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 Role of Abiotic Factors on the Development of BSF 
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Post Role of Abiotic Factors on the Development of BSF

Role of Abiotic Factors on the Development and Life History of the Black Soldier Fly, Hermetia illucens (L.) (Diptera: Stratiomyidae)

Leslie Holmes, University of Windsor


Hermetia illucens (L.) (Diptera: Stratiomyidae) has been found to successfully reduce manure in confined animal feeding operations of poultry, swine and bovine. In equatorial climates, H. illucens is active year round, however, in more temperate climates they are only active during the warmer months of the year. Since insect development is greatly influenced by the ambient environment including pupation substrate, relative humidity, daylength and temperature, it is necessary to explore the effects these abiotic factors have on black soldier fly development when proposing to utilize a species that is not active throughout the year in temperate climates for a year-round waste management process. The objectives for this study include determining the abiotic factors limiting H. illucens egg eclosion and adult emergence. The results of this study indicate pupation substrate facilitated or impeded development depending on substrate type as well development improved with increasing temperature, relative humidity and hours of daylight.

Some interesting stats about the effects of pupation substrate, relative humidity, daylength and temperature. Some of the research conducted in the laboratory of Dr. Jeffery K. Tomberlin at Texas A&M University.


I Believe The Black Soldier Fly Has The Potential To Be A Beneficial Insect Second Only To Pollinating Bees

Mon May 06, 2013 11:37 pm
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Post Re: Role of Abiotic Factors on the Development of BSF
Anyone receiving eggs early in the northern hemisphere warm season, like me in April, should find the author's chapter on eggs starting on pg. 115 of interest. For those not able to review this research yet here's a synopsis; all data is culled from the online thesis of the author who deserves full credit for the following details.
Eggs did eclose (larvae come out) at as low a temperature as 15* Celsius (59* F.), but subsequently all those new larvae died within 3 days.
As for eggs at 18* Celsius (64.4* F.) 100% will eclose, taking an average of 7.75 days to do so & from sighting 1st eclosed egg one should allow 2 more days for the rest of eggs in that same clutch to eclose. If growing on is done at 18* Celsius then those larvae's mortality rate is 63% & the pupal mortality rate is 16% (of pupae). The author roughly extrapolated that 32% of eggs that both eclose & then grow on at 18* Celsius make it all the way to emerge as adult flies.
Another determination was that to get at least 50% of eggs to eclose the relative humidity has to be a minimum of 60% RH. The minimum relative humidity for a egg cluster to retain long term prospects, according to this research, is 30% RH.
In regards to the influence of amount of light on the eggs the females exposed to 12 hours of light a day oviposit better eggs. In contrast, females exposed to only 8 hours of light a day lay out statistically more "non-viable" eggs.
Yet, to physically oviposit a female does not need any hours of light in a 24 hour period. Apparently she usually performs oviposition 2 days after the right mating. Although it should be noted the BSF used in this study were not wild caught & the stock came from captive breeding with an 8 year lineage.

