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 Troubleshooting 
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Joined: Wed Jun 17, 2015 1:47 am
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Post Troubleshooting
Hi Everyone,
I have read this website extensively and used the huge amount of information to come up with a system, that utilizes a disused coffee fermentation tank.
I have built concrete sloping walls with gutters atop to lead the pupae, this 'amphitheater' is covered with corrugated metal sheet and the whole is covered with insect net under green house plastic roll downs. The plastic is lifted/lowered to control the temperature.
I commissioned the system on the 1st of August with 600kg of avocado pulp and 60kg of pineapple pulp mixed in, this feed is 6" deep. I placed approximately 800 pupae in a tray of sawdust covered with dry leaves.
This is our cool time of year and temperatures range from 16C to 30c, once I installed the plastic the temperature has been briefly up to 48C by mistake.
I have had upwards of 60 flies hatch and witnessed dozens of matings. At one point I did see about 30 larvae of varying size, I had been splashing the food with water and was worried that this was causing them to surface for air and were suffocating. I have reduced the splashing to a minimum. The food currently has a dry surface but is still moist underneath. I no longer see any larvae on the surface and there are a lot of fruit flies. Is it likely that the larvae are all beavering away below the surface or is there something wrong with what I'm doing? After 17 days I am not sure what I should be seeing to indicate that all is ok or not! All advice would be much appreciated.


Mon Aug 17, 2015 5:16 am
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Joined: Mon Mar 21, 2011 3:26 am
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Location: Durban, South Africa
Post Re: Troubleshooting
A few thousand grubs will be totally lost in a big system like that. You'll hardly be aware of their existance.
Everything sounds about right, so just give it time. They like to be on the dark, so I would put a lightweight cover on top of the food, and you should see them there.


Mon Aug 17, 2015 5:56 am
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Post Re: Troubleshooting
Many thanks PeteB,
This is very reassuring.
As I said I have witnessed quite a lot of matings. I have provided nesting sites, namely 2mm wide saw cuts in the wood rafters that support the metal sheets. The metal sheets are 16" above the feed. I have also put strips of cardboard an inch above the food. I have not seen any eggs?! Is there a certain time lapse between mating and laying or does this vary with environmental conditions?


Mon Aug 17, 2015 6:49 am
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Post Re: Troubleshooting
Research papers say there's usually about 2 days between mating and egg laying, and I've seen for myself.


Mon Aug 17, 2015 7:00 am
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Post Re: Troubleshooting
Samaki you mentioned that "the whole is covered with insect net". This might be stopping any wild BSF from laying eggs and adding to your population. Also I wouldn't be too worried about not seeing eggs in your egg traps as a system as large as your probably has many other spots which are suitable for the gravid females to lay their eggs out of sight.

As PeteB mentioned, you probably need to be patient and give it some more time.

If you could post some pictures of your system it would be great.

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BorealWormer

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


Mon Aug 17, 2015 11:02 am
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Post Re: Troubleshooting
Thank you for your responses, I will post photos in the next couple of days once I've found out how to shrink them!!


Tue Aug 18, 2015 3:01 am
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Post Re: Troubleshooting
Hi Everyone,
Herewith some pics, as I was taking these photos a female very kindly landed in front of me and layed her eggs in the sawcut I had provided. The pics are of Charles pulping avocado with the house behind. Then there is a shot of the amphitheater with some of the cover lifted to show the pulp. Under the steps is the hatching tray which is full of sawdust and covered with leaves where I place the pupae to incubate and hatch. Any observations and advice will be much appreciated.
Attachment:
BSF house.jpg
BSF house.jpg [ 111.89 KiB | Viewed 4842 times ]


Wed Aug 19, 2015 4:39 am
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Post Re: Troubleshooting
Looks good, Samaki, nothing wrong with that. No need to pulp the avocado, I simply slice them in half.
In summer, some shade would be a good idea.
Samaki wrote:
.... Under the steps is the hatching tray which is full of sawdust and covered with leaves where I place the pupae to incubate and hatch ....
Ants will rip the new flies to shreds before they are strong enough to fly, so watch out.


Last edited by PeteB on Wed Aug 19, 2015 5:35 am, edited 2 times in total.



Wed Aug 19, 2015 5:15 am
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Post Re: Troubleshooting
Hi PeteB,
Many thanks.
Do they manage to eat the avo seed and skin or just the flesh?
My system is in the bottom of a concrete tank and I have put grease around where the timber roof frame is attached on top of the wall, I'm hoping this will discourage other insects?


Wed Aug 19, 2015 5:30 am
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Post Re: Troubleshooting
No, they don't eat the seeds or the skins ;)


Wed Aug 19, 2015 5:33 am
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Post Re: Troubleshooting
Greetings All,
I am pleased to report the first 18 pre-pupae have marched out of the goop along the intended gutters and obligingly fell into the waiting receptacles :o
One concern I have is a massive crop of fruit flies have developed. Interestingly they appear to have the same methodology as I find large quantities of tiny pre-pupae in the tubs intended for the BSF.
Do I assume that as the BSF colony develops it will take over?


