair with a male, and they got interrupted before they finished, which could be 10-30 minutes, the female will lay all the eggs. Interruptions could be a human behavior, or poor quality of the light source. If this is the case, a big portion of the eggs mass are unfertilized and will not hatch. To avoid this happening, try to set up a greenhouse for the breeding cage, or place the cage besides a big window with no filters on. Also, minimizing the interruption due to managements will help increasing the egg quality. This is being said, do not play with the flies and let them do their jobs by themselves. 

    Under condition of 27-30 Celsius Degree, after 10 days of hatching, the larvae can reach visible size and is ready to compost food scrap. When you introduce them to the compost, you can have a rough count of how many larvae you are having in your bins. 

    The larvae of black soldier fly are polyphagous--they can grow from grasses like alfalfa, vegetable waste, animal feces, to nutrient rich products like meat or carrions. If the larvae were given enough food with moisture, they will develop from egg to prepupae within 3 weeks on average. Although the black soldier fly larvae are tough growers, there are two main factors that could cause large damage to the population. The first one is high temperature, and the second one is poor substrate ventilation. When actively consuming food, the black soldier fly can generate a good amount of heat. A healthy colony has a core temperature ranging from 32-44 Celsius Degree, with fluctuation depending on the environment temperature. The larvae will stop feeding once the temperature raise above 44 Celsius, and they will aggregate on top of the substrate to dissipate the heat. If the environment temperature is close or beyond 44 Celsius Degree over 4 hours, the larvae will die and will not be able to revive by placing them in a cooler room. Poor substrate ventilation is another factor that could cause large damage, and this is especially a problem for the neonates. When larvae are large, their wriggling movements are strong enough to create some pore space to breath in a submerge situation. Yet, the neonates are not strong enough to create significant pore space to breath, if the feedstock particles are too fine, like alfalfa and corn meal, or too sticky like cooked sorghum. Therefore, it's critical to add feed stocks that have low density but high rigidity, such as wheat bran, rice bran, or wood shaving dust, into the diet to create a loose texture so that the neonates can breath underneath. Larvae die due to heat or suffocated are soft in texture.

    Ideally, the substrate should not be thicker than 3 inches, and this is because of two reasons. Firstly, the larvae tend to dig down with no stop, and if the substrate is thicker than 3 inches, sometimes you will find them fail to make it back to the surface and die due to either heat or lack of oxygen. Secondly, the fresh food you put on the surface will sink to the bottom due to the wiggling of the larvae, and if the substrate is too deep, the food will no longer be available for the larvae.

    Though the black soldier fly is known being able to self-harvest, most of the commercial producers in the world does not apply this in their main production line. JM Green (China), Enterra (Canada), and Enviroflight (USA) all use pan system, with different size of the pan.

    The advantages of the pan system are:
    1. easily control unit
    2. can be standardized in commercial level easily
    3. automated system available
    4. lower chance for mass population wipe out because of the separation
    5. able to harvest larvae at different life stage
    6. production capacity could be estimated based on the counts of the pan
    The disadvantages of the pan system are:
    1. could be very expensive
    2. could be labor intensive
    3. require higher level of understanding for the black soldier fly
    4. waste need to be shattered and homogenized
    5. have to go through sifting
    Yet, there is also company like Agriprotein (South Africa) doing self-harvesting system.
    The advantages of the self-harvesting system are:
    1. self-regulating system, minimal care
    2. waste does not need to be shattered and homogenized before feeding
    3. technology requirements lower
    4. cost effective to operate
    5. managing requirement lower
    The disadvantages of the self-harvesting system are:
    1. ​production capacity could not be projected accurately
    2. Higher degree of year round climate control required as the prepupae only self-harvested under certain conditions
    3. at risk of population wipe out due to improper management
    4. Most likely only able to harvest 5th & 6th (prepupae) instar larvae
    Depending on the industry you are in, you might find one system is more suitable for you than the other. For example, in reptile feed industry, the market are looking for larvae at different size, and only the pan system can provide this consistent accuracy; in the situation you are producing larvae for your own uses and you do not care about the sizes, you may want to go with the self-harvesting system. If you are new to the black soldier fly farming technology, you can set up pilot scale project for both systems. Once you had a better understanding what each of the system can provides, you can choose the one that meets your needs, or possibly use a combination of them both.
    Although the disease of the BSFL has been rarely explored, there are few parasites we knew that could cause damage to the colony, and they are 1) parasitic wasps 2) phorids 3) mites 4) unpreferable fungi
    • Researchers in North Central Florida have found an undescribed parasitic Hymenopteran species of Trichopria on BSFL (H. illucens), and in this case the host was developed in poultry house (Mitchell et al. 1974). In our facility, we have spotted a parasitic wasp that was targeting the pupating pupae. The parasitic wasps usually occur in large number, and could damage the pupate emergence rate. Common treatments include sticky traps and preventative procedures. 
    • Rather targeting the adult or larva of the BSF, phorids are interested in the foods that the BSFL are eating. Even though the phorids cannot out compete the BSFL on food source, they can make your facility very nasty--phorids are common pest that could contaminate human resources. More importantly, the existence of the phorids is an indicator that your BSFL colony is not at a healthy state.
    • Difference families of the mites have been observed annoying BSFL adults, larvae, and eggs.
    • Although BSFL consume fungi as food, there are unpreferable fungi that could hurt the colony, on all live stages of the BSFL, and some attacks will result in population wipeout. 
    To be continued.... Treatments to the diseases
    Post any questions you may have under here, or contact us via email.

     

     

  • How to identify male and female of adult BSF

    Distinguishing male and female in your colony is an important part to better estimate your yield, and to determine what steps you need to take to maximize your production. For instance, in a well caged colony even when all the pupae were from the same day of harvest, the hatching time will still different in days, especially during winter times they will have a wider hatching window thanks for the low temperature. When most of the flies have done mating and ovipositioning, they will start dying, and your colony starts to shrink. Just by looking at the rest of the flies, estimating the male and female ratio, you will know what to do. If it's male dominate situation you should remove the colony and start a new one right away, otherwise you will end up with a empty larvae bin for about two weeks, because no eggs were being produced during that time. If it's a female dominate situation, you might want to wait for another few days to see more eggs.

    The sex of the black soldier fly can only be determined at their adult stage, which mean the earliest point to distinguish male and female is the time they hatch. The traits of each sex are well distinguished, very easy to tell.

    The female black soldier fly's tail end up with a scissor shaped structure. It's their sexual organ for mating and for ovipositioning. When the female pull their tail out it means they are ready to mating, and the males will see this as a signal to initiate the mating, if it's able to see, and this is probably why light source is so important for successful mating.

    As you see here, the male black soldier fly's tail ends up with a plate-like structure. If you look close it looks like an open flower.

    When mating, the female and male line up on opposite side, with tails connected. The way they are connected is that the male's flower-liked tail grabs and sucks female's tail in. If you look close to the male's belly, which is generally transparent, you will see liquid flowing from the chest part toward the tails. Not sure what that is, but possibly is the sperm.