Wed Apr 16, 2014 4:57 am
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Post Re: Role of Abiotic Factors on the Development of BSF
Humidity measurement, with a hygrometer, is worthwhile being accurate. I chime in here because did not see a more likely thread on the Forum.
From sources variously found through out this Forum: eggs ideally "hatching" (eclose) in 70-80% relative humidity (R.H.), only 1/2 eggs eclose when less than 60% R.H., youngest larvae losing 1.5% of their weight/hour when in greater than 75.5% R.H. (big larvae at same R.H. lose 1% weight/hr.), pupation during lower than 40% R.H. only achieving a 59% survival rate, 80% rate of ovipositing (lay egg clutch)in more than 60% R.H., etc.
I recently bought a digital readout "LaCrosse wireless weather station" from Target (U.S.A.); no financial interest. It has a small remote sensor & a hand sized readout sensor, which gives me 2 separate movable hygrometers/thermometers. (Only the temperatures are able to be set with an alarm for ones choice of hi or low temperature alert signal beep.)
This comment is to describe how I checked the humidity calibration on the new units; it is a tactic to check any hygrometer, so you then know if your hygrometer is reading accurately.
For example, my non-digital dial hygrometer actually reads 9% less % of humidity than is accurate. When use it I know must add 9% to it's dial reading to get a better gauge of the true humidity. With dial hygrometers I would still figure for an additional margin of error of 1% going both upward & downward on the scale. So I assume even when I've accounted for the 9% too low reading on mine that I might still be off another % in either direction.
Most hygrometers, even brand name digital ones sold at pet stores to reptile owners, are likely to be off somewhat. Furthermore,inexpensive hygrometers can go out of calibration & this is a simple way to check for continued accuracy once or twice a year (or if dropped).
Here's the way I determined my brand new battery powered digital humidity monitors were reading barely 1(one)% excess humidity (an acceptable margin of error for inexpensive hygrometers).I took the remote unit & placed it in a container I could seal so no air got in or out for 12 hours - do not take all the air out before closing up. It fit in a small zip lock bag with room left over for the humidity control agent (salt + water), & if available in a suitable size for your hygrometer zip lock bags are the easiest way to set up the controlled environment.
When doing this with any hygrometer that has a readable face place the hygrometer face up so you can read it during/after 12 hours - before you take it out of the closed environment's constant relative humidity. A remote unit will send it's reading over to it's "mother" unit & you will know what it reads during/after the calibration. Similarly, if testing a battery powered hygrometer that has no remote put that hygrometer to this same test; the batteries will not cause any problem & being enclosed with salt + water won't damage the hygrometer.
However, before close the hygrometer up for 12 hours place inside the "bag" a pile of salt + water nestled together in a separate open container. It does not need to be a large amount of salt + water & I use a plastic vitamin vial's top positioned face up to hold the salt + water "control agent". I use about 5 parts of salt by volume to 1 part of water by volume.
A small hygrometer, or several small hygrometers can be calibrated at the same time in the same zip lock bag using the same humidity control agent & would only need 5/8th teaspoons of salt + 1/8th teaspoon of water. Just drip the water on top a the pile of salt. If only have a teaspoon then take 1 level teaspoon of salt, plop it onto your holder & drips scarcely 14 drops of water onto the salt. Do not stir it all up together. If it is soupy/slushy,wherein the salt started to go into solution then to not confuse your end results consider discarding that salt + water blend & remake another salt + water control agent that will hold form, more so than flow. This is what I call the control agent because inside your closed environment it will create exactly 75 degree relative humidity.
Allow 12 hours for the hygrometer & control agent (salt+water) to sit passively all closed up together. Then, if you've a dial hygrometer read through your "bag" & note the degree humidity showing, if a digital hygrometer read it's number through your "bag" & if it's a remote hygrometer unit (like I have been suggesting) read the degree humidity off it's "mother" unit before taking it out of the closed environment.
The reading after 12 hours of calibration is going to be either some number below 75, exactly 75 or a number above 75. That is then the degree of variation from 75 degree humidity your hygrometer(s) have. Thus,when you use that hygrometer later on in your projects you will know how far off from true humidity the reading(s) are. For example, if inside the calibration "bag" after 12 hours a hygrometer reads 70% whenever you use it you will want to add 5% to any humidity reading that hygrometer reading you see.
As for the dual unit alluded to a the beginning: after 12 hours the remote unit read out only 1% higher than the salt + water control agent's 75% "bag" humidity. This means whenever I use the remote for a humidity reading I will mentally lower that read out by 1% to more properly determine that reading.
The next step is (was) to use the remote unit's known deviation (in my case 1% too high)to determine what the deviation on it's "mother" unit's hygrometer has. So place the remote close to it's "mother" unit as similarly orientated as practical to let them sense humidity in parallel.
Let them alone for another 8 hours (or up to 12 hrs.)& then compare their respective humidity readings. The remote, having been enclosed for a long time with the salt + water control agent is going to be unresponsive to the outside environment. That remote will take a long time to start to send accurate temperature & humidity readings to the "mother" unit for display; don't worry it is not damaged.
You have already determined the remote unit's deviation to the salt + water control agent & whatever the reading it's "mother" unit displays after 8 hours of comparison is to be interpreted by reference to what you have previously determined the remote unit should be reading. If the remote only deviates (say) 1% too high & after 8 hours side by side with the "mother" unit they both read the same % humidity then the "mother" unit is also reading 1% too high.
Or, if the "mother" unit's digital read out is either higher or lower than the remote you must calculate the difference from your remote's reading to know how far off the "mother" unit's hygrometer is from a known reference. In other words take into account the "mother" hygrometer's variation from the remote's hygrometer & also don't forget to take into account the remote's humidity "error" you previously used the salt + water control agent calibration technique to determine how to interpret the remote's accuracy.
For my "La Crosse" after 8 hours the remote & "mother" humidity readings eventually moved into tandem showing the same % humidity. In this case both read 1% more humidity than there actually is & when reading the remote's signal of humidity on the "mother" unit ( or the "mother" unit's own humidity) all I have to do is subtract 1% for accurate humidity reading(s). They do sometimes tell a slightly different temperature reading when side by side & I have evaluated that it is the remote which can occasionally show an extra degree....
The nice thing about this dual meter product is one can put the remote up to 60 meters (200 feet) away in your project habitat & keep the "mother" unit close to where you are for monitoring what is going on over there. Be advised that these digital types of meters are NOTgood for quickly measuring a new location - you can't show up, hold it near something & in a minute get accurate readings of temperature, much less humidity. I find my dial hygrometer quicker to change what I put in near something if just want to identify what is the direction humidity is trending toward.
Lastly, if you have another apparatus set up to switch on ventilation when your pre-set humidity/temperature set point "high" triggers that apparatus (or to switch on fogger spray when your pre-set humidity low triggers that apparatus) you should check to determine how well calibrated is that apparatus' own hygrometer. Use a 12 hour/salt+water control agent evaluated hygrometers you have to know what that environmental control apparatus' dial settings for % humidity actually mean. The apparatus dial may indicate a position to set it's dial for "x" % humidity & that may not be what your hygrometer tells you is "x" % humidity.Place your reliable hygrometer for a good long period where you can test it against that automatic atmospheric controller. Take note of the % humidity your hygrometer shows you & try to find a corresponding setting that gets your automatic apparatus to turn something on (fan/spray); & then try to find a setting that gets it to turn something off. Mark the automatic apparatus so that you can know where on it's dial you established a known (more of less) % humidity; it will give you some indication of what the apparatus's printed dial numbers are in reference to the automatic apparatus's own humidity/temperature probe is telling it. Eventually recheck this type of synchronization between your hygrometer/thermometer & the automatic atmospheric control apparatus at the actual project site to fine tune the automatic responses of on/off for fan/exhaust/heat/cool/spray. Once mount ( set down) your remote unit as close to the project as possible the "mother" station allows monitoring the humidity/temperature from off site. END

Sat Apr 19, 2014 7:26 pm
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