Sat Aug 22, 2015 2:25 am
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Post Re: Troubleshooting
Yes the BSF should dominate after their population builds up.

Synomone
Excerpt from The Bio-Conversion Putrescent Wastes prepared by Dr. Paul A. Olivier

Info-Chemical

While actively feeding, the larvae secrete a chemical, more precisely an info-chemical, that permits them to communicate with other species of flies. This info-chemical or synomone allows them to tell other flies to stay away, that it makes little sense to lay their eggs within an area full of actively feeding BSFlarvae. This interspecies communication is, indeed, very effective. In the vicinity of the disposal unit, we note the near absence of house flies and all other flies that are a pest to humans.


and also in a blog by a University of British Columbia student

Pheremone vs. Synonome (link)

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BorealWormer

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


Sat Aug 22, 2015 9:11 am
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Post Re: Troubleshooting
Many thanks BorealWormer, this is fascinating. Guiding has been a large part of my life and the sophistication in nature's systems is truly humbling.
More questions for the pros,
Is there a ratio of adult flies to the system waste capacity that gives optimum production of pre-pupae?
If so at what interval should one replenish the food source?


Wed Aug 26, 2015 10:48 am
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Post Re: Troubleshooting
I don't recall seeing any statistics like that. Hopefully someone else can help.

There is this from http://www.esrint.com/pages/bioconversion.html
"SF larvae can digest over 15 kilograms per day of restaurant food waste per square meter of feeding surface area, or roughly 3 lbs per square foot per day. A 95% reduction in the weight and volume of this waste was also noted. This means that for every 100 lbs of restaurant food waste deposited into a unit, only 5 lbs of a black, friable residue remain!"

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BorealWormer

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


Wed Aug 26, 2015 1:55 pm
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Post Re: Troubleshooting
Hello again, I have attached a photo of what I believe is a BSF larva!? It is these guys that have been marching out of the food source at the rate of about 20 per day since the 21st of August. They only move at night. I am now concerned that they should not be leaving at this stage, should they not be at the brown stage before they migrate out. Please advise, are they escaping inhospitable environmental conditions?


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Thu Sep 10, 2015 3:01 am
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Post Re: Troubleshooting
Samaki they really should be brown when they march out. The final instar (transformation) where they go from pale to brown might also require a bit of space however, it's possible that the argy bargy in the bin means that they are leaving to transform, but I don't think it's likely. How big was that BSFL? usually they are more cream coloured and less 'rice-paper-roll'


Thu Sep 10, 2015 3:33 am
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Post Re: Troubleshooting
Those are hoverflies (Syrophidae) link
Seems like they're carnivorous, and eat aphids and such. :D


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Thu Sep 10, 2015 5:18 am
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Post Re: Troubleshooting
Thank you Aussiemoo and PeteB for your replies.
You are correct PeteB I have seen some of these adults in the hatchery. I confess to scooping a whole lot of unidentifiable tiny larvae from my hatchery drain and putting them inside the hatchery assuming they were BSFL escapees!!
C'est la Vie, my joy was premature. The fruit flies have subsided considerably which is a positive otherwise its back to controlling my impatience.


Thu Sep 10, 2015 9:05 am
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Post Re: Troubleshooting
Greetings Everyone,
I am now collecting a dozen or so pre-pupae. I believe they are coming from the very bottom of the feed where I had put in an initial layer of macadamia husks to provide drainage. I am still not seeing activity from larvae on the top despite having covered it with banana leaves. I have attached a photo of an insect that I think came in the macadamia husks, the fruit flies and hover flies have disappeared but this one has persisted from the beginning two months ago, should I be worried about it? I have 100 adults in the hatchery at present but am not witnessing any matings, the temperature ranges from 18C to 38C and in my inexperienced opinion all looks OK. I did add a piece of green shade net which covers half the roof as the temperature was hitting 40c, I don't think this would have reduced the amount of light conducive for mating. I feel I should be seeing a lot more activity. Was I wrong in starting with 600kg of food, should I have started with say 20kg and added as the colony developed?
As always I would appreciate advice and opinions.


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Tue Sep 29, 2015 2:32 am
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Post Re: Troubleshooting
Hi Samaki,
That looks like a Rove Beetle.

Image

Quote:
Rove beetles are beneficial because they clean up the ashes, bones and carcasses of dead and decaying animals. They also eat dung and feed on other insects that are found in decaying matter - such as maggots.


Oh Dear... They seem small though, I doubt they could take a big pupae.


Tue Sep 29, 2015 3:57 am
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